Part 2 of 2 Parts (Please read Part 1 first)
     One of the major questions that will be answered by Scorpius is how effective the plutonium in the U.S. nuclear stockpile may prove to be, given its age.
      Custer said, “The newest systems we have first went into the stockpile in the 1980s. If you bought a car in 1992 and parked it in your garage, doing nothing to it, do you think it would start tomorrow on the first turn of the key? Not a perfect analogy, but you could do experiments and simulate things all you want, but you still want to turn the key and hear the engine turn over every once in a while, to know it will start when you need it.”
     Custer goes on to say that we know that plutonium does undergo spontaneous fission. “This means that the material we first made and shaped precisely decades ago now has impurities from the fission in it, and the crystal structure has been damaged by the energetic decays. If you look at steel, very small changes to composition can make large changes to, for example, the mechanical strength. The X-ray images from Scorpius will help validate that at full scale, the plutonium still behaves as needed in spite of such changes.”
     Scorpius is designed to generate high-energy pulses of electrons. It slams the electrons into a heavy metal target to create bright X-ray flashes that will capture pictures of the plutonium.
     Custer said, “There are very good models of what happens inside a nuclear weapon. We will now be able to take detailed X-ray images of what happens as the device implodes to see if the models are right. If the models are not right, we will make them right. We can’t afford to be wrong.”
     A key part of the Scorpius design is the manner in which it can generate huge pulses of electrical energy. Instead of relying on giant banks of capacitors for this task, it will use more than forty thousand commercial printed circuit boards to create four twenty-five-thousand volt pulses. These will energize a twenty-two million electron-volt electron beam.
     Custer said, “The flexibility and programmability of the units makes it much easier to create precisely the X-ray bursts that the experimenters want for their particular experiment. Taking advantage of commercially available chips and standard electronics assembly similar to, for example, a desktop computer board, is just a good engineering choice. It also is likely that as commercial parts get more capable—higher voltages, higher currents—there are upgrade paths in the future for even higher performance of the machine if wanted.”
     With the release this year of Christopher Nolan’s movie “Oppenheimer,” the public’s attention has turned once again to nuclear weapons. Custer said, “One of the scenes in the movie was several scientists betting whether the Trinity test would ignite the atmosphere, which was disturbing—an understatement—to General Groves. There was uncertainty there, although the possibility was swiftly debunked in real life. Scorpius aims to eliminate any uncertainty.”