Calibration of 4π NaI(Tl) detectors with coincidence summing correction using new numerical procedure and ANGLE4 software

Abstract

The 4π NaI(Tl) γ-ray detectors are consisted of the well cavity with cylindrical cross section, and the enclosing geometry of measurements with large detection angle. This leads to exceptionally high efficiency level and a significant coincidence summing effect, much more than a single cylindrical or coaxial detector especially in very low activity measurements. In the present work, the detection effective solid angle in addition to both full-energy peak and total efficiencies of well-type detectors, were mainly calculated by the new numerical simulation method (NSM) and ANGLE4 software. To obtain the coincidence summing correction factors through the previously mentioned methods, the simulation of the coincident emission of photons was modeled mathematically, based on the analytical equations and complex integrations over the radioactive volumetric sources including the self-attenuation factor. The measured full-energy peak efficiencies and correction factors were done by using 152Eu, where an exact adjustment is required for the detector efficiency curve, because neglecting the coincidence summing effect can make the results inconsistent with the whole. These phenomena, in general due to the efficiency calibration process and the coincidence summing corrections, appear jointly. The full-energy peak and the total efficiencies from the two methods typically agree with discrepancy 10%. The discrepancy between the simulation, ANGLE4 and measured full-energy peak after corrections for the coincidence summing effect was on the average, while not exceeding 14%. Therefore, this technique can be easily applied in establishing the efficiency calibration curves of well-type detectors.

Impact of (nano ZnO/multi-wall CNTs) prepared by arc discharge method on the removal efficiency of stable iodine 127I and radioactive iodine 131I from water

“…According to linear and nonlinear estimation of PFOK and PFOK models, the experimental qe value is practically similar to that obtained theoretically in the case of PFOK model. The larger rate constant ( K 1 ) of the PFOK model as compared to the smaller rate constant ( K 2 ) of the PSOK model indicates the adsorption process is fast 28 , 29 .…”

Measurements correlated to efficiency studies of NaI(Tl) scintillator with vertical hexagonal radioactive source

“…To calculate the 3 ×3 𝛾-ray NaI(Tl) detector efficiency and establish the true full-energy peak efficiency curve for using any radioactive source in a certain shape and at a close location from the detector surface, there are a lot of methods used [11][12][13]. The numerical simulation method (NSM) is considered one of those methods after the routine experimental calibration procedure, which is regarded as an extremely expensive and limited method [15][16][17][18].…”

“…The calculations of the coincidence summing corrections (COI) values are slightly more problematical. The approximate system of equations used in methodology [11][12][13] to obtain the estimations values based on the decay scheme style through this work for special energies, to find the true full-energy peak efficiency for the 3 × 3 𝛾-ray NaI(Tl) detector in case of the absence the hexagonal radioactive sources. It's necessary in this situation to determine the effective solid angle, Ω eff (Hexagonal) , total efficiency, 𝜀 T(Hexagonal) , full-energy peak efficiency, 𝜀 P(Hexagonal) , and peak-to-total ratio (P/T) in case of the hexagonal 152 Eu radioactive sources.…”

“…Therefore, scientists and technicians tend to make corrections due to these special effects, which are not easy to be done, particularly in the shape of radioactive volumetric sources. In such a situation, complex algorithms and equations build on a large number of details have been expanded to consider the effect of such a phenomenon [10][11][12][13]. The main parameter in the 𝛾-ray spectrometry field that can be used in the coincidence summing corrections is the measured peak-to-total ratio (P/T) for a different set of the…”

Peak Efficiency of NaI Detector and Coincidence Summing Factor for Different Cylindrical Sources Using Geant4 Simulation

“…The CSC for measuring point and volumetric sources was discussed by several authors regarding calculating the total efficiency or the peak-total ratio using different methods, such as calculating based on Monte Carlo simulation (Arnold and Sima 2001), equations expressed in a matrix form (Semkow et al 1990;Korun and Martin 1993), the code GESPECOR (Sima et al 2001;Arnold and Sima 2004), the code KORSUM and its modification (Debertin and Sch€otzig 1997;Yoon et al 2020), the efficiency transfer code EFFTRAN (Vidmar et al 2011), or the ETNA (Lepy et al 2012), using the effective solid angle calculation to use the numerical procedure (NSM) or ANGLE4 software (Abbas et al 2001(Abbas et al , 2021Badawi et al 2017). The calculating of total efficiency is more difficult, especially for extended sources, and less accurate for voluminous sources, so the present method calculates the CSC factor for point and volumetric sources without calculating the total efficiency using two tracks in Geant4 Monte Carlo simulation.…”