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Accurate geometry-dependent efficiency calibration of High-Purity Germanium (HPGe) detectors is critical for the applications in low radiation level γ-spectrometry, rare decay studies, and assessments of environmental radioactivity. At IIT Ropar, a low-background facility, ILMI (IIT Ropar Low-background Measurement Infrastructure) is being developed to feature an array of coaxial p-type HPGe detectors with 40% relative efficiency. These detectors can operate in coincidence and are shielded with radiopure lead to minimize environmental background interference. This work presents a comprehensive spectrometric characterization and dead layer assessment of an HPGe detector, GEM40P4-83-RB/ORTEC, which is housed in a radiopure carbon fiber. The detailed Monte Carlo simulation in GEANT4 was used to model the detector response across a wide energy range (80.99-2614.50 keV). The methodology was validated by comparing the simulated results with experimental data using various gamma sources, including [Formula: see text]Cd, [Formula: see text]Cs, and [Formula: see text]Co, over a range of source-to-detector distances. Excellent agreement has been observed between simulated and experimental efficiencies, with a deviation of 2.5% for close distances (less than 5 cm) and 3.8% for farther distances (5 cm or greater). These minor discrepancies may be attributed to excluding the electronic acquisition chain effects in the simulation or photon scattering from the environment in actual experiments. The validated simulation model demonstrates high reliability and predictive accuracy, establishing a robust methodology for determining efficiency calibration in complex detector geometries.

In this work, radioactivity investigations of soil samples from neutral and agricultural sites in Punjab (India) have been carried out to study the impact of land use patterns. Analyzing soil samples radiological, mineralogical, and physicochemical attributes has employed state-of-the-art techniques. The mean activity concentration of 238 U/ 226 Ra, 232 Th, 40 K, 235 U, and 137 Cs, measured using a carbon fiber endcap p-type HPGe detector, in neutral land was observed as 58.03, 83.95, 445.18, 2.83, and 1.16 Bq kg −1 , respectively. However, in vegetation land, it was found to be 40.07, 64.68, 596.74, 2.26, and 1.90 Bq kg −1 , respectively. In the detailed activity analysis, radium equivalent (Ra eq ) radioactivity is in the safe prescribed limit of 370 Bq kg −1 for all investigated soil samples. However, the dosimetric investigations revealed that the outdoor absorbed gamma dose rate (96.08 nGy h −1 ) and consequent annual effective dose rate (0.12 mSv y −1 ) for neutral land and the gamma dose rate (82.46 nGy h −1 ) and subsequent annual effective dose rate (0.10 mSv y −1 ) for vegetation land marginally exceeded the global average. The soil’s physicochemical parameters (pH, EC, and porosity) from both sites were measured, and their correlations with radionuclides were analyzed. Various heavy metals of health concern, namely, chromium (Cr), arsenic (As), copper (Cu), cobalt (Co), cadmium (Cd), lead (Pb), mercury (Hg), selenium (Se), and zinc (Zn), were also evaluated in soil samples using Inductively Coupled Plasma-Mass Spectroscopy (ICP-MS). Pollution Load Index (PLI) and Ecological Risk Index (RI) revealed that vegetation land was more anthropogenically contaminated than neutral land, with maximum contamination from Hg and As.

High purity germanium (HPGe) detectors are deployed globally for gamma-radiation spectroscopy due to their superior energy resolution. In this work, the essential characteristics of n and p-type HPGe detectors, such as energy resolution, efficiency, minimum detectable activity (MDA), and peak shape were studied for the purpose of characterization and performance optimization. The results are obtained for various source-detector configurations in a wide energy range of 40–1408 keV using gamma sources, such as 109 Cd, 57 Co, 137 Cs, 54 Mn, 65 Zn, 60 Co, and 152 Eu. Scanning (distance, lateral, and radial) of the detectors was performed using different gamma sources to understand the orientation of the crystal with its active volume and counting efficiency and to characterize the geometry in detail. The ambient background around the n-type HPGe was reduced using Pb-shielding. As a result, an 85.85% suppression was observed in the mean integral window of 40–2700 keV. The characterization and performance tests of the detectors convincingly suggest that both the detectors can be deployed for environmental radioactivity explorations.

A Multi-Phase Transport Model (AMPT) has been extensively used to understand the physics behind the experimental observation. Like other models, the outcome of the AMPT model depends on the initial parameters. Therefore, one needs to choose suitable initial parameters before using the model. Lund string fragmentation function has been used to create quark-antiquarks pairs in the AMPT model. The Lund string fragmentation parameters determine the yields and transverse momentum (\\(p_{T}\\)) spectra of particles produced in nucleus-nucleus collisions. The values of Lund string fragmentation parameters were determined by fitting the charged particle yield and \\(p_{T}\\) spectra measured in the experiment. In this paper, we have shown the yield of strange quarks carrying hadrons, e.g. \\(\\phi\\) mesons, are more sensitive to Lund string fragmentation parameters compared to non-strange pions. Using \\(\\phi\\) meson spectra measured at RHIC, we have obtained new sets of Lund parameters for Au+Au collisions at \\(\\sqrt{s_{\\mathrm {NN}}}\\) = 11.5, 39, and 200 GeV. We have found that using the same set of parameters, we can explain \\(\\phi\\)-meson yield at \\(\\sqrt{s_{\\mathrm {NN}}}\\) = 39 and 200 GeV, however, we need a different set of parameters for \\(\\sqrt{s_{\\mathrm {NN}}}\\) = 11.5 GeV. This suggests that at low energy, \\(\\sqrt{s_{\\mathrm {NN}}}\\) = 11.5 GeV, the underlying mechanism for particle production is different compared to top RHIC energies. We have also predicted invariant yield of \\(\\pi\\) and \\(\\phi\\) mesons as a function of \\(p_{T}\\) in U+U collisions at \\(\\sqrt{s_{\\mathrm {NN}}}\\) = 196 GeV to be measured by STAR experiment.

Low background gamma spectrometry employing HPGe detectors is a sensitive technique for measuring low-level radioactivity in environmental applications, material screening, and for rare decay searches. This work presents spectroscopic performance evaluation and modelling of a low background measurement setup developed at IIT Ropar in Punjab, India, to measure trace natural radioactive elements, with a particular interest in studying low-level radioactivity in soil and/or rock samples to generate specific inputs for low background experiments. The performance test and characterization of a low background cryocooled HPGe detector with relative efficiency of \\(\\sim\\)33% have been carried out. An effective detector model has been developed using GEANT4 Monte Carlo simulation to determine the response of the detector over an energy range of 80.9-1408 keV and compared with the experimental performance of the detector. The response of the detector obtained using Monte Carlo simulations agrees reasonably well within 93% level of confidence, indicating only 7% deviation in the comparison. The present setup offers improved detection limits of primordial radionuclides (U/Th and K) to measure radioactive contamination in environmental matrices, which has been used elsewhere [1].

In this work, radioactivity investigations of soil samples from neutral and agricultural sites in Punjab/India have been carried out to study the impact of land use patterns. The analysis of radiological, mineralogical, physicochemical, and morphological attributes of soil samples has been performed employing state-of-the-art techniques. The mean activity concentration of 238U, 232Th, 40K, 235U, and 137Cs, measured using a carbon-loaded p-type HPGe detector, in neutral land was observed as 58.03, 83.95, 445.18, 2.83, and 1.16Bq kg-1, respectively. However, in vegetation land, it was found to be 40.07, 64.68, 596.74, 2.26 and 2.11Bq kg-1, respectively. In the detailed activity analysis, radium equivalent (Raeq) radioactivity is found to be in the safe prescribed limit of 370Bq kg-1 for all investigated soil samples. However, the dosimetric investigations revealed that the outdoor absorbed gamma dose rate (96.08nGy h-1) and consequent annual effective dose rate (0.12mSv y-1) for neutral land, and the gamma dose rate (82.46nGy h-1) and subsequent annual effective dose rate (0.10mSv y-1) for vegetation land marginally exceeded the global average. The surface morphology of neutral land favored more compactness, while agricultural land favored high porosity. Various heavy metals of health concern, namely As, Cd, Co, Cr, Cu, Hg, Pb, Se, and Zn, were also evaluated in all soil samples using Inductively Coupled Plasma-Mass Spectroscopy (ICP-MS). Pollution Load Index (PLI) and Ecological Risk Index (RI) revealed that vegetation land was more anthropogenically contaminated than neutral land, with maximum contamination from Hg and As.