Good afternoon, Congressional Climate Campers. Welcome to a bonus fifth installment of EESI's Congressional Climate Camp. I'm Dan Berset, Executive Director of the Environmental and Energy Study Institute. EESI was founded in 1984 on a bipartisan basis by members of Congress to provide science-based information about environmental energy and climate change topics to policymakers. We've also developed a program to provide technical assistance to rural utilities interested in on-bill financing programs for their customers. As always, everything we do and produce, from briefings to fact sheets to podcasts, is freely available and accessible online. And also, as always, the best way to stay up to date and never miss a thing is to visit us online at www.eesi.org and sign up for our bi-weekly newsletter, Climate Change Solutions. Our original plan for Congressional Climate Camp was four sessions held on the last Friday of the first four months of the year. We started in January with process and specifically budget and appropriations. Then we delved into policy and examined the emissions profiles of major sectors of the U.S. economy in February. March was a little bit of a history lesson about past climate policy development efforts with some political science tossed in about the importance of bipartisanship and compromise to a healthy functional Congress capable of delivering equitable, inclusive climate policies. And a few weeks ago, we concluded with an overview of four areas that we think are especially ripe for emissions reductions and adaptation benefits. Building energy codes, mass timber, agriculture, and nature-based solutions for coastal resilience. If you missed any of our previous series, our full webcasts are archived online, again at www.eesi.org. And summary versions are available as episodes of our podcast, The Climate Conversation. For those congressional climate campers who have been with us for a few months now, you've heard us tease the session today. We knew almost from the start of the series that our original plan would need to evolve and include a focused discussion on the budget reconciliation process. Nobody knows for sure how the climate policy debate will play out in the coming months, but it is a safe bet that the buzz about budget reconciliation as a vehicle for climate policy and infrastructure in particular will get louder and louder, sort of like what our new cicada friends are capable of doing. And so that brings us to today. We are a week away from Memorial Day. The work period that starts after that long weekend and runs through July 4th will be pretty intense. Speaker Nancy Pelosi has already stated her intention for the House to vote on an infrastructure bill by then. So our goal with the help of our two experts who will join us in just a moment is for this session to be informative and helpful just in time to be an aide for staff who will be very, very busy very, very shortly. Thinking about today, I've tried to put myself in the shoes of that staff person on Capitol Hill. I worked for a member of Congress who serves on one of the authorizing committees. We have a bill that fits broadly in the working definition of infrastructure espoused by leadership. And my boss wants to know how our priorities fit in the package coming together and what needs to change to make that possible. Of course, this has been on everybody's mind for some time, at least as far back as the passage of the American Rescue Plan, which was also passed using budget reconciliation. But a lot of unknowns will start to be known pretty soon and momentum can build surprisingly quickly and no one wants to be unprepared for that. As a reminder, our session today, including summary notes will be posted online at www.esi.org and a condensed audio only version will be of each congressional climate camp, including today will be available as an episode of our bi-weekly podcast, The Climate Conversation. We have a lot to cover and you can participate in our discussion by asking questions. You can send us a message on Twitter at EESI online. You can send us an email EESI at EESI.org. Even if we get more questions and we can possibly answer, we'll do our best and follow up to answer every question submitted during congressional climate camp. So let's get down to it. Each of our panelists today will make short presentations and then we will kick off a discussion, a longer discussion than we've normally been doing during congressional climate camp. And now I get to welcome our first panelist. Molly Reynolds is a senior fellow in governance studies at Brookings. She studies Congress with an emphasis on how congressional rules and procedure affect domestic policy outcomes. She is the author of the book, Exceptions to the Rule, the Politics of Philbuster Limitations in the United States Senate, which explores the creation, use, and consequences of the budget reconciliation process and other procedures that prevent filibusters in the US Senate. Molly's current research projects include work on oversight in the House of Representatives, congressional reform, and the congressional budget process. She also supervises the maintenance of vital statistics on Congress, Brookings long-running resource on the first branch of government. Molly, welcome to the session today. I can't wait for your presentation. Thanks, Dan. It's really good to be here. It's really good to be here with Zach who you'll hear from in a little bit. But what I'm gonna do today is to try and provide a little bit of kind of big picture context for thinking about budget reconciliation historically and in the context of the contemporary legislative process. And so I have a couple of slides that I am going to share my screen so you can see. So hopefully everyone can see my slide that says four things to know about budget reconciliation that's where we're gonna start today. And so the first thing that I wanna sort of emphasize is that budget reconciliation as conceived of in the 1974 Budget Act looks really different than how budget reconciliation came to be used in the 1980s and the 1990s. So in 1974, when Congress passed the Congressional Budget Act, that act called for two budget resolutions every fiscal year. One early in the year before the appropriations process and then a second one by September 15th. It also provided for a reconciliation process that would happen alongside that second budget resolution. The idea was that Congress might not want to set binding ceilings and floors on how much it would tax and spend as part of that first budget resolution early in the year. Rather that first resolution, the drafters of the Budget Act imagine should be a target Congress should then make whatever fiscal decisions it was gonna make. And then it would write a second binding resolution just before the start of the fiscal year. But if existing laws weren't in line with those new binding levels in September, Congress might need to act quickly before the start of the fiscal year. And that's how we got the special expedited procedures that the Budget Act provides for reconciliation bills moving to the Senate. So we know that part of what makes the reconciliation process so powerful is the fact that reconciliation bills cannot be filibustered. And that it was this need to potentially act quite quickly that is why that those expedited procedures got put in the Budget Act in the first place. But it became clear pretty quickly that this idea of moving quickly for Congress was too quick that Congress couldn't possibly keep to this calendar. And to the extent that reconciliation was meant to also help committees reduce expenditures in their jurisdictions, it became clear pretty quickly that committees weren't actually that interested in doing that. And there was little reason for the Budget committees to try and force them to do so. So for fiscal year 1981, we saw the reconciliation process moved to be in connection to the first budget resolution. And then for fiscal year 1982 is when we get the first use of the process that looks more like what we think of today in terms of substantive legislative change. So then we have this period in sort of the 80s and the 90s, and this is my second bullet point here, that the way the process was used in the 80s and the 90s really also does not look that much like it's been used more recently. And in the 80s and 90s, we were generally seeing the process used for deficit reduction. And there was a degree when that was happening to which basically all of the committees were expected to share in some, share the pain of making cuts. And so the idea was that one of the ways that reconciliation was powerful in addition to the protection from the filibuster is that it would basically require committees to buy in to this shared goal of deficit reduction. And if you, I'm gonna go to the next slide here. I feel like here, these are some tables from the Congressional Research Service that run from 1989 through 2015. And you can see that in sort of the earlier period here, the 80s, the 90s that large numbers of committees were tended to be named in the reconciliation instructions. So the way the process was being used was again, this idea that we were gonna sort of, the Congress was gonna have this goal. They were gonna try and achieve deficit reduction, but they were gonna get lots of committees to share the pain in doing so. I wanna emphasize that even in this sort of model of using the reconciliation process, we have evidence, Dan mentioned my book and this is one of the things I look at in the book, but there's evidence that Congressional majorities were using the process to try and advance goals that were important to them as a majority party, even in this model of the reconciliation process. But again, it looks different than the way the process was used to say, to help pass the Affordable Care Act to achieve the Trump tax cuts, that sort of thing. It also means, because we have this model where lots of committees were involved in the process, that sometimes we got large bipartisan majorities for reconciliation bills. So I think today we think of reconciliation as this way to do things on a partisan basis, but this is a table that just tracks the final Senate vote margins on reconciliation bills from 1980 through 2017. And if you look, sort of again, in that 80s and 90s period, you see that some of these things did get large bipartisan majorities. Where we ended up in kind of the 2000s and the 2010s is moving to this model where reconciliation became more of kind of a one neat trick for achieving party defining priorities. So again, we're helping to pass the Affordable Care Act, Republicans failed attempts to repeal the Affordable Care Act, passing the Trump tax cuts. And then today, I would say we're, this year, we've kind of find ourselves back in the middle a little bit. We know from having looked at the American Rescue Plan that that was another instance where Congress kind of went back to this 80s and 90s model of enlisting lots of committees to do things as part of the process. But we're also, the process is seen as this way to accomplish things that in this case, Democrats really want to get done and that the filibuster might be preventing them from doing. So the third point that I wanna make is that because the process has become more important for congressional majorities to try and achieve their major policy goals, we've kind of stretched the boundaries of the process that we've ended up with, in many cases, less certainty about what is and is not allowed to be done through the reconciliation process. Zach is gonna talk, I think, a little bit more about this. And I'd encourage you, I think some of the resources that we shared for this session include discussion of kind of what topics have been covered by reconciliation bills in the past. They are wide-ranging. But the sort of contextual point that I wanna make here is that as the process has borne more policy priorities, we have ended up asking you more and more questions about how to fit things in the box. In addition, another consequence of asking the process to bear more policy change is sort of the more uncertain you are that something is reconcilable, the more likely you are to end up with a real policy problem in terms of how you construct a policy to get through the process rather than simply political problems. So I think that the minimum wage in the American Rescue Plan is actually a good example of this. So there were questions about whether that could be done through the reconciliation process. Ultimately, the answer was no, but so when that had to come out of the bill, it didn't sort of take the entire rest of the structure of the bill as a policy question down with it because it was a kind of discreet priority that was in an omnibus piece of legislation with lots of other things. As we, in other cases, when the process has been, or when folks have tried to use the process to accomplish specific policy goals, we do end up with more challenges in terms of the possibility that you might unravel an entire policy proposal. The last thing I'll say about sort of why the process I think has become more complicated is because of the expansion over time in the number of things that we use the tax code to try and accomplish. And so we know that revenue provisions are something that can generally be done through the reconciliation process. And this is just a graph from GAO that is meant to give you some sense of the degree to which tax expenditures, which are as that dotted line, have increased over time. And again, as the tax codes become a more important vehicle, I think for trying to achieve lots of policy aims, there's a little bit of a chicken and an egg question here. So how much of the reason we do things through the tax code is because you can do them through the reconciliation process versus how much does the reconciliation process bear more things, because we do things through the tax code. That's an interesting, not to unravel some time, but again, this is another reason, I think, another piece of context is important for understanding where we are right now. And then the last thing I'll say before I turn it over to, back to Dan, who will introduce Zach, is that it's also really important to remember that the rules are a big constraint here, but they're not the only constraint. One important thing to remember is that there are other features of the process that don't have to do with things like the bird rule that can limit how it's used. I think perhaps the most important one of these is time going through the reconciliation process, both in terms of writing a bill and then taking it through all of the hoops that are related to moving it on the floor is a really time consuming process. And if you are a majority that has other things you also want to use floor time for, you have to kind of make some choices about how to allocate that. It's also the case that I think one of the things that Zach might talk a little bit about is the sort of discretionary mandatory spending piece here. How do you make discretionary spending look mandatory? And there's some interesting lessons from the American Rescue Plan on that front. But it's also worth remembering that there are elements of the reconciliation process that can ask committees to give up some power that they have. This is part of the story from the early 80s in terms of the use of the reconciliation process for discretionary spending, part of sort of why that was a thing that was tried and that Congress did not keep doing is because the appropriations committees really did not like the authorizing committees infringing on their jurisdictions. And so just remember that, again, we're gonna talk a lot about the rules. We're gonna hear a lot about the rules as this moves as a subsequent reconciliation bill might move through the process, but the rules are not the only thing that limits or shapes how a reconciliation process might shake out. So I will stop there and I will stop sharing my screen and I will turn it back over to Dan. Molly, that was a great presentation. Lots to build on with Zach's presentation and our discussion. Before I introduce Zach, let me just make a quick reminder that slides and materials will be available online. And that includes some supplementary materials, both Molly and Zach have passed along some additional resources that we think would be helpful to congressional staff and folks in the stakeholder and advocacy communities too as they figure out how they navigate this. I will now introduce Zach. Zach Muller is the deputy director of the economic program at Thirdway, a think tank based here in Washington, DC. At Thirdway, Zach leads a team that specializes in developing innovative policy and regularly consults with policymakers and the media on the federal budget process and other issues of economic importance. Zach got his start in DC working on the Democratic Staff of the Senate Budget Committee under chairs Patty Murray and Kent Conrad. Zach earned a degree in economics from the University of Florida and also a master's degree in economics from the University of Virginia. Welcome to the panel today, Zach. I will turn it over to you. Great, thank you so much, Dan. And thank you to EESI for having me today and let me share my screen and get to my slides. All right. So basically my role here today is to kind of talk to you a little bit more about what's in and what's out of budget reconciliation. And to that extent, it's a lot about the rules. And when we're talking about the rules, frankly, it's all about the Senate. This is a very Senate-focused process. The rules are really where they're most binding in the Senate here. Just very quickly, reconciliation requires a budget resolution to start. So the instructions that are in the budget resolution that are given to authorizing committees must be followed. That means following the committees of jurisdiction. That means meeting a savings target or not going over a cost target that may be in the reconciliation instructions. And further, these rules are not only are they binding on the base tax, they're also gonna be binding when you're on the floor. Amendments to the bill itself must be germane. The amendments cannot increase the deficit unless you're moving to strike a provision. And they're still subject to all the other rules related to budget reconciliation including the bird rule. So just very briefly on the bird rule before I get in and out because this is the thing that I think most people talk about. The bird rule itself is a surgical point of order against extraneous matter. Now what the heck does that mean? Surgical, it is a surgical point of order. Surgical means only the offending material is removed. So this does not take down the whole bill necessarily. Point of order, a senator on the floor would raise a point of order against a provision in the text or would threaten to raise such a point of order and thus it might get worked out in advance. But the point of order has a super majority threshold which means the point of budget reconciliation by not getting to get around the filibuster becomes when you have to have a point of order that has that higher threshold. And extraneous matter is defined as it's six little tests. Most are objective, one is subjective and these kind of create the boundaries of a good chunk of what you can do. But at the end of the day it's really about spending and it's about spending in tax policy. It's about budgetary changes and that's gonna be just a key thing going forward. So what is clearly allowed under budget reconciliation? I classify what's clearly allowed in kind of in four categories, four broad categories. The first category is rates and dates. These are changes to marginal tax rates. These are changes to the date in which a policy may be expiring. So changing a rate could be moving the top marginal tax rate back up to 39.6%. It could be extending and expiring tax provision. It could be extending and expiring UI provision. These things are kind of clearly allowed. Tax policy is generally quite permissive and quite able to be allowed under budget reconciliation. But I stipulate that you shouldn't be too specific about your tax policy. So a climate example would be, a tax credit for electric vehicles would be allowed but something that might be too specific and might start running into rules changes would be a tax credit where only like Tesla vehicles qualify. I'll get into a little bit more about this in a little bit. Also things that are clearly allowed are expanding or trimming existing mandatory spending programs as long as it's not social security. So you could expand Medicare by lowering the eligibility age, you could find ways to save money in the Medicare program that those things are kind of clearly allowed. And then you're allowed to establish new direct spending programs. New spending, we saw a lot of that under the American Rescue Plan. These are things like new block grants, new mandatory spending, you could create a $10,000 training voucher, things like that. But there are limits on the process. We'll get into this more I think probably in the Q&A but a lot of people wanna put a lot of policy in a spending program. You can do this. You can't use the money for A, B and C. But the more and more limits that you put on spending, the more and more policy that you're putting into it, you create a situation where things may start to, you may start running into parliamentary problems. So let's talk about the things that are clearly not allowed. You cannot change social security with budget reconciliation. You cannot do things that do not produce a CBO score that do not score in reconciliation. So this means it's gotta be about spending and revenue. You can't add new points of order. You cannot really make changes to the civil or criminal code. Regulatory changes, saying a power plant, banning the use of coal power plants, for example, that would be a regulatory change and that would not be allowed under budget reconciliation. Provisions or policies that come from the wrong committee are not allowed. So if environment public works does not get a reconciliation instruction or the finance committee tries to do something that is in that committee's jurisdiction, you're going to run into problems and that will get stripped out. And then what's also clearly not allowed is long-term deficit increases without an on-committee offset. So this means a lot of policy has to be designed in a temporary basis, so that it does not increase the deficit in any year outside of the reconciliation bill. I say an on-committee offset because this provision is governed on a title-by-title basis. So essentially the finance committee cannot pay for another committee's priorities in the long-term in simple language there. But then there's everything in between. Look, there's a lot of different things that go on here and there's a lot of gray area. One of the bird rule tests is, it's called the merely incidental test, does the budgetary change that exists is that viewed as being merely incidental to the underlying policy? This is argued in front of the Senate Parliamentary. This is a picture of Elizabeth McDonough in the lower right-hand corner. And the parliamentarian is going to make a ruling or are going to make advisement based on established precedent. Those arguments are going to be done behind closed doors. We the general public may not even know what the result is of these arguments, except for if you look closely at the bill text and see things have changed or things have removed. But practically, look, what you are arguing is, can you say what you are doing, your policy change is about spending or revenue? And you have to tie it to that point at every juncture to be successful. There are a lot of edge cases and things that kind of inform things that tend to fall out because of this challenge. If you're targeting a single entity, that can be viewed as being merely incidental. This goes back to the example I gave earlier that a tax credit for electric vehicles might be okay, but a tax credit that only affects Teslas would be too specific as only one entity is benefited. Providing general waivers, exemptions, those have been viewed as things that tend to be merely incidental. And then changing a regulation on an industry will have some challenges. Of course, you can be creative in how you construct this. Changing a regulation may be out, but making a tax if an entity does something may be okay. So it's all about being creative to how you design a policy. Now, this might mean you're not designing your preferred policy, but you're designing it to fit under budget reconciliation. And just my last slide, there's just a few lessons from the American Rescue Plan that staff need to know about. I tend to look at budget reconciliation from one particular point of view and a very narrow point of view. And then we saw the American Rescue Plan Act of 2021 come up. And a lot more things were allowed than I guess we had initially anticipated. So direct spending from an authorizing committee is more permitted than previously thought. A lot of the American Rescue Plan Act had a lot of direct spending, which means that for climate policy, for infrastructure policy, a lot could be allowed as long as the authorizing committee is the one that's spending the money. It's typically easier to fill up an existing pot of money that you know exists in law, that has restrictions on it than creating a new pot of money, a new program with restrictions. This goes into the fact that the more and more policy you pile on to a direct spending program, the further you get down a road where it's entirely possible that the parliamentarian is gonna ask you well, why is that one line? Why is this regulation important to the underlying spending? So you just have, it's easier to fill up a pot of money that's existing than create a new pot of money with restrictions. The American Rescue Plan had particular challenges with single target provisions, which is very relevant for infrastructure, which means I think it will be very difficult to get things that look like earmarks in infrastructure. Fix this road, fix this bridge. Those are gonna have huge challenges going forward. And then the last lesson that I would give to staff from the American Rescue Plan is making sure that the provisions, the bill texture working on has pretty clean jurisdictional boundaries. In the Senate, bills out in the normal process tend to get referred to by a preponderance of jurisdiction. So if you're doing something on tax policy, finance gets it. But it may be the case that, well, okay, there's probably a little bit of policy, if it's on the environment, there's maybe a little bit of policy that would normally live under EPWs jurisdiction. Well, when you're designing the policy here and because it's going through committee markups, the policy that overlaps multiple committees needs to live within the title of where the policy is actually meant to be. So you just have to be really, really careful. And thus, be very, very careful about where the jurisdictions of an individual committee may lie. So that is, those are my lessons there. And let me stop sharing my screen. Thanks Zach for a great presentation. We will now transition to Q&A and discussion. So I'll invite Ma, oh, there she is, turn your screen back on. We actually just got a question from the audience that I think it may be good just to pause to ask. Zach, on one of your slides, you had a photo of Elizabeth McDonough. She's the Senate parliamentarian. The question from the audience was where does the, what does the parliamentarian do? Who selects her and sort of what her role is. The parliamentarian serves at the pleasure of the Senate and she is generally responsible for providing advice and guidance on the rules of the Senate. She made some headlines in around the time the American Rescue Plan was coming together. She made a controversial ruling on the minimum wage. Zach or Molly, could you speak a little bit more about or just say a few words about sort of what role she functions, how the parliamentarian works with the majority and the minority right in the Senate right now? Yeah, so I'll start and then Zach can add. So I think he gave some important context in his presentation in terms of, in the context of reconciliation specifically, the parliamentarian is tasked with advising senators on whether a particular provision in a reconciliation bill does or does not comply with the bird role. This is a process that is affectionately referred to as the bird bath. Things that are removed as part of that process are affectionately referred to as bird droppings. I like puns, turns out the Senate does too. And so that's sort of a key responsibility that she has in this context. One thing I think is important to, since you mentioned Dan that the parliamentarian made some headlines in earlier in the year. I think we might talk about the parliamentarian the most sort of talking about reconciliation, but she has other functions in the context of the Senate and the fact that she has other functions including things like advising on which committees bills should be referred to. And on questions of committee jurisdiction there's value in having an entity that is seen as an honest broker by everyone in the legislative process that again extends beyond simply her role in the reconciliation process. So as kind of an institution within the institution I think that's important to remember that if she, like we might talk about her the most in this context but she has other jobs and that everyone in the Senate benefits from having someone who everyone sees as a neutral arbiter of a number of different issues. And I would just add, I think the media fascination with the Senate parliamentarian in my opinion is probably negative because at the end of the day it's political actors that are making a decision and they wanna blame, it's kind of like blaming the ref in sports or blaming the umpire specifically in baseball for someone that they're just doing their best job to call the balls and the strikes as they see them. This person has immense institutional knowledge and is a consummate professional. This isn't a person that is necessarily a political actor in their own right. So I think that's just an important thing to recognize. Thanks for that. And thanks for the question from the audience. Okay, so now we get to have the discussion and we're talking about this at a point like I said in my introduction the Congress is gonna debate infrastructure and it seems like that's gonna start happening pretty quickly and Zach, your presentation in particular sort of laid out sort of what's allowed what's not allowed and what's in the middle for someone who's thinking about how to approach reconciliation with the goal of getting their bosses priorities included in the mix. If they have something to start with that's written like a regular bill what are some of the differences between a normal bill and authorizing bill and what that has to look like to be successful in a reconciliation process. What are the types of things that might have to change? Is it just how it affects revenue how it affects spending or are there other sort of like are there other sort of construction elements that make an authorizing make authorizing texts different from reconciliation text? So let me just start here and say there are a lot of different things that make an authorizing bill and authorizing bill but I think what's key here is if your bill was already a tax policy bill and it was purely a tax policy bill you're already starting from a position where you're more likely to be able to make an argument that this can get into a budget reconciliation assuming that when you put this into the comprehensive package that the committee is putting together you don't make it be too expensive or anything like that. But if you're starting from something that's more regulatory or those sorts of things are authorizing a new program you need to make sure that it's not something that needs appropriations and the traditional appropriations process to come and backfill and provide your money. You need to make sure that there's direct spending provisions direct spending language within your bill to be fully reconciliation ready. I would suggest staffers who wanna do that make sure that they look at the American Rescue Plan and the legislative language that was used in that for a good chunk of the direct spending that was there. And then just realize you've written a bill and you've probably written a bill that you think is really great and you've done a lot of stuff in good faith to make sure that, okay, I realize that it's gonna touch four different old pieces of legislation. I've crossed my T's, I've dotted my I's. You have to recognize that you may start needing to make compromises and things that you want and you view as, oh, this was really important. This regulatory provision which prevents some gaming companies gaming the situation down the road. Well, you may run into situations where the parliamentarian is gonna say, well, is this necessary? Do you need this in there? Or you may be dealing with leadership or the committee and the committee may go, well, we just don't wanna run that risk. So, or it may conflict with other things. You recognize that you just, it may not be the exact same bill at the end of the day. So I'll add two things. So one picks up on sort of Zach's comments both here and his presentation about direct spending. And again, I will just emphasize that like, while one of the lessons from the American Rescue Plan is that we sort of saw more direct spending move to that bill than we might have otherwise thought that there may also be a limit on how much the appropriations committees are comfortable with authorizing committees, continuing to sort of take things that would have otherwise been programs that would be subject to annual appropriations and convert them into direct spending that is reconcilable. So I don't think we have a, as it's sort of like institutional political question, I'm not sure we have a great sense of that. The other thing I remind folks of is the implications of the 10-year window for reconciliation bills. So provisions that increase spending or cut taxes are, unless they're fully paid for beyond the reconciliation window, that's also a potential bird role violation. And so you might find yourself having to sort of do something over a different time horizon than you would otherwise. This is the Bush tax cuts, the parts of the Trump tax cuts. The reason they sunset is because of the 10-year window issue. So that's just another thing to keep in mind. Great, thanks. So we've talked a lot about American Rescue Plan and we're talking about sort of this in an infrastructure context. How many times can Congress actually use reconciliation? Is it something that's bound to a fiscal year? Is it bound to the lifespan of a budget resolution? Is it a calendar year? Is it a Congress? Molly, how frequently could Congress go back to this well if it chooses? And Zach, I'll definitely give you an opportunity to comment as well. So there are two pieces to answering this question, I think. There's a sort of what to the rules permit and then there's a what does the calendar as an actual thing that binds people permit. And on the what to the rules permit, under guidance from the parliamentarian that dates, I believe, to the early 2000s, the notion was that each time Congress did a budget resolution, that budget resolution could be followed by up to three reconciliation bills, one related to spending, one related to revenue and one related to the debt limit. But if you wrote a reconciliation bill that touched any one of those three areas, that sort of counted as your bite at the apple. And it's in practice pretty difficult if you wanted to sort of do anything. It can be quite difficult to do anything more than a straight like tax cut bill that doesn't touch revenue and spending. So we've seen relatively few years with actually more than one reconciliation bill attached to the same budget resolution. What happened a month or so ago is that the Senate Democrats saw an opinion from the parliamentarian on whether they could do a revision to the budget resolution for fiscal year 2021, which is the one that they adopted early this calendar year to create the reconciliation instructions for the American Rescue Plan. Could they go back and revise that budget resolution and would that permit them to do another reconciliation bill under the umbrella of the fiscal 2021 budget resolution? The Senate parliamentarian said, yes, I remain a little unsure exactly what the contours of what her yes means. So this brings me to sort of my second point before I turn over to Zach, which is that like the rules may say something about the number of times Congress could try to bite at this apple. But equally as important is the amount of time it takes to do a reconciliation bill and the sort of strategic questions about what do you wanna try and put in one versus split into two and if you split something into more than one and it takes you longer than you think to do the first one, do you ever really come back to the second one? And there's lots of, so those are questions that have to do with priorities and log rolling across issues and just the degree to which floor time, especially in the Senate and frankly, in this moment of lots of priorities for a new narrow majority that that's also, I think as binding a constraint on what we're talking about as the rules. Yeah, I agree with everything Molly said, especially this last point about political floor time. Everyone needs to realize that to do budget reconciliation you deal with the Senate Voterama process twice. For those of you that don't know or haven't lived it, Senate Voterama- Lucky for you, if you've never lived through a Senate Voterama. Lucky for you. Senate Voterama is a situation because there are time constraints built onto the budget resolution and budget reconciliation, that's what kind of gets around the filibuster at the end of the time, it's over. But at the end of the time, it's over means all the pending amendments and there are hundreds are up for a vote and you could just vote continuously. And so at that juncture, the entire Senate floor is kind of governed by unanimous consent and it's a unanimous consent agreement for when do all 100 senators get so tired of voting that they're calling it quits. And it's a really tough process, it's a tough process on staff, it's a tough process on the members and it eats up a lot of time. And so, and folks take a lot of difficult political votes, which is another constraint there. So that's part of why I thought at the beginning of, so after Democrats won the Georgia run-offs and it became a 50-50 Senate and Democrats held the House, the Senate and the White House as a result, I thought three attempts at reconciliation using the FY21 budget resolution, the FY22 budget resolution and the FY23 budget resolution would have been possible before the next election, before the November 2022 election. Whether or not the parliamentarian rules that you can revise the 21 resolution, I still think three is probably the most that this can bear over two years, but that's just my personal speculation, not a, this is technically what they could do. It's really interesting. Yeah, Voterama goes all night, it's a crazy environment. Yeah, and it's, I'll just say that like it, again to like go back to my opening comments that try to put this reconciliation moment in broader political context. In a Senate where there are far fewer opportunities for senators to get votes on amendments that they want generally, the Voterama becomes like an even more painful process because people look around and say, I have this amendment that I want to offer and I don't think there's any other time I'm going to get to do it. So I'm going to take the one chance that I have, but all your 99 colleagues are also thinking the same thing and that's part of what makes it as painful as it is. And I think it's gotten worse over time. Yeah. I think it's almost like, it's almost like a kid eating all their candy on Halloween night. It's, you've been like, I've been waiting for this, I've been waiting for this candy and then all at once, great. I have all these different options and you eat yourself sick. Is there another way to eat Halloween candy? I'm not aware. I guess not everyone just portions it out for a little bit at a time. I'm going to remember that this year when Colin brings all this Halloween candy home, I'll be like, no Voterama tonight, no Voterama. We'll parcel it out. And also like Molly, I think what you were saying is at ESI climate is, it's top of our list, but Congress has lots of other priorities, right? I mean, there's a very good reason why the American Rescue Plan came first because that was sort of the immediate. So I think that's a really important point for staff to remember as well, that Congress has lots of things on its plate, literally everything on its plate and it has to choose which priorities it prioritizes. I would like to just quickly remind everyone that if you have a question, there are two ways to ask it. You can follow us on Twitter at EESI online. You can also send us an email, EESI at EESI.org. Zach, we'll start with you on this one because you used to work there. The Budget Committee, what is the Budget Committee's role in all of this? What are their staff doing and are they available as a resource to other staff or what are they doing with all of this? I mean, they obviously have a huge role to play and I think maybe their importance generally is overshadowed sometimes by the Appropriations Committee at certain times of the year, some of the authorizing committees at certain times of the year. Yeah, so it's important to remember that budget reconciliation requires a budget resolution to get kicked off and the Budget Committees are the ones that write that budget resolution. That budget resolution contains the instructions that give the authorizing committees the ability to do that. So the political pressure on the committee to write a budget resolution that can meet what the majority wants dictates a lot of what can happen and an individual member's preferences on the Budget Committee can steer and change how it gets through committee. In 2017, there was a big debate for the budget resolution that set up the Trump tax cuts. There was a big debate inside the committee of whether or not they could get a majority based on a $1.5 trillion tax, $1.5 trillion instruction, net instruction. So who is on that committee can make a big difference. From a staff point of view, the Budget Committee contains a lot of the process experts on this. They contain the experts on where all the numbers need to be and where they may add up at the end of the day. So if you are a staffer, it's good to be in touch with your corresponding Budget Committee expert, whoever runs, if you're the environment staffer, it's important to be in touch with who is of your party and running the environment portfolio over at your committee because they're the ones that are gonna be knowing best about what's going on. And keeping those lines of communication open is something that I always recommend to congressional staff. The only thing that I'll add is this question was about the Budget Committee specifically, and Zach did a great job of sort of answering that, but the part where he was talking about the needing to get a budget resolution out of the Budget Committee. Also, because the majorities are so narrow in the House and the Senate, that's also gonna be a constraint on what that resolution might look like, especially if we're talking about a resolution that is also meant to actually set some top lines because I think that there's the potential for disagreement within the Democratic caucus from different wings of the party about sort of what things like the overall size of the defense budget should be. And that there is a potential, again, because we have fewer and fewer things that move through the legislative process, they all bear more of the political conflict. So the idea that there are things beyond just how does the budget resolution set up reconciliation that could get caught up in that debate, I think is also an important thing to remember. Yeah, just one thing on this because this is really important. The prior budget resolution that was used for the American Rescue Plan was the FY21 budget resolution. We were already halfway through, roughly halfway through fiscal year 2021 when that was utilized. If Democrats are gonna use the fiscal year 2022 budget resolution, that would be the first budget resolution after the expiration of the discretionary spending caps, which means it's a budget, it's a live budget resolution for determining the start of the appropriations process, which means it's just that more important. And we, our first congressional climate camp budget and appropriations and stimulus, we had a CRS analyst and a friend at the Bipartisan Policy Center come and talk to us about sort of the regular budget process, appropriations and sort of the role that the budget resolution plays and all of that. So, and there was a lot of discussion on spending caps actually during that. So if anyone in the audience was just intrigued by where Zach was going with that, we actually have a whole congressional climate camp on. And you should be, it's really important. It is really important. And so anyway, I would definitely encourage anyone to go back and read the, at least read the notes, but Kari and Frans did a great job presenting on those topics too back then. I'd like to sort of, we're getting close to our three o'clock stop time. And so I'd like to sort of ask a couple of last questions. This one is more about, you all have, the two of you have done a wonderful job explaining this and helping us understand sort of what this looks like and what the dynamics are. Are there quirks? There are lots of quirks with the process. But are there little things in the process or there are pieces of information that we haven't already covered that for a staff person sort of going into this process with their bosses' interests in mind trying to advance their priorities? Are there quirks of the process? Are there things that we haven't talked about yet that they should just know going in? And Molly maybe we'll start with you this time. Yeah, so I will say something that actually comes back to something that Zach said earlier and that has the potential to like interact with what feels like the possible, like pretty fast timeline here. So in your opening comments Dan, you were talking about what Pelosi has said about when the house is gonna vote on an infrastructure package. And one thing that is true particularly for things that are less clear fits in the reconciliation box is that sometimes you have to iterate over a policy idea on how exactly to get if you, so you try to take the policy kind of through the clear front door, that turns out to not fit in the reconciliation box. So you have to find a side door or maybe even a second side door or the back door. And so knowing that the, if you have a policy goal that the first idea you have may not be allowed into the process and that you might need to try and find a second way to do it. But while also knowing that the whole train is moving really quickly, I think is an important thing to remember. The issue of the individual mandate in the ACA repeal is a good example of how like first Republicans tried to go through the front door with a straight repeal of the mandate and the parliamentarian said that that was not permissible. And so they ended up going through a side door where they set the penalty for not having health insurance to zero. And so that's just an example again of how like the first thing they tried didn't work. So they tried something else. And so just kind of knowing that but also remembering that if the train is moving really quickly that like it's in your interest to try and get it right the first time but that is not unusual for it to be wrong. And then the other thing I'll say is just like this stuff is really complicated. I have one of my favorite things to show people in the context of talking about reconciliation is I have some documents that are from like the development of reconciliation bills in the 90s that are now at the National Archives. And one of them is a document prepared by the House Budget Committee where they were trying to speculate about what are possible what were gonna be possible violations of the birth rule and the bill went over to the Senate. And there are several of them where they just have these boxes with like this or provision next to the box. There's just like a series of question marks like I don't know. But again, these are people who do the who are experts and who do this as their job. And so just knowing that it's hard and it's complicated, I think it's also an important reminder. Then I'll just flag that staff need to realize that given the fact that this is essentially a democratic only exercise, it's gonna be a lot of what is in and what is out is governed in a political process held by leadership and held by the White House. And so as best as you're trying to represent your boss's interests, you have to recognize that you have to do that. You have to do that step to make sure that your leadership staff understand that your boss cares about this. And you have to do that kind of political legwork within the caucus to make sure that you understand, to make sure that leadership knows it's supported by not just New Dems but New Dems and progressives. And so that you can build that coalition to say, this should be in the bill. That being said, the more and more expensive your provision is because everything will kind of be locked in at the beginning in the budget resolutions instructions, the more expensive your provision is, the tougher it is gonna be to make that case. And what are you trading off? What are you taking out to put your provision in? And that will be on a committee by committee basis, that decision will be made. So talking with your authorizing committees, professional staff will be really important as well. Yeah, that's, we've talked about voter drama. Now it's time for cliche a polluza. Staff really need to understand that it's not just the ends, it's also the means, right? And that there's multiple ways to skin a cat. And also that you can't let the perfect be the enemy of the good. And there are, you know, it's a, in some ways it feels a little bit like it's a problem in search of a solution. So those are all of the cliches, but those are my sort of extrapolations of some of your bits of advice from that. We're just about out of time, but I would love to give each of you an opportunity to plug your work, share some additional resources that you or your colleagues at Brookings or Third Way might have on the topic. And Zach, maybe we'll start with you. Other resources that you've either authored or that you think fondly of that you would like staff to be able to use as a resource. Great, so I wrote a paper recently this January about the role of the parliamentarian in this process and how we can use budget reconciliation to help the American workers recover. That should be posted as a resource available online. I know I sent that one over. And then I'll just also flag that the Center on Budget Policy Priorities and the Committee for Responsible Federal Budget both have very good entry level refreshers or short papers on budget reconciliation. I know even though like I pay attention to this more than the normal person, I still go back to them from time to time. I think that's, I think they're just really, really helpful and worth reading. I would second everything Zach said. I would say if you are, you're interested in getting like a deep dive into the history of reconciliation. There is some of that in my book, but you really don't need to read that. And the other thing I will say is that my other invaluable resource every time I need to is anything produced by the Congressional Research Service on Reconciliation. I have an entire file on my computer of CRS reports related to different parts of the process. I showed you one table polls from one of those reports on the number of committees named the instructions over time and just really those, the team over there who works on this stuff is really top notch. And so I would particularly for the Congressional audience I would say they are a great resource to reach out to as well. That is 100% endorsed that as well. Great advice, they're pretty amazing. And when I was talking about that first installment of Congressional Climate Camp we had a CRS analyst with us and she's the best. Great presenter too. We are just about out of time. I think this topic could be the subject of multiple briefings, but what I took away from the two of you, first of all, thank you so much for your expertise and your insight and your experience, your recommendations, your guidance. And I think it's for staff people it may not be possible right now to understand everything. But I think the two of you did a wonderful job helping to orient them, hopefully for navigating the process successfully. So I thank you so much for making time today for us and our audience. Thank you so much, Molly and Zach. I would like to just take a quick moment to share a preview of what we are planning on in June. We are gonna take a little bit of a break around Memorial Day but much like Congress, we're gonna come back in June in a big way. We are going to be looking at the energy system. We are going to be looking at proposals around the National Climate Bank. We have a really busy slate that we aren't quite ready to notice yet, but keep your eyes peeled because they will be coming out shortly. And if you really don't wanna miss it and you wanna RSVP as quickly as possible, the best way to do that as always is to visit us online at www.esi.org and to sign up for our bi-weekly newsletter, Climate Change Solutions. We have a lot of great stuff coming up and I'm gonna hate for you to miss it. I will ask my colleague, Dan O'Brien, to put our slide up with our survey link. If you have the ability and two minutes to take our survey, we would really, really appreciate your feedback. We are always doing our best to improve our congressional education programming. I'm not sure how we could possibly have improved today's session with Molly and Zach, but maybe you had a tech issue, maybe my audio wasn't coming in. We really do read every comment that you submit. And so if you do have a moment, we would really appreciate your feedback. And it means a lot when you take time to do that. And just lastly, I would like to thank everyone at ESI who helped make today possible. I mentioned Dan O'Brien, big thanks to him. Thanks to Omri, Anna, Amber, Savannah, Sydney, and our interns, Jackson and Ashlyn for helping with today as well. They're two of our summer interns and they're already making a big impact on our on-bill financing work and our development work. So thanks to them. We will go ahead and end it there. Molly and Zach, once again, thank you so much. Thank you for our audience, for joining us today. If you liked what you saw, everything is available online. You can also go back and revisit the entire Congressional Climate Camp series. And I hope everyone has a great end of May, and a nice Memorial Day weekend. And we will see you all back here in June. And stay tuned. We'll be getting the briefing notices out as soon as we can. Thanks so much. Take care.


So currently we have just the enterprise now remember there's different versions of the desktop so that the pro is going to be more similar to like the company sizes as the QuickBooks online pro right or pro plus right. And those for small to midsize companies and then people that have the special needs might then go up a notch to the enterprise and the enterprise comes in different what they call flavors that you're right. We could specialize in construction or I have the general enterprise or retail or process costing stuff so but the enterprise version has everything that the other versions have plus the added features. So I'm going to look at the enterprise version and then you and then we might like try to list out when when using it what kind of features are in enterprise and what kind of features are subject just to are special for enterprise in which are not in special to enterprise so most of the normal type of bookkeeping the full accounting system bank feeds the full accounting process. Most of the general reports that most businesses need income statement balance sheet accounts receivable and stuff is in the normal normal desktop. It's when you get into more advanced type of reports for specialized areas that oftentimes the enterprise comes into play like inventory cost accounting and stuff like that or construction. So let's go ahead and hit the install file now it's installing up top so you have your installation. It should not take too long to to pull down here although it's a fairly large file even the installation file. OK so now I'm in Google Chrome so it's currently updated with this little drop down up top. That's where the temporary file is you could drag it on to your computer. Remember that this is not the actual the actual QuickBooks file. This is the file to run the software. So this is your startup file or we could just click on it from here and it should start the run process. So I'll click on it and see if I can run it from that point. So here we have the Intuit QuickBooks desktop enterprise. We've got the 30 day free trial QuickBooks desktop enterprises the most flexible version of QuickBooks design for more complex businesses. You might get some actual audio that will read this to you but I'll read it to you here too. It offers the flexibility to adopt your business needs with the look and feel of QuickBooks to help you run your business more effectively. You will be installing a 30 day user trial. If you decide to purchase QuickBooks desktop enterprise you will be given options to buy 510 or up to 30 user license. OK so we want to install the trial 2024. So this license agreement here notice there's no little button you have to actually click on it and then it opens the agreement in a browser. And then of course you want to read the entire agreement because that's what you tell them word for word.  So after you've read all that I paused it and totally read the whole thing then you're going to continue. And then it's going to say where they want to put it. So it's putting it under the program files and this is where it's located on your C drive program files into it. QuickBooks enterprise solutions. So if you want it located at some other place you can do so but that's usually a pretty cozy nice little place you might want to save that so you know where it is at. So if you want to uninstall it or remove it at some point in time it might be easier to do but there it is. And so there's going to be your license information. So you might want to write this down because oftentimes you need that license information if it forces you to input it later. But that usually happens when you are registering the software which you're not really doing here you would think because we're just using it for the 30 day free trial. So normally when you install the software you would want to save that information somewhere or you would have it online and you're into it account. But I believe you don't even need an into it account. I don't believe in order to run the 30 day free trial version here. So we're going to go ahead and install. It says the smarter way to do business as we're installing in the startup screen. This could take some time by the way because again into it kind of our QuickBooks fairly large. So more room to grow up to 40 users and capacity for one million customers vendors and inventory items. Single source for true for truth across your entire business. I like that. It's a source for truth. This is like philosophy here. This is a source of truth that we're getting we're hitting on exclusive reporting inventory and pricing tools. So there we have it. Let's wait. I'll pause it here. I won't read anymore until it downloads. And there we have it. It has been had been installation complete. Let's go ahead and a quick quickly open it. And so I'm going to open it up now. There. There it's running. Okay. QuickBooks desktop enterprise solutions product is available in several industry specific editions. So choose a QuickBooks desktop industry specific edition tailored to fit the specific needs of your business. Now if you if you were testing something out to try to get QuickBooks not enterprise then notice you wouldn't have this option in the installation right. But QuickBooks desktop would still have all the normal kind of features. If you're going to enterprise most likely because you're in a specialized industry possibly a larger company.


The first lecture in the course is really going to be sort of a taster of many of the things that you will go into more detail in from the other lecturers. I want to give you a general overview of neutron scattering, why we use neutrons, what types of methods are available, how we produce neutrons, and then give you a conceptual overview and essentially some initial reference material for some small angle scattering and how that actually works. And then in the further lectures you will hear in more detail about some of the topics that I bring up today. Okay, so let's talk a little bit first about neutrons and x-rays. People are most familiar with x-rays simply from the fact that I think pretty much everybody at some point has had a medical x-ray of some kind, be it a dental one or something to do with the bone breakage or damage or something like that. But neutrons are perhaps less familiar. So if we start talking about the comparison between the two, it'll perhaps give you a more intuitive field for the properties of the neutron. So neutrons themselves were discovered in the 1920s by James Chadwick. They'd been predicted by Ernest Rutherford. He had seen in some gold foil experiments that there must have been something else other than the charged particles that were known at the time. And in 1923 Chadwick set up an experiment where he used a source of alpha particles hitting beryllium and passing through paraffin to then show that there were indeed particles that could only be these neutral subatomic particles that were christened neutrons. And Chadwick received the Nobel Prize in physics for this discovery. And here we have some comparisons between the properties of neutrons and x-rays. And I think the key items to consider are the fact that firstly the neutron has mass whereas the x-ray does not. Neutrons travel at non-relativistic speeds. Their velocities are slower than the speed of light whereas x-rays travel at the speed of light. Neutrons have a spin half and this becomes important about their interactions with atoms. Neutrons have a magnetic moment. This is very important and this is the basis of everything that Elizabeth would tell you about when she talks about magnetic small angle scattering. And then I'll say a little bit more about these energy ranges in a minute. So if we look at x-rays they were discovered 20 years earlier, 30 years earlier by Wilhelm Röntgen when he was studying cathode ray tubes. And he also got the Nobel Prize in physics for this award. In fact it was the first Nobel Prize in physics was awarded for the discovery of x-rays. So in general discovering fundamental particles or new forms of radiation is a good way to get a Nobel Prize if you're angling for one. We then need to talk a little bit about how neutrons and x-rays interact with atoms. So in the case of x-rays there are electromagnetic radiation so they interact with the charge cloud around the outside of an atom. Whereas neutrons being neutral are not affected by the charge cloud and can directly interact with the nucleus of an atom. The one case where in fact they do interact with the electron system is in magnetic scattering and you'll hear more about that later in the week. The interaction between neutrons and the nucleus is a complicated one determined by the nuclear energy levels and the exact structure of the nucleus. And as a result what we see is the fact that the interaction varies somewhat haphazardly across the periodic table. If we look at this plot on the left hand side what we see is the fact that here the neutron scattering length which I'll explain a bit later varies in this haphazard manner across the periodic table. It can vary wildly from one element to the next and even vary from one isotope to another and this is an important fact in the use of neutrons for material science. X-rays on the other hand because they interact with the electron cloud their interaction simply goes as the number of electrons so it just goes as the atomic number of the atom. And what this means is that adjacent nuclei in the periodic table have very similar X-ray scattering factors whereas for neutrons they may have very different ones and this provides a different degree of chemical sensitivity between the two probes where neutrons can actually often be much more chemically sensitive. On the right hand side we have a sort of pictorial representation of what we call the cross section and this is essentially you can think of it as how big an atom looks. You know if you imagine you're throwing a tennis ball at something the bigger the thing is the more likely you are to hit it. Here this is not a representation of the physical size of the nucleus but a representation of the strength of the interaction and thus how big an inverted commas it looks when you fire neutrons at it. And what we see here is that we see this variation being different for X-rays in green and neutrons in red and in fact what we can see is the fact that for instance for X-rays for hydrogen deuterium you have a situation where because they have the same number of electrons the cross section is identical whereas it turns out that for neutrons hydrogen has a much larger cross section than that of deuterium and in fact also if we look at its scattering length hydrogen is negative whereas deuterium is positive and this allows us to play some interesting games with the neutron refractive index that will allows us to change how our sample scatters the neutrons and control it. The other useful fact is the fact that we have relatively low cross sections for some key metallic elements such as aluminium and iron this means that we can probe through materials that would not be transparent if we were using X-rays so materials that X-rays will be absorbed by neutrons can often penetrate and there are materials of course that neutrons don't penetrate but but X-rays do such as boron for instance. There we go. If we now look at the properties of the neutrons and X-rays that we actually use experimentally of course neutrons can have a very wide range of energies as can X-ray photons but here I'm focusing on the the energy ranges that we actually use for experiments. In the case of neutrons it's on the order of milli electron volts to electron volts whereas for X-rays it's on the order of tens of electron volts to kilo electron volts. This you can see here that the X-rays we use have a significantly higher energy however if we look at what that means in terms of wavelength those are very similar wavelengths so what this means is that in the case of the structures we can probe we can probe the same length scales. We can probe the atomic to macroscopic length scales using both X-rays and neutrons but the neutrons we use have a much lower energy and this plays importantly into a whole range of techniques that I'll come to later called a neutron spectroscopy methods which don't really have any analogs in the X-ray world. It also means that the X-rays have the potential to do a lot more damage to your sample by depositing a lot more energy into it and then the other aspect is the question of source brightness. So neutron sources for the experiments we do today range from 10 to the 10 to 10 to the 14 neutrons per square centimeter per second per steradian per angstrom of bandwidth whereas photons from lab and synchrotron sources range from sort of 10 to the 6 to 10 to the 20 photons per square millimeter per second per milliradian per 0.1 per cent bandwidth and at first glance you might say well those are similar but of course I cheated by using different units. So if you can see here for the neutrons I chose per square centimeter and per steradian whereas for the photons it's per square millimeter and per milliradian and also the bandwidth is much narrower for the photon measurement and what this means is that modern X-ray sources are probably about 10 orders of magnitude brighter than modern neutron sources and this folds itself into the way we design experiments and the types of experiments we can potentially do and I'll talk more about sources a little bit later. So what does this all mean in reality? Well what it means is that neutrons and X-rays see things differently and if we just look at the macroscopic question of radiography which is probably what you're most familiar with the type of things you would do with medical X-rays we can do things similarly. So on the left here you can see this is actually a boiling coffee pot with neutron radiography and you can see we see right through the aluminium of the mocha pot that small cross section whereas the water containing coffee or the water in fact going through the coffee has a lot of hydrogen in it and thus is much less transparent because of that large hydrogen cross section. Another example here is we take the same item in this case a small motor and we can look at it with both X-rays and neutrons and the X-rays and neutrons are able to highlight different parts of the structure depending upon the relative interaction of the neutrons and X-rays with the materials. And last example here is a rifle cartridge so here you see with the X-rays that the brass and lead are strongly attenuating whereas for neutrons the brass and lead are actually relatively transparent but the gunpowder is similarly not so transparent and we can actually then see inside materials that would otherwise not be transparent and this actually has a lot of scientific applications using radiography in things such as looking at the motion of water in fuel cells or the motion of lithium in lithium ion batteries. So this means that we can actually have different views of the material depending upon whether we use neutrons or X-rays. We can also have different views of the material using just neutrons. I mentioned before that hydrogen and deuterium have opposite signs of the scattering length and what this means in effect is the fact that we can make their refractive indices cancel out and so here you can see on the left that Lola she has made sure that her refractive index is the same as her surroundings whereas Harold unfortunately has not and so the neutron monster will eat Harold and interact strongly with him but will not interact so strongly with Lola and what we do what we call this is we call this contrast variation and this is something that Adrian will talk about in his lecture but we make use of selective deuteration to hide and show different parts of our sample and we can also combine X-ray and neutron measurements on the same sample to get more information. All right so that is a very brief overview of why we might use neutrons and how they compare to X-rays and so the next thing I'm going to talk about is the different types of neutron sources. Neutrons typically are bound up in the nucleus of atoms and we have to get them out in order to be able to make use of them for our experiments to make beams of neutrons and there are a number of different ways that we can obtain free neutrons. The one perhaps that you are most familiar with is nuclear fission so here you take an element that readily decays with neutron release and then in particular when you bombard it with a further neutron with a neutron it will also split and so we can generate a chain reaction whereby we start one atom splitting and then you get a chain reaction as it produces three neutrons which can then go on to split other atoms and of course we need to control this in nuclear weapons. This is an uncontrolled release of energy whereas in nuclear reactors we put some absorbing materials in amongst the uranium in order to control the rate of that chain reaction so that it removes some of the neutrons and then what we do is we in a normal power reactor those neutrons will interact with material and generate heat. In the case of a research reactor what we want to do is let those neutrons out so we can use them. Another way of producing neutrons is nuclear fusion. This is of course what happens in stars but there are lots of work ongoing to try and have fusion sources on earth primarily for power production. Here what we do is we take something like deuterium and tritium and fuse them under high temperature and or high pressure in order to cause them to react and produce a neutron and a helium atom and this high energy neutron in a power reactor then goes on to interact with lithium which then produces a tritium atom which can be reused and heat which can be used for generating power. These are not really practical well as as neutron sources they're terribly complex and they don't produce very many very good yield of neutrons and the final primary way we produce neutrons is through spallation and the European spallation source which is our work is the source we're building here in London that will make use of this method it's in the name. Here we take a high energy pulsed proton beam and we fire that onto a heavy metal target and what this does is this destabilizes the nucleus and causes it to give off a huge range of subatomic particles including a lot of neutrons. The reason we use heavy metals is because they contain a lot of neutrons and this word spallation comes from geology where it means sort of chipping away at something. There are several working spallation sources in the world at the moment the one in Europe the primary one in Europe is the ISIS facility but also there's the Paul Sincu facility at the Paul Scherer Institute in Switzerland and the last way we can produce neutrons is essentially the same way that Chadwick did we can bombard a light element like beryllium have it undergo a nuclear reaction and produce neutrons. We don't use helium or alpha particles so much these days what we do do though is we take a proton beam but a lower energy proton beam than we use in spallation sources and bombard beryllium targets which then undergoes a reaction that produces neutrons. These are what we call low energy neutron sources or compact accelerated driven neutron sources and these are actually of the scale that could be built at a university so you could more or less have a laboratory scale neutron source I mean they're still fairly big you need a low energy proton accelerator but a number of sources around the world are being built with repurposed research accelerators at universities. So in terms of the high flux sources that you actually will likely mostly use for doing experiments the two types we have are reactors and spallation sources in both cases we have a central source of neutron production around which basically we put holes in the wall let the neutrons out and can then direct them to experiments. However if we look at the energies that are involved in both of those types of reactions the neutrons that are produced are in the mega electron volts to the giga electron volt range and I said earlier that the ones we want to use for experiments are actually in the milli electron volt range and so what we have to do is we need to lower the energy and so we use what we call a moderator and essentially what this is is this is a hydrogen containing material remember that large cross section I mentioned that we keep at a specific temperature and then by the interaction of the neutrons with those hydrogen nuclei they will interact, lose some energy and eventually end up with an energy distribution that is representative of the thermal energy in the moderator and so if we want lower energy neutrons we use a lower energy lower thermal energy source so we use something cold and this is usually something like liquid hydrogen or liquid deuterium or possibly solid methane. If we want slightly higher energy neutrons we use what we call a thermal source, thermal moderator and that's usually just water at room temperature so we basically pass the neutrons through a bucket of water and they rattle around inside and their energy goes down to something similar to the the Boltzmann distribution of energies in water and if we want slightly higher energy still so these are wavelengths on a fraction of an angstrom then we use what we call a hot source which actually we take graphite and heat it up to about a thousand Kelvin and are higher and so then this then adjusts the energy of the neutrons down to a energy distribution that's represented by that temperature and so all this is to say is that we have a way of producing neutrons from the source that have varying wavelengths and equivalent energies and so depending on the type of experiment we want to do we can make use of different neutron sources so where can you go and do such experiments you can see that there are actually quite a lot of sources around the world unfortunately some of these have now started to shut down the Canadians Neutron Beam Centre has closed Los Alamos National Lab has closed to external users the LLB in France has closed its reactor but they are working on a compact accelerator source and the Helmholtz Centre in Berlin has also closed in the recent years but there are many other sources you can go to they're distributed more or less everywhere there are sources in South America and in Africa as well as in Australia Asia but you can see there's a very high density of sources in Europe and as a result neutron scattering as a community is actually very strong in Europe and there is a large research base which was made in a natural source place to build a place like ESS so why are we building new neutron sources what's wrong with the old ones well as you heard some are closing they get old and nuclear reactors are getting less popular and at some point the refurbishment costs outweigh the benefits and the other reason is that we want to try and produce higher and higher fluxes of neutrons so I mentioned before that the source brightness for neutrons was many odds of magnitude below that of x-rays and many of the techniques we use with neutrons are limited by the number of neutrons per second we can actually get onto our sample and so we always want brighter and brighter sources and this plot shows the brightness of sources all the way from Chadwick's source up through reactors here and spallation sources here and you might be wondering why can't we make the reactor sources brighter and the reason for that is simply that I mentioned before that the neutrons interact and produce heat and at some point we can't we're generating more heat than we can take away in power reactors they produce an awful lot of heat they might have giga gigawatt power levels compared to the maybe 20 to 100 megawatt power levels from a research reactor and the way they achieve this in power reactors is that they make the cores bigger because all they're interested in is the total amount of heat produced however this doesn't increase the number of neutrons per unit volume of of of reactor core and that's what we need for doing our experiments faster we need brighter sources of neutrons not just more neutrons overall we need more neutrons coming out per unit volume and we've really reached a limit with nuclear reactor design in terms of how dense we can make the reactor cores while still extracting the heat and this is where spallation sources come in these allow us to because they produce many more neutrons for each proton we can put in we can put more and more protons in and get more and more neutrons out of course we still reach some limits and ESS one of the main challenges we have is whilst we're aiming to be the brightest neutron source in the world we are having challenges with removing the heat and so we have a very unique source design in order to allow us to get rid of the heat that's produced in the spallation process but this is in general we see that the the brightness of spallation sources is on the rise and there are some developments also now in the US with the second target station at SNS where they will be able to produce even brighter beams but for much shorter durations so an example of a neutron source spallation source is the isis source this is what we call a short pulse source so the pulse is hundreds of microseconds long and you the the source operates at 50 Hertz so you get 50 pulses a second it has a variety of moderators as we discussed and over 30 instruments that make use of those sources and so you can see here we have a linear accelerator that produces the protons these get put into a synchrotron to bunch them up and store them and then they get extracted and sent to two target stations around which the new neutron instruments are placed so it really is you know the neutrons are produced here they hit the moderator they go off in all directions and then we take whatever comes out of the hole and guide it to the instruments in terms of a sort of canonical reactor source the Institut La Langevan in Grenoval in France is probably the world's leading reactor neutron source it's a 58 megawatt reactor and was a post war project between France, Germany and the UK with also it has 12 scientific members including Sweden and this you can see here it has the reactor core with a series of moderators around it and then a number of instruments both close to the reactor and further out that are all viewing these sources of neutrons right so that's been a whirlwind tour of how we produce neutrons so I'm just going to finish up now by saying a little bit about what we do with them and in particular some of aspects of small angle scattering that you'll need to consider so there are a huge range of methods that can then take advantage of the fact that the neutrons interact with nuclei and are scattered or absorbed and they can allow us to look at the structure of materials all the way from the atomic scale using diffraction methods through the nanometer scale with sands and surface structures with reflectometry all the way into the macroscopic regime with imaging but I mentioned before also that neutrons have a relatively low energy and what this means is the fact that we also can perform experiments where we look at how the energy of the neutron changes when it interacts with the sample and these are spectroscopy techniques and these allow us to measure the way that atoms in the case of time of flight and crystal spectroscopy or molecules in the case of spinneco spectroscopy and length scales in between move and you'll see there's this diagonal correlation and this is because the shorter wavelength neutrons are good at measuring atomic structures but and they end up having energies that are useful for measuring atomic motions whereas the the longer wavelength neutrons are good for measuring small nanometer scale structures and these have energies that are also then useful for measuring motion on the nanometer length scale so motion of molecules and so what this means is we say that neutrons allow us to measure the geometry of motion because the length scale and energy are well matched so that we probe both the have the right energy probe the motions at the same time as we can probe the right length scale in terms of structural measurements there are x-ray equivalents of all of these neutron techniques in terms of spectroscopy and there aren't so many x-ray techniques that are similar and this is because of the much higher energy of the x-rays and so we simply aren't in the right energy regime to look at these very small energies that are related to the motion of atoms and molecules and there are other techniques that are similar so for instance dynamic light scattering and spinneco can often overlap in their regime there are methods like NMR and various other spectroscopy and other optical spectroscopies that can also align with some of these other methods so I mentioned all these different techniques and I mentioned also that we can measure the fact that the energy changes but what do we really measure in a neutron scattering experiment and fundamentally all neutron scattering experiments apart from perhaps radiography are the same we have an incident beam of neutrons that some have some energy and some wave vector they hit the sample and then they leave the sample with some other energy and some other wave vector and what we measure then is the change in energy and or the change in direction or change in wave vector of the of the neutrons and we measure that change in wave vector as a function of this variable we call q which is essentially just literally the the difference between the incoming and outgoing wave vectors in vectorial terms and if we look at how the intensity of scattering varies as a function of q it turns out that this is related to the Fourier transform of how the atoms and molecules are arranged in our sample this gives us correlations in space on the other hand we can also look at how the energy of the neutron changes and we we we talk about the energy transfer omega and if we look at the intensity of scattering as a function of omega this then turns out to be related to the Fourier transform of how stuff is arranged in time so we can look at correlations in time if you've done any dynamic light scattering it's very similar to the the autocorrelation functions we look at in dynamic light scattering so we can look at how the direction of a neutron beam changes and how its energy changes but there are different ways in which its energy can change so it could not change at all we could have a purely elastic interaction and this is primarily what we think of when we think of atomic diffraction so here we're getting no information about the motion of the atoms all we're seeing is the information about their positions if we have a crystalline material such as you know assault crystal or something like this they the atoms are not actually stationary at any real temperature what they are is that they are all vibrating and they tend to vibrate in collective modes we refer to as phonons but it means that in fact the these vibrations are both collective and also quantized and so when we do see an energy change in the neutron beam it ends up being peaked at very specific energies and this structure of peaks tells us about those collective motions of the atoms if we have something like a liquid or a gas however what we don't have this quantized discrete set of motions we have a Boltzmann distribution of of energies as I mentioned before with the moderators right we make use of that but that is then a broad distribution of energies and what we see then is that the energy of the neutron beam isn't really produced in a quantized way but is spread out in a distribution of energies and this is what we call quasi-elastic scattering and the distribution of this the width of this distribution it shape tells us about the distribution of energies and motions in the sample all right so I mentioned at the beginning that neutrons scatter from nuclei so what does that really mean essentially if we treat our neutron beam as an instant plane wave it comes in it scatters off the nucleus the nucleus is very small compared to the wavelength of the neutron beam and so we get a point like scattering effect with a spherical scattered wave where the the the equation of the wave is given here and here we see that the scattering length comes in and it represents the interaction of the neutron with the nucleus the sign of the of this is actually arbitrary but was chosen such that most elements are positive and we've seen before that they vary across the periodic table in this haphazard way but the most useful difference is between hydrogen and deuterium where one is negative and one is positive single nuclei are interesting but what happens if we look at multiple nuclei and also what is this cross section that I mentioned at the beginning with those little pictures of disks so it we define the cross section here as being the total number of neutrons that are scattered per second divided by the incident number of neutrons per second so here we have our instant neutron beam it interacts with the sample and it's scattered in some direction theta phi and into some solid angle ds also some sort of angle d omega and so we can measure in our experiment the differential cross section so we measure the differential of the cross section with respect to solid angle and then the total cross section as I say is given by the integral of the differential cross section over all angles and so when we take again our single nucleus we can calculate out based upon the properties of the incoming beam and the properties of the scattered beam what the scattering cross section is and so the differential cross section ends out ends up as being simply the square of the scattering length and so then the total cross section where we integrate over 4 pi steradians a full sphere ends up being 4 pi times the square of the scattering length this simple case however only holds when we have one isotope or one element that has zero nuclear spin present and the presence of multiple isotopes and multiple elements or non-zero spin actually leads us to having a coherent and incoherent part of the cross section where the coherent part is this bit and is provide structural information whereas the incoherent part describes the variations around the mean scattering length and is does not provide structural information okay so if we take more than one scatterer then basically what we do is we simply we sum up all of the scattered waves from all of the atoms in the sample right and modulated by the the distance between them and the differences in their scattering vectors we do that same calculation for the differential cross sections that he did before and we end up here with what is sort of the fundamental equation of one of the fundamental equations of scattering which is that the differential cross section as a function of q is simply related to the sum of all of the scattering lengths and their relative positions I'll briefly mention here coherent and incoherent scattering this is here for your reference but essentially if we work through where there are variations in scattering length across the sample then we end up with a situation where we have a component that is dependent purely upon the average scattering n squared and this is the coherent scattering term I mentioned before but here we end up with a term that is not does not have any dependence upon scattering angle and is simply related to the average of the square of the scattering length subtracted by the square of the average so basically it is the average deviation from from the mean and that has no information in it but does produce background in our scattering experiments all right so we saw before that to calculate the scattering or we just sum up the scattering lengths of all of the atoms and know where all the atoms are that is kind of tricky if you don't have an ordered structure so it doesn't repeat and you are interested actually in length scales that are longer than atomic distances so what we want is a bulk property that we can use to describe the scattering and the one we choose is what we call scattering density and it is exactly what it sounds it's the total scattering length divided by the volume and what this means is that in small angle scattering because we're looking at structures that are large enough we can make use of this instead of having to worry about all the individual atomic scattering lengths and the way this works is that if you imagine we have water we start by sitting on oxygen and just use the volume around oxygen oxygen has a positive scattering length if we increase the radius of our sampling volume then we include some hydrogen atoms hydrogen is negative so it takes it negative we make it a bit bigger we now include more oxygen it goes positive make it a bit bigger more hydrogen and so on until eventually we're sampling enough that we lose the details of the atomic structure and we're now simply looking at the the average of the molecular structure and so as long as we're looking on the sufficiently long length scales we can use scattering density rather than having to worry about where all the individual atoms are so we take that equation from before the differential scattering cross section and we integrate it using the scattering density distribution across the whole sample normalized by that total sample volume because we've done by sample volume and we end up with what we call the macroscopic cross section with big sigma in it and this is related to the distribution of scattering density in the sample and we call this is the called the Rayleigh Gantz equation and this is the sort of fundamental message I want you to take away from and that is that small angle scattering is a result of inhomogeneities in scattering than the scattering intensity the neutron beam knows nothing about your sample other than that the scattering density varies with in space it's up to you to turn that information into something about your structure and we see here this is now as you can see this is essentially now the Fourier transform of the scattering scattering density distribution in the sample so as a last point I just want to talk about sands versus sacks which is really neutrons versus x-rays both methods of measurement provide us with similar information we get structural information on the nanometer to micrometer length scale the difference is in how the radiation interacts with the sample in the case of neutrons they scatter from nuclei case of x-rays they scatter from electrons we have a variation of neutrons scattering length which varies from element to element and isotope to isotope in a way that is haphazard across the periodic table and then the x-ray form factor which is the equivalent for x-rays this is simply a linear dependence upon the number of electrons we rarely need to worry about the absorption of neutrons there are certain elements that do absorb neutrons but we don't mostly have to worry about them and whereas the absorption of x-rays is common and has to be considered in the analysis and this is an additional term in the scattering length density our flux of neutrons we talked about the brightness of neutron sources versus x-rays in general it limits the rate of data collection and means we need to have much larger beams whereas with x-rays we can make extremely fast measurements or low concentrations or look at very small samples with neutrons there's essentially no concern about damaging our sample with the beam whereas in the case of x-rays because of the high energy and strong interact and strong absorption then potentially we will be depositing a lot of energy in and we could damage our sample so in summary that was sort of a introduction to the why we use neutrons how we produce neutrons a very quick overview of how neutrons interact with matter and some of the key equations and concepts such as scattering length and scattering density that you need to know to be able to do small-angle scattering data analysis and perform small-angle scattering experiments so any questions or if you're fallen asleep I got a thumbs up good somebody's there excellent all right well if there are no questions on that then we have a half hour break now well 20 minutes I'm afraid because I ran over my apologies and at 10 30 Adrienne will start to give you more information on those things such as scap and density and contrast variation and how we compare sands and sacks so I'll I'll talk to you later and have a good break thanks