Search for a command to run...
Photon-counting computed tomography (PCCT) offers a compelling opportunity to significantly reduce patient radiation dose while simultaneously improving contrast-to-noise ratio [1]. With the growing interest in PCCT, the demand for cost-effective alternatives to current semiconductorbased direct-conversion detectors has become increasingly apparent. Although direct-conversion detectors enable X-ray photon counting, the production of high-quality cadmium-telluride or CZT layers remains costly and complex. Challenges such as charge sharing and material defects continue to limit both image quality and detector performance in direct conversion detectors. Recent studies have demonstrated that indirect-conversion detectors based on scintillators not only represent a feasible alternative, but may even offer distinct advantages, including improved spectral fidelity [2]–[4]. Nevertheless, the requirements for scintillators for photon-counting applications remain stringent. In this work, we investigate the use of beta gallium oxide (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\beta-\text{Ga}_{2} \mathrm{O}_{3}$</tex>) as a potential scintillator for photon-counting CT detectors. Previous studies have shown that <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\beta$</tex> <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{Ga}_{2} \mathrm{O}_{3}$</tex> exhibits an excellent primary decay time constant of 2 ns, an energy resolution of approximately 7 % at 662 keV, and a light yield of around 8 photons per keV. Here, we present an in-depth characterization of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\beta$</tex> - <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{Ga}_{2} \mathrm{O}_{3}$</tex>, including measurements of self-absorption, nonproportionality, decay time, and afterglow. To evaluate the performance of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\beta-\text{Ga}_{2} \mathrm{O}_{3}$</tex> under realistic operating conditions, we furthermore couple <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\beta-\text{Ga}_{2} \mathrm{O}_{3}$</tex> crystals to SiPMs and assess the resulting pulse shape. Preliminary results are consistent with earlier findings, yet reveal two additional long decay components: one with a decay constant of 34.3 ns (accounting for <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\sim 26 \%$</tex> of total intensity) and another with 367 ns (with <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\sim 7 \%$</tex> intensity), which may affect counting and spectral performance.