Energy Loss and Straggling of High-Energy Electrons in Silicon Detectors

The experiment done by Aitken et al. [Phys. Rev. 179 (1969) 393] showed that the most probable energy loss in silicon detectors by relativistic electrons deviated from the theoretical value by about 4.5% and the spectrum width was broader then the Landau width. They considered that such disagreements could be understood by taking into account the absorption of radiation produced by the electron passing through the detector. More accurate measurements are made on the energy losses in silicon detectors of thickness 1.565mm and 2.905mm for electrons with energies from 50 MeV to 1 GeV. Contrary to the results observed by Aitken et al., the values of the most probable energy loss obtained in this experiment agree within about 2% with theoretical ones, but the spectra are 10-20% broader than the Landau width. These results show no apparent evidence for the increase in electron ionization loss by the radiation absorption as previously suggested by Aitken et al.