Inelastic Nuclear Reactions of Protons in Scintillators

When a scintillation counter is used as a spectrometer for energetic protons, corrections must be made for the fact that (p,n) and other nuclear reactions may occur in the scintillator, causing some of the protons to register substandard pulse heights. These corrections have been measured for thalliated sodium iodide, and for plastic scintillators at proton energies between 10 and 40 mev, by measuring the pulse-height spectrum produced by a proton beam of homogeneous energy striking the crystal. The homogeneous beam is obtained by collimating a linear accelerator beam to one-eighth inch diameter, then magnetically analyzing to get rid of the slit-scattered protons.