Οπότε τι γίνεται με γαμαραίες, μερικές εξαιρετικές εξαιρετικές. Τότε θα μιλήσουμε για τα πιο σημαντικά εξαιρετικές εξαιρετικές που βρίσκουμε με σέμπικοντακτος. Αυτό θα βλέπεις ότι αυτή είναι around 80% of the detectors we are using in Ion BIM analysis. Τις πράγματις για συντηλίες. Θα χρησιμοποιήσουμε συντηλίες mainly for gamma ray analysis, for Pige. Τότε θα μιλήσουμε για κάποιες γασουλίες και τελειώσεις. Αυτές οι δυο πιο σημαντικές εξαιρετικές που βρίσκονται mainly in Toferda. Δεν πιο σημαντικά. Οι δυνατότητες είναι όλοι μπορούν να βοηθούν να δημιουργήσουν τη δυνατότητα. Αυτό είναι το δυνατότητα. Βέβαια, αν έχεις ένα δυνατότητα που μπορεί να δημιουργήσει μια εξαιρετική εξαιρετική, για παράδειγμα, να δημιουργήσεις τη δυνατότητα ή να δημιουργήσεις τη δυνατότητα, αυτό είναι called a detector. Βέβαια από το δυνατότητα και τη συγχωρή της εξαιρετικής, θα υπάρχει κάποιες εξαιρετικές, like the efficiency of the detector, the efficiency of the resolution. Βέβαια, να μην πω ότι εδώ, εγώ λέω τα υποχή της δυνατότητας, δεν τα υποχή της εξαιρετικής. Όταν έχεις δυνατότητας, αυτή η ευσυκταία παράδει. Τι είναι οι πιο χρήματα δυνατότητα για υλαχθαλωνία ενάνθρωπες εξαιρετικών της ρόλας της εξαιρετικής. Βέβαια, έτσι όταν θέλεις να ενώ models μεms Ridge Particle, 99% θα χρησιμοποιούν υποχή για δυνατότητα. Αυτό είναι χρήματο, πιο χρήτου, δημιουργήσει να μην υπάρχει πόνο 5-6000 ευρώς, όχι περιכול, γιανητοφίσω θα πλήξεις τα νέα δυνατότητα ή τα αρχές χρησιμολφορές δυνατότητα. Για Πίγε, έχετε άλλο από τα τελευταία, τα τελευταία Γερμανίου λύθμου διτεκτος. Αυτό είναι ακριβώς χρησιμοποιημένος, αλλά όπως βλέπετε, έχετε κάποιες προβλήματα χρησιμοποιώντας. Οι πιο σημαντικές προβλήματα είναι να τους κοιμήσουν αλλιώς, όχι να χρησιμοποιηθούν. Προβλήματος Γερμανίου, αυτά είναι χρησιμοποιημένος διτεκτος. Και φυσικά, έχουμε σωδημαϊκό σιντυλαίτες. Για τοφέρδα, πρέπει να χρησιμοποιήσουμε σωδημαϊκό σιντυλαίτες για να έχουμε κάποιο σωδημαϊκό σιντυλαίτες. Και για την ενέργεια, πρέπει να χρησιμοποιήσουμε σωδημαϊκό σιντυλαίτες, όπως στην περίπτωση του ΡΜΑ, αλλά υπάρχουν also ionization chambers. Το καλύτερο thing with ionization chambers is that they live longer than surface barrier detectors. As you will see, surface barrier detectors and all silicon detectors, after using them, they have a certain lifetime. If you use surface barrier detectors for RBS and NRA, they can last for 10 years with no problem. But if you use them for TOFERDA, as the number of elements, the number of ions entering the surface barrier is much greater than in RBS and NRA, these will last for one or two years, depending always on the use of the system. On the other hand, if you use GIC, a gas ionization chamber, you don't have the problem of surface barrier detectors, you have less resolution, but they will live forever, you don't have to change them. So, let's begin with the interaction of the matter. Depending on the kind of radiation, you have different effects. So, I have split that in two. I'll talk about interaction with matter for charged particles and then I'll go to gamma rays. What does it mean? I have an interaction with the matter. When you have a charged particle entering in your medium, here I put, as an example, some ions entering, if I remember well, aluminum. You will have loss of energy, what we said, energy loss, and the deflection from the initial trajectory. As you can see here, as your ions entering the matter, they change also course, they change their destination. What are the process of energy loss? The main process is in elastic collisions with atoms, with electrons. There is also some elastic scattering from nuclei, what we call nuclear stopping power. And then you can have also Terenkov radiation, nuclear reaction with nuclei and the Brems-Tranlung. The three last give you something like 1% or less than the energy loss. So, I won't do anything about that. I'll just talk about elastic collisions with atoms and nuclei. Again, between these two, there is at least one order of magnitude difference. So, in elastic collisions, this is something easy to understand. When you have a charged particle entering your matter, your detector, they will find some electrons, and through the Coulombian interaction, they can either excite the atom or they can ionize the atom, depending on how close the interaction is taking place between the charged particle and the atom and the electron, and of course on the energy of the charged particle. But while you will excite or ionize an atom, this means that your charged particle will lose energy. How much energy will it lose? In the maximum, after one collision, it will lose something like 4 times m, the kinetic energy of your particle. If you want the 500, 1 over 500% of its initial energy. This is something very little, as you understand. So, in order for my nucleus, for my ion to lose the whole energy, it means that it has to do multiple interactions with electrons. So, whenever your ion enters the matter, it finds an electron, loses some energy, finds another electron, loses some energy, some, some, some, and continues like that, and after multiple interactions, you end up with no energy in your particle. Because these collisions are purely statistical and it's very difficult to see what's happening in any collision, we have defined what we call stopping power, which is the average energy loss per unit path length. What it means that it's statistical that if you have two ions entering your sample with the same energy, the exact same ions, it doesn't mean that they will lose the same energy. Okay, there is some difference in the energy, but as I can't see what every ion does, I take an average between a big number of ions. The good thing with inelastic collisions is that I have a perfect solution in order to find these DDX. If you go to the classical approach, the first guy who did the calculation was Bohr, and we have the Bohr's calculations, but if you go then to quantum mechanics, you use the better block formula. These are the two formulas. This is Bohr, and this is for a better block. The main thing that I want you to keep into mind about this formula is that the heavier is your element, the more energy it loses, and the lighter it is, it loses less energy. If you look here, I'm proportional to the velocity of my ion. This means that if I have a fast ion, it will lose less energy than a slow ion. You can also see over here, so here as a mean, as a matter, I use just air, plain air, nothing else, and this is the particle energy. So, for example, if you look protons, you see that slow protons lose much energy in air. As I go into higher energies, I lose less and less and less energy, so quick moving protons lose less energy than slower ones. And if you look at alpha particles, you will see that alpha particles lose much more energy from protons in the same energy. Okay, for example, if you go here at 1 MeV, you will see that this is the stopping power of protons and neutrons, almost the same, into air, while alphas lose much more energy. So alphas and heavier elements are interacting more with the matter because of the club interaction, and they are losing faster energy. These are some additional quantities that you may find in your work with interaction with matter. For example, what is a black chair? It's how my stopping power increases as I go deeper into my sample. And why is that? This is because here you have a lot of energy. As you move into your sample, you go into lower energies. The stopping power goes up. This means you have more interactions, more interactions. You reach up a peak and after that you have very low energy and your ions start, instead of ionizing the matter, they start collecting electrons from the matter and they slow down.  So here you have, if you want, the maximum number of ions interacting with the medium. This is very useful in some cases, especially for medical situations, when you have, for example, therapy of a cancer and you are using protons, you want to use maximum interaction of particles with the tumor, so you adjust the energy in order to have the black peak into the tumor and not before that or after that. Another thing that is good to know which energy is struggling, so when you have a distribution of ions with, let's say, a very narrow distribution of energies like that and you are entering matter, as the interactions are statistical, this means that some of the particles will lose more energy, some of them will lose less energy than that and as you go deeper into your sample, this Gaussian distribution goes bigger, bigger, bigger, bigger, bigger. This is a good thing to know that as you go into matter the knowledge of the energy gets worse and worse and worse and worse. Sorry. Range is how deep your particles can reach into a material. To be honest, to be precise, for the range, if you want to really define the range, the range is not where your beam stops, it's where your beam, your particles, drop to one half of their initial intensity. This is what we call range. But in ion beam analysis and in everyday physics when we say range, we are referring to the extrapolated range where this is where your particles stop. Where your particles, if you throw, for example, 100 particles into your matter, in which depth they will arrive. So if you look here, this RM is what we call range. This is the real thing of the range. But in everyday life we use extrapolated range. This means over here where my particles really stop. This is very good to know because this will also give you an idea of the thickness of the detector that you are going to use. When you use a detector in particle physics, in most of the cases you want your particles to stop into your detector. So you must know the range of the ions into this detector. If your detector is thinner, this means that your particles will go outside the detector, they will not deposit all their energy into the detector, and this may cause you problems when you are measuring. Now, of course, today we are not solving Bethes formula or Bethe-Bloch formula in order to see what is the energy loss in something, in some material, in some detector. And also we want to see the struggling, the energy struggling, or the angular struggling, or the range, how deep we go. We have SRIM. SRIM is a tool. It's not the only tool, but it's widespread used. Where you can put here the ion that you are interested for. You can put the energy of the ion. You find here the thickness of your target or your detector.  For example, here I used ions of α, α-particles of 3MeV. You can see it over here that I have α-particles of 3MeV and they are perpendicular into silicon. And you can see that this is 30 μμ. You need around 15 μμ in order to really stop all the α into your detector. Things are easier when you have the interaction of photons with matter. You have only three effects. So you have the photoelectric absorption. This means simply ionization. This is the energy of the photoelectron that you are using. This means you have an atom. You have the photon. The photon interacts with the electron. The electron goes out of your atom. This is the probability. Here the good thing to see is that it's proportional to the atomic number of the matter that you will find your gamma. And it's inverse proportional with the energy of your gamma. Now, n is not exactly known between 4 and 5 depending on the energy of the gammas that you are going to use. After the photoelectric absorption you have the copton scattering. This is also something easy to understand. You have a gamma ray. It finds an electron and both of them scatters. Because they scatter, they lose energy. They have some of the energy of the photon is taken by the electron. And this is how you can find the energy of the new electron. So you can understand that if I have photon entering the matter it can do multiple scatterings and lose all its energy. And at the end we have pair production. This is when your gammas are above one MeV. You need to be close to the Coulomb potential of a nucleus. And close to that your gamma may break up giving birth to one electron and one positron. But as the mass of these things is 511 kV this happens only for high energy gammas. If you want to see how these three effects, how these three phenomena are used for your interaction with matter this is the probabilities. So here you have the Z of the absorber and here you have the energy of your gamma ray. So for low gammas you see that the photoelectric effect is dominant. For one MeV you have the Compton effect dominant and if you go above 10 MeV then you have the pair production dominant. But using this scheme over here, this figure over here you see how your gammas are losing energy depending on their energy or their initial energy. Again now for gamma rays things that you may use is what we call linear attenuation coefficient that is defined just as the sum of the probabilities of having the photoelectric, the Compton and the pair production. This is how the intensity of your gamma ray beam is decreasing according to the linear attenuation coefficient. So this can show you how gammas are getting less and less as they are propagating into your matter. And another thing that we can define here is what we call mean free path. This means how much, what is the average length that a photon can travel into your matter before having an interaction and this as you can see here is inverse proportional to the linear attenuation coefficient. Okay, having said that let's pass to detectors. First thing that you are interested about detectors is what we call energy resolution. What is energy resolution is very simple. If I have two events with closed energies how much be, how big this difference must be in order to see these two events as two different events. This is what we call energy resolution. For particle detectors, for surface barrier detectors the energy resolution is between 13 and 15 kV for alpha particles. Have in mind that for particle detectors the energy resolution has to do also with the kind of the particle you are detected. The heavier the particle, the worse the resolution gets. So it may be 13 or 14 kV for alpha particles but if you use the surface barrier in order to detect oxygen this will go up to 40 or 45 kV. If you go to heavier elements these go worse and worse and worse. For gamma detectors the things are a little more complicated because now the resolution depends also on the energy of the gamma. So if you have higher gammas then you have worse resolution. Most of the time for gamma detectors as the resolution depends on the energy when you are talking about resolution you must also give the energy of the gamma. In most of the cases when you are talking about germanium detectors they will tell you that they have a resolution of for example 2.6 kV but they have also to tell you at what energy. Many times especially for scintillators instead of giving an absolute number you give the percentage but again you have to tell at which energy. So for example for sodium iodide detectors a typical resolution is something like 7% at 661 kV and here is just a figure to show you that the resolution changes as your energy goes higher. The second thing that we are interested about Can you tell me what is the reason for the first one that the energy gets worse when the particle gets energy resolution from the piece of the particle. It has mainly to do with the struggling the energy struggling. As here you have heavier particles they stay okay you need thinner detector but then the distribution gets really worse in the beginning. You mean with the optical detector There is also this plasma effect and deficit because when you introduce in silicon so huge amount of charges then the electric field drops locally and as it drops locally the combination probability increases and you lose some and this is why and it is also statistic. The second thing you have to know about your detector is detection efficiency. This means easily that I throw 1000 particles into my detector. How many of them are going to be detected? All of them, half of them, what does it mean? For particle detectors in most of the cases we assume a 100% efficiency. You throw 10 particles it will see 10 particles. You throw 100 particles it will see 100 particles. This is absolutely true for surface barrier detectors except if your detector has a problem. If you don't see 100% efficiency this means that you have a problem. Sorry? Yes but you don't take that into the efficiency because if the energy is too low it will never enter your detector. If it will never enter your detector it will be never detected. So it's outside let's say of the definition of efficiency. Efficiency means that I throw some particles they enter the detector do they interact with the detector and I can see them? Yes or no? If they stop for example in the dead layer of the detector Maybe they can stop inside the detector but generate a signal close to the noise or something like that. Ok but this is again it doesn't have to do with your detector it has to do let's say with the electronics. When we are talking here about efficiency of the particle detectors it means that it can enter your detector but you can see that but can you see all of them? Yes or no? In what we are talking it's entering the detector it gives you the signal but you can't see the signal if you can't see the signal either because you have much noise from your detector or you have much noise from your electronics you can't say that your detector is deficient I would call it inappropriate. Ok I would say that for example you have 5kV of protons they will be never detected but I wouldn't say that my detector is inefficient I would say that it's inappropriate for what you want to do. Ok For gamma detectors efficiency is slightly different because now the efficiency depends on the energy of the gamma and the bigger the energy the less the efficiency. In most applications when we are talking about efficiency for gamma detectors we incorporate into the calculation also the solid angle and this is easy to understand it's very difficult for a gamma detector to find its intrinsic efficiency because you should have the crystal surrounding your source this is not possible in most of the cases so you have your source here You mean like a form? Like a well you will see you have your source here you have your detector here so you measure the efficiency but this has it's not only the efficiency of the detector how good your detector can see the gammas how it can detect it it has also incorporated the solid angle that you are covering between your source and your detector. Most of the times when we are talking about gamma detectors we give a relative efficiency we don't talk about numbers like my efficiency at this energy 0.00 and this is because of the solid angle in most of the time you talk about relative efficiency with respect to a sodium iodide detector for example if you try if you go to buy a germanium detector you will ask for germanium detector of 50% efficiency this means that your detector has half the efficiency of a sodium iodine 3 inches time 3 inches placed at 12 cm ok so it's just a way of comparing detectors most of the detectors that you can buy germanium detectors have a relative efficiency of 40-50% if you go higher the price goes much much higher in our days we can have also germanium detectors with efficiencies higher than sodium iodide so you may find germanium detectors with 110% efficiency this means that they are 10% more efficient than sodium iodides but this is this costs very much so let's see now how the detectors are working 90% of the detectors that you are using in ion beam analysis it's based on semiconductors what is a semiconductor ok this is a conductor this means that I have a valence band and the conduction band and the one enters the other so this means that in the conduction band I have free electrons also in room temperature so here I have free electrons going back and forth this is a conductor the insulator means that here I have a band a gap between the conduction band and valence band this is almost 6 to 7 EVs and in room temperature or if you apply external voltage you don't have the migration of electrons from the valence band to the conduction band so you don't have any signal or any current in the conduction band while semiconductors are in between these two so you have again the valence band and the conduction band but the gap between them is not 0 but it's not also 6 EVs so for semiconductors we are talking mostly about silicon and germanium the gap here as you can see is for germanium 0.66 EVs for silicon 1.12 EVs this means that in room temperature or if you apply here an external voltage you have some free electrons jabbing from the valence band and the conduction band now if you want to use a detector to make a detector what you need you need something that when your ionization your radiation enters that it will produce a pair of electrons and holes it will ionize your your detector but you must find a way to collect these electrons or holes and distinguish them from free electrons you can't use a conductor because you always have free electrons so in free electrons you will produce also a small number of new electrons you will never be able to distinguish between them here you will produce nothing so you have to stick onto semiconductors so types of semiconductors as I told you we have intrinsic or purely you want semiconductors so you have this band gap for silicon is 1.1 EVs you have radiation the radiation goes into the valence band it finds an electron the electron is excited over here and you have the production of an electron over here and a hole over here in normal situation the number of electrons is equal to the number of holes if you have just a pure semiconductor you must find a way of increasing either the number of electrons or the number of holes and how you can do that you can do that by doping by substituting some silicon atoms with other atoms if you substitute a silicon atom with a phosphorus atom phosphorus have 5 electrons while silicon has 4 electrons you have an extra electron for the lattice of the silicon this is the first effect the second effect is that phosphorus have some intruder states as we call them some states that entering between the conduction band of the semiconductor and the valence band this means that it makes it easier for electrons to reach the conduction band because they have let's say a step as they can pass through this intermediate state for phosphorus the gap between the intruder state and the conduction band is about 0.04 eVs so the first thing you can do is to add donors add electrons so from an intrinsic you go to n type keep in mind negative type so we have surplus of protons or you can add acceptors or you can add holes how you add holes into a semiconductor you put something with less electrons than silicon so you put something that has 3 electrons for example boron so instead of putting phosphorus you put a boron here it has again an intruder state but this intruder state it's closer to the valence band and here you add up holes so instead of n type you have now a p type let's say semiconductor now how I'm going to use this trick in order to make a detector the easiest thing the first thing I could think to do is ok I have a semiconductor when radiation pass I produce electrons and holes if I just put two plates, two ohmic plates in the semiconductor I can collect the electrons or the holes I can integrate and I have a detector, perfect life is perfect the problem with just putting ohmic plates is that if you close the circuit over here you will start having electrons from the plate under the semiconductor and holes or positive carriers if you want from the other plate entering in order to keep the equilibrium of charges so if you have like that a system like that and if you apply let's say 500 volts to these two ohmic plates you will have a current, what we call a leakage current through the your detector of the order of 0.1 amps when radiation come and produces this pair of holes and electrons it will give you this is 10 to the 5 sorry, it's not 105 it's 10 to the 5 carriers this means that you will add up at 100 microns 1 micron you will never be able to distinguish a difference of 1 micron sitting on 100 microns, this means that if you are going to use that you will never succeed to use a semiconductor using ohmic plates as a detector you have to do if you want to use it as a semiconductor somehow you have to prevent electrons from the ohmic plates to enter your semiconductor or holes from the other side or if you want you have to build you have to do what we call non-injective or blocking or blocking electrons here you should put something to block the electrons or the holes under your semiconductor and mess with your signal ok how I can do that if you use the DOP surfaces this kind of thing and type in P-type detectors here you can block them and how I can use that with different ways and this is the different semiconductor detectors I have I have other diffused junction detectors surface barrier detectors that I mainly use PIN detectors and high purity detectors let's now see how we realize each thing before talking about that we are going to talk about PN junction what is a PN junction you have a P-type semiconductor and an N-type semiconductor and you bring them to contact one with another to be honest you can't do that you bring them in contact but let's say that you just press one over the other what it will happen the P-type has holes the N-type has electrons as you bring them into contact what is going to happen electrons will jump to the P-type will go over there and holes will go on the other side so you will have you start have diffusion of electrons through the P-type and holes to the N-type as an electron goes here and fills the hole here you will start having a surplus of negative charge also when an electron leaves here your semiconductor it will leave behind positive charge so by doing this diffusion of holes from here what you build you build here a zone where you have negative charge because of the electrons that jumped over here and positive charge here either because of the holes that migrated here or from the holes that the electrons left as they jumped over here in this case you will continue having this migration of holes and electrons until when they will stop somehow stop or it will continue doing that they will stop eventually why because as you have here negative and positive you start building there an electric force you have building you start building a potential and when the potential is big enough that will will embed electrons from jamming to this area or proton or holes jamming to this area this procedure will stop so I put the two they start jamming jamming my electric field starts building building building building and I'll arrive in one position that will prevent electrons from going there and then the procedure stops is what we say that we are reach an equilibrium this region over here the depletion layer of my semiconductor and this is the area that I'm going to use in order to detect my radiation keep in mind that here I still have holes and here outside the depletion layer I still have surplus of electrons now I have this nice semiconductor this nice junction and I'm going to put some voltage between them so this is unbiased this is the normal let's say situation now what it happens if I put a forward bias so if I push if I put voltage and push more electrons over here this means that my potential here is going to lower instead of being like that it will lower and this means that more electrons will jump here more holes will jump here and this means that I will have a bigger movement until I reach again equilibrium if you put an inverse biasing this means that you attract electrons over here and holes over here you are going to make your depletion layer bigger and bigger and this is what we normally use we bias inverse biasing our semiconductors in order to make the depletion layer bigger bigger depletion layer means thicker detector means more able to stop gammas or alphas so how I make this junction to semiconductors there are various ways of doing that but the first one they are not used so much in our days is what we call diffusion junction so when you begin with a p-type semiconductor and then either by implantation or using vapors of n-type donors you start implanting n-type things n-type donors into your p-type semiconductor if you do that you can reach a depletion layer of 15nm if you are using implantation up to 2 micrometers if you are using diffusion if you do this procedure you will end up with this thing over here so now you have your semiconductor here the p-type here you have an n-plus and here you have a p-plus semiconductor n-plus and p-plus the plus sign means that it is very doped so n-plus it means that I have a surplus a big surplus of electrons and here I have a surplus of holes the good thing with this detector is that if you apply now your inverse biasing these two p-plus and n-plus layers are acting as blocking electrons but they don't permit to have a big leakage current between that they drop your leakage current down to less than one microamp and then you can really see the holes, the pairs of holes and electrons that your radiation is producing nowadays most of the time we are using surface barrier detectors what you are going to end up is the same thing but it's the different thing how you produce them you begin with an n-type semiconductor and here you build a very thin electrode of gold while on the other side you build a very thin layer of aluminum now if you have a conductor or an n-type here in the junction between them you again produce something like the p-enjunction is another effect it's called the Sotki junction but let's say that it's much alike the p-enjunction so with this procedure you also end up here now what is the difference between the two and why we prefer using surface barrier detectors instead of diffusion junction detectors the problem is the thickness of the entrance window here you have this n-plus with the diffusion this is big enough this means as you ask me that if you have let's say an alpha particle of low energy this is thick enough it may stop the alpha particle into the electron never it's my semiconductor never to be seen if you are using a surface barrier using metallization you can make very thin layers of gold so you have again a dead layer but this dead layer is much much thinner than this one over here this means that surface barrier is able to detect heavier elements or if you want light elements of lower energy they can pass through the window the bad thing with surface barrier detectors almost the bad thing they are sensitive to light they can see light if you have a surface barrier detector into the air you will see your oscilloscope the 50 Hz light if you have a 50 Hz light and this is because of the thin entrance window on the other hand you don't much care because if you are going to use surface barrier detector you can put it under vacuum when you put it under vacuum you put it in chamber but it's closed with no light so you really don't care should it be here ok let's say it should be here these are some positions as detectors normally you will never use that in ion beam analysis techniques these are constructed let's say in the same way as these ones but now you have for example in these double phase strips dopped p-type or dopped n-type so you have let's say different detectors in the same paths in the same detector this means that if radiation pass over here you have the energy of the particle but you can also find the position of the particle do I care about that 95% of the cases no in similar ion beam analysis techniques no I don't care I just care about the energy as we saw in the RBS but if you are using some devices like what we saw before the high resolution RBS there you just don't need just the energy of the particle you need also the position so there you have to use some of these positions where my particle has hit the detector PIN detectors so here you have a p-type detector sorry semiconductor typically dopped with boron and here you have some lithium that is diffused in your semiconductor as lithium enters the semiconductor and it diffuses it's let's say anilates boron and it makes what we call a compensation region this is a region with no free carriers it's like the depletion layer of the previous detectors so when radiation passes over here it will again ionize give you holes and electrons you gather holes and electrons and again you have your signal you can see your radiation typical detectors was the jelly and silicon so you had a p-type germanium semiconductor diffused with lithium the problem the good thing with this detector was that the depletion layers could go up to millimeters so you could really make big thick detectors which were ideal for gamma ray detection for x-ray detection we use germanium for gamma rays because of its high Z why we use silicon silicon detectors for x-ray detection because of the lower Z what was the problem with them as you can see here they had as we said in the beginning lower efficiency than scintillators but better resolution what was the problem with these detectors the problem is lithium as lithium diffuses here and finds goes up to an equilibrium it's okay but lithium must stick there mustn't move and lithium likes to move has a great mobility so in order to make lithium stick into there you need to keep it in low temperature so you have to cool them with liquid nitrogen the problem is that you have to cool them down even if you don't use them so when you have a jelly or a silly detector they must be always always cooled with liquid nitrogen if you forget to put some nitrogen and leave them warm up what will be done lithium will drift further into the into the semiconductor or go to the surface you will destroy the commensation region and if you destroy the commensation region you don't have a detector that's why these are going slowly out of the market these were replaced with high purity germanium detectors just a comment jelly has to be cooled all the time it doesn't but again I have seen problems with silly not the cool I do the same thing I have two or three dead jelly detectors I have some silly detectors that are still working but I have seen deterioration in their resolution I thought that it was a problem of lithium drifting in germanium for example to gamma radiation after some but the problems with cool detectors come much earlier but even in any case detecting x-rays or detecting gamma rays that is intrinsically damaging yes but let's say that the life of a detector of a gamma detector if you are using normally in a normal use it's 15 or 20 years it's not something that will happen in five I don't know three or five years the biggest problem with germanium detectors is neutrons you have much problems much bigger problems if they are in an environment of neutrons not because they are detecting gamma rays surface barrier detectors are much sensitive if you want into radiation their life expectation is much less because of the damage let's say the radiation damage done by the particles that you are detecting I have killed surface barrier detectors because I put them too close to the beam so they saw 100nm of protons for five seconds not more than that and from a spin conductor it began a real conductor but there I had something like 10 to 15 protons in two seconds or three seconds if you are not planning to do that they can live for six to seven years easily germanium detectors much much more I have germanium detectors since the 80s and they are still working nicely with no problems so the solution for these two was what we call the high purity germanium detectors when you have a semiconductor by itself have some impurities so you can't use it like that but if you find a way of purifying the crystal then you can produce a same region like the one you produced with lithium but you have to do it very carefully so germanium is a crystal is a material that is used very often and they have found ways of purifying it with multiple purification process so what they do is that they take the crystal they heat it up they use some melting material on top of that to take out the impurities they cool it they heat it up again they make it liquid they purify it again and again and they can now reach something down to 10 to 9 impurities per centimeter square this work like the jelly the good thing with them is that as you don't have now lithium you don't care about drifting so you don't care to have liquid nitrogen when you don't use them when you use it of course you always use liquid nitrogen because of the small gap you have in a semiconductor you may have noise because of the thermal movement of electrons so you have to stop them you have somehow to depress the kinetic energy but you use liquid nitrogen in order to stop the thermal movement and the noise now with high purity germanic detectors also for jelly detectors you can have multiple geometries depending on what you are going to do this is a well formation so here you have the n type and this is your crystal you don't use that for ion beam analysis but at the time you use that if you want to do some environmental samples because your sample enters this hole over here and you have almost a 4 pi geometry in most of the cases when you are doing pige you are using either planar with p and 10 over here as we show there or coaxial so here you have again a detector the peak contact is in the middle and it's in contact this is better as you see the crystal is big so you have better efficiency instead of a planar but you can use both of them for pige analysis before the semiconductors everything started with scintillators what are scintillators? scintillators first of all can be organic and inorganic in most of the cases we are not using any organic scintillators for example there are organic scintillators liquid organic scintillators these are using nuclear physics not in ion beam analysis mostly for detection of neutrons you can use organic scintillators for neutrons because they have inside hydrogen but in our cases in ion beam analysis most of the time you are using inorganic the most known of that it's sodium iodide but also there are new crystals new scintillators like lanthanum bromide or chromium bromide lanthanum bromide has almost the same efficiency as sodium iodide but it has a better resolution how scintillators work? scintillators work in the principle that when you have an ionization an ionization radiation again you take an electron from the valence band you throw it up to the conduction band and here you have electrons and you leave back holes as the electron will de-excite most of the cases it will give you photons if you have just a crystal like sodium iodide the problem is that the photon that you will produce here is not in the visible range ok it is it is photon but it's not light it's not visible light in order to solve this problem sometimes you use what we call activators for sodium iodide in most of the cases you use thallium so thallium has this property that introducing some levels like the donors or the acceptors in the semiconductors between the conduction band and the valence band of the scintillator now how this help me into detecting radiation again you have radiation you produce a hole and an electron the whole propagation to the crystal it may find an activator it will find an activator it will excite the activator so it will excite the activator here you will miss an electron from the activator the electron that you produced from the radiation will find this hole and will go inside to fill it up and then it will de-excite into the activator levels but now as you can see here the distance between the levels is much less than the distance between the conduction band and the valence band of the crystal and this will give you light but this time this will give you visible light it will give you light if you see the light things are easier because you take the light you use a photomultiplier so you couple your scintillator with a photomultiplier which will see the light it will produce electrons then the electrons will be multiplied through the dinotes and will give me the signal in the anode the problem with the scintillators is while they are highly efficient much more efficient than the normal high purity germanium they don't need external cooling that's cool if you don't have to pay for liquid nitrogen the problem is first of all that most of them are hydroscopic this means that if they take some moisture they start being destroyed that's why they are always closed in aluminum cases the bad thing is that they have a very bad resolution and this is taken from Ortec just to see that here this is the spectrum that I see when I have a high purity germanium detector you can see the resolution I have in every peak if you use a sodium iodide then you look at the red line much worse here you can see that this line became like that forget all these lines you will never see that forget all these lines this line became like that if you use a cadmium cadmium efficiency cadmium zinc tellulite detector you have very poor efficiency and if you use a plastic scintillator you will see that has higher efficiency but no resolution you can't see anything so in most of the cases when you are talking about PGE you are obliged to use either a germanium detector or if you can't afford the germanium detector you can use a sodium iodide detector but have in mind that the resolution of the sodium iodide will be much worse you can do some job over here but I have seen papers from various groups but it's not let's say used for every case sorry and let's go let's finish with some very specific detectors gas detectors hide the work it's very easily most of the time gas detectors as I told you the beginning are used in TOFERDA instead of a surface buried detector at the end as an energy detector so you have here a cylinder you have inside a gas your radiation produces again protons and ions you have a voltage difference between them you collect to the end of the electrons you measure the electrons and that's all how many protons and holes and sorry ions you are going to create depends first of all to the gas that you are going to use so by changing the gas over here you have different number of pairs of ions and electrons the second thing you are interested of is the proportionality of this thing what does it mean proportionality is the number of pairs that I'm producing here proportional to the energy of the radiation yes or no if you look at this sorry, diagram over here this is the different regions of operation of a gas detector depending on the voltage that you are going to apply here as you can see you are proportional in the number of ions and the energy that you are going to produce and this is the region that we are using for ion chamber regions here the proportionality is lost is what you are using for proportional counting detectors and here over here you already are saturated so here you have no proportionality and here the only thing that you care is if something arrived or not and this is why this region is used for Geiger Geiger Miller detectors here the only information you have if something arrived something didn't arrive nothing else so we care about this region over here and this is how a gas ion chamber looks like so here you have your gas you have a nano and a cathode your radiation pass produces ions and electrons the electrons are drifted towards the anode ions are drifted towards the cathode now the signal that you are going to measure depends on the position of the radiation where your radiation passed it passed over here because it depends on X as you understand this is a problem because if I have a particle an alpha particle let's say of 3 MeV going here and an alpha particle of 3 MeV again but if they give me a different signal how I'm going to distinguish the two how can I know where it entered for this reason just keep in mind that here the signal you have it's not only produced by the collection of electrons but also it's produced by the use current on the anode by the electrons and by the movement of the ions so the solution is to use this freeze grid this freeze grid is kept in a voltage between the anode and the cathode and what it does it shields the anode from the movement on electrons and ions so your anode doesn't see anything as the electrons move and the ions move until the ions, sorry until the electrons pass through the grid when they pass the grid then they are visible from the anode and then the anode starts measuring and this is good because like that you don't care where they are produced if they are produced here and they move nothing happens when they pass the freeze grid then you start measuring and it's the same if they are produced here or here or here this is the reason we are using a freeze grid when you are using a freeze grid then you must be very precise when you construct that because you want to have a big shielding from the electrons on the other hand you want it to be transparent to the electrons and the last detectors that we are going to talk it's again used in TOFERDA is timing detectors so the trick here is the following you have here the ions entering your chamber or whatever you have over here and here you have a carbon foil as the ions pass through the carbon foil they will start emitting electrons ok they ionize if you want the carbon foil they extract electrons between the carbon foil and what we call here an electrostatic mirror you have a voltage difference so electrons are accelerated towards the grid this mirror bends the electrons towards a multichannel plate over here and electrons are detected this is not good detector if you want to use it for energy measurements because it doesn't give you any information about the energy of the ion that pass the carbon foil on the other hand it's very quick and you can use it as a timing signal it can tell you just something passed in TOFERDA measurement this is what I need I need something very quick to tell me something passed this is a start or a stop signal and then I have at the end either a gas ionization chamber or TOFERDA or a surface barrier detector that they measure the energy of the ion so that was all do I left you time?


And welcome to OEG Live, I'm Alan Levine, and I'm running the show today, but I'm really not in charge of anything, but I'm really excited to bring you this project that I've been following from Dan McGuire and Catherine Kure are here with us to tell us all about this amazing effort that's going on with bringing, putting OER to use for elementary learning in Africa. And so I'm not gonna try to explain it, but we're just gonna have a casual conversation here. And this of course will be recorded. And first of all, you know, sadly disappointed that we can't make this work at the conference next week for OEG Level, but this is sort of a way to open things up. And so hello and welcome, I'll start, I'm gonna start with Catherine. Dan comes first, but Catherine it's great to have you here tuning in from South Africa and in a very interesting location, right? Yes, I'm in, I'm in a guest house in the Kroot, Mariko. So we're in the Northwest province. So I'm having to borrow ethernet. It's 36 degrees today. So yeah, it's a fairly 36 degrees Celsius. What's that in Fahrenheit, Dan? Hot. Upper 90s probably. That's what I'm sort of, yeah. So, but thank you. It's wonderful to be here. And I guess it's this kind of remote area with, we have issues with electricity as well as with Wi-Fi connectivity. And those are exactly the kinds of problems that the Moodlebox has been designed to solve in terms of the challenges of being in poor areas with a lack of resources. And I was incredibly blessed that Dan called me and said, hey, I've got this project already going in Angana. Would you like to join us in South Africa and bring South Africa on board? So it was just really very exciting. Thank you. Thank you. I'm really keen to learn about Moodlebox. I followed a little bit from Dan, but can you tell us about the STEAM Foundation that is your organization? SEED funded by Siemens Stiftung, which is the German based nonprofit. We've always had a very strong focus on science, education and under resourced schools. And what we find is that the context between the global South and the global North is so very, very different. That solutions for the global North are just not applicable in the global South. So we've been really, we love the concept. We loved how they looked at hands-on experimentation, but we've been really trying to ensure that we solve it in terms of enabling very strong lesson plans for teachers where we consider our teacher to be our first learner. And then obviously during the pandemic, we pivoted to online. And then we've been looking at various alimeses and more sort of blended learning approaches. But one of our key problems is that it just breaks down when you are now dealing with a remote area with intermittent electricity with little to no cellular signal. You might be in areas where there's literally no mobile signal. So how do you do that? And then obviously that's where the Moodlebox and its promise comes into play. That you can run it off a power bank. Obviously somewhere along the line, you need data and connectivity, but it can be that the teacher uses the cell phone, downloads, puts it onto the Moodlebox. And then the Moodlebox basically, which is a credit card size, you know, Raspberry Pi, it's basically a portable server. And then it starts, it's its own little Wi-Fi. There we go, Dan's got one. And in South Africa, we've also, as you can see, we're 36 degrees and we're not one of the hottest places in Africa. So the case that we bought has a little fan as well. So that we can sort of work with it. But we've been looking at all the different challenges around that and this really is very, very exciting in terms of its promise because obviously not every school is like that. But if we cannot solve for the poorest and least resource schools, then you cannot actually scale to the whole country. And those are the schools with the greatest need for equipment, often the logistics of getting there. We've got a lot of mountainous terrain. We've got river crossings. I mean, when we delivered books or in other projects, you've had to get four by fours with river crossing capabilities and mountain, whereas something like this is really solves a lot of those challenges and we now having to get it to work within the country. This is so exciting. And so we're going to see more hopefully and learn more about this. And Dan, thank you for showing the box. I've been eager to see one. But hello and welcome, your OE artist. I love that title, but tell us a little bit about yourself. Yes, the title I will credit to my wife, Casey. She was, we were on a walk one day and she says, you know, how do I tell people what you do? Nobody understands that. I started, so it's all about her. She said, well, are you then kind of like an OE artist? I said, well, yeah, I kind of like that. Let's go with that. So I really do like that. Anyway, so I've been doing professional development for teachers relative to the use of a digital tool, specifically open source learning management systems, and then added in OER in about 2011. I've been doing that all through the pandemic, but what was really interesting was a little over a year ago when I started exploring the Moodle box, this device that I just held up, which is a version of Moodle, which is the learning management system, which is most widely used all across the globe. The Open University in UK uses it. Most of the universities in South Africa use it. It's used by universities all over the world. And as Catherine so nicely put it, we do have to those solve for those who have the least resources. And so that's what the Moodle box does. So I was looking at that and trying to figure out how it works and how we can apply it. And I happened on LinkedIn to meet up with Peter. I'm a lobby who lives in Tamali Ghana. And he has started a several years ago, a nonprofit to acquire resources for his school and the neighboring schools and his northern suburb part of Tamali. And we connected and I chat, I said, would you be interested in looking at maybe using this technology device? And he said, yes, let's try it. And it's just been delightful working with him. He's an incredible, talented, innovative teacher that is just so dedicated. And he has helped me learn how to apply this in classrooms. So we've built this over the year and we've got, we, as Catherine pointed out, tried various devices. But one of the issues we struggled with was what was the best device to use with students to access the Moodle box in the classroom. And we ended up, after experimenting with cell phones and various other and laptops, settling on a 10-inch tablet, which we were able to acquire in Tamali. And then, so we developed that device and then I started showing Peter how to add content onto the Moodle box so the students could access it. And we then found African Storybook, which is a phenomenal organization that was founded by Sadie, the South African Institute for Distance Education, several years ago. And it's probably one of the largest OER repositories that lots of people at OE Global don't know about, primarily because it's all early literacy, primary books, picture books. But we're able to download those, put them on the Moodle box and the students loved seeing them, they're bright in color. And then Peter found that on African Storybook, they actually have books in Dagbani. I'd never heard of the Kingdom of Dagbani, which has been in existence for many centuries. And it's the area around Tamali and all of the people in that area speak Dagbani. Well, that's their first language. And he was able to find books on African Storybook in Dagbani, which he was able to put onto the Moodle box. So now the students are looking at their mother tongue in books on their devices, which is phenomenal for them. And these are students who had never had a device in their hands, who their families don't own electronic devices. There is not internet available in the area. So now these fifth graders can look at their mother tongue on their own devices. This is like a wow, this is big. Not only that, but we can, the books that are on African Storybook in English, and translate them into Dagbani. So that's just a matter of finding, I tried it in, I tried doing it with ChatGPT and ChatGPT doesn't get Dagbani. So, we're relying on the translating. And then we go on to add assessments, because that's one of the things about the learning management systems, is that you can also add assessments. Because as a teacher, we know that just presenting the book to the student, is this only the first step? Has the student actually read the book? Do they understand it? What are their misunderstandings as they're reading the book? This is true at every level of education. We have to find out what the system is about. So we use the assessment tools in the learning management system to do that. Because it's open source and because the content is all OER, we can translate it into Dagbani. This teacher can modify it for the specific needs of their students. We don't have to rely on the legacy publishers to provide us with the assessment. The teacher can do that. And I'll show you an example of that at some point here too, how we can actually do that. But I'll pause and let you ask a question. I just think it's worth explaining this situation that exists in Ghana and South Africa as I understand it, of mandating education in local languages, which is commendable, but leaving teachers to figure it out on their own. And so what do teachers typically do when they're forced to do this and what are they able to do now? Catherine, do you wanna speak to that a bit? I can't, sure. I can't really speak so much for the Ghanaian situation, but in South Africa, we have 11 different official languages. And only quite recently have we really realized the impact of not starting in your mother tongue. And the importance of that. So the reality is they are publishing books out there, but again, you've got issues of logistics, distribution, access in terms of accessibility, in terms of price point and so on. And that is where something like being able to take a digital book, because with one Moodle box, you can have 100 books, 200 books, you know. There are organizations like Book Dash as well, which is translating into mother tongues and story weaver, but again, if you're wanting, they come with straight story books, they're not going to be using a learning management system and so on. So yes, there is a big deficit. And I think in the presentation, Dan, it was something like 43% of households in South Africa don't even have a single book.  And we see it now, you know, impacting on the literacy and the literacy levels that we are not performing as well as we should in terms of Pearl's terms, all of the international standardized tests. And there is now a big drive, especially in the early years. And up until recently, your kindergarten year was your gracious, your early education centers were actually handled by the Department of Social Development. We had lots of small centers with not necessarily a woman who were particularly well, predominantly women obviously. And now that's recently been incorporated within the Department of Basic Education. So kindergarten was never a formal year of schooling. It was often being run by a lot of independent people in groups. And there's again, this just highlights how critical those early literacy books are. I don't know, it's a similar situation with the 11 languages in Ghana as well. Dan? Same, interesting that there's the same number. Both Ghana and South Africa have 11 English languages. And English is one of them in both countries, you know. So, and as Peter has pointed out, I said, well, I mean, doesn't the Department of Education send you books? And he said, well, yeah, sometimes. And that's 10 books, and rarely in Daibani. Because as a practical matter, how is a country, the Department of Education in a country that's struggling to meet its basic needs in some cases, how are they going to afford to print large quantities of books in 11 different languages? I mean, that's almost going to be hard to do if they had the money. As Catherine pointed out, then delivering of them becomes an issue. So digital LMS is really, really address a huge problem. And that's true of all over Africa. And it's also true in South Asia and lots of places in the world where, the literacy people are figuring out that it's better to teach kids, as Catherine pointed out, in their mother tongue first, how to read. And then introduce the dominant official language of the government. Then we have multilingual kids, which is what we want. But trying to force them to learn a new language as they're learning this concept of, well, you know, CAT means cat. Well, what's a cat if that's not in your language? It's sort of obvious when you think about it, we've been getting it the wrong way for many years. Exactly. Well, let's give us a little, oh, go ahead, Catherine. No, I think one of the other things I'm wanting to heart out is that English is about as non-transparent to languages you get. Most of your African languages or of the parts, what you read is what you say. You don't have said spelled, said should be S-E-D, not S-A-R-D, you know. So you've got the complexity of English being the dominant language or the lingua franca as it were of the world, but now it's an extraordinarily difficult language even for a first language English speaker to learn to read and write because it's just grabbed every noun from every other country in the world and not, so it's a very non-transparent language. And that just adds to the complexity. So now you're having to learn a different language from your mother tongue and it's non-transparent. So your capacity to learn quite quickly is obviously impacted. And what's been really exciting, I was recently at a NASCII conference, the National Association for Social Change Entities and Education, and the University of Selibosh, their ReCEP group, R-E-S-E-P, have actually created a template for working out at the end of, let's say, kindergarten or grade one. If you, Issy Cosa or Issy Zulu, how many words should you have mastered? And they actually went all the way back to scratch and they've created a very exciting methodology for understanding because, you know, the funders who are coming in are saying, well, okay, so in mother tongue, what should we be expecting? What are the benchmarks? How do we assess the child? How many words should they have mastered and so on? One of the women involved in the research gave us a very exciting presentation, which like really, and what was interesting was that again, it's a global self-solution. It's got nothing, you know, they said these methodologies will not work in this country and they went all the way back down to scratch and they've created a whole new template. So that's exciting. Yes. All right, so let's, if you don't mind, Dan, let's get a sense about how this all works. You're gonna do a little bit of screen sharing demo, right? Sure, happy to, I'd love to, I guess. So this is obviously the Lion Runs and Cow Walks. It's a first year reading book that is popular all over the world. This one is actually written in Cambodia, I think, by the South Asia and it's been translated into lots of different languages. I'll just run through it real quick here. So the Lion Runs, Cow Walks, that goes in water. All right, so obviously this is very concrete animals things, water, air, wood, the things that we wanna teach students in the beginning. Now, we took this book and we worked with the chat GPT and I asked in Cambodia for some help in fixing it and this is what it looks like when you translate it into Isihosa. We just had to reformat it a little bit, but again, it shows up pretty much the same. I'm not gonna try to pronounce those words, but anyway. All right, so, but now we have, that's actually how easy it is, really. Again, we just need to have a few. Thankfully, we have an envoy here to translate this and make it right. And we're working with limited languages, but it's a pattern and it's a model that I think we can expand on and use in other places. We've done the same thing with that Bonnie in Ghana. I don't actually have one of those to pull up for you. But now let me jump to the other capabilities of the Moodlebox that I'd like to show you. So, okay, so now, first question is, this says name the insect. So this is actually, we're using the stem concepts. This is science, we're naming insects and when we're talking about the R level it says which is what the envoy calls her kindergarten for a seven year, which is a term I actually like. So this says name the insect. So the Moodlebox, and this is a feature that's available both in Moodle and on Moodlebox. There's the capability of, let's see, if I play this, did that, could you hear that audio? No, I think we didn't get the shared audio, but we can imagine, yeah. But that was my voice trying to say this word, umakula. The point is that the student is able to, so the question is name the insect and so they get an audio prompt. So now what we're asking them to do is say, which one of these words did I just say? And they choose this one and they get this prompt. So, and if I click that, it's actually, that's gonna say, we're very proud of you, good choice. And so they get an audio prompt for confirming that they got the answer right. Now, what's, I think very important here is because this is OER, the content on here, I created this in my voice, but we want the teachers to create it in their voice because obviously the kids in the Western Cape are going to respond better, I think, to their teacher's voice than, you know, an old grandfather from Minnesota. Grandfather type, I don't actually have grandkids yet, but you know, I think that'll work. But the point is the teacher gets to choose. The teacher could hire an actor to do it if they want, if the department will pay for it, of course. But the key is that they get voice prompts, they get voice confirmation on their choice, they get, and then we can do some video prompts too. Here's the same thing, you know, how many, I don't know if you can say that, Catherine, that's the, it's a closer word for butterfly. This probably makes as much sense as butterfly does for a name of this animal. But here again. That's small for me to see. Oh, sorry. But yeah, it's something like, you know. And here's where I try to pronounce that. And again, so this is what happens if a student answers wrong. Oh, and the question is how many of them are there? So the answer is there's one, two, so the student answers three, no, that's three. And the correct answer, we can give them a prompt if I played this, this would be, that's a video response of me saying, you'll have to try a different one. So the R-level students get audio prompts, video prompts, all of these things then can be recreated by their teacher in the classroom using the teacher's own face and voice to do that. That's, this is one of the really powerful tools of being able to use the Moodle box. Cause these are all tools that are built into the Moodle box. There's no additional, nothing needs to be added. So everything that you can do in Moodle in terms of this interaction is run off of the Moodle box locally. Yeah. So it's incredibly powerful. The one thing the Moodle box tends not to allow the plugins because obviously it's quite small. So they do prefer no plugins. So you are finding that Moodle itself is starting to look at, we had a Moodle moot in South Africa recently, which was very exciting, which I attended. And the founder was saying that they are looking at their most popular plugins and trying to incorporate them into core Moodle. Because if it's that popular and that used, then it really should be part of the platform. So there is that distinction that, you know, you might, that there are some functionalities around plugins that you've got to be aware of, but hopefully the most important ones will be incorporated in future. And also is it doing the full like, you know, keeping track of what individual students are doing in terms of, okay. Absolutely. That's one of the other things we've done in Ghana is pull up student achievement reports. Say we've created some math quizzes there too. So Peter can actually show, he can actually pull up and create a Excel spreadsheet of how well each of his individual students are doing on the math quizzes that he's been giving them. And that's, I'm going to bet that the people in Acre that are visiting his classroom probably haven't seen that in Accra. I think he's leading, you know, doing some cutting in stuff. Right. And then I know a big piece of the project is the professional development for teachers. So they can, so if I'm a teacher in a remote area with my Moodle box, I can do some of these changes that you're describing in terms of, yeah, okay. And that's the point of the professional development. Yeah. Is that we show them how to create a quiz, how to make the modifications, how to add content, how to add quizzes. It's, you know, it's not rocket science. But again, we're talking about elementary teachers who have anywhere from 20 to, in some cases, 40 students in their room. And they're, of course, like everywhere in the world overworked and underpaid. So whatever support we can give them to be able to do this. And as Catherine was saying, in some places in South Africa, it's true all over, but the amount of work we're requiring of our teachers for these to introduce the future students of the world to literacy, we're kind of doing it wrong, I think. We need to provide more support. The more support we can provide, the better off everybody. Yeah. And I don't know. I mean, this is probably like, I don't know if it's even possible, but like, let's say I've done some of these customizations as a teacher, wouldn't they be of interest to other? Is there some way of like, you know, organizing all of this content into, I see all the head nodding. So I'll stop and you'll answer. Well, I guess that's part of that, the MoodleNet project to enable sort of a repository of not only open education resources, but also put into an LMS that are then available for anyone worldwide to use, you know, and adapt, obviously, as need be. I mean, that's the whole point of open education, isn't it? There's a little net. Yeah. I'm confused people. We have Moodle, which is the running management system. MoodleBox is the version of Moodle designed for a small server, remote server. MoodleNet is the repository that Moodle and Martin Dougiamas has created to store OER content. If you pull up MoodleBox to show people, it's still in it, they're still building it out, but it's possible to add things to it right now. And you can sort for things and search things. And one of the nice things about MoodleNet is that if you're using Moodle, you can add it to your course with a click, click, click boom in your course. That's it. That's all you have to do. I think it's three clicks. Now, if you're in the US or Canada and using something other than Moodle, you can still download the content and upload it to your LMS, presuming that the proprietary LMS people have given you the ability to do that. It's still possible to do. You just need to have the permissions to do it. Right. And just because people might ask, like, are there creative comments licenses on this content or other kind of things which make this sharing apparent? Okay. Of course. Yeah. And then they weren't necessarily on these test course that we put up here, but yeah, everything is CC licensed. Fantastic. And so, obviously. And with you. Go ahead. I was gonna say with the appropriate license that is OER because not all CC licenses are. If it's ND, it's no derivatives, which means you can't even translate. So, yes, it has to be the correct one. In fact, at the moment, I've still got, I'm waiting for some, a previous work that I did where I'm asking them to re-license it as OER and they initially wanted to last. Anyway, so there's a lot of, we're trying to get content that's been, that is either copyright or is under a Creative Commons license, but which isn't OER to be re-released under a license that enables us to use it in this environment. So, hopefully I'm gonna get some good news on that soon. So, because that is the big issue is that there are a lot of non-profits or education departments out there for whom copyright is just an automatic unthinking application. It's not really. It's like, okay, that's what you do with your material. So, there's a lot of conversations I'm having around in South Africa, including with the Tax Authority to try and get that, that those repositories released under as open education resources so that we all can benefit, not just the few schools or even if it's a lot of schools who've benefited. But yes, it is a requirement with the project that we can only work with such materials. I mean, it's illegal otherwise, really. You know, that's the last thing any funder wants is that risk. Ah, no, you know, no. But that brings up one of the other issues is just the promotion of this whole concept. OER is still a secret for too many people in the world. Especially when we're talking about K-12. Now, OER has tended to operate only in higher ed so far, for the most part. Yes. I think it's a fair thing to say and it's, but that's, we're actually, that's only at the most 20% of the population of students. And maybe, you know, Catherine's got some numbers where it's even less than that. But you said at one point, it's one out of 13. One thirteenth. Yeah, so. Yeah, we'll do the math. Yeah, but so what? Yeah, I'll quickly do that. So far, we haven't, we haven't even really gotten to the students in the world. We're just dealing with the tip of the iceberg or the low hanging fruit, whatever metaphor you want. We need to get to the large group. So if we want to actually promote OER, let's actually start where the students start. We start them out in kindergarten it'll be a no brainer by the time they get to higher ed, what they're, you know, they'll have to use OER. And I think, you know, what you've done is replicable in other places that need this. So are you already working or thinking of other parts of the world that you might put this into play? Yeah, we're actually having conversations. I got off the phone an hour ago with a person in Kenya, where we're starting there. And via this Siemens Stifton Foundation, which Catherine mentioned it as started Steam Foundation, we've been introduced to their South African, I'm sorry, South American CREA department. So Stifton has a different organization that operates in the Spanish speaking world of South America. You know, again, it's a slow process to get everybody changing.  So getting them to do it differently takes, so all the promotion you can help us with, Alan will appreciate. I'm trying, but like, what kind of things would you need or what should people do if they're interested in this? I think, begin talking about it for one thing. The other thing is at the higher ed level where lots of people who are going to hear this presentation first are going to say, well, okay, so what should we do? Let's go over to the education department. We train teachers and ask them if they know about OER and ask the people in the education departments if they're showing teachers how to use OER. That would be the first thing. What I found is that the answer is going to be for the most part, not really. Maybe not. Yeah, hard to say, like, you know, yeah. I'll say, not really, I'm pretty sure the answer is going to be that in most education departments. And I did an analysis of research that was done by JET Education Services during the pandemic of what was available. For South African students, and it was a vanishing lyre, a tiny, tiny set. Yes, you've got African Storybook, you've got Sea of Woola, you've got Thunderbolts Kids, but that's pretty much it, you run out. So you've got a lot of stuff there that's simply not available. So there's, and again, you know, STEAM has a traditional focus on science. So there is some material out there, but there's a huge amount of material that isn't out there. And so part of it is just to try and get people, I think people, and I'm working on OER policy with universities as well. And what I find is that people see it as giving and they don't realize that they can also take, that there's a reciprocity. You're not merely giving what you create, but you also are able to jumpstart. You're able to get into a place where, you know, I was working on policy and I was saying, hey, I've got all these policies from the Commonwealth of Learning. We can jumpstart this whole process. We're not starting from, okay, clause one, we've got 10 policies here that are open education resources that we can work with.  Believe you me, if you're trying to put something out and you know that it can be, you're gonna be a lot more worried about what it looks like than if you're simply running it in a school or so. So I think part of it is just to shift that and to shift the fear because, you know, it's relatively easy to put something up on an LMS if you've got the content, but if you don't have the content, you first have to develop the content and then you put it onto the LMS, you know. So I think that that is one thing. The other challenge that I have been working with very much because of my history in development is we actually are now working with a cellular manufacturer or they assemble, they South African based, they're throughout Africa, but they are looking at creating for us as large and robust devices possible, but one without any cellular capability because I know from working with the Siemens Stiftung funded organizations in South America that the provision of devices is a real problem in terms of theft. So we've got a whole lot of other challenges we are looking at in terms of trying to make sure that the devices are not known to be, that you know that you can't turn it into a cell phone for instance. And then the other thing we have looked at as well is if you do provide the devices, you know, make sure you provide the power banks and so on, but that we are looking at switching profiles. So you don't necessarily need a device, a child, but a device a grade and the students can switch profiles. So there are quite a lot of those kinds of things that I think we think of within our context and I know that the South American context is very similar in terms of poverty and the associated theft, which again, if you're living in West Germany, you don't think about because it's a small amount, but I mean the devices, I mean, we're looking at the devices are coming around about 10% of the volume because again, that is the solution that Africa needs.  You need to solve the problem first, you know. And I think for me, it would be getting people to be a lot more consistent about licensing education materials in K-12 as OER and not just automatically copywriting them because then you've got a lot of resources you can utilize. And I'll just add into that what Catherine's saying as far as changing the mindsets. And we're already spending, when I say we, I mean globally education, we're already spending the money. It's not a matter of sustainability. It's a matter of changing the flow of the money. We're already spending lots of money, more money than we need to actually where the money should be diverted to creating the OER books and the teacher professional development. That's one thing. So it's just a shift in that some people think, well, it will cost them. No, it's not a cost. It's a shift of the focus of the money. The other big thing of thinking that needs to change I think is in K-12, we need an LMS or an LMS like that. We would also like it to be open source. That's why we promote Moodle because it is an LMS and it's open source. And again, from a higher ed perspective, it's like, well, why do we need an LMS? Well, because when we're talking about K-12, we need to assess very frequently.  We give them feedback. We see if they got it right. As an elementary teacher, you're assessing all day long. And that's very different from a higher ed where traditionally a lecturer lectures all day long and then they assess two or three times a year to get to the semester. Well, when you're an elementary teacher, you're assessing as they come in the door and as they're leaving. So that's why the LMS helps with that part of the instructional process. All right, so we need to encourage the development of many more OER artists out there. And so I really appreciate so much taking time out to bring this to us. And we hope we can get some more people interested in this fantastic work you're doing. Thank you. Thank you, Alan. Thank you so much. Sure, and this, of course, the same link to watch this is now the recording. So this is available for sharing right away. And just thank you again. Fantastic. And we hope we can keep this going. Thanks, Alan. Sure. Excellent. Stay cool, Kat. Thank you so much. Thank you. Thank you. Thank you.