The peak efficiency for photons hitting the frontal surface of a medium volume n-type HPGe coaxial detector is mapped using acutely collimated beams of energies between 31 and 383 keV from a (133)Ba radioactive source. Simulated values obtained with the Monte Carlo radiation transport code penelope, using a model that respected actual detector dimensions and physical constants while varying dead-layer thicknesses, allowed us to fit the experimental results in the detector bulk but not near its rim. The spectra of a (137)Cs source were measured using the detector shielded from the natural background radiation, with and without a broad angle collimator. The corresponding simulated spectra, using the fitted dead-layer thicknesses, underestimate the continuum component of the spectra and overestimate the peak efficiency, by less than ten percent in the broad angle collimator arrangement. The simulated results are sensitive to the photon attenuation coefficients.
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http://dx.doi.org/10.1016/j.apradiso.2015.12.001 | DOI Listing |
Radiat Prot Dosimetry
August 2024
Atomic Minerals Directorate for Exploration and Research Hyderabad 500016, India.
The integration of the ORION digital signal processing-based MCA system coupled with a 3″ × 3″ NaI(Tl) detector assembly with a GM detector for counting beta (β) has eliminated the need for a standalone β-γ method in which U3O8 is determined by gross β and gross γ counting. Uraniferous and mixed U-Th samples were taken up for study and compared with the results obtained from Canberra p-type coaxial high resolution gamma ray spectrometry detector. In uraniferous samples, U3O8 values obtained are within ±10%, whereas in the case of mixed U-Th samples, U3O8 values are within ±15%.
View Article and Find Full Text PDFRadiat Prot Dosimetry
December 2023
Atomic Minerals Directorate for Exploration and Research, Nagarbhavi, Bengaluru, India.
The precision measurements of U3O8 and Ra(eU3O8) concentrations were evaluated in 23 geological rock samples by high resolution gamma ray spectrometry (HPGe) using two P-type HPGe detectors. The use of Detector 2 (DET2) (GC5019) has increased the sensitivity by a factor of two for both the measurements in comparison to Detector 1 (DET1) (GCD30180). The Minimum Detection Limit (MDL) and Limit of quantification (LOQ) for U3O8 in DET2 has increased significantly because of negligible background counts in 1.
View Article and Find Full Text PDFIn this work, a classical approach was used for calibrating the GESPECOR detector model for computing the full-energy peak efficiency of p-type coaxial HPGe detectors that is based on the use of linear least squares optimization. The key element of the work is the multiplicative model developed for approximating the values of the full-energy peak efficiency provided by GESPECOR code. It was linearized using the logarithmic transformation to allow an easy use of the linear least squares optimization.
View Article and Find Full Text PDFJ Environ Radioact
December 2023
Lithosphere Fluid Research Laboratory, Institute of Geography and Earth Sciences, Eötvös Loránd University, Pázmány Péter sétány 1/C, 1117, Budapest, Hungary; Institute of Earth Physics and Space Science, HUN-REN, Csatkai E. u. 6-8, 9400, Sopron, Hungary. Electronic address:
Primordial radionuclides can be found in all environmental compartments. Since coal-fired power plants (CFPP) can be a source of additional radionuclide contamination because coal contains natural radioactive isotopes such as U (Ra) and Th. This study investigated the impact of such possible radionuclide contamination from former heavy industrial activities, namely a former local coal-fired power plant, in urban soils and attic dust in Salgótarján, Hungary.
View Article and Find Full Text PDFAppl Radiat Isot
June 2023
INFN Sezione di Milano Bicocca, Piazza della Scienza 3, Milano, I-20126, Italy.
In this work, gamma-ray spectrometry with HPGe detectors is used to measure radionuclides' specific activity (A) in soils. The main purpose of the paper is to present a general procedure to assess A in soils from in-situ acquisitions. The soil from two experimental sites was analyzed both in the field, with a portable HPGe detector, and in the laboratory, with a BEGe detector.
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