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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%. Regression graphs drawn between the outcomes from the two analytical systems indicate R2 > 0.95 for Ra(eU3O8) and ThO2. In uraniferous samples, the R2 value for U3O8 was found to be > 0.99, but in mixed U-Th samples, it is 0.92. The closeness of agreement between the results obtained from two methods at various concentrations over the analytical range shows that the integrated system is suitable for the quantitative determination of eU3O8, U3O8, Ra(eU3O8), ThO2 and K in geological rock samples. [ABSTRACT FROM AUTHOR]

Abstract: The Hawking evaporation process, leading to the production of detectable particle species, constrains the abundance of light black holes, presumably of primordial origin. Here, we reconsider and correct constraints from soft gamma-ray observations, including of the gamma-ray line, at 511 keV, produced by electron-positron pair-annihilation, where positrons originate from black hole evaporation. First, we point out that the INTEGRAL detection of the Large Magellanic Cloud provides one of the strongest bounds attainable with present observations; and that future MeV gamma-ray telescopes, such as GECCO, will greatly enhance such constraints. Second, we discuss issues with previous limits from the isotropic flux at 511 keV and we provide updated, robust constraints from recent measurements of the diffuse Galactic soft gamma-ray emission and from the isotropic soft gamma-ray background.

In the present study, the highly recommended lead iodide (PbI2) nanoparticles and thin films based on PbI2 nanoparticles have been prepared for optoelectronics and solar cell applications. PbI2 is an anisotropic p-type semiconductor with a band gap of 2.57 eV at room temperature. PbI2 material has large potential applications in optical detector, digital X-ray imaging, gamma ray detector, etc. PbI2 layered semiconductor nanoparticles were stabilized using thioglycerol and investigated by Ultraviolet-Visible (UV-Vis) absorption spectroscopy, X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), transmission electron microscopy (TEM) and photoluminescence (PL) spectroscopy. The chemical bath deposition (CBD) method was used to deposit PbI2 thin films on fluorine-doped tin oxide (FTO) glass substrates. These films were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), mapping and atomic force microscopy (AFM). The thicknesses of the PbI2 thin films were estimated using a laser profilometer. The blue shift was observed in UV-Vis absorption and PL spectra of PbI2 nanoparticles. TEM was used to obtain quantitative information on the PbI2 particle size distribution. Due to the low solubility of PbI2 in acetonitrile, approximately 20-30 nm sized circular particles are obtained. The variation of 18 Å was observed in the lateral dimensions of PbI2 nanoparticles. Pb4fXPS core level appeared at 138.5 eV corresponding to PbI2. There is no report published wherein the PbI2 nanoparticles and the PbI2 thin films were prepared by the aqueous chemical method and the CBD method respectively. In this study, the characterization results of PbI2 nanoparticles and PbI2 thin films were better than many other materials. [ABSTRACT FROM AUTHOR]

In recent years, rare earth silicate compounds have attracted the extensive attention of researchers owing to their potential for applications in scintillation crystals in gamma ray or X-ray detectors, as well as in thermal or environmental barrier coatings. Large high quality crystals of three members of the rare earth monosilicates family of compounds, R 2 SiO 5 (with R = Dy, Ho, and Er), have been grown by the floating zone method, using a laser-diode-heated floating zone furnace. Crystal growths attempts were carried out using different parameters in order to determine the optimum conditions for the growth of these materials. The phase purity and the crystalline quality of the crystal boules were analysed using powder and Laue X-ray diffraction. Single crystal X-ray diffraction experiments were carried out to determine the crystal structures of the boules. The optimum conditions used for the crystal growth of R 2 SiO 5 materials are reported. The phase purity and high crystalline quality of the crystals produced makes them ideal for detailed investigations of the intrinsic physical and chemical properties of these materials. [ABSTRACT FROM AUTHOR]

Scientific payloads onboard CubeSats usually have complex geometries and occasionally narrower allowed temperature ranges with respect to the rest of the spacecraft. In these cases, the capability to correctly predict the thermal behaviour of the payload once in orbit is mandatory. To achieve this ability, a thermal balance test is required to correctly identify the thermal model of the payload. The test consists in the application of different external thermal boundary conditions together with the addition of heat dissipation to simulate the thermal load produced by active electronics during operation. Those experimental data are fundamental to validate the numerical thermal model and make its predictions reliable. This paper presents the configuration and procedures of the thermal balance test performed on the Demonstration Model of the payload to be embarked on each satellite of the HERMES constellation. The test data is compared with the results of a finite volume thermal model of the payload, proving the application of this method to be reliable for space thermal analyses. The obtained test results show the temperature jumps caused by the heat dissipation applied to active components. A weak correlation between the payload interface and internal equipment has been observed, thus proving that the payload is almost decoupled from the Service Module temperature variations. Based on test outcomes, some modifications in the payload design have been implemented, with the aim to lower the operative temperature on critical, temperature-sensitive equipment. [ABSTRACT FROM AUTHOR]

Recently, there has been considerable interest in x-ray and gamma ray detectors with large volume and high energy resolution that operate at room temperature. To improve detector energy resolution, the carrier mobility-lifetime product needs to be increased, and the electronic trap state concentration needs to be minimized. Defect concentrations in the part per billion range can alter the charge transport and carrier recombination lifetime. In this work, thermally stimulated current spectroscopy measurements were systematically carried out in bulk halide perovskite single crystals of CsPbBr3 over a temperature range of 80–320 K. The origins and trap parameters of CsPbBr3 crystals from the solution growth and melt growth procedures were determined and compared. Trap concentrations were ranged from 1 × 1011 to 1 × 1016 cm−3. Appreciable detector performance was observed for CsPbBr3 crystals with trap concentrations less than 1 × 1014 cm−3. The comparison of spectral responses of crystal samples grown using two different methods shows that, after purification, solution-grown crystals are comparable to melt-grown crystals in terms of low defect concentration and improved detector performance. For an improved mobility-lifetime product and enhanced spectral response to high energy radiation from fissile materials, trap states in either type of a crystal ingot must be reduced closer to 1011 cm−3. [ABSTRACT FROM AUTHOR]

The Gamma Ray Imager (GRI) is a pinhole camera providing 2D imaging of MeV hard x-ray (HXR) bremsstrahlung emission from runaway electrons (REs) over the poloidal cross section of the DIII-D tokamak. We report a series of upgrades to the GRI expanding the access to RE scenarios from the diagnosis of a trace amount of REs to high flux HXR measurements during the RE plateau phase. We present the implementation of novel gamma ray detectors based on LYSO and YAP crystals coupled to multi-pixel photon counters, enabling a count rate in excess of 1 MHz. Finally, we highlight new insights into the RE physics discovered during the current quench and RE plateau phase experiments as the result of these upgrades. [ABSTRACT FROM AUTHOR]

Background: Radiotracer extravasations, caused largely by faulty tracer injections, can occur in up to 23% of 18F-fluorodeoxyglucose (FDG) PET/CT scans and negatively impact radiological review and tracer quantification. Conventional radiological assessment of extravasation severity on PET has limited performance (e.g., extravasations frequently resolve before scanning) and practical drawbacks. In this study, we develop a new topical detector-based FDG extravasation severity classifier, calibrated from semi-quantitative PET measurements, and assess its performance on human subjects. Methods: A retrospective study examined patients whose FDG injections had been monitored as part of their standard workup for PET/CT imaging. Topical uncollimated gamma ray detectors were applied proximal to the injection site and on the same location on the opposing arm, and readings were acquired continuously during radiotracer uptake. Patients were imaged with their arms in the PET field of view and total extravasation activity quantified from static PET images through a volume of interest approach. The image-derived activities were considered ground truth and used to calibrate and assess quantification of topical detector readings extrapolated to the start of PET imaging. The classifier utilizes the calibrated detector readings to produce four extravasation severity classes: none, minor, moderate, and severe. In a blinded study, a radiologist qualitatively labeled PET images for extravasation severity using the same classifications. The radiologist's interpretations and topical detector classifications were compared to the ground truth PET results. Results: Linear regression of log-transformed image-derived versus topical detector tracer extravasation activity estimates showed a strong correlation (R2 = 0.75). A total of 24 subject scans were cross-validated with the quantitatively based classifier through a leave-one-out methodology. For binary classification (none vs. extravasated), the topical detector classifier had the highest overall diagnostic performance for identifying extravasations. Specificity, sensitivity, accuracy, and positive predictive value were 100.0%, 80.0%, 95.8%, and 100.0%, respectively, for the topical detector classifier and 31.6%, 100.0%, 45.8%, and 27.8%, respectively, for the radiological analysis. The topical detector classifier, with an optimal detection threshold, produced a significantly higher Matthews correlation coefficient (MCC) than the radiological analysis (0.87 vs. 0.30). Conclusions: The topical detector binary classifier, calibrated using quantitative static PET measurements, significantly improves extravasation detection compared to qualitative image analysis. [ABSTRACT FROM AUTHOR]

Inorganic lead-halide perovskite, cesium lead bromide (CsPbBr3), shows outstanding optoelectronic properties. Both solution- and melt-based methods have been proposed for CsPbBr3 crystal growth. The solution-based growth was done at low-temperature, whereas the melt-based growth was done at high-temperature. However, the comparison of optical, physical, and defect states using these two different growth conditions has been scarcely studied. Here, we have compared the thermal and optical properties of solution-grown and melt-grown single crystals of CsPbBr3. Positron Annihilation Lifetime Spectroscopy (PALS) analysis showed that melt-grown crystal has a relatively smaller number of defects than the chemical synthesis method. In addition, crystals grown using the chemical method showed a higher fluorescence lifetime than melt-grown CsPbBr3. [ABSTRACT FROM AUTHOR]

An experimental method was described to calibrate the depth of interaction (DOI) of high-energy $\gamma $ -ray in large-size thick pixel CdZnTe detector. The experimental results indicated that the ratio of the cathode and anode amplitude strongly showed linear relationship with the DOI of incidence $\gamma $ -rays and the detector. The correlation coefficients were optimized. Based on the experimental calibration of DOI, the photoelectric effect signals from the depth range where the energy resolution and the photopeak location are high were screened out to draw the energy spectrum. In this way, the energy resolution of the CdZnTe pixel detector was improved to 0.707% for 137Cs@662 keV. Further combined with the anode rise time, the electron mobility of CdZnTe in 2-D (1 mm accuracy) and 3-D (2 mm $\times $ 2 mm $\times $ 1 mm accuracy) scales was calculated. At different pixel positions and depths in CdZnTe detector, the electron mobility varies between 1000 and 1150 cm2/($\text{V}\cdot \text{s}$). [ABSTRACT FROM AUTHOR]

Graph Carrie Olheiser, a scientist within RTI's Center for Water Resources, is a cold-regions hydrologist with more than 20 years of professional experience in snow hydrology. These essential data allow The National Weather Service to create more precise forecasts related to snowmelt flooding. We go wherever the snow is to help with the data collection and better predict snowmelt flooding. [Extracted from the article]

The article focuses on the U.S. Department of Energy's Advanced Research Projects Agency-Energy (ARPA-E) funding for Low-Energy Nuclear Reactions (LENR) research projects. Eight research teams have received funding to explore LENR as a potentially transformative carbon-free energy source. The projects will investigate various aspects of LENR, including optimizing cathode design, detecting nuclear reactions in metal hydrides, measuring neutron emissions, and exploring nuclear anomalies.

A systematic study of the distribution of the Naturally Occurring Radioactivity in stone dust and crushed stone, has been carried out with an objective of establishing reliable baseline data on the radiation level and hence to evaluate hazard indices approach and the production of radioactive heat (RHP) due to radiation exposure to the workers and to the inhabitants of the studied area. Twenty-six samples have been collected from different locations in the State of Rio de Janeiro (Brazil). To calculate the specific activity, gamma ray spectrometry and a detector of High Purity Germanium (HPGe; Canberra, 30% relative efficiency) was used. The activity concentration of 238U, 226Ra 232Th and 40K ranged from 29.3 ± 18.6 to 206.8 ± 21.5 Bq kg−1, 30.3 ± 1.0 to 134.3 ± 1.8, 27.9 ± 0.7 to 86.2 ± 0.9 Bq kg−1, and 734.9 ± 35.1 to 1204.8 ± 53.5 Bq kg−1, respectively. The mean values of the I ex , I in , I γ , I α , A UI , I RP112Rn , I PA , I PI and I Yu indices were 0.68 ± 0.09, 0.92 ± 0.12, 0.93 ± 0.12, 0.43 ± 0.07, 0.88 ± 0.20, 1.25 ± 0.21, 0.34 ± 0.05, 0.75 ± 0.10, 0.63 ± 0.08 and 34. ± 6.31, respectively. The average radioactive heat production (RHP) of 2.01 ± 0.28 μ Wm−3 was above the values found in the literature, which may contribute to the heat flow in the study area because the raw materials that make up the samples showed a high value of environmental radioactivity. The Brazilian Hazard Index to assess the radiological risk of crushed stone and stone dust was created and the average value was 0.74 ± 0.10, a value below 1, which means only moderate control over the use of these materials, with no indication of restriction to the its use. • High-res gamma spectrometer measured levels of natural radionuclides in stone dust, crushed stone. • Study assesses radionuclide exposure risks in building materials, safety for workers & residents. • Research helps build database to minimize ionizing radiation damage, inform public policy. • A Brazilian Risk Index for samples was created to better adapt to the reality of using these materials in Brazil. [ABSTRACT FROM AUTHOR]

In this work, the attenuation capability of new Borate-based-glass system reinforced with titanium oxide containing PbO, CaO, TiO 2 and B 2 O 3 with different percentages was determined. Four different glass samples were synthesized by experimental technique using high pure germanium detector at different gamma ray sources using narrow beam method. The experimental method was verified by XCOM software. The values of the two methods were close and the relative deviation was satisfactory (less than 5 %) for all gamma energies (0.060, 0.662, 1.173 and 1.333 MeV). The highest linear attenuation coefficient (LAC) values achieved at low radiation energy of 0.0595 MeV. The Highest LAC values were 13.64, 13.97, 14.32 and 14.67 cm−1 for samples PCBT-1, PCBT-2, PCBT-3 and PCBT-4 in the same order, respectively. Conversely, the lowest LAC values in the examined energy range were found at 1.333 MeV. The lowest LAC values were 0.259, 0.266, 0.272 and 0.279 cm−1 for the aforementioned glasses, respectively. At 0.662 MeV, the transmission factor (TF) values decreases as 64.18, 63.54, 62.88 and 62.19 % as TiO 2 content increases as 5, 10, 15 and 20 mol % in the same order, respectively. The decreases in TF values was linked to an observable increase in the radiation protection efficiency (RPE). The increase in RPE with the increase of TiO 2 content confirms that the addition of TiO 2 leads to an improvement in the radiation shielding performance for the prepared glasses. • New borate based glasses were prepared for radiation shielding. • The experimental method was verified by XCOM software. • The highest LAC values achieved at 0.0595 MeV, varied between 13.64 and 14.67 cm−1. • The addition of TiO2 causes an increase in the RPE. [ABSTRACT FROM AUTHOR]

The response of a gamma-ray spectrometer is generally determined by analyzing full-energy peaks. However, full-energy peaks cannot be measured easily in the case of scintillation detectors that consist of light elements, such as glass scintillators. Only a strong Compton plateau appears in the spectrum of such detectors. Therefore, Compton edgers were used to evaluate the response of these detectors. The response of a low-resolution 6 Li-glass detector to gamma rays was measured for the first time by a coincidence method with a high-resolution LaBr 3 :Ce detector using cascade gamma rays (2.75 and 1.37 MeV) from a 24Na source. Coincidence gates were applied at the peaks of the spectrum of the LaBr 3 :Ce detector at the 0.51 MeV annihilation peak, and the sum peaks of a gamma ray and a backscattered gamma ray. By analyzing the gated spectra of the 6 Li-glass detector, the energy-dependent detector response (i.e., the output strength and its dispersion) was determined. • Evaluation of the response characteristics, including signal output and broadening, of a low-resolution 6Li-glass detector to gamma rays up to approximately 2.5 MeV. • Coincidence measurement of cascade gamma rays emitted from a 24Na source with a high-resolution detector, a LaBr 3 :Ce detector. • Peak analysis of the spectra of the 6Li-glass detector gated at gamma ray peaks of the LaBr3:Ce detector. [ABSTRACT FROM AUTHOR]

High-flux X-ray measurements with high-energy resolution and high throughput require the mitigation of pile-up and dead time effects. The reduction of the time width of the shaped pulses is a key approach, taking into account the distortions from the ballistic deficit, non-linearity, and time instabilities. In this work, we will present the performance of cadmium–zinc–telluride (CdZnTe or CZT) pixel detectors equipped with digital shapers faster than the preamplifier peaking times (ballistic deficit pulse processing). The effects on energy resolution, throughput, energy-linearity, time stability, charge sharing, and pile-up are shown. The results highlight the absence of time instabilities and high-energy resolution (<4% FWHM at 122 keV) when ballistic deficit pulse processing (dead time of 90 ns) was used in CZT pixel detectors. These activities are in the framework of an international collaboration on the development of spectroscopic imagers for medical applications (mammography, computed tomography) and non-destructive testing in the food industry. [ABSTRACT FROM AUTHOR]

A group from the University of Science and Technology of China in Hefei used rare earth ion-doped crystals to test the world's first quantum repeater segment based on absorptive quantum memories, and achieved the longest, record-breaking optical storage time of 1 hour. A list of the top 10 domestic science and technology stories was jointly released by the Chinese Academy of Sciences and the Chinese Academy of Engineering in Beijing on 18 January 2022. Graph: Tianwen-1, China's first mission to Mars, was decalred a success. [Extracted from the article]

Prompt gamma-ray neutron activation analysis (PGNAA) is a useful approach for determining the concentrations of a variety of elements in natural materials, either online or in situ, without affecting their chemical forms in matter. The current research aimed to improve the yield of a portable PGNAA setup using a dc beam of 2.5 MeV neutrons and a CeBr3 detector to record gamma rays from neutron inelastic scatterings. It is impossible to avoid the superimposition of heavy metal gamma rays and those from the detector's element. However, tests were carried out to improve the signal-to-background ratio. By assessing the minimum detectable concentrations (MDC) of chrome, titanium, and zinc in soil samples, the effectiveness of the new optimization was confirmed. The study shows an improvement in the MDC values. [ABSTRACT FROM AUTHOR]

The prime objective of this study is to estimate the natural radioactivity and their associated radiological hazards in soil samples of Uttara Kannada district having different geological conditions. The 226Ra, 232Th and 40K activities were estimated using HPGe detector based gamma ray spectrometer. The average 226Ra, 232Th and 40K activity concentrations are 36.13 ± 0.96, 48.47 ± 1.26 and 415.76 ± 6.83 Bq kg−1 respectively. The mean annual effective dose equivalent value was found to be 0.40 mSv y−1 and is less than the ICRP proposed value of 1 mSv y−1. The radiological hazard indices were computed and compared with internationally agreed values. [ABSTRACT FROM AUTHOR]

The concentration levels of 226Ra, 232Th and 40K in soil have a great concern in the recent decades, due to its effect on the human health. The radioactivity of some soil samples taken from selected locations in Sylhet District have been measured using a High Purity Germanium Detector based on gamma ray spectroscopy. The present investigation shows that the level of natural radioactivity for 226Ra, 232Th and 40K in such soil is slightly higher than World average value of UNSCEAR, 2000. The artificial radionuclide 137Cs was not observed in statistically significant amounts above background level in this study. The radiological hazard parameters i.e., radium equivalent activity, absorbed dose rate, external hazard index, internal hazard index, representative level index and annual effective dose equivalent are calculated from the measured activity concentrations of the radionuclides 226Ra, 232Th and 40K from soil samples in this study and compared with the world averages. The experimental soil data were subjected to statistical analysis using IBM SPSS software (version 20). Descriptive statistics of the radionuclides of the soil, Pearson's correlation matrix and Cluster Analysis have been carried out in this study. [ABSTRACT FROM AUTHOR]

In a scintillation detector, the light generated in the scintillator by a gamma interaction is converted to photoelectrons by a photodetector and produces a time-dependent waveform, the shape of which depends on the scintillator properties and the photodetector response. Several depth-of-interaction (DOI) encoding strategies have been developed that manipulate the scintillator's temporal response along the crystal length and therefore require pulse shape discrimination techniques to differentiate waveform shapes. In this work, we demonstrate how maximum likelihood (ML) estimation methods can be applied to pulse shape discrimination to better estimate deposited energy, DOI and interaction time (for time-of-flight (TOF) PET) of a gamma ray in a scintillation detector. We developed likelihood models based on either the estimated detection times of individual photoelectrons or the number of photoelectrons in discrete time bins, and applied to two phosphor-coated crystals (LFS and LYSO) used in a previously developed TOF-DOI detector concept. Compared with conventional analytical methods, ML pulse shape discrimination improved DOI encoding by 27% for both crystals. Using the ML DOI estimate, we were able to counter depth-dependent changes in light collection inherent to long scintillator crystals and recover the energy resolution measured with fixed depth irradiation (~11.5% for both crystals). Lastly, we demonstrated how the Richardson-Lucy algorithm, an iterative, ML-based deconvolution technique, can be applied to the digitized waveforms to deconvolve the photodetector's single photoelectron response and produce waveforms with a faster rising edge. After deconvolution and applying DOI and time-walk corrections, we demonstrated a 13% improvement in coincidence timing resolution (from 290 to 254 ps) with the LFS crystal and an 8% improvement (323 to 297 ps) with the LYSO crystal.

Cadmium Zinc Telluride (CdZnTe) is a ternary Ⅱ- Ⅵ undeviating band gap semiconductor with cubic Zinc blende formation and it is a propitious material for ambient temperature xray as well as gamma ray sensor detectors. Cadmium Zinc Telluride (CdZnTe) thin layer coating were developed on nickel substrate by chemical bath deposition in non-aqueous approach. The as grown films were inspected by X-ray diffraction (XRD), Field emission scanning electron microscope (FESEM), Scanning electron microscope, Fourier transform infrared spectroscopy (FTIR), PL spectra, UV spectra, Raman spectroscopy and Four- Probe analysis. Studies tell that as grown films are poly-crystalline in nature along with cubic zinc blende formation. The structural properties like crystallite size, lattice constant, micro strain as well as dislocation density were evaluated. FESEM and SEM analysis reveals that the as developed films are smooth and equal sized uniform spherical grains distributed in single state as well as in cluster form. The average size of grain film is observed to be 12.33 nm. Optical study reveals the broad transmittance escorted by the band gap energy of 2.2eV. Electrical study reveals that resistivity of as grown film is 5.1×105 Ω-cm at room temperature. [ABSTRACT FROM AUTHOR]

Cs2 LiYCl6∶ Ce(CLYC) is a novel scintillation crystal with the capability of neutron and gamma-ray detection. It can be used in the field of neutron and gamma-ray detection. The CLYC scintillation crystal with 95% enrichment of 6 Li was grown by the vertical Bridgman method. After processing and moisture-proof packaging, a housed sample of ϕ50 mm ×50 mm CLYC scintillation crystal was obtained. 4. 22% energy resolution is measured at 662 keV of 137Cs gamma rays. Neutron-gamma discrimination is also achieved. The figure of merit (FOM) of pulse shape discrimination (PSD) measured with a 252Cf neutron source is 3. 45. With its excellent performance, CLYC scintillation crystal is expected to replacement for Helium-3 gas in the field of neutron detection, and can be used as the preferred material for n/ γ dual detection. So CLYC crystal can be used in neutron radiation detectors, radioisotope identification instruments, personal radiation dosimeters, and other neutrons gamma detection. [ABSTRACT FROM AUTHOR]

CdZnTe detectors play an important role in international astronomy research. In this paper, the spectra response of CdZnTe planar detector for γ-ray was numerically simulated using GEANT4 Monte-Carlo simulation toolkit, and the influence of the factors, such as transport properties of electrons and holes, applied bias voltage, thickness of detector and other factors were studied. The calculated results show that when the charge collection efficiency ( CCE) of electron is high, the dependence of energy resolution on the ratio of electron and hole mobility-lifetime product ((μτ)e/ (μτ)h) is strong, and the resolution increases with the decrease of the ratio. The energy resolution and CCE of carrier can be improved by raising up the bias. When the CCE of electron is high, increasing thickness can weaken the hole signal contribution to the total induced charge, and improve the energy resolution. The value of (μτ)eE /d can be used to evaluate CCE of planar CdZnTe detectors for rays of low energy, and the corresponding relationship was calculated. [ABSTRACT FROM AUTHOR]

Since the discovery of X-rays by Röntgen in 1895, radiation detection technology have developed rapidly and have been widely used in many fields such as medical imaging, security inspection, industrial non-destructive testing, nuclear safety monitoring, resource exploration, basic science and space science. In terms of detection materials and working principles, radiation detectors can be divided into gas detectors, scintillator detectors and semiconductor detectors. This article focuses on semiconductor detectors, starting from the interaction between various radiation and semiconductor materials, as well as the working principle and signal processing process of semiconductor detectors, and discusses the performance requirements and main points of detector design of semiconductor radiation detectors in different types of radiation and different application requirements. The performance and research progress of semiconductor materials in the field of radiation detection are reviewed according to the order of element family. [ABSTRACT FROM AUTHOR]

Recently, there have been several significant improvements in the area of the radiation detection system and its instruments, especially those using scintillation or semiconductor gamma ray detectors. Scientists and technicians are interested in studying this progress, which can be useful for the detector's operation and its basic properties, such as energy, shape, and efficiency calibration. In this work, an extended study of various mathematical formulas was conducted to obtain the efficiency best-fitting function, that covers the measured values from low to high energy regions. They can be used to represent the efficiency of a high-purity germanium detector in the regions where accuracy and maximum speed in optimizing the calibration process are very important for gamma spectroscopy. Determination of the activity of environmental samples mainly depends on the efficiency calibration curve of the detection system. The gamma ray energy in the range from 59.54 up to 1408.01 keV used in this work was obtained by using a set of standard radioactive gamma ray sources of certified intensity. The current data analysis shows that most of the mathematical formulas, which represent the fitting curve for the detector full-energy peak efficiency, were quite agreeable with the experimental results. [ABSTRACT FROM AUTHOR]

The present work deals with a 10 x 10 array of (Lu0.7Y0.3)AP:Ce 2 x 2 x 10 mm³ pixels, manufactured by Crytur (Cz), that has been utilized in a previous paper. The crystal-array has been coupled to an 8 x 8 anodes H10966 model Hamamatsu (Jp) Position-Sensitive Photo Multiplier Tube (PSPMT) connected to electronics for single events scintillation read-out. The response of such a detector has been studied under Co-57, or Ba-133, or Cs-137 gamma-ray emissions, as well as with Lu-176 self-activity only. The present work is aimed at characterizing the individual crystal- pixels' single-event responses in terms of pulse-height and of spreads of the 2-D charge-distributions. In particular, the charge-spread characterization pointed out several defects in the crystal-array assembly, not detected by usual pulse-height studies. The diagnostic method based on charge-spread analysis seems also well suited for scintillation array characterizations for gamma-ray detectors studies, as well as for quality controls of such pixelated devices during the lifetime of systems in the field of radionuclide medical imaging (SPECT and PET). The method is also appropriate for other applications where gamma-ray spectroscopy is required, like nuclear physics, astrophysics, astroparticle physics, homeland security, and non-proliferation. [ABSTRACT FROM AUTHOR]

Ceres' regolith contains water ice that has receded in response to insolation‐driven sublimation. Specially targeted, high spatial‐resolution measurements of hydrogen by Dawn's Gamma Ray and Neutron Detector (GRaND) reveal elevated hydrogen concentrations in and around Occator, a young, 90 km diameter, complex crater located at 19.82°N where near‐surface ice is not expected. The excess hydrogen can be explained by impact excavation of water‐rich outer crustal materials and their emplacement in the crater floor and ejecta blanket. This is supported by thermophysical models that show water ice could survive at sub‐meter depths, given Occator's relatively young age (∼20 Myr). We hypothesize that the regolith can be replenished with ice from large impacts and that this process partially controls the distribution and depth of near surface ice. This is supported by results from Occator and similarities in the global distribution of hydrogen and the pattern of large craters (20–100 km diameter). Plain Language Summary: The outermost meter of dwarf planet Ceres contains water ice that is gradually sublimating in response to heating of the surface by sunlight. Since Ceres' axis of rotation is nearly perpendicular to the Sun's rays, ice has receded to greater depths at the equator than the poles. The distribution of subsurface ice within this outer layer was inferred from measurements of hydrogen by Dawn's Gamma Ray and Neutron Detector. Special operations during Dawn's last mission phase brought the spacecraft close to the surface, enabling measurements within and around a large, young crater called Occator. Anomalously high concentrations of hydrogen were detected, suggesting the impact that formed Occator excavated water rich materials from the crust and deposited them on the surface. Comparison of the global distribution of hydrogen with the pattern of large craters on Ceres further supports excavation of crustal ice by impacts as a partial control on the depth of ice near the surface. Results confirm that Ceres' crust is rich in water ice and show that ice can survive in materials ejected by impacts into airless, icy bodies. Key Points: Neutron spectroscopy reveals enhanced hydrogen concentrations in the outermost meter of the surface of a prominent young, complex craterResults confirm Ceres outer crust is ice rich and support retention of water ice within impact ejecta on airless, icy bodiesThe data imply partial control of regolith ice content by large impacts, relaxing constraints on surface age and regolith grain size [ABSTRACT FROM AUTHOR]

Another radon detector measuring in a more shallow well did not observe any changes of radon before or during the earthquake [[3]]. The first observation of radon as a precursor to an earthquake was made in connection to the Tashkent earthquake in 1966, where increased levels of radon were observed prior to the earthquake and then reported in the scientific literature [[4]]. Each one has their own distinct decay chain involving mainly alpha but also beta and gamma radiation, through which different isotopes of the noble gas radon are produced via the alpha decay of radium (Rn). [Extracted from the article]

Imaging atmospheric Cherenkov telescopes (IACTs) are ground-based indirect detectors for cosmic gamma rays with energies above tens of GeV. The major backgrounds for gamma-ray observations in IACTs are cosmic-ray charged particles. The capability to reject these backgrounds is the most important factor determining the gamma-ray sensitivity of IACT systems. Monte Carlo simulations are used to estimate the residual background rates and sensitivity of the systems during the design and construction phase. Uncertainties in the modeling of high-energy hadronic interactions of cosmic rays with nuclei in the air propagate into the estimates of residual background rates and subsequently into the estimated instrument sensitivity. We investigate the influence of the difference in the current hadronic interaction models on the estimated gamma-ray sensitivity of the Cherenkov Telescope Array using four interaction models (QGSJET-II-03, QGSJET-II-04, EPOS-LHC, and SIBYLL2.3c) implemented in the air shower simulation tool CORSIKA. Variations in background rates of up to a factor 2 with respect to QGSJET-II-03 are observed between the models, mainly due to differences in the π0 production spectrum. These lead to ∼30% differences in the estimated gamma-ray sensitivity in the 1–30 TeV region, assuming a 50 h observation of a gamma-ray point-like source. The presented results also show that IACTs have a significant capability in the verification of hadronic interaction models. [ABSTRACT FROM AUTHOR]

The realization of pulsed-laser diffused, thin n + contacts on high purity germanium (HPGe) and their successful segmentation is described. The contacts have been obtained by a laser-induced diffusion of Sb atoms, deposited by sputtering on Ge surface, and then segmented by means of a photolithographic technique. Three small prototypes of gamma ray detectors have been implemented, using the same n + contact (laser diffused Sb) but with three different geometries and a B implanted p + contact. Electrical and detection properties of the prototypes have been characterized, showing low leakage currents and good spectroscopy data with different gamma-ray sources. The stability of the detector performance has also been tested subjecting one of the prototypes to a typical annealing treatment. [ABSTRACT FROM AUTHOR]

Internal conversion electron and gamma-ray spectroscopy measurements were carried out on the 10.551 y 133Ba electron-capture decay with our electron and gamma spectrometers—a mini-orange electron transporter paired to a Si(Li) detector and a large-volume HPGe detector, respectively. The relative and absolute gamma-ray intensities of all the nine transitions in 133Cs were determined. We also report the relative conversion intensities of eighteen conversion lines and their corresponding internal conversion coefficients (ICCs), four of which are being reported for the first time. Transition intensity balance at each energy level, showed that the measured values are self-consistent. This exhaustive dataset of gamma-ray intensities, internal conversion electron intensities and the ICCs that have low uncertainty, will be highly valuable for the purposes of energy and efficiency calibration of semiconductor gamma ray detectors and electron spectrometers. [ABSTRACT FROM AUTHOR]

One of the goals of the MICADO Euratom project is to monitor the gamma-rays emitted by radioactive waste drums in storage sites on a medium to long term basis. For this purpose, 36 low-cost gamma-ray counters were designed and built to act as a demonstrator. These counters, named SciFi, are based on a scintillating fiber readout at each end by a silicon photomultiplier, assembled in a robust arrangement in the form of 80 cm long pipes. Several counters will be placed around radwaste packages in order to monitor the gamma dose-rate by collecting a continuous data stream. The 36 sensors were thoroughly tested with a 22Na and a 137Cs gamma-ray sources, and with an AmBe neutron and gamma-ray source, the results are quite satisfactory, and the next step will be the test in a real environment. [ABSTRACT FROM AUTHOR]

[Display omitted] • Quality non-polar GaN films (which itself is believed to be challenging) are deposited on the polar substrates using PLD route. • These non-polar GaN films exposed to 60Co Gamma radiations varying dose values from 40 kGy to maximum value of 260 kGy under atmospheric conditions. • The critical investigations reported on the non-polar GaN films for the first time, clearly demonstrate the resistive nature of the films against expose to energetic gamma rays is highly impressive. • The result reported herewith demonstrate use of non-polar GaN films can be one of the options to fabricate next generation of gamma ray detectors. The GaN films/layers exposed to γ-radiations is known to harvest defects and vacancies in the crystals producing donor, acceptor and recombination centers within the bandgap. Therefore it is important to investigate and study the γ- ray irradiation effects on various physical and chemical properties of a material before any optoelectronic and/or electronic devices are being fabricated. To avoid Stark effect which is observed in most of the optoelectronic devices fabricated using GaN films grew along polar face, use of non-polar GaN films is suggested by researchers. To address such issues the article reports the investigations of physical and chemical properties of non-polar GaN films grown on polar substrate using pulsed laser deposition, which were exposed to the 60Co gamma rays varying dose values. Resistive nature against the impairment of the films caused by γ-rays observed herewith is highly encouraging, suggesting the use of non-polar GaN films as radiations harden material suitable for fabricating new generation γ-ray detectors. To our knowledge very limited information is available that report such investigations. [ABSTRACT FROM AUTHOR]

The electrical signals generated by radiation detectors are often subject to undesired effects that can affect the energy resolution of the detector. These effects may be caused by the measurement system itself or by the high rate of events. Traditional methods for shaping the signals and mitigating these effects often have limitations, such as requiring explicit information about the signals. In this paper, the authors propose a deconvolution method based on least square filtering and non-negative sparsity theory to address these limitations. The method is evaluated using simulated data representing a gamma ray detector with a NaI(Tl) crystal and a photomultiplier tube (PMT). The electrical pulses in this system are pre-processed using a CR coupling circuit and a RC integrator. The energy resolution obtained with the traditional method was 6.60%, while the proposed method resulted in an energy resolution of 5.65%. In addition to improving accuracy, the proposed method also reduces implementation complexity. [ABSTRACT FROM AUTHOR]

In this study, albedo parameters are experimentally measured to determine radiation scattering features of some thermoluminescent dosimetry materials (TLD 100, TLD 100h, TLD 200 and TLD 400). In experimental setup, it was used scattering angle of 168°, 59.54 keV gamma rays and HPGe detector. The effective atomic numbers of the investigated materials were determined from the coherent to Compton scattering intensity ratio. Also, the mass attenuation coefficient, the mass energy absorption coefficient and kerma relative to air and ICRU tissue were calculated for the TLD materials. It was observed that TLD 100h is the best tissue equivalent material among other TLD materials and best reflects 59.54 keV gamma rays. • The effective atomic numbers of some thermoluminescent dosimetry materials were obtained from scattering ratios. • The effective atomic number and albedo parameters are obtained for 59.54 keV photon energy. • TLD 100h is the material that best reflects 59.54 keV gamma rays. [ABSTRACT FROM AUTHOR]

Initially intended as student-led projects at universities and research institutions, the CubeSats now represent a unique opportunity to access space quickly and in a cost-effective fashion. CubeSats are standard and miniaturized satellites consisting of multiple identical units with dimensions of about 10 × 10 × 10 cm 3 and very limited power consumption (usually less than a few W). To date, several hundreds of CubeSats have been already launched targeting scientific, educational, technological, and commercial needs. Compact and highly efficient particle detectors suitable for payloads of miniaturized space missions can be a game changer for astronomy and astroparticle physics. For example, the origin of catastrophic astronomical events can be pinpointed with unprecedented resolution by measuring the gamma-ray coincidence signals in CubeSats flying in formations, and possibly used as early warning system for multi messenger searches. In this paper, we will discuss and analyze the main features of a CubeSat mission targeting intense and short bursts of gamma-rays. [ABSTRACT FROM AUTHOR]