CR-39 nuclear track detectors have been used in this experiment to stu
dy the killing effect of low energy protons on V79-753B Chinese hamste
r cells and to monitor the proton beam. The estimated surviving fracti
ons and the beam parameters are comparable to those found with convent
ional electronic devices. The surviving fractions fitted by the linear
quadratic model support the idea of single-hit mechanism for the cell
killing.