Gamma Source Research Articles

Influence of the gamma source on the radiolytic stability of N,N,N′,N′-tetra-n-octyl-diglycolamide (TODGA)

Abstract In nuclear reprocessing, hydrolytic and radiolytic stability of ligands, extractants, diluents and solvents is of particular importance. The strength of extraction systems can only be fully exploited when process conditions are predictable and essential molecules, which are in close proximity to radioactive isotopes, are resistant to the radiation. During the development of novel extraction systems, testing of the radiolytic stability is often evaluated by exposing the molecules to high energetic gamma rays. In this work, the influence of the source of gamma rays is evaluated. TODGA was irradiated from 0–500 kGy using different sources of gamma rays, and its degradation was followed using UPLC-HRMS. Pool-type gamma irradiation facilities BRIGITTE B (Co-60) and GEUSE II (spent nuclear fuel) at SCK CEN were employed to serve as gamma sources. In this work, it is found that there is no significant influence on TODGA degradation which can be attributed to the origin of the gamma source.

Correction to: Feasibility study of the photonuclear reaction cross section of medical radioisotopes using a laser Compton scattering gamma source

Correction to: Feasibility study of the photonuclear reaction cross section of medical radioisotopes using a laser Compton scattering gamma source

Investigating the Suitability of Cu2ZnSnS4 Thin Films for Gamma Radiation Dosimetry Applications in Non-Medical Environments

Abstract The need for the replacement of cadmium, indium, and tellurium in their compounds for sensor applications is a novel study. The Cu2ZnSnS4 thin films were synthesized from Cu (99.99%), Sn (99.99%), and Zn (99.99%) using thermal evaporation method. The same volumetric parameters were maintained throughout the synthesis process. The films were further irradiated using an isotope of cesium-137 from a gamma source at different doses (0–0.6 kGy) and dose rates of 0.1007 kGy/hr at room temperature. Both the pristine and irradiated films were characterized with Raman spectroscopy, field emission scanning electron microscope (FESEM), energy dispersive X-rays (EDX), UV-Vis spectroscopy, and four-point probe techniques. The Raman results confirmed that all the films for both pristine and irradiated films have a main and secondary phases. The EDX results showed the pristine and 0.1 kGy films were Cu-rich film, while the 0.3 kGy and 0.6 kGy films turned out to be Zn-rich films with an increase in gamma dose. The optical property of all the films showed that the band gap decreased from 1.6 eV to 1.48 eV for the pristine and irradiated films. While the electrical resistivity results decreased after irradiation dose. The structural, optical, and electrical properties results responded linearly with the increasing gamma radiation dose, which suggested the possibility of using films as a new solid-state sensor to replace CdTe and CIGS thin films.

Mean global field power is reduced in infantile epileptic spasms syndrome after response to vigabatrin.

Infantile epileptic spasms syndrome (IESS) is associated with abnormal neuronal networks during a critical period of synaptogenesis and brain plasticity. Hypsarrhythmia is a visual EEG biomarker used to diagnose IESS, assess response to treatment, and monitor relapse. Computational EEG biomarkers hold promise in providing unbiased, reliable, and objective criteria for clinical management. We hypothesized that computational and visual EEG biomarkers of IESS would correlate after treatment with vigabatrin and that these responses might differ between responders and non-responders. A retrospective analysis was conducted at a single center, involving children with IESS at initial diagnosis and following first-line treatment with vigabatrin. Visual EEG biomarkers of hypsarrhythmia were compared with computational EEG biomarkers, including spike and spike fast-oscillation source coherence, spectral power, and mean global field power, using retrospective analysis of EEG recorded at initial diagnosis and after vigabatrin treatment. Responders and non-responders were compared based on the characteristics of their follow-up EEGs. In this pilot study, we observed a reduction in the EEG biomarker of hypsarrhythmia/modified hypsarrhythmia from 20/20 (100%) cases at the initial diagnosis to 9/20 (45%) cases after treatment with vigabatrin, indicating a 55% (11/20) responder rate. No significant difference in spike frequency was observed after treatment (p = 0.104). We observed no significant differences after treatment with vigabatrin in the computational EEG biomarkers that we assessed, including spike source coherence at 90% (p = 0.983), spike source coherence lag range (p > 0.999), spike gamma source coherence at 90% (p = 0.177), spike gamma source coherence lag range (p > 0.999), spectral power (0.642), or mean global field power (0.932). However, when follow-up EEGs were compared, there was a significant difference in mean global field power (p = 0.038) between vigabatrin responders and non-responders. In contrast, no such difference was observed for spike source coherence at 90% (p = 0.285), spike course coherence lag range (p = 0.819), spike gamma source coherence at 90% (p = 0.205), spike gamma source coherence lag range (p > 0.999), or spectral power (p = 0.445). Finally, our treated group did not differ significantly from healthy controls at initial diagnosis or follow-up in terms of spectral power (p = 0.420) or mean global field power (0.127). In this pilot study, we show that mean global field power is a computational EEG biomarker that is significantly reduced in IESS after treatment with vigabatrin. Although computational EEG biomarkers of network connectivity using spike source coherence appear to be a promising tool, future studies should further explore their potential for assessing treatment responses in IESS.

Clay and Cement Shielding Behavior from Gamma Sources

Clay and Cement Shielding Behavior from Gamma Sources

Fabrication and testing of a 3D double-stack RPC with 30 gas gaps for detection of high energy gammas

Multigap Resistive Plate Chambers (MRPCs) are cost-effective detectors with a high-performance. They are easy to build and offer the possibility to cover large areas. They provide excellent time resolution and potentially good spatial resolution. In this context, a 3D RPC with 15 double-stack layers (30 gas gaps) free of parallax error is fabricated. The designed RPC has a 2D pixelated readout and the induced charge on the ground electrodes, gives the position in the third dimension. The simulation results show that in the X–Y plane the Full Width Half Maximum (FWHM) resolution is around 70 μm for 511 keV gammas, while for the Z-axis, which is perpendicular to the detector plane, a spatial resolution of around 560 μm can be achieved. The fill factor of the proposed detector with a pitch of 6.25 mm for SNR of 17 is around 0.13%, and the maximum achievable fill factor for the same setup and SNR of 42.5 is around 23%. The measured spatial resolution of the detector for a collimated Cs-137 point source is in good agreement with the simulation results. For an isotropic 511 keV gamma source at 0.95 cm distance of RPC detector, the experimental detection efficiency of constructed RPC at 1900V applied voltage is around 2.1%, which with a relative error of 7% is in good agreement with the simulation result obtained by GEANT4 (2.25%). With the same detector, at larger distances of the gamma source from the detector (clinical PET camera) a detection efficiency of around 5.09% is achievable. For small animal PET (100 mm radius) with 18F point source, the spatial resolution (Γ) of a PET system composed by 3D MRPC detectors with 2.25∗2.25 mm2 and 1∗1 mm2 pixel sizes, fabricated by commercial PCB technology (pitch = 6.25 mm) and Microlithography technology (pitch = 1.25 mm), would be 1.64 mm and 0.91 mm, respectively.

Investigation of thermal, acoustic, mechanical, and radiation shielding performance of waste and natural fibers

It is crucial to address two pressing global issues, energy shortage and environmental pollution, when producing building insulation materials. Using waste and natural fiber groups can be part of the solution. The insulation material was produced using pumpkin fiber, chicken fiber, cotton waste, vermiculite, and epoxy as binders. The samples were tested for thermal conductivity coefficient, ultrasonic sound transmission rate, density, water absorption rate, compressive and bending strength, and fire resistance at temperatures of 75, 100, 125, and 150C. The samples produced using natural and waste materials yielded a thermal conductivity value of 0.041 W/mK, an ultrasonic sound transmission speed of 0.25 km/s, a compressive strength value of 1.57 MPa, and bending strength values of 0.91 MPa. It has been clearly demonstrated that, with its low volume loss, it can serve as an alternative to the EPS-XPS types available in the market. Furthermore, the linear attenuation coefficients (LAC) were examined to obtain radiation shielding properties of the samples at 1173 and 133 keV energies using a 60Co gamma source. Also, LAC values determined between 0,1167 ± 0,0452 cm−1-0,2315 ± 0,0065 cm−1 for 1173 keV and 0,1042 ± 0,0488 cm−1 - 0,2141 ± 0,0062 cm−1 for 1333 keV. Accordingly, it has been revealed that waste compositions are effective in protecting against radiation.

Plaque Radiotherapy for Ocular Melanoma

Plaque radiotherapy is an effective treatment modality for medium-sized ocular tumors such as uveal melanoma. The authors review the available literature and concisely summarize the current state of the art of ophthalmic plaque brachytherapy. The choice of radioisotope, which includes Ruthenium-106 and Iodine-125, depends on the intended treatment duration, tumor characteristics, and side effect profiles. Ophthalmic plaques may be customized to allow for the delivery of a precise radiation dose by adjusting seed placement and plaque shape to minimize collateral tissue radiation. High dose rate (HDR) brachytherapy, using beta (e.g., Yttrium-90) and photon-emitting sources (e.g., Ytterbium-169, Selenium-75), allows for rapid radiation dose delivery, which typically lasts minutes, compared to multiple days with low-dose plaque brachytherapy. The efficacy of Ruthenium-106 brachytherapy for uveal melanoma varies widely, with reported local control rates between 59.0% and 98.0%. Factors influencing outcomes include tumor size, thickness, anatomical location, and radiation dose at the tumor apex, with larger and thicker tumors potentially exhibiting poorer response and a higher rate of complications. Plaque brachytherapy is effective for selected tumors, particularly uveal melanoma, providing comparable survival rates to enucleation for medium-sized tumors. The complications of plaque brachytherapy are well described, and many of these are treatable.

Development of a low energy loss micro-channel plate based position-sensitive detector for the Rare Radio-Isotope Ring

A position-sensitive micro-channel plate type detector has been developed for use in the Rare Radio-Isotope Ring at RIKEN, Japan. It uses secondary electrons emitted from a conversion foil and deflected at 90° to create a position signal. Design constraints included operation in a high-vacuum, a large area to cover the ring acceptance and low beam interaction to reduce energy loss. It must achieve a precision sufficient to measure the in-ring dispersion and perform position diagnostics for tuning the injection. Reducing the time-of-flight of secondary electrons was principal in improving resolution as it reduces their final gaussian spread. This was implemented by compacting the geometry of the detector and raising the acceleration potential. Electric field homogeneity was also improved by decreasing the electrostatic grid wire pitch from 2 mm to 1 mm. Offline tests with alpha sources and online tests with a 200 MeV/u 84Kr beam were conducted, reaching a final average position resolution of σ=1.3 mm. This is sufficient for conducting beam diagnostics in the storage ring.

Study on Characteristics of Epoxy Resin-Based Plastic Scintillators for Detectors with Simulation Using Monte Carlo Code

Abstract To determine the presence of radioactive materials emitting gamma rays entering or exiting nuclear facilities, ports, airports, international borders, or other strategic locations, radiation portal monitors (RPMs) capable of detecting such gamma radiation need to be installed in these places. National Research and Innovation Agency of Indonesia (BRIN) is currently developing RPMs with detector components made of plastic scintillator based on epoxy resin and augmented with aromatic fluorescent materials to produce visible light, which is the working range of the photomultiplier tube (PMT) or silicon photomultiplier (SiPM). This research aims to study the characteristics of the gamma photon radiation energy spectrum from Co-60, Cs-137, and Ir-192 sources in an epoxy resin plastic scintillator and study the absorbed dose of the scintillator to gamma photon radiation energy from Co-60, Cs-137, and Ir-192 sources as a function of source distance and incidence angle of gamma rays with simulations using the MCNPX code. The scintillator is modeled in the form of a cylinder with a diameter of 5 cm and a height of 5 cm. To simulate the gamma photon radiation energy spectrum in the scintillator, the F4 tally was used and to simulate the scintillator absorbed dose, the F6 tally was used. This simulation used gamma sources of Co-60, Cs-137, and Ir-192 of 1 mCi each. These characteristics of the epoxy resin plastic scintillator have been successfully simulated. Data on the characteristics of epoxy resin plastic scintillators is important to know and study as supporting data in making plastic detectors as part of the manufacture and development of RPM.

Single-photon elimination in liquid scintillation counting with pulse shape discrimination and delayed coincidence

Liquid scintillation counting is widely used in the rapid measurement of beta activity in environmental and biological samples. However, the single-photons generated by chemiluminescence and photoluminescence in liquid scintillation cocktails seriously affect the measurement accuracy of low-energy beta activity. A novel method based on the combination of the signal characteristic analysis and selective gate to eliminate the single-photon signal was developed. A preprocessing circuit made of a fast response time photomultiplier tube (PMT, Hamamatsu R9420), two charge-sensitive preamplifiers (CSP), two comparators, an analog switch and delay-line devices were designed and developed to verify the feasibility and effectiveness. The output signals from the last dynode were characterized in the pulse time and were used to discriminate the beta signals from the single-photon ones. The beta signals were “tagged” through pulse width detection, pulse width-amplitude transform and pulse-height discrimination with the first comparator, the first CSP and the second comparator. The “tagged” beta signal were applied to control the analog switch. The anode signals were specially delayed and then selected by the analog switch to achieve the single-photon signal elimination. Liquid scintillation cocktails containing 14C or NaOH used as beta or single-photon sources were provided to verify the feasibility of the principle. The results showed that the typical fall time of the single-photon and beta signal was 16.05ns and 43.17ns. The single-photon rejection ratio is 2.76 × 10−3 ± 3.89 × 10−5, and the detection efficiency is up to 93.02%±0.59%.

Experimental investigation of fired clay bricks for gamma radiation shielding

In this study, the focus was on evaluating how the physical and structural attributes of red clay bricks influence their ability to shield γ-rays. The red clay brick samples' density (ρ, g/cm3) was measured using the MH-300A density meter. The minerals present in the selected clay were identified through the application of X-ray diffraction. Moreover, the material's morphology and chemical composition were studied using scanning electron microscopy. By increasing the pressure rate (PR) from 7.61 to 114.22 MPa, the density of the synthetic clay bricks was increased from 1.50 to 1.69 g/cm3. Subsequently, the gamma-ray shielding effectiveness of the clay bricks produced was investigated through experiments utilizing a NaI (Tl) detector with exposure to various gamma sources. The experimental data illustrated a rise in the linear attenuation coefficient (μ) of the proposed clay bricks, progressing from 1.352 ± 0.040 to 1.559 ± 0.068 cm−1, from 0.111 ± 0.003 to 0.123 ± 0.005 cm−1 and from 0.087 ± 0.002 to 0.099 ± 0.003 cm−1 at γ-ray energies of 0.033, 0.662, and 1.332 MeV, respectively. The rise in μ resulted in a reduction in the half-value thickness (Δ0.5), lead equivalent thickness (Δeq) and transmission factor (TF), in the synthetic bricks. Additionally, samples with increased thickness exhibited enhanced effectiveness in shielding gamma radiation, making them suitable for various applications requiring radiation protection. Moreover, the detection of pressure rate's influence on the physical and shielding characteristics of clay bricks was observed at specific gamma energies. (0.033, 0.662 and 1.332 MeV).

Fabrication, photovoltaic analysis, and electrical characterization of Au/ZnTPyP/p-Si/Ag heterojunction under gamma radiation effect for solar cell applications

The main objective of the current study is to investigate the impact of gamma rays on the characteristics and behavior of a fabricated heterojunction device based on tetra pyridyl-porphine zinc (ZnTPyP). The importance of this study includes determining critical parameters such as conversion efficiency (η). A cobalt-60 gamma source has been employed to investigate the effects of gamma exposure dosages ranging from 0 to 5 kGy on the morphological and optical features of the studied material. An atomic force microscope (AFM) was used to examine the morphological characteristics of the ZnTPyP film that formed on the glass substrate. The thin film’s optical characteristics were investigated on quartz for both as-deposited and irradiated films at various gamma doses (1 kGy and 3 kGy). Additionally, ZnTPyP is evaporated on p-type silicon substrates to create ZnTPyP/p-Si heterojunction. The current–voltage (I–V) curves at various doses of gamma radiation at 0, 1, 3, and 5 kGy for Au/ ZnTPyP /p-Si/Ag heterojunction device are experimentally measured. The predominant conduction processes are the thermionic emission and single-trap space-charge-limited current (SCLC). Furthermore, the values of the barrier height φB\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\left( {\\varphi_{B} } \\right)$$\\end{document} are estimated using two different methods, including I–V method and Norde’s equations at different doses, and their values are comparable. Under illumination at 0 kGy, we found the values of short-circuit current (Isc), open-circuit voltage (Voc), and photoconversion efficiency (η) to be 0.92 mA, 0.41 V, and 4.28%, respectively. On the hand, some important optical parameters are determined for both as-deposited and irradiated ZnTPyP films, such as skin depth (δ), and found that δ values reduce with increasing gamma doses, reflecting the efficiency and performance of photovoltaic cells. Finally, the study indicated the alteration in the studied optical parameters and slightly enhanced the Au/ZnTPyP/p-Si/Ag heterojunction efficiency when subjected to gamma radiation.

Electrodeposition of actinides: Optimization of deposition parameters by chronoamperometric studies

To quantify alpha-emitting radionuclides by alpha spectrometry, it is necessary to prepare a thin and uniform alpha source on a suitable substrate. Electrodeposition is the most used electrochemical technique for this purpose. In order to better understand the electrochemical process carried out in the electrodeposition of actinides, in particular the selection of the current densities applied, a chronoamperometric study of the electrodeposition of actinides (Th, U, Pu, Am and Cm), in three different electrolytes (Na2SO4/H2SO4, NH4NO3, NaF) using stainless steel and platinum as cathode and anode, respectively, is presented. The corresponding polarization curves (potential vs. current density), characteristic for each electrolyte and actinide used, were constructed from the chronoamperometric data, The limiting diffusion current as well as the minimum current necessary for the electrodeposition process to take place were determined. To achieve a quantitative electrodeposition of actinides, a balance between OH- production and the thickness of the OH- layer formed near the cathode must be reached. These parameters are controlled by the electrolyte used and the current density applied to the electrochemical system. Actinides were electrodeposited mainly in the form of oxides, according to Raman spectroscopy results.

Feasibility study of the photonuclear reaction cross section of medical radioisotopes using a laser Compton scattering gamma source

Feasibility study of the photonuclear reaction cross section of medical radioisotopes using a laser Compton scattering gamma source

Experimental study of gamma-ray attenuation capability of B2O3-ZnO-Na2O-Fe2O3 glass system

In the present work, a glass system with developed composition consisting of B2O3, ZnO, Na2O and Fe2O3 samples has been investigated. Glass samples were prepared using the melt quenching method and the density of the system was measured using Archimedes’ principle. Spectroscopic analysis using a gamma source and a high-purity germanium detector at four energies of 0.0595, 0.6617, 1.173, and 1.333 MeV emitted from Am-241, Cs-137, and Co-60 were used to determine the attenuation parameters of present glass composites. The sample containing 45 B2O3 + 10 Na2O + 40 ZnO + 5 Fe2O3 (coded BNZF-4) had the highest mass attenuation coefficient (MAC) value at all the energies discussed compared to the other composites. Whoever, the BNZF-1 sample had the lowest value at all ranges of energies. The transmission factors (TF, %) of the manufactured samples were calculated, at 0.0595 MeV (TF, %) values are 32.6429 and 6.4612 for samples BNZF-1 and BNZF-4, respectively. The statistical results demonstrated significantly better to increase the ZnO concentration in the sample, where the percentage of zinc oxide inside the prepared glass samples has the following direction BNZF -4 > BNZF -3 > BNZF -2 > BNZF -1. The significance of this study is that transparent, environmentally harmless glass composites with relatively high density have been prepared that can be used as shielding materials against gamma rays, especially at low energies.

Characterization of a novel polyurethane-based plastic scintillator for neutron and gamma detection in mixed radiation fields

We present studies of a novel plastic scintillator branded M600, which was developed and provided by Target Systemelektronik. This new material is, in contrast to other solid organic scintillators offered by commercial providers, based on a polyurethane matrix complemented with scintillating and wavelength-shifting additives. This paper covers measurements of absolute light output, LO, (photons per 1 MeV-γ), γ-non-proportionality (NP), light pulse shapes, and neutron-gamma (n/γ) discrimination. The measurements were carried out either using standard calibration gamma sources (LO, NP) or in a mixed field of neutron and γ radiation from an intense (∼4 × 105 neutrons/s/4π) AmBe source (n/γ discrimination). The measured light output was 9650 ± 1000 ph/MeV and the PSD's figure of merit (FoM) was found as 2.2 ± 0.1 at ∼1000 keVee for ∅2.54 cm × 2.54 cm M600 sample. The bigger sample (∅5.08 cm × 5.08 cm) exhibits about 25% lower LO and poorer FoM when compared to the ∅2.54 cm × 2.54 cm M600, due to self-absorption.

Long-Range Imaging of Alpha Emitters Using Radioluminescence in Open Environments: Daytime and Night-Time Applications.

Alpha emitters like plutonium pose severe health risks when ingested, damaging DNA and potentially causing cancer. Traditional detection methods require proximity within millimeters of the contamination source, presenting safety risks and operational inefficiencies. Long-range detection through alpha radioluminescence (RL) offers a promising alternative. However, most of the previous experiments have been carried out under controlled conditions that preclude the overwhelming effect of ambient light. This study demonstrates the successful detection of a 3 MBq alpha emitter in an open environment using a compact alpha camera. This camera incorporates a deep-cooled CCD and a low f-number lens system designed to minimize the blue shift effects of filters. Night-time imaging was achieved with a dual-filter system using a sandwich filter assembly centered at 337 nm and 343 nm for capturing alpha RL and subtracting background light, respectively. At night, the alpha source was detected from 1 m away within one minute, and the lowest detection limit can be calculated as 75 kBq. The system was also evaluated under simulated urban lighting conditions. For daytime imaging, a stack of tilted 276 nm short pass filters minimized sunlight interference, enabling the detection of the alpha source at 70 cm within 10 min under indirect sunlight. This research highlights the viability of long-range optical detection of alpha emitters for environmental monitoring in real-world settings.

Determining beta radiation doses from Y-90 microsphere for the treatment of hepatic tumors by using Monte Carlo and analytical methods

The very short range of beta radiation is a potential radiation treatment for tumor, which can preserve sensitive structures. However, due to the limited range of beta radiation, practical dosimetry of beta sources may be a point of concern, and theoretical dosimetry methods play an important role. A resin microsphere loaded with the Yttrium-90 (Y-90) radionuclide can be applied in the radioembolization of hepatic tumors. In this work, we present initial calculations of dose rates around a microsphere loaded with the Y-90 radionuclide uniformly distributed on its exterior surface. Two approaches were used to carry out the estimations: the first one by means of Monte Carlo simulations using the PENELOPE code and the second one by means of the beta-point dose function formalism. A Fortran code was developed to handle with the various quantities necessary to perform the numerical integration of the beta-point dose function. A comparison between results obtained by means of both methods indicated a maximum difference of ~5% up to the 0.3 cm distance from the center of the sphere.

Structural evolution of zirconium diboride under gamma irradiation and thermal annealing

Understanding the thermal properties and enhancing the performance of zirconium diboride (ZrB2) under extreme conditions is crucial, especially given its role as a burnable absorber in nuclear fuel pellets and its potential applications in accident-tolerant fuels. This study explores the structural alterations of ZrB2 crystals induced by gamma irradiation and subsequent thermal annealing. ZrB2 crystals were exposed to absorption doses of 300 kGy, 1000 kGy, 1500 kGy, and 3000 kGy using a 60Co gamma source, followed by thermal treatment at 1173 K under vacuum conditions. Also, Monte Carlo simulations were utilized to analyze the energy deposition and distribution of gamma quanta within the material during irradiation, highlighting Compton effects up to 0.23 MeV. X-ray diffraction analysis elucidated the impact of gamma radiation on ZrB2 crystal lattice parameters, space group, and volume expansion coefficient. Post-irradiation analysis revealed a maximum degree of amorphization and investigated mechanisms governing lattice parameter expansion. Thermal annealing at 1173 K significantly enhanced crystallinity, reducing amorphization to 0.2 % at an absorption dose of 3000 kGy and facilitating the restoration of the crystal's columnar structure. This comprehensive investigation provides insights into the intricate interplay between gamma irradiation, thermal processing, and resulting structural changes in ZrB2 nanocrystals, essential for applications in radiation-exposed environments.