 In a 17-foot-long trailer, a laboratory on wheels at a height of 14,125 feet, Powell and assistant Henry Meyer took about 12,000 photographs in order to capture a photo of the particle.He had made improvements to the cloud chamber, such as a new lighting system that enabled him to take pictures in one thirty-thousandth of a second.During this expedition, Henry Allen Moe, then president of the Guggenheim Foundation, Professor Raymond Birge, head of the physics department at the University of California, Berkeley, and German physicist Hans Bethe visited the mountaintop laboratory.