High-purity Germanium Detector Research Articles

Novel Cu/Zn Reinforced Polymer Composites: Experimental Characterization for Radiation Protection Efficiency (RPE) and Shielding Properties for Alpha, Proton, Neutron, and Gamma Radiations.

In this study, brass (Cu/Zn) reinforced polymer composites with different proportions of brass powders were fabricated. Different types of nuclear shielding parameters such as mass and linear attenuation coefficients, radiation protection efficiency, half and tenth value layers, and effective atomic number values were determined experimentally and theoretically in the energy range of 0.060–1.408 MeV in terms of gamma-ray shielding capabilities of fabricated polymer composites. A high Purity Germanium detector (HPGe) in conjunction with a Multi-Channel Analyzer (MCA) and twenty-two characteristic gamma-ray energies have been used in the experimental phase. In addition, the exposure and energy absorption buildup factors of reinforced Cu/Zn composites were calculated, and relative dose distribution values were computed to verify them. Proton mass stopping power (ΨP), proton projected range (ΦP), alpha mass stopping power (ΨA), and alpha projected range (ΦA) parameters, which indicate the interactions of the produced composites with charged particle radiation, were investigated. Fast neutron removal cross-section (ΣR) results were determined to give an idea in terms of neutron shielding. According to the obtained results, it is reported that the CuZn20 coded sample’s ability to attenuate gamma-ray and charged particle radiation is more efficient than that of other prepared composites. A CuZn05 coded sample was found to be more suitable for neutron shielding capability.

A Comparison of Current Methods for the Determination of Ra-226 and Ra-228 in Water by a Modified Georgia Tech Gamma Method Vs. US Environmental Protection Agency Drinking Water Methodologies.

Radium is a significant source of human radiation exposure both from natural sources (NORM, or Naturally Occurring Radioactive Material) and from technologically enhanced natural radioactive material (TENORM). Gamma analysis for 226Ra and 228Ra in water using high purity germanium (HPGe) detectors was compared with current methods from the US Environmental Protection Agency (EPA) using alpha scintillation and gas proportional counters. Extensive evaluations of a modified version of the original Georgia Tech HPGe method were performed. Known value 226Ra samples from the US Department of Energy (DOE) Mixed-Analyte Performance Evaluation Program (MAPEP) program, mixed 226Ra and 228Ra samples from the Environmental Resource Associates Quality Assurance Program (ERA), and mixed 226Ra and 228Ra samples from the Laboratory Proficiency Testing Program of the International Atomic Energy Agency (IAEA) were used for cross-check comparisons of the modified Georgia Tech method with other methodologies (EPA 903.1 and Ra-05 for 226Ra and 228Ra, respectively). Minimum counting times for our gamma instrumentation to reach a minimum detectable activity (MDA) of 0.04 Bq L-1 were also determined.

The muX project

The project is conducting a series of muonic X-ray measurements in medium- and high-Z nuclei at PSI, utilizing a high-purity germanium detector array, in-beam muon detectors, and a modern digital data-acquisition system. A novel hydrogen target for muon transfer was developed, enabling measurements with as little as a few micrograms of target material. First measurements with radioactive Cm and Ra targets were conducted, aimed at determining their nuclear charge radii. These serve as important input for upcoming atomic parity violation experiments. The apparatus is also used to perform a feasibility study of an atomic parity violation experiment with the 2s-1s2s−1s muonic X-ray transition. In addition, the setup has been made available for a wider range of nuclear, particle, and solid-state physics measurements.

The effects of various types of phosphate fertilizers on the environment and their natural activity

In this study, the effect of various types of fertilizers on natural radioactivity levels in agricultural soil was investigated in this research. The activity concentration of 226Ra, 232Th, and 40K in fertilizer samples were determined by using gamma-ray spectroscopy and a high-purity germanium (HPGe) detector to determine the activity concentrations 226Ra, 232Th, and 40K. The activity concentrations for 226Ra, 232Th, and 40K in fertilizers and phosphate raw were (2300-5400) Bq/kg, (9-53) Bq/kg, and (56-3000) Bq/kg, respectively. This research could serve as a baseline data for understanding the effects of fertilizer radiation on human health.

Transfer from soil to grass and statistical analysis of naturally occurring radionuclides in soil from phosphate mining and processing sites in Maritime Region of Togo

Natural radionuclides activity concentrations of 226Ra, 228Ra, and 40K in soil and grass samples, statistical analysis of these radionuclides, and transfer factors (TFs) from soil to the grass were carried out from phosphate mining and processing sites in southern areas of Togo using gamma-ray spectrometry-based high-purity germanium (HPGe) detector. The average activity concentrations of 226Ra, 228Ra, and 40K were found within the range usually measured worldwide. Statistical analysis was done by investigating the skewness, the kurtosis, and the density distribution of radionuclides in the study areas. Both skewness and kurtosis displayed that the activity concentrations of soil and grass samples in the discharge waste site (Kpémé) and mining site (Hahotoé) exhibited slightly positively skewed, negatively skewed, leptokurtic, and platykurtic distributions. The TFs for 226Ra, 228Ra, and 40K from discharge waste soil to grass were evaluated. The average transfer factors of 226Ra, 228Ra, and 40K in the phosphate processing area were found to be 0.16, 0.32, and 8.42, respectively. 226Ra and 228Ra TFs values were found to be within the limit of worldwide measure values, while that of 40K was found to be larger than the values measured in other countries. The average TF value of 8.42 for 40K was eight times higher than the average value of unity, showing its large intake by vegetables. The high TFs for 40K could be explained by the extensive application of phosphate fertilizers to soils when growing vegetables.

Measurement of Natural Radioactivity Level in Selected Phosphate Fertilizer Samples Collected from Iraqi Markets

The Gamma-ray spectrometry (spectra line Gp) and a high-purity germanium (HPGe) detector were used to determine the activity concentrations of 226Ra, 232Th, and 40K in fertilizer samples. 226Ra, 232Th, and 40K activity concentrations in fertilizers and phosphate raw. In this study the gamma index(I), Radium equivalent dose(Raeq),dose rate(DR),external hazard index(Hex) internal hazard index(Hin), annual effective dose outdoor(AEDout) and annual effective dose indoor(AEDin)were found. This study could serve as a starting point for figuring out how fertilizer radiation affects human health.

Activity concentrations of 226^Ra, 232^Th, and 40^K in common maize meal consumed in Namibia and their potential radiation hazards

Gamma spectroscopy was performed to determine the concentrations of 40K, 226Ra and 232Th in maize meal samples collected from shop outlets and open markets in Namibia. The activity concentrations and Excess Lifetime Cancer Risk were determined using a high purity germanium (HPGe) detector. The average activity concentrations of 40K, 226Ra and 232Th were found to be 29.98 ± 4.05, 0.99 ± 0.40 and 0.35 ± 0.08 Bq.kg – 1 in the maize meal samples. The result showed the activity concentrations of 40K significantly higher than the other radionuclides in all the maize meal samples. The average excess life cancer risk varies from 1.33 x 10 – 13 to 6.05 x 10 – 13 for 40K, 8.76 x 10 -13 to 1.19 x 10 – 12 for 232Th and 2.43 x 10 -11 to 2.83 x 10 – 11 for 226Ra. Hence, when compared with internationally acceptable limits, all values fall within the safety limits. Thus, the study concludes that the maize meals consumed in Namibia are radiologically safe for consumption.

Natural Radionuclides in Medicinal Plants and Forages from a Granite Mountain area, Phangan Island, Surathani Province.

The radioactive nuclides were a cancer causing agent. They have a source of origin from nature and man-made. The natural radioactive elements were found in granite rock. The purpose of this research were analyze the activity of radioactive nuclides (226Ra, 232Th and 40K) in herbs and forage plant samples from Koh Phangan District, Surat Thani Province and to analyze the Annual external effective dose rate (E). A total of 20 species of plants, including medicinal plants and food chains plant were randomly sampled. The plant samples were analyzed by the gamma spectrometry system with high-purity germanium (HPGe) detector. It was found that the radioactive nuclides of 226Ra, 232Th and 40K were ranged from 6.75 ± 0.16 to 61.55 ± 0.48, 1.76 ± 0.15 to 34.24 ± 0.25 and 330.74 ± 0.37 to 1337.54 ± 0.64 Bq/kg, respectively. In addition, the Annual external effective dose rate (E) in all plants were lower than required (UNSCEAR, 2000).

Low-energy resonances in the O18 ( p,γ)19F reaction

Background: Shell hydrogen burning during the asymptotic giant branch (AGB) phase through the oxygen isotopes has been indicated as a key process that is needed to understand the observed O18/O16 relative abundance in presolar grains and in stellar atmospheres. This ratio is strongly influenced by the relative strengths of the reactions O18(p,α)N15 and O18(p,γ)F19 in low-mass AGB stars. While the former channel has been the focus of a large number of measurements, the (p,γ) reaction path has only recently received some attention and its stellar reaction rate over a wide temperature range rests on only one measurement. Purpose: Our aim is the direct measurement of states in F19 as populated through the reaction O18(p,γ)F19 to better determine their influence on the astrophysical reaction rate, and more generally to improve the understanding of the nuclear structure of F19. Method: Branchings and resonance strengths were measured in the proton energy range Eplab=150–400keV, using a high-purity germanium detector inside a massive lead shield. The measurement took place in the ultra-low-background environment of the Laboratory for Underground Nuclear Astrophysics (LUNA) experiment at the Gran Sasso National Laboratory, leading to a highly increased sensitivity. Results: The uncertainty of the γ branchings and strengths was improved for all four resonances in the studied energy range; many new transitions were observed in the case of the 334keV resonance, and individual γ decays of the 215keV resonance were measured for the first time. In addition a number of transitions to intermediate states that decay through α emission were identified. The strengths of the observed resonances are generally in agreement with literature values. Conclusions: Our measurements substantially confirm previous determinations of the relevant resonance strengths. Therefore the O18(p,γ)F19 reaction rate does not change with respect to the reaction rate reported in the compilations commonly adopted in the extant computations of red-giant branch and AGB stellar models. Nevertheless, our measurements definitely exclude a nonstandard scenario for the fluorine nucleosynthesis and a nuclear physics solution for the O18 depletion observed in Group 2 oxygen-rich stardust grains.3 MoreReceived 18 June 2020Revised 12 April 2021Accepted 6 July 2021DOI:https://doi.org/10.1103/PhysRevC.104.025802©2021 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasH & He burningNuclear astrophysicsNuclear reactionsRadiative captureProperties6 ≤ A ≤ 19Nuclear Physics

Simulation of semiconductor detectors in 3D with SolidStateDetectors.jl

The open-source software package SolidStateDetectors.jl to calculate the fields and simulate the drifts of charge carriers in solid state detectors, especially in large volume high-purity germanium detectors, together with the corresponding pulses, is introduced. The package can perform all calculations in full 3D while it can also make use of detector symmetries. The effect of the surroundings of a detector can also be studied. The package is programmed in the user friendly and performance oriented language julia, such that 3D field calculations and drift simulations can be executed efficiently and in parallel. The package was developed for high-purity germanium detectors, but it can be adjusted by the user to other types of semiconductors. The verification of the package is shown for an n-type segmented point-contact germanium detector. Additional features of SolidStateDetectors.jl, which are under development are listed.

Calibration of the Gerda experiment

The GERmanium Detector Array (Gerda) collaboration searched for neutrinoless double-beta decay in ^{76}Ge with an array of about 40 high-purity isotopically-enriched germanium detectors. The experimental signature of the decay is a monoenergetic signal at Q_{beta beta }=2039.061(7) keV in the measured summed energy spectrum of the two emitted electrons. Both the energy reconstruction and resolution of the germanium detectors are crucial to separate a potential signal from various backgrounds, such as neutrino-accompanied double-beta decays allowed by the Standard Model. The energy resolution and stability were determined and monitored as a function of time using data from regular ^{228}Th calibrations. In this work, we describe the calibration process and associated data analysis of the full Gerda dataset, tailored to preserve the excellent resolution of the individual germanium detectors when combining data over several years.

A Development of a 40-Gb/s Readout Interface STARE for the AGATA Project

The Advanced GAmma Tracking Array (AGATA) multidetector spectrometer will provide precise information for the study of the properties of the exotic nuclear matter (very unbalanced proton (Z) and neutron (N) numbers) along proton- and neutron-drip lines and of super-heavy nuclei. This is done using the latest technology of particle accelerators. The AGATA spectrometer consists of 180 high-purity germanium detectors. Each detector is segmented into 38 segments. The very harsh project requirements are to measure gamma-ray energies with very high resolution ( <; 1×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-3</sup> ) at a high detector counting rate (50 K events/s/crystal). This results in a very high data transfer rate per crystal (5-8 Gb/s). The 38 segments are sampled at 100 MHz with 14 bits of resolution. The samples are continuously transferred to the control and processing (CAP) module, which reduces the data rate from 64 to 5 Gb/s. The CAP module also adds continuous monitoring data, which results in total outgoing data rate of 10 Gb/s. The serial transfer acquisition and readout over Ethernet (STARE) module is designed to fit between the CAP module and the computer farm. It will package the data from the CAP module and transmit it to the server farm using a 10-Gb/s user datagram protocol (UDP) connection with a delivery insurance mechanism implemented to ensure that all data are transferred.

Experiment-based determination of the excitation function for the production of Ti44 in proton-irradiated vanadium samples

In this paper, the excitation function utilizing the nuclear reaction $^{\mathrm{nat}}\mathrm{V}(p,X)$ $^{44}\mathrm{Ti}$ was determined. The seven investigated metallic vanadium disks were proton irradiated within an energy range of 111--954 MeV between 1995 to 1996. The experiments' cross sections were validated using two independent measurements by combining $\ensuremath{\gamma}$ spectrometry with both a low-energy germanium detector and a high-purity germanium detector. The maximum cross section was observed for energies of 145 $\ifmmode\pm\else\textpm\fi{}$ 1.2 and 150.2 $\ifmmode\pm\else\textpm\fi{}$ 1.2 MeV with values of 803 $\ifmmode\pm\else\textpm\fi{}$ 28 and 805 $\ifmmode\pm\else\textpm\fi{}$ 27 $\ensuremath{\mu}\mathrm{b}$, respectively. In this regard, it was demonstrated that our data were in good agreement with the former, however, unpublished results which were investigated over a similar energy range. Thus, combined with these earlier measurements, a consistent data set for the $^{\mathrm{nat}}\mathrm{V}(p,X)$ $^{44}\mathrm{Ti}$ excitation function from 111 to 1350 MeV is provided. Model calculations using Li\`ege Intranuclear Cascade (INCL)/ABLA reproduce the shape of the excitation function correctly but overpredict the absolute values by factors of 2 to 3. Some considerations regarding this already earlier observed systematic overestimation of neutron-poor residues are given. The results will trigger new approaches in code development in order to improve the predictions.

Determination of the Petro-physical and Natural Radioactivity Properties of Nubian Sandstone Aquifer at the Area of Northwest El Ain Village, Sharq El-Oweinat Area, Southwestern Desert, Egypt

The Nubian sandstone aquifer's hydrogeophysical and natural radioactivity parameters at the Northwestern part of El Ain village, Sharq El Oweinat, Southwestern desert, Egypt are resolved using geophysical well logging and natural radioactivity techniques. The study aims to monitor the phenomenon of appearing an unusual high gamma-ray at a zone of high resistivity record. A nest of well logs is collected to assess how the phenomenon is widespread. Results of correlated well logs are clarified that this phenomenon at zone between 80 and 100 m and zone of 200 and 230m depth is noticed. The petro-physical properties are estimated from the recorded well logs. The results showed that the percentage of the average of effective porosity % varies between 20 and 28.2%, while average vary from 2 to 12.5 %, which indicates that the aquifer of Nubian Sandstone is classified as a clean aquifer. The natural radioactivities of the studied area in the rock samples were evaluated using high-purity germanium (HPGe) detector. The results indicated that the average value of Th-232 is (51.32 ±4.92%) Bq/kg, Ra-226 is (29.03 ± 4.68%) Bq/kg while the radioactivity concentration of K-40 exists only in one sample with low concentration.

Measurement of natural radioactivity and its health hazards associated with the use of different branded cement samples collected from different manufactures in Dhaka city using gamma spectrometry

The radioactivity of naturally occurring radionuclides 226Ra, 232Th, and 40K was determined in thirteen cement samples collected from different manufactures of Dhaka city. The measurement was performed by gammaray spectrometry system using high purity germanium (HPGe) detector. The average activity of 226Ra, 232Th, and 40K in cement samples are fon und to be 30.23±15.04 Bqkg-1, 20.10±11.76 Bqkg-1 and 145.27±24.14 Bqkg-1, respectively. The average values of radium equivalent activity (Raeq), absorbed dose rates (D), internal hazard and external hazard index (Hex), and annual effective dose equivalent are 370 Bqkg-1, 0.27, 0.18, and 27.99 nGyh-1, respectively. The average annual effective dose is found 0.13 mSvy-1, which is less than the recommended value (1 mSvy-1) by the International Commission on Radiological Protection (ICRP-60, 1990), as the maximum permissible annual effective dose to the members of the public. The present study results are discussed and compared with those reported in similar studies and with internationally recommended values. No artificial radioactivity was found in the present study. The results show that the analyzed cement samples do not pose any significant radiation hazard from naturally occurring radionuclides 226Ra, 232Th and 40K reported here and also considered safe for use in buildings construction.&#x0D; J. Bangladesh Acad. Sci. 45(1); 95-104: June 2021

Short-lived photofission product yields from [formula omitted] and [formula omitted] at Bremsstrahlung X-ray endpoint energies of 8, 14, and 20 MeV for nuclear forensics isotope production applications

The existing photofission product yield data sets are often based on nuclear models, and limited experimental measurements of these fission product yields have been performed. These experiments resulted in measured cumulative fission product yields (CFPYs) for 238U and 232Th for the bremsstrahlung X-ray endpoint energies of 8, 14, and 20 MeV. The half-lives of the reported fission products range from 1.07–40.8 s. This work is motivated by a demonstrated need for novel isotope production methods for nuclear forensics and improved nuclear data to support the nonproliferation community. A high-purity germanium detector and a pneumatic transfer system were employed for measurements of short-lived fission products, collecting data between cycles of accelerator irradiation and measurement.

PbSe Quantum Dots for X-ray and γ-Ray Sensors

Nanocrystalline (NC) semiconductors exhibit exploitable properties, such as a tunable energy band gap and multiexciton generation, which arise due to strong quantum confinement. Lead selenide (PbSe), with a relatively large Bohr radius of 46 nm, possesses an extensive literature of organic synthesis routes with which one can explore the strong confinement regime in quantum dots, nanorods, and nanowires. The intrinsically high charge mobility combined with a high atomic number and density of the lead chalcogenides makes them attractive for sensing applications with highly penetrating quanta, such as X-rays and γ-rays. In sensing architectures, the exploitation of these properties for each individual nanocrystallite is hampered by the need to transport the charge carriers throughout the active volume, a motion that can be retarded by energetic surface barriers typically in the form of insulating oxides. Here, we prevent surface oxidation through the fabrication of PbSe NCs via tris(diethylamino)phosphine and a purified selenium precursor, a process that results in PbSe NCs that are chemically and optically stable for at least 1.6 years. If one endeavors to measure high-energy quanta, then the micrometer-scale stopping layers typical of optical photon sensors are insufficient and one must therefore find methods to interconnect the NCs through millimeter- to centimeter-scale thicknesses. Here, we report on the growth of millimeter-scale PbSe colloidal solids that are directly grown within the NC solution. Finally, in contrast to optical photon sensors that typically measure photocurrent, high-energy particle and photon sensors that measure the energy from each interacting quantum are typically hampered by the solid’s thermal noise and the counting statistics associated with discretizing a single quantum into a finite number of information carriers. We show that one can exploit the weaker phonon–electron coupling in nanocrystalline materials to produce room-temperature sensors of X-rays and γ-rays that have comparable resolution to state-of-the-art high-purity germanium detectors. The results thus suggest that multiexciton generation in nanocrystals can be profitably employed in sensing applications that target quanta that create hot-carrier populations that are well above the band gap.

Evaluation the nonlinear response function of a HPGe detector for 59 keV to 10.7 MeV gamma-rays using a Monte Carlo simulation and comparison with experimental data

Modeling of High Purity Germanium (HPGe) detector on a wide energy range is important in gamma-ray spectroscopy. The precisely modeled detector can be used for proton-induced prompt gamma-ray spectroscopy. In this work, we used both the gamma-rays of calibration sources and prompt gamma-rays emitted in proton capture reactions to model a coaxial p-type HPGe detector using Geant4 Monte Carlo simulation for the gamma-ray energy range of 59–10764 keV. The calibration sources were 137Cs, 241Am, 60Co, 152Eu, and 133Ba, while the prompt gamma-rays were due to the gamma-ray cascades following the 27Al(p,γ)28Si reaction capture at the resonant energies of 992, 1317 and 2483 keV, as well as the 23Na(p,γ)24Mg reaction capture at the resonant energies of 1417 and 1395 keV. According to the results obtained, the presented simulated and experimental spectra show a good agreement. In addition, the mean and maximum relative deviations between experimental and simulated efficiencies corresponding to 27 major peaks are smaller than 5% and 15%, respectively.

Full-volume characterization of an AGATA segmented HPGe gamma-ray detector using a $$^{152}Eu$$ source

Scanning tables use collimated gamma-ray sources to perform full volume characterization of position sensitive detectors. One of such tables is hosted at IPHC Strasbourg. It was designed and built within the AGATA collaboration. It exploits the pulse shape comparison scanning (PSCS) technique to build databases of pulses used to characterize the response of high purity germanium (HPGe) detectors and perform R&D on such crystals. Ultimately, measured databases could be used by the pulse shape analysis (PSA) algorithms employed in AGATA experiments. The table can perform full volume scans of large volume detectors in short times, with a good spatial resolution and at different energies. Lately, the table was upgraded with a new \(^{152}Eu\) source, which emits gamma rays in cascades of different energies. A scan with such source is performed for the first time. It allows to build different energy databases in one single scan. The present work aims at testing the performances of the PSCS technique with a multi-energetic source and verifying some assumptions of the Shockley–Ramo theorem which are at the base of the PSA algorithms used for gamma-ray tracking arrays.

Assessment of radiation hazard indices for sand samples from Ma'rib in Yemen

Background: This study aimed to investigate the radiation hazard indices from sand samples of Ma’rib Governorate in Yemen, where the majority of oil and gas facilities are installed. Methods and Materials: Thirty five samples of desert sand from Ma’rib Governorate in Yemen were collected and tested their radiation hazard indices by using High Purity Germanium (HPGe) detector. Results: Based on the measurement of the concentrations of 226Ra, 232Th, and 40K, the radium equivalent activity (Raeq), the activity concentration index (Iγ), the external hazard index (Hex) and the internal hazard index (Hin) were all calculated. Also, the absorbed dose rate in Air (ADR) and the annual effective dose (AED) are calculated. Conclusions: Comparing the practically attained results with internationally permissible values, it was found that most of the radiological parameters, including the radiation hazard indices of the studied samples, fall within the world's permissible limits and don't expose risks to the human beings and environments.