Beta-induced X-rays in Gadolinium Pyrosilicate Crystal Scintillator in the FRIB Decay Station Initiator

A gadolinium pyrosilicate (La-GPS) scintillator was used in the FRIB experiment as an implantation detector. During measurements with the Modular Total Absorption Spectrometer, we observed X-ray emission induced by energetic beta particles from radioactive decays. In a series of experiments, we quantified the X-ray production using the LaGPS array and large CeBr3 and NaI detectors. Testing with a 90Sr source produced a low-energy photopeak in surrounding gamma radiation detectors. This was postulated to be the Gd(Kα) X-ray resulting from deexcitation following interactions with beta radiation. During measurements, the shielding and distance between the beta and gamma detectors were varied. The results of these measurements will be used to quantify the impact of these X-rays on the response of the FDSi detection system, which uses a segmented scintillator detector for experiments with exotic nuclei [Yok19, Cox24].

[Yok19] R. Yokoyama et al., Phys. Rev.. C 100, 031302 (2019)

[Cox24] I. Cox et al., Phys.Rev. Lett. 132, 152503 (2024)