Detection characteristics for neutrons in an InGaP solar cell under high-temperature conditions

InGaP solar cells are popularly used as detectors that output a current signal due to incident radiation. The device has a bare surface structure having a thickness of approximately 1 µm, which may facilitate the detection of high-energy charged particles with short ranges. When neutrons react with boron, they emit alpha rays and charged particles of lithium nuclei. This study demonstrates that InGaP solar cells can be applied as neutron-detection devices by installing a boron-conversion film on the surface of the cell. In addition, its performance in high-temperature environments is also investigated to develop its applicability as a detector in nuclear reactors and space exploration. InGaP solar cells irradiated with neutrons at the compact accelerator neutron source RANS exhibited an increase in the current signal proportional to the flux. A slight degradation was also observed after long-term neutron irradiation. The temperature dependence of the current behavior was also evaluated by fabricating a chamber that can perform neutron irradiation in a high-temperature environment. The current behavior of the InGaP solar cell at 275°C presents a slightly higher sensitivity than that at 20°C, thus confirming the narrow-band-gap effect in high-temperature environments.