For a proton recoil detector, you probably want (and need) the gain that a photomultiplier can provide. They multiply the incoming light signal by about 10^6. Cascaded amplifiers could possibly be devised to do the same thing, but it's hard to beat the simplicity of a PMT. Special silicon diodes can be used to directly count protons (remember that the D-D reaction produces protons 50% of the time), but they need to be made specially for the job and also placed inside the fusor vacuum chamber. The protons never make it through the walls of the vacuum chamber, while the neutrons zip right through. Canberra and Ortec/Perkin-Elmer both make specialized silicon diodes for charged particle and gamma detection. The Perkin Elmer web site has a lot of downloadable basic information on these detectors.
Detecting neutrons on the outside of the chamber is easier from a construction standpoint, and the vacuum chamber walls stop electrons and X-rays that would make your measurement job a lot messier, not to mention your immediate environment...
Created on Tuesday, May 08, 2001 2:40 AM EDT by Richard L. Hester