Alpha, Proton, Deuteron, and Triton Spectroscopy

Protons, deuterons, tritons, and alpha particles behave similarly as far as energy loss and straggling are concerned. As they travel in a medium, they are deflected very little from their direction of incidence, as a result of which backscattering is insignificant and their range is almost equal to their pathlength. 

To avoid significant energy loss, the particles must go through as small a mass as possible when they move from the source to the detector. This is accomplished by making the source cover and the detector window as thin as possible. The entrance window of such detectors consists of a metallic layer, usually gold, with a thickness of 4 X 10 kg/m (40 /ag/cm ) or less. The measurements are performed in an evacuated chamber to avoid energy loss in 

The discussion in the rest of this section uses examples from alphas, but the points made are valid for the other particles of this group. Alphas have been studied and used much more extensively than the others, providing a basis for discussion. 

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