Thallium bromide-based detector probe for particle-induced gamma-ray emission analysis

In this study, a gamma-ray detector probe with a thallium bromide (TlBr) semiconductor detector was developed for particle-induced gamma-ray emission (PIGE) analysis. Owing to the high atomic numbers of thallium (81) and bromine (35) and high density (7.56[Formula: see text]g/cm³) of TlBr, it exhibits a high photon stopping power, making it promising for PIGE analysis. An approximately 5-mm thick TlBr detector was fabricated from a crystal grown through the traveling-molten zone method using a zone-purified material. The detector comprised a planar cathode and small anode ([Formula: see text][Formula: see text]mm) surrounded by a guard electrode. The detector obtained full-width-at half-maximum (FWHM) energy resolutions of 1.7 and 1.6% for 356- and 511-keV gamma rays, respectively, at room temperature using a depth correction and rejection method based on the cathode-to-anode signal ratio. The TlBr detector probe was installed in a beamline at the Aomori Prefecture Quantum Science Center, Japan, where PIGE analysis was conducted using a 20-MeV proton beam. Gamma rays at 478[Formula: see text]keV from ⁷Li(p,p[Formula: see text])⁷Li reactions, 197 and 110[Formula: see text]keV from [Formula: see text]F(p,p[Formula: see text])[Formula: see text]F reactions, and 718[Formula: see text]keV from [Formula: see text]B(p,p[Formula: see text])[Formula: see text]B reactions were successfully detected using the proposed TlBr detector probe in PIGE analysis.