PMT Signal Transmission for Hard X-Ray Diagnostics of Future Tokamaks

Abstract A pair of a scintillator and Photomultiplier Tube (PMT) is often used as Hard X-Ray (HXR) radiation detector in existing tokamaks such JET, EAST, COMPASS or ASDEX-U. Future nuclear fusion reactors ITER DEMO will use more powerful magnets confine larger volume hot plasma. Placement the detectors for plasma diagnostic be constrained by high temperatures, magnetic fields ionizing present near tokamak vessel. It might necessary to move away from safer location. This generate problems with pulse discrimination transmission signal. In case tokamak, sensitive electronics digitizers cannot installed close reactor due harsh environmental conditions. new approach component placement needed protect those devices. The PMT signal transmitted via an over 100 m long coaxial cable digitizer located adjacent building. cables introduce additional attenuation. Also, RF noise environment can couple into To improve signal-to-noise ratio dedicated amplifier output range (from + 1.5 ? 11 V) was proposed.The paper presents issues HXR systems includes discussion on methodology conditions future tokamaks. proposal guidelines selection chain components design part this paper.