Design and fabrication of runaway probe for studying the behavior of runaway electrons in IR-T1 Tokamak

Several theoretical and experiential studies of runaway electrons in the well-known Tokamaks of the world have been made over the past few decades. In the present study, the measurements of runaway electrons energy were carried out by a new runaway probe in the IR-T1 Tokamak. In the IR-T1 Tokamak, the hard X-ray diagnostic system is used as a diagnostic global measurement system at the vessel wall of Tokamak. Runaway probe was first designed and fabricated for local measurement near the plasma edge in IR-T1 Tokamak. The new diagnostic has the advantage that the local interaction of runaways with materials can be evaluated, along with the direct measurement of the runaway electrons. The runaway probe consists of 2 LYSO (Lu 1.8Y.2SiO5:Ce) crystals covered by a graphite housing which is shielded by tungsten filter placed in the direction of runaway electrons. The main elements of the runaway probe are LYSO crystals which convert the energy of runaway electrons into visible light which is instructed to silicon photomultipliers. The present study aimed to evaluate a new runaway probe in the IR-T1 Tokamak to detect beta and gamma rays. The results indicated that electron spectrum is between 500 keV and 2 MeV at the plasma edge in the IR-T1 Tokamak.