Speaker
Description
Tritium is crucial for fueling fusion reactions in tokamaks, and its production occurs through neutron-lithium interactions in the Breeding Blanket (BB). Developing and validating BB designs is challenging due to the lack of neutron sources with fluences similar to those in tokamaks. Fast neutron detectors are critical for measuring tritium production and validating neutron multiplication rates. While diamond detectors have been used in past and planned tokamak projects, they face performance issues at high temperatures. Silicon Carbide (SiC) detectors are emerging as promising alternatives for neutron detection in tokamak environments due to their better high-temperature performance. The radiation resistance of 4H-SiC p-n diode detectors was studied under deuterium-tritium fusion neutron irradiation at 14.1 MeV, across temperature range of 25–500 °C. These detectors, with an active thickness of 250 μm and an active area of 25 mm², A p+ layer 0.3 μm thick with a doping concentration of 1018 cm-3 has been performed though ion implantation. Despite performance degradation due to increased dark current and defect formation, the detectors remained functional. Neutron-induced lattice damage, traps, and compensating centers reduced free carrier concentrations, built-in voltage, and capacitance. The effects worsened at higher temperatures up to 250 °C, as traps altered charge distribution and increased resistivity. Defects like silicon and carbon vacancies captured carriers, reducing the electric field and dopant activation. Electrical measurements (I-V and C-V) confirmed these impacts, showing reduced donor and acceptor concentrations and changes in dopant uniformity. In addition, neutron-induced defects in the epitaxial layer were identified and quantified using a deep-level transient spectroscopy measurement system.
