Scintillation response of gallium oxide to charged particle and gamma radiation produced by radioisotope and accelerator sources

We have measured the response of the wide band gap scintillator Ga₂O₃ (Sn-doped) to a variety of radiation sources, including energetic ion beams, alpha- and beta-emitting radionuclides, and gamma sources to assess its scintillation behavior and possible use as a radiation spectrometer. Energetic ion beams of hydrogen, helium and nitrogen were directed onto Ga₂O₃ to assess the relative scintillation efficiency as a function of ion mass, and the limits of the ion energy which could reasonably be measured using this material coupled to a photomultiplier tube.

The material was also exposed to beta-emitting sources including ¹⁴C, ⁹⁹Tc, ³⁶Cl and ⁹⁰Sr for energy calibration and to assess its use as a beta spectrometer, reproducing energy spectra in general agreement with spectra calculated using Betashape model (accessed through IAEA LiveChart of Nuclides). The response to combined beta- and gamma-emitting sources ¹³⁷Cs and depleted uranium (²³⁸U) was also measured, and the scintillation response characterized separately to obtain pure beta spectra for each source. Although the scintillation response of Ga₂O₃ to gamma radiation is relatively low, we were able to measure Compton electron distributions using both gamma-emitting radioisotopes and accelerator-generated gamma rays.

To demonstrate how the material could be used as a simple beta spectrometer, various filters, both inorganic and organic, were placed between beta-emitting sources and the scintillator/PMT system to obtain information regarding the absorption of betas in thin filter materials. Such detailed data regarding beta energy absorption as a function of energy in organic materials could be valuable in the area of beta-source radioisotope therapy, as well as inform the design of radioisotope power sources.