Speaker
Description
With the advancement of high-luminosity accelerator experiments, future hadron collider projects following the LHC are expected to require tracking detectors with radiation tolerance approximately ten times greater than the level at the high-luminosity LHC. Therefore, the development of semiconductor detectors capable of stable operation in such high-radiation environments is crucial to realize the future hadron collider experiments.
Two types of GaN-based detectors: p-n junction diodes (GaN-PND) and low gain avalanche diodes (GaN-LGAD) have been evaluated. The GaN-PND consists of a 550 nm p-GaN layer over a 10 μm n$^{-}$-GaN active layer. The GaN-LGAD has a similar structure but features a 250 nm n$^{+}$-GaN gain layer directly beneath the p-GaN layer, above a 10 μm n$^{-}$-GaN sensor layer. Pixel electrodes of 150 μm × 150 μm are used for signal readout.
We measured responses of GaN-PND and GaN-LGAD detectors with 5.4 MeV α-particles from $^{241}$Am and 170 MeV/n $^{132}$Xe$^{54+}$ ions, the latter of which were irradiated at the HIMAC, QST in Japan. We successfully achieved two-dimensional detection of these charged ions using GaN devices. In GaN-PND, the charge collection was measured as a function of bias voltage. Approximately 76 fC was collected for α-particles at a bias voltage of 200 V, and about 570 fC was collected for Xe ions at 160 V. In the case of GaN-LGAD, a collected charge of approximately 83 fC was obtained for α-particles at 200 V, and below this voltage, the behavior of charge collection was almost consistent with that of the GaN-PND. For Xe ions, a collected charge of about 94 fC was observed even at 5V. Furthermore, we present results from the GaN-PND samples irradiated with 50 MeV protons at the RARiS, Tohoku University in Japan with fluences up to 1.1×10$^{16}$ n$_{\rm{eq}}$/cm$^{2}$.
