Gamma-ray Interaction Research Articles

Effect of mechanical ball milling on the microstructure and radiation shielding performance of nano-PbO

This study probes the shielding efficacy of nano-PbO, examining the effects of milling on its microstructure and the consequences on X- and gamma-ray absorption. Characterization techniques, including XRD, Raman spectroscopy, TEM, and positron annihilation spectroscopy of commercial (milled for 10, 20, and 40 h) samples, as well as the synthesized PbO, reveal that milling induces a partial phase transformation from orthorhombic to tetragonal, alters particle morphology, and increases pore volume. Notably, milling does not significantly affect X-ray attenuation. The growing particle size with lower surface area, reduction of vacancy-type defects, and expanded pore size resulting from ball milling negatively influenced the probability of interaction of gamma-rays (<250 keV). Principal component analysis highlights the interplay between particle size, surface area, defect density, and pore size in determining shielding efficacy. This investigation underscores the importance of considering multiple parameters, beyond particle size, to optimize the radiation shielding performance of any material.

Characterization of TlBr gamma detector based on electrical charge and Cherenkov light analysis

Thallium Bromide (TlBr) semiconductors have been extensively studied for their potential as room-temperature gamma-ray detectors, owing to their advantageous material properties. Recent advancements have demonstrated that timing performance in TlBr detectors can be enhanced by incorporating Cherenkov photon detection during gamma-ray interactions. In this study, TlBr detector (5 × 5 × 5 mm3) was investigated through a combined analysis of electrical charge and Cherenkov light signals. The depth of interaction (DoI) correction applied to the trapezoidal filter output yielded significant improvements in energy resolution, reducing it from 5.6% to as low as 2.51% FWHM at 511 keV and from 4.6% to as low as 1.94% FWHM at 662 keV, within specific C/A ratio ranges. The drift time, ranging from 2 to 30 μs, was found to be proportional to the C/A ratio, covering 4 to 9 photoelectrons. Furthermore, a time resolution of 511 ps was achieved at 6 photoelectrons, based on the FWHM of the time difference distribution in coincidence measurements at 511 keV using a 22Na source. These results highlight the potential of TlBr detectors for achieving high energy and timing resolution in gamma detection, particularly for Compton-PET systems.

Gamma-Ray Burst Interaction with the Circumburst Medium: The CBM Phase Following the Prompt Phase in GRBs

Progenitor stars of long gamma-ray bursts (GRBs) could be surrounded by a significant and complex nebula structure lying at a parsec-scale distance. After the initial release of energy from the GRB jet, the jet will interact with this nebula environment. We show here that for a large, plausible parameter space region, the interaction between the jet blast wave and the wind termination (reverse) shock is expected to be weak, and may be associated with a precursor emission. As the jet blast wave encounters the contact discontinuity separating the shocked wind and the shocked interstellar medium, we find that a bright flash of synchrotron emission from the newly formed reverse shock is produced. This flash is expected to be observed at around ∼100 s after the initial explosion and precursor. Such a delayed emission thus constitutes a circumburst medium (CBM) phase in a GRB, having a physically distinct origin from the preceding prompt phase and the succeeding afterglow phase. The CBM phase emission may thus provide a natural explanation for bursts observed to have a precursor followed by an intense, synchrotron-dominated main episode that is found in a substantial minority, ∼10% of GRBs. A correct identification of the emission phase is thus required to infer the properties of the flow and of the immediate environment around GRB progenitors.

A study on the interaction parameters of charged and uncharged radiation types with some indoor plants

This study investigates how gamma rays, neutrons, and electrons interact with five commonly found indoor plants: Spathiphyllum wallisii (SW), Ficus elastica (FE), Dieffenbachia camilla (DC), Schefflera arboricola (SA), and Ficus benjamina (FB). Utilizing experimental measurements (with HPGe detector), Monte Carlo simulations (GEANT4 and FLUKA), and theoretical calculations (ESTAR and WinXCOM), some radiation interaction parameters for gamma rays, fast neutrons, thermal neutrons, and electrons were determined. Secondary particle generation was also analyzed to provide a comprehensive assessment. The determined linear attenuation coefficients with the help of the WinXCOM are 0.1376, 0.1662, 0.1385, 0.1651 and 0.1698 cm−1 for SW, FE, DC, SA and FB, respectively. The calculated total macroscopic cross sections for indoor plants in the same sample order are 2.0290, 2.0350, 2.0285, 2.0363 and 2.0362 cm−1. Among the investigated plants, FB exhibited the highest gamma ray interaction, while SA and FB showed superior interaction against fast neutrons compared to SW and DC. The findings reveal significant variations in interaction effectiveness and secondary radiation production across these plants, offering valuable insights for radiation safety and environmental health evaluations.

Synthesis and characterization of metakaolin-based geopolymers doped with CRT waste glass for radiation shielding applications

This study presents the influence of CRT glass on the gamma-ray interaction processes in metakaolin-based geopolymers. Four batches of G-CRT composites (namely, G, G-10CRT, G-20CRT, and G-30CRT, which represent geopolymer (G) samples doped with 0, 10, 20, and 30 wt% of CRT glass) were prepared using the cold hydrostatic press method. The mass attenuation coefficients of the prepared C-xCRT samples were computed using XCOM and FLUKA simulations for photons within the energy range of 15 keV–15 MeV. The density of the pristine geopolymer increased from about 1.86 g/cm3 to 2.09, 2.26, and 2.34 g/cm3 for G-10CRT, G-20CRT, and G-30CRT, respectively. The photon mass and linear attenuation coefficients of the geopolymers increased with CRT glass concentration. The half-value layer and mean free path were within the ranges 0.070–18.079 cm and 0.101–26.083 cm for G; 0.036–15.110 cm and 0.052–21.799 cm for G-10CRT; 0.024–13.197 cm and 0.014–19.039 cm for G-20CRT; and 0.018–12.074 and 0.026–17.419 cm for G-30CRT. The G-30CRT had the best gamma attenuating prowess in contrast to other G-xCRT. CRT-rich G-xCRT had a higher effective atomic number. For 10 mm thick geopolymer, the absorbed dose rates were 0.211 μR/h, 0.66 μR/h, 1.11 μR/h, and 1.55 μR/h for G, G-10CRT, G-20CRT, and G-30CRT, respectively, for 100 keV photons. The introduction of CRT glass into the geopolymer matrix improved their photon interaction cross-section. The geopolymers showed outstanding photon interaction ability compared to ordinary concrete and some shielding glasses at low photon energies. The CRT glass-doped geopolymer samples are useful for preparing radiation shielding concrete.

Scintillation event imaging with a single photon avalanche diode camera

Position and time measurements of scintillation events encode information about the radiation source. Single photon avalanche diode (SPAD) arrays offer multiple-megapixel spatial resolution and tens of picoseconds temporal resolution for detecting single photons. Current lensless designs for measuring scintillation events use sensors that are lower in spatial resolution. Camera-based designs use sensors that are lower in temporal resolution or readout rate and cannot image individual interactions. Here we propose to image scintillation events in a thick, monolithic scintillator using a high-resolution SPAD camera. We demonstrate that a commercial SPAD camera is able to gather sufficient signal to image individual scintillation events and observe 3D shifts in their spatial distribution. Simulations show that a SPAD camera can localize individual scintillation events in 3D. We report direct imaging of gamma-ray interactions in a scintillator with a SPAD camera. The proposed design may allow to measure complex signatures of individual particles interacting in the scintillator.

Enhanced radiation shielding efficiency of polystyrene nanocomposites with tailored lead oxide nanoparticles

In this study, we investigated a novel polymer nano-composite, PS-PbO, containing two distinct nano-sizes of lead oxide nanoparticles (PbO-A and PbO-B), in addition to the bulk size (PbO-K). These nanoparticles were embedded separately in a polystyrene (PS) matrix at different weight percentages (10%, 15%, 25%, and 35%) using roll mill mixing and compressing molding. Our evaluation focused on the radiation attenuation ability of PS-PbO and the effect of particle size, considering gamma-ray energies ranging from 0.06 to 1.3 MeV (from sources like 241Am, 133Ba, 137Cs, and 60Co). The linear attenuation coefficient (LAC) was determined by analyzing samples of the synthesized composite with different thicknesses. Then, various shielding parameters were calculated, including total molecular, atomic, and electronic cross-sections (σmol, σatm, σel), as well as the effective atomic number and the electron density (Zeff and Neff). Surprisingly, modifying PbO particle sizes had a significant impact on shielding efficiency. For instance, the composite with 25 wt% of the smallest PbO-B particles showed a 26.7% increase in LAC at 0.059 keV compared to the composite with 25 wt% of PbO-K (larger particles). Notably, the LAC peaked at low energy (0.059 keV), close to the K-edge of Pb, where interaction is directly proportional to Z4. With increasing PbO concentrations, the LAC of PS-PbO composites increased steadily. Additionally, as PbO concentration increased, the composite’s effective atomic number Zeff and the electron density Neff increased, leading to a greater total Gamma-ray interaction cross-section. Furthermore, when comparing the Half-Value Layers of the novel nanocomposite to traditional lead shielding, a 70% reduction in mass was observed. Notably, the composite containing the smallest nano-size of PbO exhibited the highest radiation-shielding efficiency among all combinations and could therefore be used to create inexpensive and lightweight shields.

Open-Source Optimization of Hybrid Monte Carlo Methods for Fast Response Modeling of NaI (Tl) and HPGe Gamma Detectors

Modeling the response of gamma detectors has long been a challenge within the nuclear community. Significant research has been conducted to digitally replicate instruments that can cost over USD 100,000 and are difficult to operate outside of a laboratory setting. The large cost and availability prevent some from making use of such equipment. Subsequently, there have been multiple attempts to create cost-effective codes that replicate the response of sodium-iodide and high-purity germanium detectors for data derivation related to gamma-ray interaction with matter. While robust programs do exist, they are often subject to export controls and/or they are not intuitive to use. Through the use of hybrid Monte Carlo methods, MATLAB can be used to produce a fast first-order response of various gamma-ray detectors. The combination of a graphical user interface with a numerical-based script allows for open-source and intuitive code. When benchmarked with experimental data from Co-60, Cs-137, and Na-22, the code can numerically calculate a response comparable to experimental and industry-standard response codes. Evidence supports both savings in computational requirements and the inclusion of an intuitive user experience that does not heavily compromise data when compared to other standard codes, such as MCNP and GADRAS, or experimental results. When the application is installed on a Dell Intel i7 computer with 16 cores, the average time to simulate the benchmarked isotopes is 0.26 s. Installation on an HP Intel i7 four-core machine runs the same isotopes in 1.63 s. The results indicate that simple gamma detectors can be modeled in an open-source format. The anticipation for the MATLAB application is to be a tool that can be easily accessible and provide datasets for use in an academic setting requiring gamma-ray detectors. Ultimately, this article provides evidence that hybrid Monte Carlo codes in an open-source format can benefit the nuclear community in both computational time and up-front cost for access.

Experimental investigation of gamma-ray interaction parameters and buildup factors in lanthanide compounds: Insights into penetration depth

This experimental investigation focuses on the gamma-ray interaction parameters and the buildup factor in lanthanide compounds (CeO2, Ce(SO4)2, Dy2(SO4)3, C3O9Sm2, C3Gd2O9, Pr2O3). These compounds were exposed to weak radioactive gamma sources with energies of 356, 511, 662, 1173, 1275, and 1332 keV by adopting narrow and broad beam geometry experimental arrangements. The incident and transmitted radiation intensities were measured using a NaI (Tl) detector. Experimentally measured values of mass attenuation coefficient and effective atomic number of lanthanide compounds were found to be in precise agreement with theoretical values obtained from NIST XCOM and Direct-Zeff database respectively. Additionally, the experimentally determined buildup factor values were compared with energy absorption buildup factor (EABF) and exposure buildup factor (EBF) values obtained from Phy-X/PSD software, providing insights into the gamma-ray penetration depth in terms of mean free path (MFP). At 356 keV, the EABF analysis showed that most compounds had a penetration depth of around 8 mean free paths. In contrast, the EBF analysis indicated penetration depths exceeding 10 mean free paths for all compounds except Ce (SO4)2. This new approach holds immense potential for transformative advancements in medical diagnostics, therapy, and the development of innovative technologies in nuclear sciences.

Gamma-ray interaction studies of concrete with waste glass fillers.

In the present work, the efficacy of waste glass as fillers in concrete for gamma-ray shielding has been studied. Glass fillers of 0, 15, 30, 45, and 60% concentrations have been incorporated into the concrete mixture. The attenuation measurements were performed using gamma spectrometer with NaI(Tl) detector at 511, 662, 1173, and 1332keV gamma energies. Gamma-ray shielding parameters, such as the mass attenuation coefficient (μ/ρ), are determined for all filler concentrations. The mass attenuation coefficient of the prepared samples was found to be varied from 0.081 to 0.088, 0.071 to 0.088, 0.05 to 0.058, and 0.05 to 0.055 (cm2 per g) for 511, 662, 1173, and 1332keV gamma energies, respectively. It was observed that experimentally determined (μ/ρ) values were in very good agreement with theoretical values calculated from EDAX data. Furthermore, it was observed that (μ/ρ) showed an increasing trend with an increase in filler concentration, which is attributed to the increase in the shielding property of the material. Therefore, the glass-concrete composite can be accustomed to reduce the intensity of gamma radiation.

Study on polymer composites with glass for gamma ray shielding.

The shielding of gamma radiation is of the utmost importance in industries, such as nuclear power plants, medical imaging, and space exploration. For the purpose of shielding objects in such an environment, it is essential to design materials with flexibility as well as high shielding capability. In order to enhance the radiation attenuation effectiveness of polymers, such as polyvinyl alcohol (PVA), glass has been blended with varying percentages. The fabricated composite has been subjected to gamma-ray interaction studies. The radiation shielding parameter, such as mass attenuation coefficient (μ/ρ), has been determined for various energies, such as 137Cs (661.6keV) and 60Co (1173 and 1332keV). It is observed that the PVA composite with glass exhibits improved gamma radiation shielding properties compared to PVA. Therefore, the present work paves the way for the utility of PVA polymer with glass, offering a cost-effective and sustainable approach to gamma radiation shielding in radiation environments.

Response of a high-pressure 4He scintillation detector to nuclear recoils up to 9 MeV

Helium-4-based scintillation detector technology is emerging as a strong alternative to pulse-shape discrimination-capable organic scintillators for fast neutron detection and spectroscopy, particularly in extreme gamma-ray environments. The 4He detector is intrinsically insensitive to gamma radiation, as it has a relatively low cross-section for gamma-ray interactions, and the stopping power of electrons in the 4He medium is low compared to that of 4He recoil nuclei. Consequently, gamma rays can be discriminated by simple energy deposition thresholding instead of the more complex pulse shape analysis. The energy resolution of 4He scintillation detectors has not yet been well-characterized over a broad range of energy depositions, which limits the ability to deconvolve the source spectra. In this work, an experiment was performed to characterize the response of an Arktis S670 4He detector to nuclear recoils up to 9 MeV. The 4He detector was positioned in the center of a semicircular array of organic scintillation detectors operated in coincidence. Deuterium–deuterium and deuterium–tritium neutron generators provided monoenergetic neutrons, yielding geometrically constrained nuclear recoils ranging from 0.0925 to 8.87 MeV. The detector response provides evidence for scintillation linearity beyond the previously reported energy range. The measured response was used to develop an energy resolution function applicable to this energy range for use in high-fidelity detector simulations needed by future applications.

Examining Low-Energy Gamma-Ray Protection of a New Promising Saudi Cement Product as Alternative Cementitious Material Using Geant4 Software

In modern life, cement products have become an essential material for the foundations in many structural building designs. Because of this, the natural effects of this material need to be tested and cannot be ignored. Modeling interactions of gamma rays with several cementitious compounds is the focus of this study. Gamma radiations exist naturally and artificially, but with limited gamma-ray energies, which are not easy to access for experimental gamma attenuation studies. So in the current work, a wide range of low gamma-ray energies (0.01 to 0.356 MeV) are applied to investigate the gamma radiation attenuation properties theoretically for different cement materials. Also, the Monte Carlo statistical method is applied using the Geant4 toolkit to simulate the results. The outcomes are compared with theoretical values using XCOM to validate at these energies. The effective atomic number ( Z eff ), electron density ( N eff ), and half-value layers (HVLs) for the studied samples are computed based on the simulated mass attenuation coefficient ( μ m ), as expected. The outcomes show good agreement between the simulated results with those calculated theoretically by XCOM within an 11% deviation. The silica fume sample showed a slightly higher μ m value compared with the other samples. The dependence of the photon energy and cement composition on the values of the μ m and HVLs are investigated and discussed. In addition, the values of Z eff and N eff for all cement samples behaved similarly in the given photon energy range, and they decreased as the photon energy increased.

Precise positioning of gamma ray interactions in multiplexed pixelated scintillators using artificial neural networks

Introduction. The positioning of γ ray interactions in positron emission tomography (PET) detectors is commonly made through the evaluation of the Anger logic flood histograms. machine learning techniques, leveraging features extracted from signal waveform, have demonstrated successful applications in addressing various challenges in PET instrumentation. Aim. This paper evaluates the use of artificial neural networks (NN) for γ ray interaction positioning in pixelated scintillators coupled to a multiplexed array of silicon photomultipliers (SiPM). Methods. An array of 16 Cerium doped Lutetium-based (LYSO) crystal pixels (cross-section 2 × 2 mm2) coupled to 16 SiPM (S13360-1350) were used for the experimental setup. Data from each of the 16 LYSO pixels was recorded, a total of 160000 events. The detectors were irradiated by 511 keV annihilation γ rays from a Sodium-22 (22Na) source. Another LYSO crystal was used for electronic collimation. Features extracted from the signal waveform were used to train the model. Two models were tested: i) single multiple-class neural network (mcNN), with 16 possible outputs followed by a softmax and ii) 16 binary classification neural networks (bNN), each one specialized in identifying events occurred in each position. Results. Both NN models showed a mean positioning accuracy above 85% on the evaluation dataset, although the mcNN is faster to train. Discussion The method’s accuracy is affected by the introduction of misclassified events that interacted in the neighbour’s crystals and were misclassified during the dataset acquisition. Electronic collimation reduces this effect, however results could be improved using a more complex acquisition setup, such as a light-sharing configuration. Conclusions The methods comparison showed that mcNN and bNN can surpass the Anger logic, showing the feasibility of using these models in positioning procedures of future multiplexed detector systems in a linear configuration.

Design of GRETA Cooling Systems

The Gamma-Ray Energy Tracking Array (GRETA) is a full 4π gamma-ray tracking detector capable of reconstructing the energy and three-dimensional position of gamma-ray interactions within a compact sphere of high-purity germanium crystals. The GRETA Detector Array Sphere will have the capacity to accommodate a total of 30 Germanium Quad Detector Modules (QDM). The 30 QDMs are to be cooled and maintained below 100 K using liquid nitrogen (LN) at all times while the array is in normal operation, and will require regular filling of a LN Dewar on each module. The Dewar is designed to allow the Quad Module to be operated in any orientation with a LN holding time of no less than 12 hours when the detector module is fully powered. An automated LN cooling and refilling system is required to supply LN to the 30 QDMs and ensure them maintained below 100 K. Each of the GRETA QDMs houses a total of 148 pre-amplifier units within the module, and with the high power consumption of each pre-amplifier, active cooling of the pre-amplifier compartment is required. Additionally, each Quad Module will have 4 digitizer modules attached to it, which generate heat and require cooling as well. A closed-loop liquid (Glycol) cooling system will provide the required temperature stability and dissipate power generated heat for electronics. This paper presents design of the GRETA LN cooling system for detectors and the closed-loop liquid cooling system for electronics including technical requirements, design schemes, key components, operation modes, and so on.

Computational Codes for Fast Neutrons and Gamma Ray Interactions Coefficients in Different Material

In this research, many materials used as shields against ionizing radiation (neutrons and gamma rays) were studied. Seven glass systems compounds and five polymeric compounds were used to test their effectiveness in attenuating fast neutrons. These compounds are (S1-S7) as shown in table (1) and polymeric compounds as shown in table (3), many attenuation coefficients for these compounds were calculated through the use of a computer program called (SAZ) written in the Python programming language, which is used to calculate a number of basic parameters based on certain semi-empirical equations. The results showed that the sample (S7) and C9H9O is the best glass system compound and polymeric compound for neutrons attenuation, because they have a largest value of ΣR. Also, a number of Eco-friendly metallic compounds as shown in table (2) were used, to test them in shielding against gamma rays. The mass attenuation coefficient was calculated through the NIST-XCOM program for a range of energies starting from 59.53 keV up to 1 GeV. These compounds differed in their ability to attenuate gamma rays, as the results showed that the best studied compound against gamma rays was the PbS compound because it contains the Lead element, which has a largest atomic number.

Radiation attenuation of fly ash and rice husk ash-based geopolymers as cement replacement in concrete for shielding applications

Due to the economic and environmental cost of producing cement for concrete, research into the use of alternative materials such as geopolymers for the partial replacement of cement has become popular. In an attempt to understand the effect of such replacement on the shielding behavior of concrete, this study evaluated and analyzed the gamma-ray interaction parameters of fly ash- and rice husk ash-based geopolymers (G-RHA-F1, G-RHA-F2, G-RHA-F3, and G-RHA-F4). The mass attenuation coefficient (μρ), mass energy absorption coefficient (μenρ), effective atomic number (Zeff), specific gamma-ray dose constant (Г), dose rate (Dr), and photon buildup factors (BFs) were computed for photon energies within 15,000 eV and 15,000 keV. The evaluated parameters showed differences in value for the materials. For G-RHA-F1, G-RHA-F2, G-RHA-F3, and G-RHA-F4, μρ values are within the range 0.0208–6.5169 cm2/g, 0.0208–6.3631 cm2/g, 0.0209–6.70611 cm2/g, and 0.0208–6.2149 cm2/g, respectively. The corresponding ranges of are 0.0155–5.9433 cm2/g, 0.0155–5.7934 cm2/g, 0.0156–6.4016 cm2/g, and 0.0155–5.6775 cm2/g, accordingly. Fly ash slightly improved the gamma photon absorption capacity of the geopolymers, especially at the low energies. The investigated geopolymers have relatively higher photon absorption cross-sections relative to some existing polymers and shielding glasses. They could therefore be used to construct effective concrete shields.

Investigations of Gamma and Neutron Shielding Parameters of Ti-Nb-Fe-Cr Alloys with Varying Cr Concentrations

The Ti-Nb-Fe-Cr alloys are used in various fields, such as nuclear radiation shielding, cladding material in nuclear reactors, and implants in the medical field. It is one of the best materials for biomedical applications as it is biocompatible, is corrosion resistant, and has good mechanical properties. As nuclear radiation emanates from various sources in a nuclear reactor, the behavior of this alloy with the interaction of gamma and neutrons has not been well studied. In the present investigations, the interaction of gammas and neutrons with Ti-27Nb-7Fe-xCr (x = 0, 2, 4, 6, and 8 wt%) alloys is studied in order to understand the radiation shielding properties and their usefulness in biomedical applications. Gamma-ray–interaction parameters such as MAC, HVL, MFP, Zeff, Zeq, Neff, and multilayer energy absorption buildup factor (MLEABF) are estimated using EpiXs, PyMLBUF, and NGCal software in the energy range of 1 keV to 15 MeV. The multilayer buildup factor (MLBF) is calculated for cortical bone and for alloys with varying Cr concentrations. Comparison of the MLBF values of alloys with cortical bone shows that in the lower-energy region as well as the higher-energy region above 0.5 MeV, alloys and cortical bone yield the same values, indicating that the alloys behave as cortical bone in this energy region. Mass attenuation factors (MAFs) of thermal and fast neutrons are also calculated for various elastic modulus values of selected alloys at thermal and fast neutrons. It is found that the elastic modulus increases with increasing MAF values of both fast and thermal neutrons. By increasing the Cr content in the Ti-27Nb-7Fe alloy, the elastic modulus decreases. The relationship between the MAF of neutrons and the elastic modulus of the alloy is established for the first time.

Calibration of a compact ASIC-based data acquisition system for neutron/[formula omitted] discrimination and spectroscopy with organic scintillators

Segmented neutron detectors that use silicon photomultipliers (SiPMs) are receiving significant attention in nuclear security applications. Some of these detectors employ hundreds of channels and would therefore benefit from the use of high-channel-density and low-cost-per-channel data acquisition (DAQ) systems. Candidate DAQ systems that meet these requirements exist, but few perform full waveform digitization, which permits neutron and gamma-ray interaction discrimination via pulse shape. In this work, we study the performance of the TOFPET2 (PETsys Electronics), an ASIC-based DAQ designed for positron emission tomography, which has been adapted to provide sensitivity to pulse shape by the use of variable-period charge integration. We use a light-emitting diode to calibrate a combination of an ON Semiconductor (SensL) 60035-64P J-Series SiPM and TOPFET2 DAQ and evaluate the linearity of their response and dynamic range. The calibration curve was obtained by comparing the DAQ response to that measured with a photodiode interfaced with a traditional waveform digitizer. This calibration process was used for rudimentary spectroscopy of various neutron and γ sources.

An experimental approach to determine the gamma radiation interaction mean free path and exposure buildup factor for biomolecules

This experimental approach was designed to understand the gamma interaction parameters for the essential biomolecules, including starch soluble, cholesterol, myristic acid, glucose, oxalic acid, dextrose, salicylic acid, ethyl cellulose and sucrose. The empirical determination of gamma interaction parameters, such as interaction mean-free-path (MFP), buildup factor, and effective atomic number (Zeff) was performed by measuring mass attenuation coefficient (μ/ρ) at energies of 356 keV, 511 keV, 662 keV, 1173 keV, 1275 keV and 1332 keV. This was achieved using weak radioactive sources and a NaI(Tl) scintillation spectrometer with collimated and non-collimated transmission geometry. The experimentally determined values of gamma-ray interaction parameters were obtained non-destructively and precisely agreeing with the expected values from simulations and codes. In addition, the research findings also revealed a novel trend in gamma interaction mean free path as a function of energy and variable buildup factors for the selected biomolecules. These research findings provide valuable insight into the process of gamma radiation interaction. This approach may fulfil the increasing demand of medical, technical and academic research laboratories for a cost-effective and reliable empirical methodology to understand gamma radiation interaction with matter.