GEOMETRICAL EFFECT ON THE MEASUREMENT OF STOPPING POWER - ANGLE-DEPENDENT ENERGY-LOSS 5 MEV PROTONS IN CU

The angle-dependent energy loss of 5 MeV protons has been measured for a Cu target which has good thickness uniformity. In order to examine the effect of target texture, measurements were performed for three different target angles. Energy loss was found to show substantially the same angular dependence regardless of target tilt angles. The present results are hence proved to be free from serious influence of target texture. Energy loss increased by up to about 1.5% with increasing emergence angle and seemed to be saturated at angles larger than 2.5-degrees. The effect of thickness nonuniformity was too small to reproduce the observed angle-dependent energy loss. The relation between angle-dependent energy losses due to thickness nonuniformity and the true geometrical effect is discussed. Theoretical predictions by Shindo were found to agree well with the present results.