High-purity Germanium Detector Research Articles

Different manifestations of triaxial shapes of the positive and negative parity bands in Os187

The excited states of $^{187}\mathrm{Os}$ have been studied via $^{186}\mathrm{W}(^{4}\mathrm{He},3n)^{187}\mathrm{Os}$ reaction at a beam energy of 36 MeV. The $\ensuremath{\gamma}$ rays were detected using the Indian National Gamma Array at the Variable Energy Cyclotron Centre having seven Compton-suppressed clover high-purity germanium (HPGe) detectors and one low-energy photon spectrometer (LEPS) detector with a digital data acquisition system. The level scheme of $^{187}\mathrm{Os}$ has been extended substantially up to $\ensuremath{\approx}$3.86 MeV of excitation energy and $37/2\phantom{\rule{0.16em}{0ex}}\ensuremath{\hbar}$ of spin with the placement of more than 90 new $\ensuremath{\gamma}$ rays. All known bands have been extended and new band structures have been identified. The results show evidence of triaxial shapes for different configurations of $^{187}\mathrm{Os}$ and different manifestations of nonaxial shape have been observed in the same nucleus. A comparison of the observed band crossing frequency in $^{187}\mathrm{Os}$ with neighboring nuclei gives evidence of a deformed shell gap at $N=110$. The experimental results are well explained using total Routhian surface calculations.

Identification of Activation Isotopes in a CS-30 Cyclotron Vault

A CS-30 cyclotron has been in operation at King Faisal Specialist Hospital and Research Center (KFSHRC) since 1982. The CS-30 cyclotron has been used to produce medical radioisotopes for positron emission tomography (PET) and single-photon emission computed tomography (SPECT). Some of the nuclear reactions of radionuclide production are associated with the intense release of a wide range of fast neutrons. In this work, we investigated the radionuclides produced from neutron interactions with the cyclotron facility walls. Activation isotopes were determined by performing gamma ray spectrometry utilizing a high-purity germanium (HPGe) detector. The major radionuclides found were 152Eu, 154Eu, 134Cs, 65Zn and 60Co. Activation isotope accumulation had increased the dose rate inside the facility. The surface dose rates were measured at all of the surrounding walls. The maximum surface dose rate was found to be 1.2 µSv/h, which is much lower than the permissible occupational exposure of 15 µSv/h based daily 5 work hours.

Хүрэн нүүрсэнд цацраг идэвхийн тэнцвэрийг тодорхойлсон нь

This work presents the results of measurements of radionuclide concentrations and radioactivity equilibrium in brown coals of the eastern part of Mongolia.
 Using the gamma spectrometry method based on high-purity germanium (HP Ge) detectors, it has been found that U/Ra equilibrium is significantly disturbed ranges from 1.4:1.5 in brown coal samples.
 The mechanism of formats of equilibrium ratios between Natural Radioactive elements in Uraniumcontcuning coal samples are considered ...

Stellar s -process neutron capture cross sections of Ga69,71

The stable gallium isotopes, $^{69,71}$Ga, are mostly produced by the weak slow ($s$) process in massive stars. We report here on measurements of astrophysically-relevant neutron capture cross sections of the $^{69,71}$Ga$(n,\gamma)$ reactions. The experiments were performed by the activation technique using a high-intensity ($3-5\times10^{10}$ n/s), quasi-Maxwellian neutron beam that closely mimics conditions of stellar $s$-process nucleosynthesis at $kT \approx$ 40 keV. The neutron field was produced by a mA proton beam at $E_p=1925$ keV (beam power of 2-3 kW) from the Soreq Applied Research Accelerator Facility (SARAF), bombarding the Liquid-Lithium Target (LiLiT). A 473 mg sample of Ga$_2$O$_3$ of natural isotopic composition was activated in the LiLiT neutron field and the activities of $^{70,72}$Ga were measured by decay counting via $\gamma$-spectrometry with a high-purity germanium detector. The Maxwellian-averaged cross sections at $kT$ = 30 keV of $^{69}$Ga and $^{71}$Ga determined in this work are 136(8) mb and 105(7) mb, respectively, in good agreement with previous experimental values. Astrophysical implications of the measurements are discussed.

Determination of dose derived from building materials and radiological health related effects from the indoor environment of Dessie city, Wollo, Ethiopia

The eight most common construction materials in Dessie City were collected in order to determine the amount of natural radiation released and its effects on humans. This is the first time that such research has been conducted. A B13010 Gamma-ray spectrometry was used to determine the concentration of the daughter element photo peak (High Purity Germanium detector). These studies can be used to track changes in radioactivity caused by industrial and other human activities. The mean radioactivity concentrations of 226Ra, 232Th, and 40K were calculated to be 26.59 ± 3.26, 26.59 ± 2.76, and 115.65 ± 2.73 Bq kg−1, respectively. The calculated Radium equivalent activity (Raeq) and absorbed dose were lower than the global average. The estimated annual effective dose equivalent was 0.08 ± 0.01 mSv y−1. External and internal radiation hazard indices (Hex and Hin), activity utilization indices, alpha indices, and gamma representative indices are all lower than the world's recommended standards. The mean of the ELCR is lower than the global mean. The annual effective dose equivalent is slightly above the global average.

Measurement of natural radiation, calculation of radiation doses of agricultural environmental samples in the western region - Kingdom of Saudi Arabia

The activity concentrations of the NORM were measured in thirty samples of plant cultures in agricultural soil irrigated with groundwater from different locations in the Makkah region in Saudi Arabia, using a high purity germanium detector HPGe system. The mean values of the activity concentrations for 226Ra, 232Th, and 40K were found in plants samples 10.41, 1.92, and 4154.92 in Bq. kg−1, for agricultural soil samples were 18.11, 16.12, and 1603.73 Bq. kg−1 respectively, and the irrigation water samples were found 1.57, 0.58, and 118.44 Bq. l−1 respectively. The mean values of Raeq, dose rate, annual effective dose, hazard indices Hex and Hin were 333.09 Bq. kg−1, 179.23 nGy h−1, 1.09 mSv.y−1, 0.89 and 0.92 respectively for plant samples. The gamma doses were higher than world limit values and the Hex and Hin were less unity. The mean values of annual effective doses for ingestion of radionuclides in the plants samples were 2.12 mSv.y−1 for children and 1.86 mSv.y−1 for adults, these results were higher than the world values. These results indicate that, the highest doses refer to the samples location in farm 1, while the lowest values were in farm 3 and farm 6, while the other farms were relatively high than recommended dose values. So, samples of soil, water and plant must be studied in the farm 1 for the highest results of the annual effective doses mSv.y−1 of ingestion of radionuclides in the plants samples for children and adults.

Radiological risk assessment in sediment of Namal Lake, Mianwali, Pakistan.

This study is concentrated on the radiological risk assessment of sixteen surface sediment samples recovered from Namal Lake, District Mianwali, Punjab, Pakistan. The activity of 137Cs, 40K, 226Ra, 228Ra, and 232Th was carried out with the help of a high purity germanium detector (HPGe) in the sediment, varied in the ranges of > 0.02-3.73 ± 1.31, 98.32 ± 21.45-341.02 ± 58.67, 18.34 ± 2.16-34.23 ± 4.34, 1.62 ± .30-2.34 ± .52, and 0.14 ± 0.10-2.34 ± 0.59Bqkg-1 with average values 0.74 ± 0.29, 237.26 ± 37.97, 25.06 ± 4.74, 1.97 ± 0.39, and 1.73 ± 0.33Bqkg-1, respectively. The measured concentrations in the current study have been compared with other earlier studies in the world. The data was also used for determining the other useful parameters like radium equivalent activity, absorbed dose rate, annual effective dose rate, and external and internal hazards index to assess the radiological risk assessment for the environment around the study area. The ERICA Tool software was also applied for radiological risk assessment for lake fish due to the radioactivity present in the lake sediments. It was concluded from the results of ERICA tool that the risk quotient in this study is less than one indicating that no toxic effects of radioactivity for Namal Lake fish.

Experimental setup for elemental analysis using prompt gamma rays at research reactor IBR-2

The new experimental setup has been built at the 11b channel of the IBR-2 research reactor at FLNP, JINR, to study the elemental composition of samples by registration of prompt gamma emission during thermal neutron capture. The setup consists of a curved mirror neutron guide and a radiation-resistant HPGe high-purity germanium detector. The detector is surrounded by lead shielding to suppress the natural background gamma level. The sample is placed in a vacuum channel and surrounded by a LiF shield to suppress the gamma background generated by scattered neutrons. This work presents characteristics of the experimental setup. An example of hydrogen concentration determining in a diamond powder made by detonation synthesis is given and on its basis, the sensitivity of the setup is calculated being ∼4 μg.

Cross-section measurements of (n, 2n) and (n, p) reactions on 124,126,128,130,131,132Xe in the 14 MeV region and theoretical calculations of their excitation functions * *Supported by the National Natural Science Foundation of China (11875016, 12165006)

The reaction cross-sections of 124Xe(n, 2n)123Xe, 126Xe(n, 2n)125Xe, 128Xe(n, 2n)127Xe, 130Xe(n, 2n)129mXe, 132Xe(n, 2n)131mXe, 130Xe(n, p)130I, 131Xe(n, p)131I, and 132Xe(n, p)132I were measured at the 13.5, 13.8, 14.1, 14.4, and 14.8 MeV neutron energies. The monoenergetic neutrons were generated via the 3H(d,n)4He reaction at the China Academy of Engineering Physics using the K-400 Neutron Generator with a solid 3H-Ti target. A high-purity germanium detector was employed to measure the activities of the product. The reactions 93Nb(n, 2n)92mNb and 27Al(n, α)24Na were adopted for neutron flux calibration. The cross sections of the (n, 2n) and (n, p) reactions of the xenon isotopes were obtained within the 13–15 MeV neutron energy range. These cross-sections were then compared with the IAEA-exchange format (EXFOR) database-derived experimental data, together with the evaluation results of the CENDL-3, ENDF/B-VIII.0, JENDL-4.0, RUSFOND, and JEFF-3.3 data libraries, as well as the theoretical excitation function obtained using the TALYS-1.95 code. The cross-sections of the reactions (except for the 124Xe(n, 2n)123Xe and 132Xe(n, p)132I) at 13.5, 13.8, and 14.1 MeV are reported for the first time in this study. The obtained results are beneficial in providing better cross-section constraints for the reactions in the 13–15 MeV region, thus improving the quality of the corresponding database. Meanwhile, these data can also be used for the verification of relevant nuclear reaction model parameters.

Erratum to: Measurement of the background activities of a 100Mo-enriched powder sample for an AMoRE crystal material by using a single high-purity germanium detector

Erratum to: Measurement of the background activities of a 100Mo-enriched powder sample for an AMoRE crystal material by using a single high-purity germanium detector

Studying Concentrations of Radionuclides in the Soil of Taza Khurmato - Kirkuk Governorate Using High Purity Germanium Detector

The study included the evaluation of the level of normal and industrial natural radiation activity of soil samples using the spectroscopy technique of the high purity germanium detector. 10 soil samples were collected at a depth of 10 cm from the city of Taza Khurmato and its suburbs of Kirkuk Governorate. It was found that the Specific Activity Concentration which is measured by Bq.kg-1 for Thorium 234T, Radium 226Ra, Lead 214Pb, Protactinium 234Pa, Lead 212Pb, Actinium 228Ac, Cesium 137C and Potassium 40K in the studied models ranged between ( B.D.L - 65±17.2) at a rate of (7.46±2.02), (22.2±3.9 - 41.8±9.3) at a rate of (28.88±5.35), (10.2±0.9 - 14.6±2.6) at a rate of (12.24±1.37), (B.D.L - 46.2±4.5) at a rate of (11.58±1.26), (5.7±1.2 - 12.4±1.2) at a rate of (9.11±0.88), (8.2±0.6 - 13±1.6 ) at a rate of (10.46±1.81), (B.D.L - 5.6±1.2) at a rate of (1.94±0.34), (160±11.2 - 264.6±14.4) at a rate of (206.5±17.65). respectively. All these values are globally admissible and do not affect human health or the environment. As well as calculating the Radium Equivalent (74.728 – 46.246)Bq.kg-1, the Activity Concentration Index (0.534-0.336), the Internal Hazard Indices (0.312-0.184), the External Hazard Indices (0.201-0.124) , the values of Absorbed Dose Rate in Air (35.21-22.02)nGy.kg-1, the values of Internal Annual Effective Dose Equivalent (0.172-0.108)mSv.y-1, the values of External Annual Effective Dose Equivalent (0.0431-0.027)mSv.y-l, Excess Lifetime Cancer Risk (0.151-0.094)*10-3, External Annual Effective Dose (0.332-0.207)mSv.y-1. After balancing the results obtained with the global results, we found that the levels of radiation for samples studied were lower than their corresponding allowed limits.

Vibration Reduction in a Pulse Tube-Cooled High Purity Germanium Detector

High-purity germanium (HPGe) is a vibration-sensitive, high-resolution detector. It has been found that microphonic noise induced by vibration and electromagnetic interference from EMC causes energy resolution degradation in HPGe detectors. In this paper, to enhance the energy resolution of a pulse tube-cooled high purity germanium detector, a passive vibration isolation system for the portable pulse tube cooler (PTC) was employed and investigated. In order to evaluate the performance of the vibration isolation system, micro-vibration tests of the compressor with a vibration isolation kit and detector mounting interface were performed. Meanwhile, detector energy resolution and detector signal noise were tested, respectively, under the PTC, with the isolation system switched to either an on or off condition. The test results indicate that the effectiveness of passive vibration isolation techniques is confirmed, and no degradation was induced by PTC vibration on detector energy resolution.

Experimental study of single- vs two-close-frequency heating impact on confinement and loss dynamics in ECR ion source plasmas by means of x-ray spectroscopy and imaging

We hereby report a study on confinement and electron loss dynamics in the magnetic trap of an electron cyclotron resonance ion source using a special multi-diagnostic setup that has allowed the simultaneous collection of plasma radio-self-emission and x-ray images in the range 500 eV–20 keV. Argon plasmas were generated in single- and two-close-frequency heating (SFH and TCFH) modes. Evidence of turbulent regimes has been found: for stable and unstable configurations quantitative characterizations of the plasma radio self-emission have been carried out, then compared with local measurements of plasma energy content evaluated by x-ray imaging. This imaging method is the only one able to clearly separate x-ray radiation coming from the plasma from that coming from the plasma chamber walls. X-ray imaging has also been supported and benchmarked by volumetric spectroscopy performed via silicon drift and high-purity germanium detectors. The obtained results in terms of x-ray intensity signal coming from the plasma core and from the plasma chamber walls permit the estimation of the average ratio: plasma vs. walls (i.e. plasma losses) as a function of input RF power and pumping wave frequency, showing an evident increase (above the experimental errors) of the intensity in the 2–20 keV energy range due to the plasma losses in the case of unstable plasma. This ratio was well correlated with the strength of the instabilities, in SFH operation mode; in TCFH mode, under specific power balance conditions and frequency combinations, it was possible to damp the instabilities, and thus the plasma losses were observed to decrease and a general reconfiguration of the spatial plasma structure occurred (the x-ray emission was more concentrated in the center of the plasma chamber). Finally, a simplified model was used to simulate electron heating under different pumping frequencies, prompting discussion of the impact of velocity anisotropy vs the onset of the instability, and the mechanism of particle diffusion in the velocity space in stable and unstable regimes.

Effect of front, lateral and back dead layer thicknesses of a HPGe detector on full energy peak efficiency

As well known, High Purity Germanium (HPGe) detectors have a wide range of applications in every area where radiation detection and measurements are involved. One of the most important parameters in this respect is the determination of the full energy peak (FEP) efficiency. There are certain parameters affecting the so-called FEP efficiency. Perhaps the most important one is the thickness of dead layers of the crystal itself. In the current study, we investigated the effects of the thickness of front, lateral and back dead layer thicknesses of the detector crystal on the FEP efficiencies for the energy range 30 keV–5 MeV using EGS4 Monte Carlo simulation package. It was shown that the change in the thickness of the front dead layer has significant effect on the efficiency values for the energy interval 30–400 keV. The change in the thickness of the lateral and back dead layer was shown to have significant effects on the efficiencies for the energy intervals 2–3 MeV and 3–5 MeV, respectively. The results were checked using GEANT4 and a good agreement was observed.

Monte Carlo calculated calibration settings for commercially available nuclear medicine ionization chambers.

A method for calculating nuclear medicine ionization chamber (NMIC) calibration settings with a Monte Carlo model is presented and validated against physical measurements. This work provides Monte Carlo-calculated calibration settings for select isotopes with no current manufacturer recommendations and a method by which NMIC manufacturers or standards laboratories can utilize highly detailed specifications to calculate comprehensive lists of calibration settings for generalisotopes. A Monte Carlo model of a Capintec PET series NMIC was developed and used to calculate the chamber response to relevant radioactive decay products over an energy range relevant to nuclear medicine. The photon detection efficiency (PDE) of a high purity germanium (HPGe) detector was modeled and physically validated to facilitate measurements of NMIC calibration settings with HPGe detector spectroscopy. Modeled NMIC response to various isotopes was compared against spectroscopic measurements and National Institute of Standards and Technology (NIST)-validated calibration settings to validate the Monte Carlo-calculated NMIC calibrationsettings. HPGe detector PDE was validated against the physical measurements to within at confidence and used to measure calibration settings, which produced activity readings , , , and different than those validated by NIST for C, F, Ga, and Cu respectively. The Monte Carlo model of the NMIC reproduced measured calibration settings to within at confidence for isotopes with a sufficiently small yield of low energy photons. A method of calculating NMIC calibration settings with Monte Carlo modeling has been developed and validated against HPGe detector spectroscopy. NMIC manufacturers or standards laboratories can use more detailed specifications of the chamber geometries to extend the applicability of this method to a wider range of isotopes.

222Rn and 226Ra Concentrations in Spring Water and Their Dose Assessment Due to Ingestion Intake.

222Rn and 226Ra concentrations of less than a few to several thousands of Bq L−1 have been observed in several underground bodies of water around the world. Although regulations for these concentrations in water have been implemented internationally, there are currently no regulations in place in Japan. However, concentrations that exceed these internationally recognized regulatory values have also been observed in Japan. In this study, concentrations in spring water in the northern part of Japan were measured and the effective dose from intake of the water was evaluated. 222Rn concentrations were measured using a liquid scintillation counter, and 226Ra concentrations were measured using a high purity germanium detector after chemical preparation. The measured 222Rn concentrations (=12.7 ± 6.1 Bq L−1) and 226Ra concentrations (<0.019–0.022 Bq L−1) did not exceed the reference values set by international and European/American organizations. A conservative estimate of the annual effective ingestion dose of 8 μSv for 222Rn and 226Ra obtained in this study is much smaller than the estimated overall annual effective dose of 2.2 mSv from natural radiation to the Japanese population. However, this dosage accounts for 8% of the WHO individual dosing criteria of 0.1 mSv/year for drinking water.

Validation and Optimization of Activity Estimates of the FiR 1 TRIGA Research Reactor Biological Shield Concrete

FiR 1 is a TRIGA Mark II-type research reactor in Finland. It was in operation between 1962 to 2015 and will be dismantled in 2022 to 2023. Preliminary calculations of the activities in the reactor main structures were performed in an earlier stage of the decommissioning project. Samples of the activated parts of the reactor biological shield concrete were drilled in December 2018 to validate these estimates. This paper describes the calculations and gamma activity measurements performed for the activated concrete samples to determine the boundary between radioactive parts and concrete that can plausibly be free-released from regulatory control. The activities have been estimated with a two-step calculation process using the MCNP and ORIGEN-S calculation codes and measurements using an ISOCS gamma spectrometer with a high-purity germanium detector.

Synthesis and characterization of newly developed phosphate-based glasses through experimental gamma-ray and neutron spectroscopy methods: Transmission and dose rates

In this study, four new phosphate-based glasses with the compositions of CaO–Na2O–K2O–P2O5 (PN system), CaO–Na2O–K2O–Al2O3–P2O5 (PA system) and CaO–Na2O–K2O–Al2O3–SiO2–P2O5 (PS system) were synthesized and characterized through experimental gamma-ray and neutron spectroscopy methods. Glass densities were then measured experimentally and evaluated theoretically. Next, a high purity Germanium (HPGe) detector was used for determining the fundamental gamma-ray transmission parameters in 35.4–383 keV gamma-ray energies emitted from 133Ba source (Radioactivity: 3Ci). Additionally, the experimental setup was used to determine the equivalent dose (EAD) to get a better knowledge of fast neutron attenuation. Our findings indicate that experimental gamma-ray transmission measurements are consistent with standard theoretical data (EpiXS). Consequently, PA10 was shown to have higher gamma-ray and neutron attenuation capabilities when compared to the other glass samples studied. Our outcomes showed that increasing the molar contribution of Al2O3 to the phosphate-based glasses increased not only their transparency but also their gamma-ray and neutron attenuation capacities. It can be concluded that substituting Al2O3 for P2O5 is a functional and monotonic tool for improving the optical, gamma-ray, and neutron attenuation of phosphate-based glasses, which are being evaluated as prospective shielding materials for medical and industrial radiation facilities.

A METHOD TO IDENTIFY AND LOCALIZE A SINGLE HOT PARTICLE IN THE LUNGS USING AN ARRAY OF HIGH-PURITY GERMANIUM DETECTORS FOR IMPROVED ESTIMATE OF THE DEPOSITED ACTIVITY.

A new method has been developed to identify and localize a single hot particle in the lungs using an array of four high-purity germanium detectors. The method is based upon calculating a set of three count rate ratios (generated by each individual detector in the array) that are evaluated in sequence to designate whether the measured deposition can be associated with a hot particle rather than the default assumption of a uniform activity distribution. Identification and localization of the hot particle are determined from a single in vivo measurement in which detectors are positioned above and below the thorax. The method was tested using an anthropomorphic thorax phantom in which point sources of 241Am, 137Cs and 60Co were individually inserted in the lungs at 15 different locations and were measured using a scanning bed whole-body counter. Depending upon source location and photon energy, a bias of -35% up to +76% could be introduced by falsely assuming a uniform activity distribution in the lungs. This bias would directly translate to an erroneous dose estimate to the lungs. It was demonstrated that by using the appropriate detector efficiencies for the single hot particle, the bias associated with the activity determination is reduced to <10% and~2% in average.

Radiation Shielding Tests of Crosslinked Polystyrene-b-Polyethyleneglycol Block Copolymers Blended with Nanostructured Selenium Dioxide and Boron Nitride Particles.

In this work, gamma-ray shielding features of crosslinked polystyrene-b-polyethyleneglycol block copolymers (PS-b-PEG) blended with nanostructured selenium dioxide (SeO2) and boron nitride (BN) particles were studied. This research details several radiation shielding factors i.e., mass attenuation coefficient (), linear attenuation coefficient (), radiation protection efficiency (RPE), half-value layer (HVL), tenth-value layer (TVL), and mean free path (MFP). The irradiation properties of our nanocomposites were investigated with rays from the 152Eu source (in the energy intervals from 121.780 keV to 1408.010 keV) in a high-purity germanium (HPGe) detector system, and analyzed with GammaVision software. Moreover, all radiation shielding factors were determined by theoretical calculus and compared with the experimental results. In addition, the morphological and thermal characterization of all nanocomposites was surveyed with various techniques i.e., nuclear magnetic resonance (NMR), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and transmission electron microscopy (TEM). Acceptable compatibility was revealed and observed in all nanocomposites between the experimental and theoretical results. The PS-b-PEG copolymer and nanostructured SeO2 and BN particles exerted a significant effect in enhancing the resistance of the nanocomposites, and the samples with high additive rates exhibited better resistance than the other nanocomposites. From the achieved outcomes, it can be deduced that our polymer-based nanocomposites can be utilized as a good choice in the gamma-irradiation-shielding discipline.