Application of RadFET for dosimetry of ionizing radiation

Bremsstrahlung gamma radiation and neutrons are produced during the operation of high-energy linear accelerators. A single circular tunnel is built for the X-ray Free Electron Laser (X-FEL), therefore most of electronic devices used to control the machine are going to be placed in the same vault as the main beam pipe. Therefore, the devices will be subjected to neutron and gamma radiation influence. Knowledge of neutron and gamma doses are crucial to understand and interpret radiation effects on electronic devices and systems dedicated to the operation in the environment of high-energy linear accelerators. Indeed, it is advisable to monitor radiation produced in the tunnel of X-FEL in real time to estimate the danger and the life-time of electronic components and devices. The realtime monitoring system dedicated to measure radiation produced in a linear accelerator tunnel was designed. The system utilizes two different types of detectors to gauge neutron fluence and gamma radiation dose during the operation of the accelerator driving X-FEL. Research described in this paper is focused on real time gamma radiation dosimetry. Silicon-based gamma-sensitive dosimeter RadFET was employed to quantify radiation produced during an operation of a linear accelerator. In order to fully investigate the feasibility of RadFET detector for gamma dosimetry various experiments and gamma radiation exposure tests were carried out using a cesium source and inside FLASH (Free Electron Laser At Hamburg) facility placed in a high-energy Research Centre DESY.