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At present, an urgent problem is the study of temporal variations of various types of nuclear radiation from the lithosphere in foothill and desert landscapes. This refers to the fluxes of neutrons, gamma quanta, beta particles, and emanations of heavy chemical elements. The problem of studying such distributions in the surface atmospheric layer of the Earth remains relevant, owing to the fact that they are concentrated in the human habitat and have a direct impact on the health of the population. This work is devoted to the study of beta spectra of the natural radiation background in the surface atmospheric layer of the Earth. The origin of the measured beta spectra is associated with the daughter products of the decay of radon isotopes 219Rn, 220Rn, and 222Rn in three natural radioactive series. Measurements of the spectra were performed from October 2018 to October 2019 in the foothills of the Zailiysky Alatau of the Tien Shan in Almaty. The frequency of measurements, on average, was about 10 measurements per day with an exposure of at least 2000 s. A database of daily, seasonal, and annual variations in beta spectra has been accumulated. For the analysis of the data obtained, a special software program Analyzer of the Beta Spectra Array was developed, which made it possible to process the standard output files of the Sputnik spectrometric installation and to integrate each spectrum in a given time interval. Time variation over the measured period was described using a standard mathematical computer package for wavelet analysis. The wavelet spectra obtained as a result of integration are used to identify daily, seasonal, and annual effects in variations of beta emanations. Along with this, similar mathematical processing was performed to predict the impact of external factors in the temporal variations of beta particles. [ABSTRACT FROM AUTHOR]

P-type point contact (PPC) germanium detectors are used in rare event and low-background searches, including neutrinoless double beta (0νββ) decay, low-energy nuclear recoils, and coherent elastic neutrino-nucleus scattering. The detectors feature an excellent energy resolution, low detection thresholds down to the sub-keV range, and enhanced background rejection capabilities. However, due to their large passivated surface, separating the signal readout contact from the bias voltage electrode, PPC detectors are susceptible to surface effects such as charge build-up. A profound understanding of their response to surface events is essential. In this work, the response of a PPC detector to alpha and beta particles hitting the passivated surface was investigated in a multi-purpose scanning test stand. It is shown that the passivated surface can accumulate charges resulting in a radial-dependent degradation of the observed event energy. In addition, it is demonstrated that the pulse shapes of surface alpha events show characteristic features which can be used to discriminate against these events. [ABSTRACT FROM AUTHOR]

The conditions for the hydrothermal synthesis of industrially significant zeolite with the Beta structure are optimized by reducing the amount of toxic reagents used (tetraethylammonium hydroxide), acting as structure directing agents, reducing the temperature, and shortening the synthesis time relative to the known method. The use of stirring the reaction medium during the synthesis using the Premex Avalon reactor system, the addition of Zeolite Beta seeds, and the aging of the initial gel are considered as factors allowing the optimization of the synthesis conditions. The results of X-ray phase analysis and the study of the morphology of the samples show the possibility of synthesizing zeolite Beta with the average particle diameter of 200 to 300 nm at 130°C for 20 h with a significant decrease (by 75%) in the amount of tetraethylammonium hydroxide in the initial gel relative to the known methods. [ABSTRACT FROM AUTHOR]

We designed a beta radiation detector to measure beta particles from Nickel-63. Since the beta radiation has energy below 66.7 keV, a PIN diode was used. Film dosimetry and a liquid scintillation counter were used to measure the absorbed dose rate and radioactivity of the source. These results were compared with the detector count. The measured count rate increased proportionally to the radioactivity of the source, while the absorbed dose rate was not correlated to the activity. The beta radiation detector can be used to measure surface emission rates of Ni-63 quickly without destruction of the source. [ABSTRACT FROM AUTHOR]

Neuroendocrine neoplasms (NENs) are a very diverse group of tumors with a worldwide rise in incidence. Systemic therapy remains the mainstay treatment for unresectable and/or metastatic NENs. 177Lu-DOTATATE, a radiopharmaceutical which emits beta particles, has emerged as a promising therapy for metastatic gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs). However, limited treatment options are available particularly after the failure of 177Lu-DOTATATE therapy. This review aims to identify and summarize the available evidence for, and potential adverse events of, targeted alpha-particle therapy (TAT) in the treatment of metastatic NENs, specifically GEP-NENs. The MEDLINE, EMBASE, SCOPUS, and Cochrane Library databases were searched. Two articles which met the inclusion criteria were identified and included in the review. Putative radiopharmaceuticals that can be considered for metastatic NEN treatment include 225Actinium (225Ac)-DOTATATE and 213Bismuth (213Bi)-DOTATOC. There was evidence of partial response using both radiopharmaceutical agents without significant hematological, renal, or hepatotoxicity. Future studies should consider longer term, randomized controlled trials investigating the role of TAT, in particular, 225Ac-DOTATATE, in the treatment of metastatic NENs. [ABSTRACT FROM AUTHOR]

Common patterns of calcium-phosphate coating formation by the method of micro-arc oxidation (MAO) in the anodic potentiostatic mode on the Mg0.8Ca alloy surface in an electrolyte containing disperse particles of beta tricalcium phosphate (β-TCP) are studied. As a result of plasma-chemical reactions of interaction between the components of the electrolyte and the magnesium substrate, with the MAO voltage varied in the range of 350–500 V, a porous ceramic-like coating with β-TCP particles is formed on the surface. The influence of the structural-morphological properties of the coatings, formed under different voltages, on their adhesion properties is determined. The highest adhesive strength at a value of the ultimate load of 19 N is exhibited by the coatings with a thickness of 80 μm, a roughness of 8 μm, a surface porosity of 23%, and an average pore size of 5.9 μm, deposited at the MAO voltage of 500 V. The fracture of these coatings is completed at the interface between the coating and the intermediate oxide layer between the coating and the magnesium substrate. [ABSTRACT FROM AUTHOR]

45S5 bioglass system is a sol-gel specifically composed of SiO2+CaO+Na2O+P2O5 that has superior features for bone regeneration. In this article, the effects of MgO addition (0, 1, 2, 3, and 5 mol %) on the radiation attenuation properties of 45S5 bioglass system were investigated. For photons beam, we determined the linear attenuation coefficient (LAC), gamma dose rate (GDR), and effective atomic number (EAN). Moreover, the total stopping power and projectile range were calculated for charged particles such as beta (electron), proton (hydrogen ion), and alpha (helium ion). Finally, the attenuation properties of 45S5+MgO bioglass system were studied in detail for thermal and fast neutrons. The obtained results indicate that the maximum LAC was around 0.2175 cm−1 at 0.6 MeV for the studied bioglass system. The highest GDR was noted at 10 MeV in the distance of 1 mm with the value of 1.09 × 108 R/h for 45S5+MgO1 bioactive glass. For neutron attenuation, we found that the removal cross-section (RCS) values were 0.0894, 0.0896, 0.0898, 0.0901, and 0.0904 cm−1 for the studied bioactive glasses of 45S5+MgO1, 45S5+MgO2, 45S5+MgO3, 45S5+MgO4, and 45S5+MgO5, respectively. It was concluded that the MgO addition has an insignificant influence on the radiation attenuation properties of the 45S5 bioglass system. [ABSTRACT FROM AUTHOR]

The ionising power of beta-emitting radionuclides is intermediate between the more ionising alpha particles, and gamma radiation, although they are similarly harmful on penetration into human tissue. When entering the body, they may be harmful to humans. This review, the first of this kind, focuses on the most significant measurable natural and anthropogenic beta-emitting radionuclides in wild macrofungi, including many edible species around the world. Macrofungi have been documented to be good bioindicators of environmental contamination of some anthropogenic agents, including radioactivity. The available literature has indicated the artificial beta-emitter, 90Sr, has been accumulated at the highest levels (13 kBq/kg dry weight) in macrofungi from Ukraine, while among natural beta-emitters, the highest level of 210Pb (0.202 kBq/kg dw) was reported in Spain. Wild macrofungi foraged for consumption from areas of high natural radiation background or anthropogenic pollution pose a health risk through potential exposure to radiotoxic decay particles produced by beta emitters. This pathway's total effective radiation dose could range from 0.163 to 518 μSv/kg dw and depends on geographical location and actual consumer behaviour. Following pollution episodes, such consumption may expose consumers to radiotoxic beta particles in addition to other emitted nuclides. • The beta-emitting radioactive nuclides may be harmful to humans. • Wild mushrooms are good bioindicators of contamination, including radionuclides. • Among anthropogenic radionuclides, 90Sr has been accumulated at the highest levels. • Among natural beta-emitters, 210Pb was present at the highest level. • Mushrooms collected from areas of high radiation background pose a health risk. [ABSTRACT FROM AUTHOR]

Introduction: 166Ho is one of the most effective ra radionuclides in cancer radio - immunotherapy (RIT). It has been well applied in nuclear medicine because of its good nuclear characteristics such as short half - life (26.8 hours), emission of beta particles with an average energy of 665.7 keV, emission of gamma particles with suitable energy (80.6%, 80 keV) for imaging and the high production possibility using a nuclear reactor. 166Ho can be produced through direct (165Ho (n,γ)166Ho) and indirect (164Dy(2n,γ)166Dy(ß -)166Ho) methods. In this study, the production of carrier - free 166Ho (166Ho - CF) using a 166Dy/166Ho generator based on the indirect method was performed. Methods: In this research, the first 166Dy produced by 164Dy (n,γ)165Dy(n,γ)166Dy reaction through irradiation of the enriched Dy - 164 target with thermal neutrons in the Tehran research reactor. Then, the extraction chromatography method based on Ln resin was used to separate the daughter radionuclide from the parent. The effective parameters on the radio - chemical separation, such as eluent concentration, temperature, and flow rate have been optimized. Results: Under the optimized conditions (HNo3 1.5 M, temperature 50ºC, and flow rate 1.5 mL/min) average separation yield of 83% was achieved. 166Ho was milked from the column in the three - step process. The milking time of the 166Dy/166Ho generator is 2.5 days. The radionuclide purity of 166Ho - CF was determined using the HPGe gamma - spectrometry method. The radionuclide purity of Ho - 166 obtained by this method was ≥99%. Conclusions: The obtained results showed that the final product of 166Ho - CF, with radionuclide purity above 99%, activity 40.95 mCi, and specific activity of 100 Ci/mg can be achieved from the 166Dy/166Ho generator. Dy leakage in the final production is insignificant (less than 0.2 µCi per mCi of 166Ho). [ABSTRACT FROM AUTHOR]

A parallel-plate ionization chamber (PPC) with a nominal volume of 8.16 cm³ was developed based on theoretically simulated design parameters. Its purpose is to serve as a transfer standard for dosimetry in a beta radiation field. The entrance window of the PPC consists of an aluminized Mylar sheet with a thickness of 1.4 mg/cm2. The collecting and guard electrodes are created by applying a graphite coating on a Poly Methyl Methacrylate (PMMA) substrate with a thickness of 5 mm. The nominal sheet resistance of the graphite-coated PMMA substrate was measured using a four-probe technique and found to be approximately 800 Ω per square (Ω/□). Dosimetric characterization of the PPC was performed in the ISO 6980 reference beta radiation field, utilizing 90Sr-90Y and 85Kr beta radiation sources. The assessment included studies on short-term stability, linearity, current-to-voltage characteristics, stabilization time, and leakage current. The PPC was calibrated and established as a transfer standard using the 'Extrapolation Ionization Chamber,' recognized as an absolute standard for dose to tissue in 90Sr-90Y and 85Kr beta sources within the laboratory. The calibration coefficient of the PPC indicates an energy dependence of 0.6 % for 90Sr-90Y and 85Kr beta sources. • A parallel plate ionization chamber (PPC) of volume 8.16 cm3 is developed as per simulated design parameters. • Dosimetric characterization of this PPC is carried out for leakage current, stability, stabilization time and linearity etc. • Reference beta radiation field from 85Kr and 90Sr/90Y are standardized by absolute standard extrapolation ionization chamber. • Calibration of the newly developed PPC to establish it as transfer standard for dosimetry of beta particles field. [ABSTRACT FROM AUTHOR]

This scientific work explores the development of luminescent nanocomposite materials for radiation sensors in Fiber Optic Dosimetry (FOD). The study emphasizes the use of YVO 4 :Eu3+ as a scintillator material due to its high luminescent efficiency. However, the challenge arises from its higher effective atomic number compared to soft tissue. To address this issue, the work explores the dispersion of YVO 4 :Eu3+ as nanoparticles (NPs) in a biocompatible polymeric matrix, specifically considering poly(methyl methacrylate) (PMMA) and poly(ethylene glycol) dimethacrylate (PEGDMA). Both PMMA/YVO 4 :Eu3+@TMSPM and PEGDMA/YVO 4 :Eu3+@TMSPM formulations were synthesized with minimal impact on the glass transition temperatures of the polymers. Under UV and beta particle excitation, these formulations exhibit emission spectra characteristic of Eu3+ f-f transitions. The decay times of the main emission peak at 620 nm were 615 μs, 584 μs, and 567 μs for the NPs, PEGDMA- and PMMA-based polymeric nanocomposites (PNCs), respectively. These decay times fall within the range suitable for scintillators in LINAC pulsed radiation facilities. Also, PEGDMA- and PMMA-based PNCs with varying contents of YVO 4 :Eu3+ NPs showed radioluminescence spectra under beta particle irradiation. This work demonstrates the feasibility of developing PEGDMA- and PMMA-based PNCs containing dispersed YVO 4 :Eu3+ NPs for their application as scintillators in radiotherapy dosimetry. [Display omitted] • Luminescent nanocomposites were developed with YVO 4 :Eu3+@TMSPM nanoparticles and PMMA or PEGDMA as polymeric matrices. • YVO 4 :Eu3+@TMSPM nanoparticles were incorporated in both polymer matrices by in-situ polymerization. • The addition of nanoparticles in both matrices did not show a significant effect on the T g of the polymers. • Polymer-based nanocomposites irradiated with β-particles show RL with the characteristic features of the Eu3+ emission. • Both materials could be suitable detectors for fiber optic dosimetry due to the decay time of the signal is around 600 μs. [ABSTRACT FROM AUTHOR]

This article describes a new concept of developing a composite plastic scintillator (PS) with better light out and detection efficiency of ionizing radiations by loading high Zeff radioluminescence (RL) phosphor powder. Gamma-ray interaction in PSs has been enhanced due to increased photoelectric absorption in the loaded BaFBr:Eu2+ phosphor powder. RL BaFBr:Eu2+ powder has been synthesized by a high-temperature solid-state diffusion method in reducing atmosphere. Polystyrene-based PS sheets of 250 ± 50 μm thickness have been prepared with 2.5-diphenyl oxazole (PPO) and 1.4-bis(5-phenyl-2-oxazolyl) benzene (POPOP) as primary and secondary fluors, respectively, mixed with the synthesized phosphor powder in different weight percentages. Radiation detection properties of the composite PS have been studied for alpha, beta, neutron, and gamma radiations of different energies. The composite PS sheet loaded with 20 wt% of phosphor powder showed maximum intensity for RL and photoluminescence (PL). Studies also confirmed a significant increase in the radiation detection efficiency in composite PS for various energies of beta and gamma rays. The lifetime measurement of the composite PS showed same nanosecond lifetime which is appropriate for fast counting and matches closely with the PS without loading. Pulse height analysis for various ionizing radiations of different energies confirmed significant improvement in the detection efficiency of loaded PSs. [ABSTRACT FROM AUTHOR]

Recently, it has been proposed that the doses received from 133Xe released during the accident in 1979 at the Three Mile Island (TMI) plant in Pennsylvania were much higher than has been conventionally assessed, due to a gross underestimation of the relative biological effectiveness of electrons from beta-particle-emitting radionuclides within the body. The central evidence cited in support of this proposal was the doses derived from cytogenetic analyses of blood sampled in the mid-1990s from people living near TMI at the time of the accident. However, the chromosome aberration data show a marked discrepancy in biodosimetric estimates evaluated from the frequencies of stable translocations and unstable dicentrics (corrected for temporal attenuation), strongly suggesting that exposures to clastogenic agents occurred long after the TMI accident. Few details have been reported on the people providing the blood samples and how they were selected for study. Crucially, this lack of information includes the distributions in the exposed and control groups of age at sampling, which is a critical factor in interpreting translocation data. Contrary to the recent claim, these cytogenetic data offer no support to the suggestion of a serious underestimation of internal doses from beta particles or from 133Xe discharged during the TMI accident. [ABSTRACT FROM AUTHOR]

The goal of this study effect radiation on a number of Staphylococcus aureus bacterial isolates collected from Hilla Teaching Hospital and Imam Ali Hospital in Babil Governorate and Baghdad hospitals different patients randomly from from burns, wounds, urinary tract infections and skin with burn and wounds infections. Identification by VITECK2-GP, S.aureus were implanted on Nutrient broth and Nutrient agar, then placed within test tube containing distilled water 5ml, then exposing to an different radiosources including CS137 and CO60, with activity 1-10 µc with different radiation doses for different peroids 1-2-3 hrs.; implanted on Petridishes plates of Nuterinat agar incubated in the incubator for 24 hrs. at 37 ° C. The results of exposure to beta and gamma rays emitted by CS 137 and CO 60 radiosources with activity 10 µci and 1 µci. for 1hrs.,2hrs. 3hrs, with different doses including Cs (10 µci) Beta 3.160*10-1 (1hrs.), 6.32*10-1 (2hrs.), 9.48*10-1 (3hrs.) 98.3%, 99.5%, 99.5% respectively; Cs (10 µci) Gamma5.815*10-1 (1hrs.), 11.63*10-1 (2hrs.), 17.445*10-1 (3hrs.) 98.9%, 99.6%, 99.5% respectively; Cs (1 µci) Beta 3.417*10-1 (1hrs.), 6.835*10-1 (2hrs.), 9.253*10-1 (3hrs.), 99.3%, 99.5%, 99.9% respectively; Cs (1 µci) Gamma 6.289*10-1 (1hrs.), 12.678*10-1 (2hrs.), 18.867*10-1 (3hrs.) 99.2%, 99.6%, 99.8% respectively; Coblit with Co(1 µci) Beta 1.2*10-1 (1hrs.), 2.4*10-1 (2hrs.), 3.6*10-1 (3hrs.) 99.4%, 99.2%, 99.8%; Co(10 µci) Beta, 1.86*10-1 (1hrs.), 3.7*10-1 (2hrs.), 5.5*10-1 (3hrs.) 99.6%, 99.8%, 99.9% respectively; Co(10 µci) Gamma, 2.33*10-6 (1hrs.), 4.66*10-6 (2hrs.), 6.99*10-6 (3hrs.), 95.2%, 99.8%, 99.8% respectively. Calculate number of colonies with percentage of killing. [ABSTRACT FROM AUTHOR]

Transarterial radioembolization (TARE) effectively treats unresectable primary and metastatic liver tumors through intra‐arterial injection of Yttrium‐90 (90Y) beta particle emitting microspheres which implant around the tumor. Current dosimetry models are highly simplistic and there is a large need for an image‐based dosimetry post‐TARE, which would improve treatment safety and efficacy. Current post‐TARE imaging is 90Y bremsstrahlung SPECT/CT and we study the use of these images for dosimetry. Retrospective image review of ten patients having a Philips HealthcareTM SPECT/CT following TARE SIR‐Spheres® implantation. Emission series with attenuation correction were resampled to 3 mm resolution and used to create image‐based dose distributions. Dose distributions and analysis were performed in MIM Software SurePlanTM utilizing SurePlanTM Local Deposition Method (LDM) and a dose convolution method (WFBH). We sought to implement a patient‐specific background subtraction prior to dose calculation to make these noisy bremsstrahlung SPECT images suitable for post‐TARE dosimetry. On average the percentage of mean background counts to maximum count in the image across all patients was 9.4 ± 4.9% (maximum = 7.6%, minimum = 2.3%). Absolute dose increased and profile line width decreased as background subtraction value increased. The average value of the LDM and WFBH dose methods was statistically the same. As background subtraction value increased, the DVH curves become unrealistic and distorted. Background subtraction on bremsstrahlung SPECT image has a large effect on post‐TARE dosimetry. The background contour defined provides a systematic estimate to the activity background that accounts for the scanner and patient conditions at the time of the image study and is easily implemented using commercially available software. Using the mean count in the background contour as a subtraction across the entire image gave the most realistic dose distributions. This methodology is independent of microsphere and software manufacturer allowing for use with any available products or tools. [ABSTRACT FROM AUTHOR]

We report the detailed analysis of thermoluminescence (TL) glow curves and the evaluation of kinetic parameters of Sm3+-incorporated BaSi2O5.The effect of various heating rates on TL kinetics and glow peak temperatures of Sm3+-doped BaSi2O5 phosphors exposed to beta particle irradiation at room temperature are investigated. The glow curve of the phosphor exposed to β-irradiation consists of two main peaks with maxima at about 91°C and 193°C and exhibits good linearity between 1 and 10 Gy. The activation energies and frequency factors of trap centers involved in the TL emission were calculated from the TL glow curve of the sample by means of variable heating rate (VHR), repeated initial rise (RIR), and computerized glow-curve deconvolution (CGCD). Analysis of the main dosimetric peak techniques indicate that activation energies (E) and pre-exponential factor (s) vary between 0.93 and 1.72 eV, 1010 and 1013 s−1. It is found that the temperature of the glow peaks shifts toward the higher temperatures and the TL intensity smoothly decreases as the heating rate increases. The behavior of the TL intensities and glow peak temperatures as a function of the heating rate are discussed with regards to thermal quenching. [ABSTRACT FROM AUTHOR]

The first cycle of measurements of the ratio of cumulative spectra of beta particles originating from the isotopes U and Pu undergoing thermal-neutron-induced fission was performed. It is found that the curve obtained from our present measurement of the U Pu ratio of beta-particle spectra lies 5 lower than the analogous curve following from the measurement of a group from Institute Laue–Langevin (ILL). The present analysis reveals that this is due to an erroneous 5 overestimation of the U beta-particle spectrum measured by the ILL group. As a consequence, the results obtained for the U spectrum at the production instant via a reconstruction from the cumulative spectrum of beta particles from U also turned out to be overestimated by 5 . These data explain the effect of the reactor antineutrino anomaly. [ABSTRACT FROM AUTHOR]

In this work, the spatial uniformity of the polymerization growth of the MAGIC gel in the case of an internal irradiation with iodine-131 was studied. A compartmental mathematical model taking into account the kinetics of polymerization of the MAGIC gel was developed and validated by experimental measurements. In order to check the radioactivity homogeneity distribution in the samples, we performed their scintigraphy, while -- in order to study the rate of polymerization -- we measured the intensity of the MRI signal emitted by each of the samples. The wide dispersion in signal strength observed between different regions of the same sample indicates that the value of the relaxation time T2 varies from one point to another. Scintigraphy and MRI images showed that a homogeneous distribution of 131I activity does not necessarily imply isotropic polymerization. The phenomenon is probably due to the fact that iodine-131 emits beta particles with different energies and the length of polymers does not increase with the same speed for all the polymers in formation. On this basis, we have established a mathematical model which compartmentalizes different species of protons which participate in the modification of the MRI signal. [ABSTRACT FROM AUTHOR]

177Lu-DOTATATE peptide receptor radionuclide therapy (PRRT) alone has lesser potential in the clinical setting of neuroendocrine tumor (NET) with large bulky disease and nonhomogeneous somatostatin receptors (SSTR) distribution, owing to lower energy (Eβmax 0.497 MeV) and a shorter particle penetration range (maximum 2–4 mm) of177Lu. In large bulky NETs,90Yttrium (90Y) has the theoretical advantages because of a longer beta particle penetration range (a maximum soft tissue penetration of 11 mm). Therefore, a combination of177Lu and90Y is a theoretically sound concept that can result in better response in metastatic NET with large-bulky lesion and non-homogeneous SSTR distribution. The aim of the study was to determine the feasibility of combining90Y-DOTATATE with177Lu-DOTATATE PRRT as sequential duo-PRRT in metastatic NET with (≥5 cm) including the post90Y-DOTATATE-PRRT imaging and also to determine early toxicity of the duo-PRRT approach. A total of 9 patients received combination of177Lu-DOTATATE with90Y-DOTATATE (indigenously prepared and approved) through sequential duo-PRRT approach. These 9 NET patients were included and analyzed in this study. All 9 patients had undergone post-PRRT90Y-DOTATATE imaging, including a whole-body planar bremsstrahlung imaging followed by regional single-photon emission computed tomography (SPECT)-computed tomography (CT) imaging and also a regional positron emission tomography–computed tomography imaging. Grading of90Y-DOTATATE and177Lu-DOTATATE uptake was done on post-PRRT imaging by both modalities. The size of the lesions ranged from 5.5 cm to 16 cm with average size of 10 cm before sequential duo-PRRT was decided. Sequential duo-PRRT was administered because of stable, unresponsive disease following177Lu-DOTATATE in 5 patients (55.6%), progressive disease after177Lu-DOTATATE in 2 patients (22.2%), and with neoadjuvant intent in 2 patients (22.2%). The total cumulative dose of177Lu-DOTATATE before duo-pRRT ranged from 11.84 GBq to 37 GBq per patient and average administered dose of 27.21 GBq per patient in this study. Out of 9 patients, 8 patients received single cycle of90Y-DOTATATE (ranging from 2.66 GBq to 3.4 GBq per patient with average administered dose of 3.12 GBq per patient). One patient received two cycles of90Y-DOTATATE (total dose of 6.2 GBq). Out of 9 patients, 8 patients showed excellent tracer concentration in lesions on post-PRRT90Y-DOTATATE imaging and the remaining 1 patient showed fairly adequate90Y-DOTATATE tracer uptake in lesion on visual analysis. There was matched90Y-DOTATATE uptake with68Ga-DOTATATE and also with177LuDOTATATE in all 9 patients. The sequential duo-PRRT was well tolerated by all patients. Two patients (22.2%) developed mild nausea, one patient (11.1%) developed transient mild-grade hemoglobin toxicity, and one patient (11.1%) developed mild-grade gastrointestinal symptoms (loose motion and abdominal pain). No nephrotoxicity, hepatotoxicity, and other hematological toxicity was observed. The combination of the indigenous90Y-DOTATATE with177Lu-DOTATATE PRRT in NET as sequential duo-PRRT was well tolerated, feasible and safe in stable, unresponsive/progressive disease following single isotope177Lu-DOTATATE therapy and also in neoadjuvant PRRT setting with large bulky lesion (≥≥5cm). Post-PRRT90Y-DOTATATE imaging showed excellent90Y-DOTATATE uptake in nearly all NET patients. Mild-grade early adverse effects were easily manageable and controllable in this sequential duo-PRRT approach. [ABSTRACT FROM AUTHOR]

Pollution due to natural radioactivity is still a poorly known topic among young people. This paper describes the contents for an introductive university course or lecture conceived in a multitask program. Along with a so-called "flipped" configuration, where students are able to receive didactic materials prior to face-to-face lessons, multimedia contents should be shown to the students, who are at first faced with known anthropogenic accidents. Moreover, field and laboratory experimental activities can provide further insight regarding the radiological assessment strategies. Here, the most important principles and effects concerning the radioactive decay of naturally occurring radionuclides are described. The greatest part of natural radioactivity derives from terrestrial radionuclides occurring in soil and rocks. The radionuclides are atoms characterized by an excess of nuclear energy, which makes them unstable giving rise to decay. The radionuclides emit gamma rays, as well as alpha and/or beta particles. People are constantly subjected to indoor and outdoor exposure due to natural radioactivity. The possible sources can be considered as external due to natural sources located outside the human body, and internal provoked by ingestion or inhalation of radionuclides. The indoor exposure from natural sources is mainly related to radiation from building materials and to radon entering buildings from soils and rocks though cracks in walls and floor. The outdoor exposure mainly accounts for the terrestrial gamma radiation that crosses the soil-air interface, and for the radon emitted from soils in seismic and volcanic areas. In this regard, there is a strong relationship between health diseases (e.g. cancer, necrosis and DNA and RNA modifications) and high-levels of natural radioactivity. For this reason, the radiological assessment of the most vulnerable areas represents a key point in order to mitigate hazard and risk connected to the human exposure to natural radioactivity. [ABSTRACT FROM AUTHOR]

The influence of Nd:YAG laser on Klebsiella pneumoniae while effect of Beta, Gamma ray by utilizing Cs137, Co60, Sr90, Na22 Tl and Cs137. The exposure of was in dose 0.3863*10-8, Co60 in dose 1.826*10-8, Sr90 in dose 1.973*10-8, Na in Gamma ray 0.31993*10-8 and 1.4157*10-8 in Beta ray in 3hr with done control, also exposing K.pneumoniae into Nd:YAG laser in Wavelenghth1064A° in 500, 1000,1500 pulse between each pulse 6 second with triplicate. Results of exposing Nd:YAG laser and Beta, Gamma radiation on viability of K. pneumoniae resistant colistin were counted was become fewer than control (outwardly exposition to laser and radiation) with high proportion of killing. Nd:Yag laser and Beta, Gamma radiation were efficient for killing K. pneumoniae resistant colstin that cause several infection to human and may be cause death. [ABSTRACT FROM AUTHOR]

Temporal and spatial analysis of air particulates sampling collection from the in and outside the Al-Tuwaitha, south of Baghdad, was carried out to measure daily gross alpha and beta activity concentrations (AAC and BAC) during the period from January to April of 2017. The results show that most frequencies are within the interval 1-1.49 Bq/m³ for AAC and 3-3.49 Bq/m³ for BAC. Also, the radioactivity levels within the site for both AAC and BAC were found to be higher than those around the outside. Across all air samples at the studied site, the monthly arithmetic means were 3.0 ± 0.5 and 6.7 ± 0.9 Bq/m³ for both AAC and BAC. It was found that a hotspot for both AAC and BAC in air layer with values of 4.0 and 8.5 Bq/m³ respectively situated at ITR-5000 reactor northwest of the site, which is a major source of radioactive contamination, but with wind action. This contamination disperses according to its prevailing direction that is southeast. 6.7 ± 0.9. [ABSTRACT FROM AUTHOR]

We harvest electrical energy from a radionuclide beta source via the direct-charging method and characterize the parameters that govern the process. The idea is to collect the beta-particles emitted from the source and convert their energy into usable electrical energy without intermediate steps. This is accomplished experimentally with a 63Ni source in a parallel-plates arrangement where the source is the positive electrode and the electrons are collected on the negative electrode. Measurements of the energy harvesting rate are performed with different collector materials, gap sizes, and potential differences between the source and the collector. The resulting efficiencies and the volumetric power densities as functions of these parameters are determined, and the associated energy-loss mechanisms are discussed. The highest measured efficiency of 13.2% was achieved with a carbon collector at a 5-kV potential difference between the electrodes. The maximal volumetric energy density is approximately one-tenth of a common lithium-ion battery. [ABSTRACT FROM AUTHOR]

Purpose: This study aims to experimentally validate the Monte Carlo generated absorbed doses from the beta particles emitted by 90Y and 177Lu using radiochromic EBT3 film‐based dosimetry. Methods: Line sources of 90Y and 177Lu were inserted longitudinally through blocks of low‐density polyethylene and tissue‐equivalent slabs of cortical bone and lung equivalent plastics. Radiochromic film (Gafchromic EBT3) was laser cut to accommodate orthogonal line sources of radioactivity, and the film was sandwiched intimately between the rectangular blocks to achieve charged particle equilibrium. Line sources consisted of plastic capillary tube of length (13 ± 0.1) cm, with 0.42‐mm inner diameter and a wall thickness of 0.21 mm. 90Y line sources were prepared from a solution of dissolved 90Y resin microspheres. 177Lu line sources were prepared from an aliquot of 177Lu‐DOTATATE. Film exposures were conducted for durations ranging from 10 min to 38 h. Radiochromic film calibration was performed by irradiation with 6‐MV‐bremsstrahlung x rays from a calibrated linear accelerator, in accordance with literature recommendations. Experimental geometries were precisely simulated within the GATE Monte Carlo toolkit, which has previously been used for the generation of dose point kernels. Results: The mean percentage difference between measured and simulated absorbed doses were 5.04% and 7.21% for 90Y and 177Lu beta absorbed dose in the range of (0.1–10) Gy. Additionally, 1D gamma analysis using a local 10%/1 mm gamma criterion was performed to compare the absorbed dose distributions. The percentage of measurement points passing the gamma criterion, averaged over all tests, was 93.5%. Conclusions: We report the experimental validation of Monte Carlo derived beta absorbed dose distributions for 90Y and 177Lu, solidifying the validity of using Monte Carlo‐based methods for estimating absorbed dose from beta emitters. Overall, excellent agreement was observed between the experimental beta absorbed doses in the linear region of the radiochromic film and the GATE Monte Carlo simulations demonstrating that radiochromic film dosimetry has sufficient sensitivity and spatial resolution to be used as a tool for measuring beta decay absorbed dose distributions. [ABSTRACT FROM AUTHOR]

The nuclear transmutation in the nanosilicon under the influence of epithermal neutrons and the formation processes of charge carriers under the influence of gamma and beta rays emitted by unstable nuclei were theoretically and experimentally investigated. These studies may provide information on the origin and number of electroactive defects in neutron-irradiated nanosilicon. [ABSTRACT FROM AUTHOR]

Source efficiency in planar betavoltaic batteries is drastically reduced by self-absorption and directional loss. In this paper, we present a technique for improving source efficiency by the use of beta particles reflectors based on metals. A metallic layer with a high atomic number is an effective electron reflector, capable of reflecting up to 50% of the escaping energy from the backside of a source and they are more efficient for thinner radioactive layers. The obtained results show that the design of separate planar one-sided sources with electron reflectors could be optimized to reach high efficiency before assembly with semiconductor converters. Using a Pb reflector for a 200 nm thick Ni-63 source, 38.5% of the directional lost energy could be recovered. They can lead to cost-effective technology compared to sandwiched, porous, or three-dimension microstructure designs. [ABSTRACT FROM AUTHOR]

Introduction: Most of the radionuclides that are used for diagnostic purposes emit Auger electrons and can thus cause damage to the DNA molecule on a nanometer scale. Therefore, the nanodosimetric calculation of these radioisotopes is necessary to achieve better understanding on their effects. Aim: The aim of this study was to calculate the mean number of DNA strand breaks (single-strand breaks and double-strand breaks) caused by direct and indirect effects for six widely used Auger electron-emitting diagnostic radioisotopes, including 123I, 125I, 99mTc, 67Ga, 201Tl, 111In and two therapeutic radioisotopes of 131I(beta + Auger + CK emitter) and 211At(alpha + Auger + CK emitter). Materials and Methods: Geant4-DNA simulation tool was used to evaluate the effects of Auger electrons, beta and alpha particles of these radioisotopes on DNA molecules. Two different DNA molecule geometric models were simulated and the results of these two models were compared with each other as well as with the results of previous studies. Results and Conclusion: The results showed that the geometric shape of the sugar-phosphate groups may have a significant effect on the number of single-strand breaks (SSBs) and double-strand breaks (DSBs) of the DNA molecule. Among the most widely used diagnostic radioisotopes, 201Tl and 125I, had the greatest impact on the number of SSBs and DSBs, respectively, while therapeutic radioisotope of 131I almost had no effect, therapeutic radioisotope of 211At had the moderate effect on the number of breaks in the DNA chain. [ABSTRACT FROM AUTHOR]

A betavoltaic cell, which directly converts beta particles into energy, is composed of a junction diode and a beta-emitting source. Because the cells can deliver electricity over a long operation life ranging from several years to a decade, they are promising devices for applications in remote locations such as outer space, deserts, and underground areas. Herein, we report efficient energy conversion using a diamond pn junction. We characterized the betavoltaic performance under electron-beam irradiation using scanning electron microscopy and observed an open-circuit voltage of 4.26 V, a fill factor of 0.85, and a semiconductor conversion efficiency of 28%. These are the best values reported thus far for betavoltaic cells. The efficiency is close to the theoretical Shockley–Queisser efficiency limit for betavoltaic cells. [ABSTRACT FROM AUTHOR]

Beta and neutron attenuations of poly(imide siloxane) block copolymers were compared to evaluate radiation penetrations into flexible sheet (BI) and pellet form BII grains. The modification of BII polymer has improved its radiation shielding properties of poly(imide siloxane) block copolymer as the result of the pelletization. The linear attenuation coefficient of BII sample was determined as ∼0.073 (1/cm) and the half value layer was at ∼9.5 cm for negative beta particles. Besides, the total macroscopic cross section was at 0.047 (1/cm) and the half value layer of BII sample was determined at 14.74 cm for neutrons. The variations of beta and neutron attenuations indicated the structural changes in the poly(imide siloxane) block copolymer depended on the critical production parameters at the production step. The pelletization of the grains of BII improved beta and neutron shielding properties of poly(imide siloxane) block copolymers for the use in medical applications. [ABSTRACT FROM AUTHOR]

This paper describes a personal journey in ESR dating and gives some insights of the progress made over 35 years in ESR dating of tooth enamel. When I started, samples were irradiated with four additive dose steps of 5, 10, 15 and 20 krad and the linear extrapolation yielded the dose value. An assumed dose rate of 100 mrad/a yielded the age of the sample. Since then I learned that one actually has to measure the dose rate. I also learned that the dose response can be described by a single saturating function, or perhaps two, and that errors can be appropriately calculated. Rather than having a single anisotropic CO 2 − radical, tooth enamel consists of two anisotropic CO 2 − radicals and two isotropic CO 2 − radicals, one stable, one unstable. Also, the dose response shows spatial differences in the production of these different radicals in response to beta and gamma rays. Then there is the problem of uranium uptake over time. We solved this by combining ESR and U-series analyses. We can even measure appropriate beta attenuation factors including sequential laser ablation U-series analyses. Even better, all analyses can be carried out on small enamel fragments, which can be glued back into their original position with little to no visible damage. Still, when using the most sophisticated dose rate calculations, they're often close to 1000 μGy a−1. [ABSTRACT FROM AUTHOR]

Background: Recently, a flexible DROP-IN gamma-probe was introduced for robot-assisted radioguided surgery, using traditional low-energy SPECT-isotopes. In parallel, a novel approach to achieve sensitive radioguidance using beta-emitting PET isotopes has been proposed. Integration of these two concepts would allow to exploit the use of PET tracers during robot-assisted tumor-receptor-targeted. In this study, we have engineered and validated the performance of a novel DROP-IN beta particle (DROP-INβ) detector. Methods: Seven prostate cancer patients with PSMA-PET positive tumors received an additional intraoperative injection of ~ 70 MBq 68Ga-PSMA-11, followed by robot-assisted prostatectomy and extended pelvic lymph node dissection. The surgical specimens from these procedures were used to validate the performance of our DROP-INβ probe prototype, which merged a scintillating detector with a housing optimized for a 12-mm trocar and prograsp instruments. Results: After optimization of the detector and probe housing via Monte Carlo simulations, the resulting DROP-INβ probe prototype was tested in a robotic setting. In the ex vivo setting, the probe—positioned by the robot—was able to identify 68Ga-PSMA-11 containing hot-spots in the surgical specimens: signal-to-background (S/B) was > 5 when pathology confirmed that the tumor was located < 1 mm below the specimen surface. 68Ga-PSMA-11 containing (and PET positive) lymph nodes, as found in two patients, were also confirmed with the DROP-INβ probe (S/B > 3). The rotational freedom of the DROP-IN design and the ability to manipulate the probe with the prograsp tool allowed the surgeon to perform autonomous beta-tracing. Conclusions: This study demonstrates the feasibility of beta-radioguided surgery in a robotic context by means of a DROP-INβ detector. When translated to an in vivo setting in the future, this technique could provide a valuable tool in detecting tumor remnants on the prostate surface and in confirmation of PSMA-PET positive lymph nodes. [ABSTRACT FROM AUTHOR]

aptamers are short artificial, single-strand oligonucleotide sequences (DNA, RNA or modified RNA), capable of binding to biological molecules with high affinity and specificity. Due to their relatively low cost of production and scarce immunogenicity, many efforts have been made to produce aptamers directed against specific molecular targets, such as receptors or transporters overexpressed by malignancies. the technological approaches for generating aptamers are reviewed. Furthermore, the applications of radiolabeled aptamers for the in vivo imaging of several oncological biomarkers through single photon emission computed tomography (SPECT) or positron emission tomography (PET), are covered. Lastly, targeted therapy based on the utilization of aptamers labeled with radionuclides emitting beta particles is discussed, with particular emphasis to the oncological perspectives. The main limitation of radiolabeled aptamers is represented by their in vivo sensitivity to endogenous nuclease, so that several strategies have been developed to increase the stability of these compounds. Although the applications of aptamers are still in a preliminary and pre-clinical phase, it is reasonable to hypothesize that this technology will play a major role for personalized medicine in the next years. [ABSTRACT FROM AUTHOR]

• Singular Value Decomposition a new method to the continuous internal bremsstrahlung spectrum for deconvolution procedure. • Internal bremsstrahlung spectrum of 90Sr/90Y isotope obtained using 5.08 × 5.08 cm NaI(Tl) detector. • Detector response functions of NaI (Tl) detector are determined using peak to total ratio and detector efficiencies. • The result of stripping procedure shows a very good agreement between theory and experiment. We have tried to obtain the spectrum of internal bremsstrahlung photons which are released simultaneously with beta particles and neutrinos from the 90Sr-90Y source in secular equilibrium. Detector parameters of the 5.08 cm × 5.08 cm NaI(Tl) detector are determined using standard calibration sources. A detector response function is generated for a single-energy gamma photon using detector parameters and Monte Carlo method. The Singular Value Decomposition (SVD) method is used for stripping of the detector response function effects from the raw experimental spectrum. The stripped experimental data are compared with KUB theory and a different stripping method that we used our former work on the same isotope. There is a much better agreement between experimental and theoretical findings comparing the former experimental data. [ABSTRACT FROM AUTHOR]

Background: Brachytherapy of thin skin tumors using beta particles can protect underlying sensitive structures such as the bone because of the rapid dose falloff of this type of radiation in tissue. The current work describes a skin brachytherapy applicator, based on beta radiation, that can provide the needed cell‐killing radiation dose matched to the shape of individual skin tumors. Materials and methods: The applicator and its template were fabricated using 3D printing technology. Any clinically approved beta‐emitting isotope in the form of a radioactive gel could theoretically be used in this applicator. Monte Carlo simulations were employed to study the capability of the applicator in conforming dose distribution based on the shape of the tumor. Dose profile in the shallow depth, transverse dose profiles at different depths, and the percent depth dose from this applicator were calculated. The radioisotope of choice for our calculations was Yttrium‐90 (Y‐90). Results: Using the proposed applicator, it is possible to create a desired dose profile matching the tumor surface shape. Conclusion: The short‐range of the beta radiation, together with the dose conforming capability of the applicator, may lead to minimal interactions with the healthy tissue around the skin lesion. [ABSTRACT FROM AUTHOR]

SrMoO 4 powders, produced by co-precipitation, are investigated employing thermoluminescence (TL) and optically stimulated luminescence (OSL). The effects of microwave-assisted hydrothermal (MAH) treatment, beta particle irradiation, and thermal treatment are studied to understand their role on defect density and location in the band-gap. The powder X-ray diffraction showed that the SrMoO 4 powders crystallize in a tetragonal structure. The raman studies confirmed the presence of active vibration modes characteristic of molybdates, whereas the Fourier Transformed Infrared (FTIR) data exhibit the symmetric and asymmetric stretch vibrations. The trapping depth energies, determined from TL glow curves, range from 0.9 eV to 1.95 eV. The TL data show that the MAH treatment decreases the defect density and favors the formation of defects with lower activation energies. The residual TL signal shows the formation of shallower traps with a glow peak occurring at lower temperatures. The OSL emission only taken place for samples submitted to heating cycles and depends on the heating rate. These results indicate that shallow traps induced by thermal treatment are responsible for the OSL signal. The shape and intensity of the OSL curve depend on the number of heating cycles and on the heating rate, revealing that thermal treatment has a profound influence on this emission. The OSL signal for MAH-treated SrMoO 4 samples subjected to thermal treatment increases linearly with beta irradiation dose. The results give insight that SrMoO 4 phosphors may have potential applications in the design of a radiation sensor. [ABSTRACT FROM AUTHOR]

Several theoretical and experiential studies of runaway electrons in the well-known Tokamaks of the world have been made over the past few decades. In the present study, the measurements of runaway electrons energy were carried out by a new runaway probe in the IR-T1 Tokamak. In the IR-T1 Tokamak, the hard X-ray diagnostic system is used as a diagnostic global measurement system at the vessel wall of Tokamak. Runaway probe was first designed and fabricated for local measurement near the plasma edge in IR-T1 Tokamak. The new diagnostic has the advantage that the local interaction of runaways with materials can be evaluated, along with the direct measurement of the runaway electrons. The runaway probe consists of 2 LYSO (Lu 1.8Y.2SiO5:Ce) crystals covered by a graphite housing which is shielded by tungsten filter placed in the direction of runaway electrons. The main elements of the runaway probe are LYSO crystals which convert the energy of runaway electrons into visible light which is instructed to silicon photomultipliers. The present study aimed to evaluate a new runaway probe in the IR-T1 Tokamak to detect beta and gamma rays. The results indicated that electron spectrum is between 500 keV and 2 MeV at the plasma edge in the IR-T1 Tokamak. [ABSTRACT FROM AUTHOR]

Beta-decay of the very neutron-deficient Kr isotope, 70Kr, was studied at RIKEN-RIBF using the EURICA cluster array. The experiment significantly increased our knowledge of the beta-decay of this isotope. Namely, 16 new γ-ray transitions were identified and the half-life was derived from time correlations of the beta particles (tiβ 1/2 = (44.99±0.16) ms) and from thedecaycurvesoftheobserved γ-raytransitions(tiβγ 1/2 = (45.16±0.71) ms), respectively. [ABSTRACT FROM AUTHOR]

Black fungi withstand extreme stresses partly due to the presence of melanin. Melanin is associated with structural integrity and resistance to chemical and radiation stress. This results in improved health and fitness, specifically in extreme conditions. Our goal was to exploit the radiation sensing nature of melanized fungus in order to develop a radioadapted strain capable of responding to radiation in the environment. The protracted exposure of a melanized fungus , Wangiella dermatitidis , to a mixed source of radiation altered the electron transport properties. There was no effect in an albino mutant wdpsk1. We then tested the growth response to radiation in the environment, with shielding from direct exposure to the radiation. Gamma radiation caused increased colony growth irrespective of exposure history in melanized fungus. Beta particles produced growth inhibition. The previously exposed melanized strain demonstrated colony growth in response to alpha particles in the environment. Alpha particles have a higher linear energy transfer, which produces more reactive oxygen species. Our previously exposed melanized strain was resistant to the toxic effects of H 2 O 2 , while the naïve and non-melanized strains were sensitive. We propose that previous radiation exposure introduces adaptations that equip melanized fungi to tolerate, sense, and respond to radiation byproducts. Image 1 • Radioadapted fungi can be developed by protracted exposure to radiation. • Radioadapted fungi respond to radiation in the environment without direct exposure. • Radioadapted melanized fungus have increased resistance to H 2 O 2. [ABSTRACT FROM AUTHOR]

Background: Lutetium oxyorthosilicate or lutetium yttrium oxyorthosilicate (LYSO) scintillation crystals used in most current PET scanner detectors contain 176Lu, which decays by beta emission to excited states of 176Hf accompanied by the emission of prompt gamma rays or internal conversion electrons. This intrinsic radioactivity can be self-detected in singles mode as a constant background signal that has an energy spectrum whose structure has been explained previously. In this work, we studied the energy spectrum due to the intrinsic radioactivity of LYSO scintillation crystals of two opposing detectors working in coincidence mode. The investigation included experimental data, Monte Carlo simulations and an analytical model. Results: The structure of the energy spectrum was completely understood and is the result of the self-detection of beta particles from 176Lu in one crystal and the detection of one or more prompt gamma rays detected in coincidence by the opposing crystal. The most probable coincidence detection involves the gamma rays of 202 and 307 keV, which result in two narrow photopeaks, superimposed on a continuous energy distribution due to the beta particle energy deposition. The relative intensities of the gamma ray peaks depend on crystal size and detector separation distance, as is explained by the analytical model and verified through the Monte Carlo simulations and experiments. Conclusions: The analytical model used in this work accurately explains the general features of the coincidence energy spectrum due to the presence of 176Lu in the scintillation crystals, as observed experimentally and with Monte Carlo simulations. This work will be useful to those research studies aimed at using the intrinsic radioactivity of LYSO crystals for transmission scans and detector calibration in coincidence mode. [ABSTRACT FROM AUTHOR]

In this work, a betavoltaic combined with photovoltaic mechanism using strontium-90 as a radioactive source was built up. A transparent yttrium aluminum garnet ceramic doped with a cerium ion is used as an intermediate conversion layer to avoid direct irradiation to a semiconductor conversion device and translates most of the high energy beta particles into photons. The traditional crystalline silicon conversion device with an NþPPþ junction structure functions as a betavoltaic and photovoltaic conversion device simultaneously. Radiation resistance is demonstrated by a 0.9 MeV electron beam irradiation aging experiment. In the optimized betavoltaic setup with a 0.5mm transparent yttrium aluminum garnet ceramic, the crystalline silicon conversion device can bear 5-1015 e/cm2 by degrading output power less than 15%. Loaded with 1.3 mCi strontium-90, this betavoltaic setup produces a short circuit current of 282 nA, an open circuit voltage of 0.168 V, a fill factor of 0.58, and a total conversion efficiency of 0.32%. [ABSTRACT FROM AUTHOR]

This article presents a procedure for optimizing the charge comparison method (CCM) used for pulse shape discrimination (PSD). Without prior knowledge of the signals or the readout system, our procedure automatically optimizes the integration periods maximizing the discrimination ability of the radiation detector. This procedure is innovative in its adaptability and automation without being complicated to implement on a standard computer. Another advantage of this approach is the possibility to use it even if the operation of the readout system and the recording process of the signal is not fully known. Therefore, it enables all detection systems generating signals whose temporal evolution depends on the origin to optimize the integration periods of the CCM. Our procedure is based on verifying that two criteria are met in terms of the number of components and the correlation of Gaussian fits made on the distribution of the tail-to-total integral resulting from the CCM. We tested the procedure for different application cases. First, the optimization of the integration periods of the CCM was performed for the discrimination between fast neutrons and gamma rays with a plastic scintillator and a silicon photomultiplier (SiPM) in the energy range [250 keVee; 4.5 MeVee]. The integration periods, from the laboratory’s experience with photomultiplier tubes (PMTs) and plastic scintillators, gave a Figure of Merit (FoM) of 0.58 corresponding to a rejection ratio (RR) of 8.6%. The procedure improved the FoM up to 0.88 corresponding to a RR of 1.9%. We also applied the procedure to the discrimination between beta and gamma rays with a PMT and a phoswich organic detector and to the discrimination between signals collected from neutrons or partial discharges within a fission chamber. [ABSTRACT FROM AUTHOR]

A mathematical model of Ni-63 source for betavoltaic batteries is presented, based on the Monte Carlo calculation. Trajectories of beta particles are simulated in Ni-63 source until their escape or total energy dissipation. Analysis of the effect of physical and technological factors on the performance of a source is carried out. Special attention is given to self-absorption and substrate backscattering because of their impact on power emission. Addition of a protective layer diminishes the source emission because of further absorption. The model has been tested successfully for Ni-63/GaN structure. [ABSTRACT FROM AUTHOR]