Application of CR-39 track detector for detection of protons; 3He and 4He ions

The successful detection is reported of 10-MeV protons, 70-MeV 3He ions, and 52-MeV 4He ions in CR-39 plastic track detector. The normalized track etching rate as a function of residual range for these particles has been obtained. A response function is suggested. It is concluded that CR-39 will register tracks of perpendicularly-incident particles with Z/β as low as 8. The implications of these results with particular reference to detection of light-ion flux in the neutron beams used for cancer therapy are discussed. The results also indicate that clear discrimination would be possible between 3He ions and 4He ions in these energy bands. (author)