Electron Beam Loss Monitor of Areal Accelerator Based on Pin-Photodiodes

A prototype PIN-photodiode-based electron system for flux measurement of the AREAL accelerator electron beam (energy up to 5 MeV) was developed and tested. The system can be eventually used to measure beam losses from the vacuum chamber of the SASE100 undulator, which is intended for the generation of radiation in the terahertz range and will be installed in the AREAL accelerator tract during its modernization. The method of using the PIN-photodiodes as a beam loss monitor is based on the effect of electron–hole pairs formation when ionizing particles pass through the photodiode barrier layer. Calculations of the interaction of electrons with the substance of the barrier layer are performed using the PCLab program. The experiments carried out on the accelerator electron beam showed that the developed system can effectively register the electron fluxes of both the main beam of the AREAL accelerator and its dark current.