Real-time radiation monitoring system for FLASH

During the operation of a linear accelerator gamma and neutron radiation is produced. Radiation poses a potential threat to electronic systems installed in an accelerator tunnel. Therefore, monitoring of radiation in accelerators is especially important for Free Electron Lasers (FELs), like Free Electron Laser in Hamburg (FLASH) or X-ray Free Electron Laser (XFEL), that require sophisticated control systems. The system monitors in real-time gamma and neutron radiation and can be used to generate warning or trigger interlock subsystems when the level of radiation reaches a threshold level. The pilot facility of XFEL, called FLASH, enables to carry out initial tests of the control system, investigate the radiation environment of the linear accelerator and execute first physical experiments. This paper describes the design and experimental results of the radiation monitoring system installed in six various places of FLASH accelerator at Deutsches Elektronen-Synchrotron (DESY).