Optical, scintillation and radiation tolerance properties of Pr-doped pyrosilicate crystals

Abstract

A series of Pr-doped pyrosilicate crystals, Y2Si2O7 (YPS), Pr2Si2O7 (PrPS), Gd2Si2O7 (GPS), and Lu2Si2O7 (LPS), were synthesized by the floating zone (FZ) method to investigate whether the positive hysteresis phenomenon was observed or not. In all crystals, no impurity phases were observed in X-ray diffraction (XRD) analyses. In photoluminescence (PL) spectra, Pr3+ 5d–4f emission was observed from 270 to 400 nm in all the samples, and the PL decay times of them were around 10 ns. In radioluminescence (RL) spectra, they showed Pr3+ 5d–4f emission from 270 to 400 nm in all the samples, and the scintillation decay times were around 20 ns. When we irradiated with γ-rays from 137Cs, the scintillation light yields of YPS, GPS, and LPS were 8300, 1800, and 9700 ph/MeV, respectively. After these basic characterizations, we irradiated 0, 200, and 400 Gy γ-rays exposure by using 60Co. As a result, the positive hysteresis was not observed and YPS and LPS showed relatively high radiation resistivity.

Inorganic scintillating materials and scintillation detectors

“…In our most recent study, 140) we found that Pr-doped LPS did not show any positive hysteresis (confirmed by the pulse height analyses), and we thought that the positive hysteresis of the pioneering report in Pr-doped LPS may have been be affected by radiation-induced afterglow (their study was based on a radioluminescence analysis). Therefore, in my opinion, the materials confirmed to show positive hysteresis up to now are CsI, GSO and GAGG.…”

Scintillation Characteristics of Pr-doped Gd2Si2O7 Single Crystal

“…Finally, the signals were sent to a personal computer. In the PH analysis, the scintillation light yield was calibrated using 1.0 mol% Pr-doped LPS, which had a light yield of 9700 ph/MeV (28) with a similar emission spectrum to that of Pr-doped GPS. The linearity and energy resolution were evaluated using the same setting to that of various γ-ray sources such as 22 Na (511 keV), 57 Co (122 keV), 133 Ba (356 keV), 137 Cs (662 keV), and 241 Am (60 keV).…”

“…The broad emission from 340 to 410 nm originated from the 5d-4f transition of Pr 3+ . (28,34) The scintillation decay time profiles are shown in Fig. 6.…”

“…Photoabsorption peaks of the 0.1, 0.3, 0.5, 1.0, and 2.0% Pr-doped samples were observed at 180, 200, 210, 770, and 520 channels, respectively. Taking into account the light yield with the reference sample of 1.0% Pr-doped LPS, (28) the absolute scintillation light yields of 0.1, 0.3, 0.5, 1.0, and 2.0% Pr-doped samples were 530, 600, 640, 2290, and 1550 ph/MeV, respectively. In this measurement, the typical error for the light yield was ±10%.…”

“…(27) Recently, a comparative study of LPS, YPS, and GPS single crystals doped with Pr and undoped Pr 2 Si 2 O 7 (PrPS) has successfully been performed at a fixed Pr doping concentration of 1.0 mol%. (28) Despite recent advancements, it is necessary to investigate more the Pr concentration dependence of the GPS crystal. In this work, GPS single crystals with different Pr doping concentrations were systematically studied in terms of both photoluminescence (PL) and scintillation properties, such as PL emission spectrum, PL decay time, scintillation spectrum, scintillation decay time, scintillation light yield, and energy resolution.…”