Optimization of an underwater in-situ LaBr 3 :Ce spectrometer with energy self-calibration and efficiency calibration

Abstract

An underwater in-situ gamma-ray spectrometer based on LaBr:Ce was developed and optimized to monitor marine radioactivity. The intrinsic background mainly from La andAc of LaBr:Ce was well determined by low background measurement and pulse shape discrimination method. A method of self-calibration using three internal contaminant peaks was proposed to eliminate the peak shift during long-term monitoring. With experiments under different temperatures, the method was proved to be helpful for maintaining long-term stability. To monitor the marine radioactivity, the spectrometer's efficiency was calculated via water tank experiment as well as Monte Carlo simulation.

Characterization of monolithic GAGG:Ce coupled to both PMT and SiPM array for gamma imaging in Nuclear Medicine

“…A 24 hours measurement without any radiation source has been performed. As shown in figure 2, in the energy range for PET and SPECT application (about 100-500 keV) the GAGG:Ce radioactivity background is almost negligible (background count rate under 0.04 s −1 at 140 keV, under 0.01 s −1 at 511 keV compared with LaBr 3 :Ce self-activity count rate of 0.81 s −1 at 511 keV, acquired in the same condition [22]), allowing measurements also in low activity condition.…”

Response of LaBr3:Ce scintillation detector itself to fast neutrons

“…The energy threshold was set at 25 keV. The more detailed information about the detector was described in a previous article [7]. Limited by experimental conditions, there were not enough monoenergetic neutron sources to verify the responses of the detector to neutrons with different energies.…”

“…Based on a second-order polynomial equation, the energy calibration of the detector was achieved with three standard gamma sources, including 241 Am, 137 Cs and 60 Co. To eliminate the peak-shift during the measurements, a method of self-calibration [7] was used and the calibrated spectra were corrected using three known peaks from the intrinsic radioactivity background of LaBr 3 :Ce.…”

“…The LaBr 3 :Ce scintillation detector has been widely used in various gamma radiation measurements fields [1][2][3][4][5][6][7][8][9][10] since it has good energy resolution, high detection efficiency and excellent time resolution. In addition, the detector has recently been found to be sensitive to neutrons and can be used for neutron detection using some neutron-induced gamma rays generated in the neutron inelastic scattering process.…”

A marine radioisotope gamma-ray spectrum analysis method based on Monte Carlo simulation and MLP neural network

“…In Fukushima nuclear accident in 2011, radionuclides were released to the oceanic environment via atmospheric fallout and wastewater discharge, with 137 Cs activity of 3.1-3.6 PBq [1,2]. Due to the long half-life (30.17 y) and transportation to east by currents in the Pacific ocean, it is important and necessary to implement extensive and long-term seaborne monitoring.. A seaborne monitoring device has been developed to monitor the radioactive isotopes [3,4]. As shown in Fig.…”