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The computation of the solid angle and the detector efficiency is considering to be one of the most important factors during the measuring process for the radioactivity, especially the cylindrical γ-ray NaI(Tl) detectors nowadays have applications in several fields such as industry, hazardous for health, the gamma-ray radiation detectors grow to be the main essential instruments in radiation protection sector. In the present work, a generic numerical simulation method (NSM) for calculating the efficiency of the γ-ray spectrometry setup is established. The formulas are suitable for any type of source-to-detector shape and can be valuable to determine the full-energy peak and the total efficiencies and P/T ratio of cylindrical γ-ray NaI(Tl) detector setup concerning the truncated conical radioactive source. This methodology is based on estimate the path length of γ-ray radiation inside the detector active medium, inside the source itself, and the self-attenuation correction factors, which typically use to correct the sample attenuation of the original geometry source. The calculations can be completed in general by using extra reasonable and complicate analytical and numerical techniques than the standard models; especially the effective solid angle, and the detector efficiency have to be calculated in case of the truncated conical radioactive source studied condition. Moreover, the (NSM) can be used for the straight calculations of the γ-ray detector efficiency after the computation of improvement that need in the case of γ-γ coincidence summing (CS). The (NSM) confirmation of the development created by the efficiency transfer method has been achieved by comparing the results of the measuring truncated conical radioactive source with certified nuclide activities with the γ-ray NaI(Tl) detector, and a good agreement was obtained after corrections of (CS). The methodology can be unlimited to find the theoretical efficiencies and modifications equivalent to any geometry by essential sufficiently the physical selective considered situation.

A radiation hardness study of semi-insulating GaAs detectors against 5 MeV electrons is presented in this paper. The influence of cumulative dose in the range from 136 up to 2000 kGy on alpha-spectrometry of 241Am is evaluated for investigated detectors. The characterising parameter, the charge collection efficiency, was negatively affected by cumulative dose applied. At 200 V detector reverse bias it rapidly decreased from initial 45% it to 15% at 600 kGy proceeding with mild deterioration down to 6% at 2000 kGy. The operability of detector was well preserved through whole range of doses. The alpha- and gamma-spectrometry of the same radioactive source are compared.

Background: This work aims to develop a new imaging system based on a pulse shape discrimination-capable Cs2LiYCl6:Ce (CLYC) scintillation detector combined with the rotational modulation collimator (RMC) technique for dual-particle imaging.Materials and Methods: In this study, a CLYC-based RMC system was designed based on Monte Carlo simulations, and a prototype was fabricated. Therein, a rotation control system was developed to rotate the RMC unit precisely, and a graphical user interface-based software was also developed to operate the data acquisition with RMC rotation. The RMC system was developed to allow combining various types of collimator masks and detectors interchangeably, making the imaging system more versatile for various applications and conditions.Results and Discussion: Operational performance of the fabricated system was studied by checking the accuracy and precision of the collimator rotation and obtaining modulation patterns from a gamma-ray source repeatedly.Conclusion: The prototype RMC system showed reliability in its mechanical properties and reproducibility in the acquisition of modulation patterns, and it will be further investigated for its dual-particle imaging capability with various complex radioactive source conditions.

Alpha energy spectrum measurement has been employed in the nuclear waste disposal of transuranic nuclides (such as 239Pu and 241Am), supervision, and disposal process. The alpha spectrum is made up of alpha particles, which have a fast-moving helium nucleus and an energy of 4–8 MeV with weak penetration ability. Removing alpha particles from radioactive nuclides is an important scientific issue. In this study, a transuranic nuclide alpha particle pulse generator that produces simulated alpha particle pulses similar to real particles was designed. Field programmable gate array (FPGA) was adopted as its core chip and we obtained the digital pulse waveform using software tracing points while simulating real alpha particles by random numbers. Accordingly, the alpha energy spectrum of a radioactive source 241Am was obtained using a passivated ion-implanted planar silicon (PIPS) detector. Afterward, the alpha particle was extracted from the energy spectrum and was then compared to the alpha particle pulse of the two methods, deriving a result. Here, both groupings of particle pulse waveforms were found to be very similar, and the periodic error of the particle was observed to be less than 1%. Furthermore, the amplitude and time interval of the particle were apparently similar to the actual spectrometry pulse.

Designing airborne gamma-ray surveys for geological purposes, mineral prospecting, environmental applications or radioactive contamination mapping requires the optimal choice of survey parameters such as the survey altitude, line spacing and survey speed with respect to the sensitivity of the instruments employed and the presumed size and intensity of the detected anomalies. The gamma-ray field attenuates significantly with the distance from the source; being able to model gamma-ray field intensity in various detector positions can be very useful. In recent years, the use of mini-airborne UAV radiometric measurement has developed rapidly. On the one hand, the low payload capacity of UAV results in low sensitivity of the employed detectors; the possibility of increasing gamma-ray signals from low altitude surveys and low speeds on the other hand raises the demand for simulating the gamma-ray field of local inhomogeneous radiometric anomalies. The gamma-ray field modelling method introduced in this paper is based on the monoenergetic approach and discretization of geological radioactive sources utilizing a three-dimensional net of point sources. The optimal density of point sources depends on the detection altitude and the degree of inhomogeneity of the radioactive source. The designed modelling method was verified by comparing the model data with experimental data from three localities where uranium anomalies occur. The degree of conformity of the model and experimental data is acceptable and confirms the applicability of the modelling method. The paper describes a relatively fast and simple gamma-ray field modelling method that is appropriate for ground planar radioactive anomalies. The method is useful for designing survey parameters and for interpretation of detected airborne gamma-ray anomalies.

In this study, energy resolution dependent on K-Parameters (Trapezoidal filter system optimizing the count rate) of EXOGAM2 detector with newly developed NUMEXO2 digital electronics using 152Eu radioactive source measured and analysed. This experimental study was carried out at the GANIL (Grand Accelerature National d'Ions Lourd) nuclear research center in France. The measurement and analysis results for different K parameters using a 152Eu radioactive source with low and high gamma energy levels were performed for two EXOGAM2 detectors. Without applying any K parameter, the resolution values expressed by FWHM for the 1.EXOGAM2 detector are measured as 2.360% FWHM for (344.2785 keV), 2.820% FWHM for (1408.006 keV), and 2.451% FWHM for (344.2785 keV), 2.975%FWHM for (1408.006 keV) for the 2.EXOGAM2 detector, respectively. For different K parameters (K=2µs, K=5µs ve K=10µs) detail results are shown below., Bu çalışmada, yeni geliştirilen dijital elektronik NUMEXO2 dijital elektronik ile EXOGAM2(EXOtic GAMma array spectrometer) dedektörünün K-Parametrelerine (sayım oranını optimize eden Trapezoidal filtre sistemi) bağlı enerji çözünürlüğü için 152Eu radyoaktif kaynak kullanılarak ölçüm ve analiz yapılmıştır. Yapılan bu deneysel çalışma Fransa’da bulunan GANIL (Grand Accelerature National d’Ions Lourd) nükleer araştırma merkezinde gerçekleştirilmiştir. Düşük ve yüksek gama enerji seviyesine sahip 152Eu radyoaktif kaynak kullanılarak farklı K-parametreleri için gerçekleştirilen ölçüm ve analiz sonuçları iki EXOGAM2 dedektörü için gerçekleştirilmiştir. Herhangi bir K-parametresi uygulamadan 1.EXOGAM2 dedektörü için FWHM ile ifade edilen çözünürlük değerleri sırası ile (344. 2785 keV) için 2.360% FWHM, (1408.006 keV) için 2.820% FWHM olarak ölçülürken 2.EXOGAM2 dedektörü için ise sırasıyla 2.451% FWHM ve 2.975% FWHM olarak ölçülmüştür. Farklı K-parametreleri (K=2µs, K=5µs ve K=10µs) için ise sonuçlar detayları ile aşağıda gösterilmiştir.

The aim of this work is to develop a Geiger-Muller (GM) detector system for robot to look for a radioactive source in case of a nuclear emergency or in a high radiation environment. In order to find a radiation source easily, a detector system, including 3 detectors, was designed to search γ-ray radiation sources autonomously. First, based on GEANT4 simulation, radiation dose rates in 3 Geiger-Muller (GM) counters were simulated at different source-detector distances, distances between detectors and angles. Various sensitivity analyses were performed experimentally to verify the simulated designed detector system. A mono-energetic C 137 s γ-ray source with energy 662 keV and activity of 1.11 GBq was used for the observation. The simulated results were compared with the experimental dose rate values and good agreements were obtained for various cases. Only based on the dose rates in three detectors, the radiation source with a specific source activity and angle was localized in the different location. A method was adopted with the measured dose rates and differences of distances to find the actual location of the lost γ-ray source. The corresponding angles of deviation and detection limits were calculated to determine the sensitivity and abilities of our designed detector system. The proposed system can be used to locate radiation sources in low and high radiation environments.

A new method has been developed and evaluated for density measurement of liquid materials based on conventional gamma density meter, whether a low strength gamma radioactive source as the backscatter technique with collimated detector cannot be properly used for density measurement. In this comparative study, proposed method aimed to improve the linearity of the density measurement without using time consuming spectroscopy. Both transmission and backscatter methods for density measurement were used together in a combined model. The whole measurement system was designed, constructed and simulated for nuclear gamma–gamma density measurement. MCNP modeling results were benchmarked with experimental data, showing a good correlation between combined density measurement method and conventional transmission density measurement while values of MRE(%), RMSE and MAE(%) are lower in combined model. This study shows that, MRE(%) in combined model, and for both experimental and simulation results, is improved with the average of about 41% in comparison with the conventional density measurement. Also in this comparative study, RMSE decreased significantly about 56%. Additionally, average MAE (%) reduced about 36%. Furthermore, R-square values were also improved in both experimental and simulation results. Evaluating different methods of nuclear density measurements led us to propose an innovative formula, to investigate an accurate density measurement. This paper discusses advantages of proposed model in comparison with the conventional transmission method for gamma interaction with lower percentage errors and better calibration curve fitting.

The thickness gauge systems based on beta radiation were widely used in the industry for online, continuous and non-contact measurements. One of the important parameters in beta thickness gauge is the accuracy which the system was evaluated based on it. The effective factors in the measurement accuracy of these systems consist of the mechanical and detection sections. In the mechanical section, the detection system (source and detector) was moved throughout the factory line (without sheet) in order to measure the mechanical error. In the detection part, the detection set-up was stopped in its parking lot and the biaxially oriented polypropylene sheets with different thicknesses were placed between the source and detector to determine the contribution of detection error. In this research, a beta thickness gauge with a 147Pm source (half-life of 31 months) was evaluated in biaxially oriented polypropylene sheet production lines in order to determine the mechanical and detection errors. The contribution of the mechanical error due to system motion and the contribution of the system’s detection error were measured individually. The total error is the sum of the acquired errors of two mechanical and detection sections. In this study, the 2sigma (standard deviation) criterion was used as a system error. The mechanical error was calculated 0.12 by moving of system and without the sheet. Also, the detection error was determined 0.1 by placing the sheet between source and detector and stopping of the system. The total error was estimated 0.16 using the error correlation relation. The acquired results showed for producing of biaxially oriented polypropylene sheets with 15-µm thickness and the maximum acceptable error of ±0.2 µm, the system can be used for 40 months at the precision measurement time (zero time). If the mechanical error is reduced by 50%, the using time of the radioactive source increases to 16 months (56 months). The reducing of the mechanical error can minimize cost, radiation safety, and shielding requirements.

In this paper, we present a straightforward analytical method for calculating the efficiencies of an ovoid shape (elliptical cylindrical) detector by using a randomly located point source. To determine the activity of an unknown radioactive source, absolute efficiency is required and we should take into account the attenuation of the gamma-ray photons by the source container and the detector housing materials. The soundness of the resultant straightforward analytical method was successfully confirmed by comparison with some published data.

Safeguards system with high effectiveness and efficiency must comprise a set of measurements with capabilities satisfactory for the verification of nuclear materials. In this paper, we present key parameter measurements of detector modeling in a commercial n-type low energy germanium detector of a planar crystal with a relative efficiency of nearly 15 %. The detector optimization will hold a significant function in measuring nuclear materials for safeguards application. Standard nuclear materials with diverse enrichment (depleted and low enriched) of uranium and point-like sources (137Cs, 60Co) and mixed radioactive source for Eu isotopes (152Eu, 154Eu, and 155Eu) were benefited to explore the energy resolution and detector efficiency. The energy resolution is measured over a wide range of rise time and flattop. In addition to the experimental work, the Monte Carlo simulation code is used for modeling the setup configuration to obtain the absolute efficiency at different energies. A fast and reliable method was applied in detector efficiency measurements. The data are discussed and interpreted.

The advanced image sensors installed on now-ubiquitous smartphones can be used to detect ionising radiation in addition to visible light. Radiation incidents on a smartphone camera’s Complementary Metal Oxide Semiconductor (CMOS) sensor creates a signal which can be isolated from a visible light signal to turn the smartphone into a radiation detector. This work aims to report a detailed investigation of a well-reviewed smartphone application for radiation dosimetry that is available for popular smartphone devices under a calibration protocol that is typically used for the commercial calibration of radiation detectors. The iPhone 6s smartphone, which has a CMOS camera sensor, was used in this study. Black tape was utilized to block visible light. The Radioactivity counter app developed by Rolf-Dieter Klein and available on Apple’s App Store was installed on the device and tested using a calibrated radioactive source, calibration concrete pads with a range of known concentrations of radioactive elements, and in direct sunlight. The smartphone CMOS sensor is sensitive to radiation doses as low as 10 µGy/h, with a linear dose response and an angular dependence. The RadioactivityCounter app is limited in that it requires 4–10 min to offer a stable measurement. The precision of the measurement is also affected by heat and a smartphone’s battery level. Although the smartphone is not as accurate as a conventional detector, it is useful enough to detect radiation before the radiation reaches hazardous levels. It can also be used for personal dose assessments and as an alarm for the presence of high radiation levels.

Geant4 simulation is used to calculate peak efficiency and correct the effect of coincidence summing in detecting volumetric gamma-ray sources; this simulation was applied to a standard 152Eu source with different volumes as a test case. The source is a liquid cylindrical shape of various volumes. Peak efficiency was calculated using two tracks in the Geant4 simulation: single-energy track and "monoenergetic Track" without coincidence summing. Here, the energy of the source is known, and the track of radionuclides, including the coincidence summing, depends on the decay scheme of the radioactive source. The ratio between the peak efficiency of the two tracks gives us the correction factor (CF). The experimental method was used to calculate the peak efficiency and was amended by the correction factor computed with Geant4 tracks. The results showed a good agreement between experimental efficiency after correction and free-summing simulated efficiency. The comparison indicated that the present method is valid and useful for voluminous gamma-ray sources.

We developed a novel, accurate and robust energy calibration algorithm for single X-ray photon counting detectors suitable for the use of high-Z sensor materials. The calibratable energy range was demonstrated to extend over a wide interval from 12 keV up to 150 keV and the same method can also be applied to lower or higher X-ray energies. Fluorescence lines of several elemental targets are used as reference up to 75 keV. For higher energies, the reference is given by direct X-ray tube spectra end-points — extracted with a semi-empirical model independently of the broadening by electronic noise. The pixel-wise threshold trimming relies on a target curve fitting iterative procedure which is able to cope with offset, gain and flat-field variations. The algorithm is highly parallelizable and can profit from modern multi-core machines. The proposed method is able to deal with the spectral complexity introduced by atomic fluorescence effects arising in high-Z sensor materials such as CdTe, CdZnTe and GaAs for energies above the corresponding K-edges and enhanced by a decreasing pixel size. We report the qualification results for the case study of a 1 mm-thick CdTe sensor with 150 μ m pixel size, bonded to an IBEX ASIC and calibrated in the range 12–150 keV. The validity of the method was assessed by analyzing calibrated pulse height spectra recorded with Sn and W fluorescence samples and with a 99mTc radioactive source. The global deviation was found to be smaller than 0.5% at 140.5 keV. The residual threshold dispersion was 0.54 keV rms at the Sn K α peak and 1.71 keV rms at the 99mTc γ -decay peak, still with a limited impact on the overall energy resolution of the system.

To identify the distribution of fuel debris remaining in the reactor vessel and/or the containment vessel of Fukushima Daiichi NPS, we focused on the inverse estimation of radioactive source distribution using the measured radiation counts. The M aximum L ikelihood- E xpectation M aximization (ML-EM) and the M oore- P enrose M atrix I nverse (MPMI) methods are examined. The ML-EM method has been used for the image reconstruction of computed tomography, and the MPMI method is one of the solution methods for simultaneous linear equations with the underdetermined condition. A simple calculation model simulating a containment vessel was constructed including detectors and radiation sources. In an actual situation, a sufficient number of radiation measurement positions would not be available owing to the complexity of structures inside the containment vessel. Thus, the number of radiation measurement points (number of constraints) is smaller than that of radiation source positions. It means that an underdetermined inverse problem should be solved. The detection probability of radiation (neutron or photon) is calculated by the adjoint transport calculation since the detection probability is used as the coupling coefficient between radiation counts at a detector and a radioactive source. The result of estimation using the ML-EM or the MPMI method indicates that the accuracy of estimation depends on the distance between a radiation source and a detector, and measurement positions of radiation count. The ML-EM and the MPMI methods show different prediction accuracy depending on the prediction condition. It is found that reasonable prediction accuracy would be obtained when the detectors are placed at the vicinity of radiation sources of interest.

Koksal, Oguz Kagan/0000-0003-2671-6683; UNAL, Ersin/0000-0002-3183-9592; Apaydin, Gokhan/0000-0002-4647-344X WOS: 000457819000005 PubMed: 30508729 In this study, K-beta-to-K-alpha X-ray intensity ratios of Ni in Ni-B alloy coatings were investigated. These samples were excited by 59.5 keV gamma-rays from a Am-241 annular radioactive source. K X-rays emitted by the samples were counted using an Ultra-LEGe detector with a resolution of 150 eV at 5.9 keV. The K-beta-to-K-alpha X-ray intensity ratios of Ni-B alloys are compared with pure Ni and each other. Deviations between the results were explained by the change in valence electronic structures of Ni in Ni-B alloy coatings.

We have developed a compact gamma-ray beam based on a beam collimator using a lead tube for X-ray fluorescence (XRF) systems. A 59.5-keV gamma-ray from 241Am radioactive source was collimated by a lead tube for excitation of the sample. The spot size of the excited beam was examined experimentally by using a wire scanning method. The elemental compositions of the surface layer of pieces of Sangkhalok and Ban Chiang pottery were investigated using this system. By exciting pieces of the pottery with a gamma-ray beam, the X-ray spectra of the surface layer of the pottery were successfully obtained. The paint and substrate positions of the pottery were separately excited and the X-ray fluorescence spectra of the pottery were collected by a CdTe diode X-ray detector. We were able to develop a compact XRF system and present preliminary results of the elemental compositions of the surface layers of the pottery which clearly showed the differences between paint patterns and substrate positions.

In the first hours or days after an unplanned release of radioactive material to the environment, the radiation detection instruments most widely available to local first responders may be those currently fielded for interdiction missions. This study investigated how such preventative radiological/nuclear detection instruments could perform if repurposed for consequence management missions. A representative sample of three archetypes (body-worn, human-carried, and other/large-detection-volume equipment) encompassed six categories: personal radiation detector, extended-range personal radiation detector, personal emergency radiation detector, radioisotope identification device, human-portable detector/backpack, and vehicle-mounted large-detection-volume detector. Overall 19 models of equipment were included in the study. Laboratory evaluations were designed to assess the capabilities of the instruments in four consequence management missions: exposure rate, integrated exposure, radiation survey, and contamination screening. As applicable, the evaluations included measurement of exposure rate, integrated exposure, overrange response, and angular response. The results were compared to benchmarks from the American National Standards Institute N42.49A. The performance of the instruments for initial screening for contamination was assessed by an automated radioactive source moving past the detectors at various speeds and distances. The results demonstrate that if the equipment is used in accordance with the mission analysis and categories and within the original equipment manufacturer specifications, it is possible to achieve sufficient accuracy to estimate and document doses to responders, plan entries into contaminated areas, detect contamination, and protect the public until such time as outside resources arrive with sufficient numbers of standard health physics instruments and personnel dosimetry to replace the preventative radiological/nuclear detection instruments. This evaluation campaign was conducted to complement the National Council on Radiation Protection and Measurements Report 179, Guidance for Emergency Response Dosimetry.

We present a method for localizing an unknown source of radiation in an urban environment using a distributed detector network. This method employs statistical parameter estimation techniques, relying on an approximation for the response of a detector to the source based on a simplified model of the underlying transport phenomena, combined with a Metropolis-type sampler that is modified to propagate the effect of fixed epistemic uncertainties in the material macroscopic cross sections of objects in the scene. We apply this technique to data collected during a measurement campaign conducted in a realistic analog for an urban scene using a network of six mobile detectors. Our initial results are able to localize the source to within approximately 8 m over a scene of size 300 m × 200 m in two independent trials with 30 min count times, including a characterization of the uncertainty associated with the poorly known macroscopic cross sections of objects in the scene. In these measurements, the nearest detectors were between 20 m to 30 m from the source, and recorded count rates between approximately 3 and 13 times background. A few detectors had line-of-sight to the source, while the majority were obscured by objects present in the scene. After extending our model to account for the orientation of the detectors and correcting for anomalies in the measurement data we were able to further improve the localization accuracy to approximately 2 m in both trials.

The efficiency coefficient (ξ) of CR-39 detector for radon measurements was determined in this study by using radioactive source (241Am). Sealed can-technique was applied in this study to a...

As public awareness of the threats related to ultrafine aerosols increases, there is a growing need for inexpensive, real-time exposure assessment devices. In this work, the well-established technology used in the smoke detector with a radioactive source was tested in laboratory conditions to check its suitability for determining the number concentration of the ultrafine aerosol. It has been shown that the sensor output changes linearly with the change of diesel soot concentration in the range up to 8.3 × 105 particles cm−3. The sensor has also been shown to be able to detect rapid changes in aerosol concentration. Empirical equations describing the influence of air velocity, temperature, relative humidity, and pressure on the sensor output were determined. The collected results confirm that the ionization sensor can be used to assess ultrafine aerosol exposure, although additional engineering work is required to increase the resolution of the output signal measurement and to compensate for the effects of weather conditions. The presented method can be used for concentration monitoring and risk assessment in environmental engineering, materials engineering, cosmetics industry, textiles, sports, chemical, mining, energy, etc.

The Timepix3 hybrid-pixel readout chip consists of a matrix made of $256\times256$ square-shaped pixels with a 55- $\mu \text{m}$ pitch, which can be hybridized to several semiconductors, such as silicon (Si) or cadmium telluride (CdTe) with thicknesses up to 5 mm. Working as an event-based readout chip, it simultaneously records the time-over-threshold (ToT) in each pixel, measuring the deposited energy, as well as the time-of-arrival (ToA), with a time resolution of 1.5 ns. In this article, we present the energy calibration of two Timepix3 chips: the first one was bump-bonded with a 300- $\mu \text{m}$ -thick silicon sensor and the second one with a 1-mm-thick CdTe sensor. Both detectors were calibrated with per pixel calibration, using the monochromatic SOurce of Low-Energy X-rays [SOLEX from Henri Becquerel National Laboratory (LNHB) at CEA Saclay] and a set of calibration-grade sealed radioactive sources. Evaluations were carried out over the energy range 6–122 keV for Timepix3 Si and 20 keV–1.332 MeV for Timepix3 CdTe. Based on this experimental procedure, an energy resolution of 2.6 keV (3.4%) at 59.5 keV was observed for Timepix3 Si. For Timepix3 CdTe, this parameter was 5.6 keV (9.4%) at 59.5 keV, 27.24 keV (4.1%) at 661.7 keV, and 47.4 keV (3.5%) at 1.332 MeV. It is the first time that CdTe bump-bonded Timepix3 spectral performances were evaluated for gamma rays above 1 MeV. The reconstruction of the full-energy peak for such high energies is possible due to the ToA information, which allows the identification of all interactions caused by a given gamma ray within the detector.

We proposed a simplified image reconstruction method in 4$\pi$ Compton imaging to determine the intensity and location of point-like gamma-ray sources. The proposed method can be quickly done by fixing an apex of each Compton cone to a center of a Compton imaging detector and using a lookup table of cone projection profiles for all possible combinations. Using a prototype CdTe array detector with the proposed reconstruction method, 4$\pi$ Compton images for a 137Cs gamma-ray point source far from the detector were obtained. Also, the identification of a 137Cs point source in a plastic box was successfully demonstrated.

We have characterized a Cerium doped Lanthanum Bromide (LaBr3(Ce) ) crystal coupled with the position-sensitive photo-multiplier system for the gamma-ray imaging application. One can use this detector set-up for the scanning of high purity germanium detectors for pulse shape analysis in gamma-ray spectroscopy experiments and the image formation of an object by Compton back-scattering . The sensor has been tested for energy, timing and position information of the gamma-rays interacting within the detector crystal. The GEANT4 simulation results are consistent with the experimental results. We have reconstructed the image of irradiation spots in different positions throughout the detector crystal. Position resolution is found to be around 3.5 mm with the 2 mm collimated gamma-rays. The 2-d image of hexagonal Bismuth Germanate (BGO) crystal and a cylindrical LaBr3(Ce) crystal have been reconstructed in coincidence technique. The performance of the detector for imaging application has been investigated by coincidence technique in GEANT4 simulation and compared with the experimental data. We have reconstructed the 2-d images of objects with various geometrical shapes by Compton back-scattered events of the gamma-rays. This position-sensitive detector can be used as an absorber of a Compton camera for the image reconstruction of an extended radioactive source. One can also use this kind of set-up as in radiation imaging and many other applications where the energy and source position of the gamma-ray is the main interest.

Background: Each GECAM satellite payload contains 25 gamma-ray detectors (GRDs), which can detect gamma-rays and particles and can roughly localize the Gamma-Ray Bursts (GRBs). GRD was designed using lanthanum bromide (LaBr3) crystal as the sensitive material with the rear end coupled with silicon photomultiplier (SiPM) array for readout. Purpose: In aerospace engineering design of GRD, there are many key points to be studied. In this paper, we present the specific design scheme of GRD, the assembly and the performance test results of detectors. Methods: Based on Monte Carlo simulation and experimental test results, the specific schematic design and assembling process ofGRDwere optimized. After being fully assembled, theGRDswere conducted performance tests by using radioactive source and also conducted random vibration tests. Result and conclusion: The test results show that all satellite-borne GRDs have energy resolution, 10 pages, 15 figures

The Multi-gap Resistive Plate Chambers (MRPCs) provide excellent timing as well as position resolutions at relatively low cost. We have designed and fabricated several six-gap glass MRPCs and extensively studied their performance. In this paper, we describe the detector, the electronics, and the data acquisition system of the setup. We present the data analysis procedure and initial results of our studies to measure the absolute position of a radioactive source (\(^{22}Na\)). We use Time Of Flight (TOF) as well as the hit coordinate information to demonstrate potential applications of MRPCs in medical imaging.

In order to reduce radiation hazards, a mobile robot for detecting and grasping radioactive sources is designed. The robot is based on the ROS platform, uses the radioactive source detector to locate the radioactive source and moves to the radioactive source, and uses the mechanical gripper carried by the body to grab the corresponding radioactive source. In order to improve its stability and adaptability, a remote real-time control method is used to realize the motion capture of the detection robot. The robot operates the radioactive source, reducing the environmental pollution of the open-air radioactive source, and at the same time avoiding the radiation damage to the corresponding staff.

An Associated Particle Imaging (API) system consists of a high vacuum chamber where deuterium ions are accelerated on a tritium-loaded target, resulting in alpha particles and neutrons emitted back-to-back, the latter escaping the chamber and used, for example, for tomography of a high-Z sample. An accurate determination of the alpha position is crucial to determine the trajectory of the neutron. Existing API systems have several limitations which a semiconductor-based API detector placed inside the vacuum chamber should not present. The semiconductor material can be either silicon or diamond. In particular, large and fast signals are generated by the alpha interactions in these materials. A pixelated API detector will measure the time and hit position of the alphas produced in the reaction. However, during the lifetime of the generator, the semiconductor detector will be exposed to an intense flux of alpha particles that will degrade its performance over time. To assess the radiation hardness of silicon and diamond against the alpha particles, we exposed single diodes made of either of the two materials to a 5 MeV alpha flux generated by an 241Am radioactive source. During irradiation, the diodes were biased and mounted on current-sensitive preamplifier boards. We have therefore been able to measure insitu the evolution of the waveforms as the damage was accumulating in their substrates.

Due to the exponential attenuation of photons in materials, thick samples will attenuate a large portion of photons. This is a source of error in methods such as neutron activation analysis, which use gamma spectroscopy to characterise a radioactive source. A method is developed to quantify the magnitude of self-shielding with the help of MCNP6. Then the mass of an unknown sample is determined by comparing the known sample mass and the photopeak counts of the unknown and the known samples following activation. The inclusion of self-shielding effects is shown to make this comparative mass analysis measurement technique more accurate. Accounting for the self-shielding effects allows the true source, instead of the shielded source, to be resolved by correcting for the photons that are attenuated as they try to escape the sample and reach the detector. The $$\gamma $$ -ray measurements were made using several samples of varying shapes.

This paper focuses on gamma camera motion parameters estimation applied in accurate radioactive source image reconstruction. Compared with traditional experimental and medical detection scenarios, the practical application scene of a radioactive source detector is more complex, where the detector’s motion is unknown and cannot be directly measured by fixed devices such as trivial encoders. So we used a binocular camera as an auxiliary tool to indirectly estimate motion parameters, whereas this method also brings about the problem of cumulative error. Therefore, we proposed an optimization algorithm to minimize the cumulative error in three steps. The experimental results show that the cumulative error of motion parameters can be greatly reduced. Moreover, It can be confirmed that the binocular camera can be conveniently used as an aid in accurate radioactive source reconstruction, especially if no fixed measurement hardware is provided.

WOS: 000519335200007 K-alpha, K-beta and total K X-ray fluorescence cross-sections, K shell fluorescence yields, K-beta/K-alpha X-ray intensity ratios, K to L shell vacancy transfer probabilities and Auger electrons emission ratios of some selected Mn and Ni compounds have been investigated. The measurements were carried out by using Am-241 radioactive source and high-resolution Si(Li) detector. The measured results were compared with other experimental values and theoretical calculations. Our values are in good concordance with calculated theoretical and other experimental values.

Due to the complexity of finding formation porosity from the original “count rate” neutron tools that topic was covered in detail in Chapter 5. Now we turn our attention to all that followed the pioneering neutron logging tools and address the epithermal neutron tools and the compensated, (dual-detector) thermal neutron tools. In this chapter, we also provide a perspective of all the many combinations and permutations of the types of radioactive source, atomic particles propagated and detected, and the number of detectors and their spacings as used in what we may call the nuclear logging “zoo.”

Straw tube detectors are single wire proportional counters that are widely used as tracking devices. We have carried out R&D activity with a straw tube detector prototype. The aim of this work is to study the stability of the performance in terms of gain and energy resolution of these types of detectors under high rate of radiation. The gain and energy resolution of the detector are studied along with its variation with ambient temperature and pressure. X-rays from a radioactive source are used to irradiate the detector and to monitor the energy spectra simultaneously for calculating the gain. The method followed here is unique as the ageing measurements have been performed without using an accelerated particle beam or any radiation generator. The performance of a straw tube detector has been studied in a laboratory for more than 800 h at a stretch using a single sealed radioactive X-ray source with high intensity. Variation of gain and energy resolution of the straw tube detector under X-ray irradiation in $$\hbox {Ar}/\hbox {CO}_2$$ gas mixture (volume ratio 80/20) is discussed in this article. The gain of an aged straw depends on gas flow rate. We have estimated the time required for the gain of a straw tube detector under ageing tests to recover on increasing the gas flow rate. We have also estimated the time resolution of the straw tube detectors by using cosmic rays as the trigger for the $$\hbox {Ar}/\hbox {CO}_2$$ gas mixture in 70/30 volume ratio (different gas mixture was used for the measurement of the time resolution). This type of ageing and time resolution measurements in $$\hbox {Ar}/\hbox {CO}_2$$ gas mixture has not been reported earlier. The details of the measurement process and the experimental results are presented in this article.

In radioactive source surveying protocols, a number of task-inherent features degrade the quality of collected gamma ray spectra, including: limited dwell times, a fluctuating background, a large distance to the source, weak source activity, and the low sensitivity of mobile detectors. Thus, collected gamma ray spectra are expected to be sparse and noise dominated. For extremely sparse spectra, direct background subtraction is infeasible and many background estimation techniques do not apply. In this paper, we present a statistical algorithm for source estimation and anomaly detection under such conditions. We employ a fixed-hyperparameter Gaussian processes regression methodology with a linear innovation sequence scheme in order to quickly update an ongoing source distribution estimate with no prior training required. We have evaluated the effectiveness of this approach for anomaly detection using background spectra collected with a Kromek D3S and simulated source spectrum and hyperparameters defined by detector characteristics and information derived from collected spectra. We attained an area under the ROC curve of 0.902 for identifying sparse source peaks within a sparse gamma ray spectrum and achieved a true positive rate of 93% when selecting the optimum thresholding value derived from the ROC curve.

The Local manufacturing scanning gamma system designed in Tuwaitha site for nondestructive assay method of radioactive waste drums, where it consist of two main parts with their belongings for controlling the of detector and drum movements up-down and rotation respectively. The volume of the used drum is 220 L with 85 cm height. The drum filled with Portland cement. Six cylindrical holes were made within cement drum and distributed in radial arrangement.The152Eu source inserted in these holes individually, to measure the average angular count rate of gamma radiation. The full energy efficiency value for geometry of drum and detector is computed for thirteen photo peaks. The average efficiency represented by the curve of these peaks indicated the decreasing of efficiency value with increasing the cement thickness and the distance between the detector and the location of radioactive source inside the drum.

Number, energy and dose albedos are measured at a scattering angle of 180° for a broad beam of 662 keV gamma rays obtained from a radioactive source of 137Cs (having strength in µCi; 1 Ci = 3.7 × 1010 disintegrations per second). The gamma beam is incident on semi-infinite thick targets of variable atomic numbers. The scattering media is divided into three sets, which are pure elements, alloys and composite materials. Experiments are carried out using a 3″ × 3″ NaI(Tl) scintillation detector. To obtain precision in data, the response unfolding of a scintillation detector is used, which converts the observed pulse-height distribution to a true photon spectrum over the energy range of 2.5 to 640 keV. The detector response unfolding results in the true intensity of back-scattered gamma flux by shifting the events resulting from partial absorption of photons to the full energy peak of the spectrum. In the present study, albedo factors are studied as a function of target thickness and their atomic numb...

The CMS drift tubes (DT) muon detector, built for withstanding the LHC expected integrated and instantaneous luminosities, will be used also in the High Luminosity LHC (HL-LHC) at a 5 times larger instantaneous luminosity and, consequently, much higher levels of radiation, reaching about 10 times the LHC integrated luminosity. Initial irradiation tests of a spare DT chamber at the CERN gamma irradiation facility (GIF++), at large (~O(100)) acceleration factor, showed aging effects resulting in a degradation of the DT cell performance however, full CMS simulations have shown almost no impact in the muon reconstruction efficiency over the full barrel acceptance and for the full integrated luminosity. A second spare DT chamber was moved inside the GIF++ bunker in October 2017. The chamber was being irradiated at lower acceleration factors, and only 2 out of the 12 layers of the chamber were switched on at working voltage when the radioactive source was active, being the other layers on standby. In this way the other non-aged layers were used as reference and as a precise and unbiased telescope of muon tracks for the efficiency computation of the aged layers of the chamber, when set at working voltage for measurements. An integrated dose equivalent to two times the expected integrated luminosity of the HL-LHC run had been absorbed by this second spare DT chamber and the final impact on the muon reconstruction efficiency was measured. Direct inspection of some extracted aged anode wires presented a deposition of materials. Investigation on the outgassing of cell materials and of the gas components used at the GIF++ are underway. Strategies to mitigate the aging effects are also being developed. From the long irradiation measurements of the second spare DT chamber, the effects of radiation in the performance of the DTs expected during the HL-LHC run will be presented.

The main purpose of this paper is to calibrate the detection efficiency and energy linearity of a hard X-ray imager (HXI), one of the payloads on the ASO-S satellite. In this experiment, HPGe calibrated by radioactive source was used as the standard detector, and the experimental device used was a double crystal calibration device. The experimental method is to first measure the single energy peak of the corresponding energy point with a standard detector, and then use the HXI LaBr3 crystal detector probe to obtain the same single energy peak. It should be noted here that in order to eliminate the statistical fluctuations and other factors, we set the detection time of both detectors to 1000 seconds. Then, the dobule crystal parallelism is detuned (ie, non-parallel) to measure the unfiltered background and the electronic noise. Finally, the open source software Root is used to perform relatively clean single-energy X-ray beam data obtained after subtracting the background data of the beam.

Several experimental anomalies in neutrino physics may point to the possible existence of one or more additional neutrino species that do not interact weakly, the so-called sterile neutrinos. The third phase of the Borexino experiment (SOX) is devoted to verification of this hypothesis. Within the first stage (CeSOX) the count rate of antineutrino events in the liquid scintillation detector from the artificial source 144Ce–144Pr placed in the special pit beneath the setup will be measured. The smaller antineutrino flux, as compared to the original one, would indicate the presence of oscillations into sterile states. This paper gives a survey of the CeSOX experiment, including the general description, the characterization of the radioactive source and the specific features of its use, the description of the method for data analysis, and the expected results. Depending on the significance of the obtained scientific information, the decision on carrying out the second stage of the SOX experiment with the 51Cr source of electron neutrinos will be made.

The focus of my research is based on the gas electron multiplier (GEM) foil test, repairing and effective gain calculation of GEM detector. During my research work define procedure of GEM foil testing short-circuit, detection short-circuits in the foil. Study different ways to remove the short circuits in the foils. Set and define the GEM foil testing procedures in the open air, and with nitrogen gas. Measure the leakage current of the foil and applying different voltages with specified step size. Define the Quality Control (QC) tests and different components of GEM detectors before assembly. Calculate the effective gain of GEM detectors using 109 Cd and 55 Fe radioactive source.

In this study, we developed a method for continuous PAN measurements by gas chromatography (GC) with a non-radioactive pulsed discharge detector (PDD). Operational parameters were optimized based on the ratio of peak height over baseline noise (P/N ratio). The GC/PDD system was compared with a traditional radioactive electron-capture detector (ECD). In the lab, the method detection limit (MDL) of the new GC/PDD method (9 pptv) was lower than the radioactive GC/ECD method (15 pptv), demonstrating its excellent potential. The MDL of GC/PDD in the field campaign at the Mt. Bachelor Observatory (MBO) was 23 pptv, higher than in the lab. This was caused in part by the decreased slope of the calibration curve resulting from the low air pressure level at MBO. However, the MDL level of GC/PDD at MBO is still low enough for accurate PAN measurements, although special attention should be paid to its application at high-elevation sites. Observations of PAN were conducted at MBO in the summer of 2016 with the GC/PDD system, and provided more evidence of the performance of the system. PAN was found to be highly correlated with CO. The promising performance of GC/PDD which does not require a radioactive source makes it a useful approach for accurate PAN measurements in the field.

Southwest Research Institute investigated the response of a microchannel plate (MCP) detector to isotropic radioactive source emissions at photon energies of 0.662 and approximately 1.25 million electronvolts (MeV) and to a beam of monoenergetic photons (gamma rays) at 2.5, 5, 7, 10, 13, and 20 MeV in the Free Electron Laser Laboratory at Duke University. These measurements were performed to quantify anticipated noise levels of a mass spectrometer instrument for space exploration in a harsh radiation environment and included various incident angles of radiation on the MCP. Measured photon detection efficiencies at 0° incident angle to 0.662 and 1.25 MeV were approximately 0.3%–0.4% and are bracketed by previously published data. In the 2.5- to 20-MeV energy range for which comparable published data are not available, measured detection efficiencies were on the order of 0.02%–0.2%. Radiation transport simulations were compared to the experimental results and showed decent agreement. The measured detection efficiency increased as the incident photon angle was changed from being normal to the MCP surface (0°) to being aligned with the MCP edge (90°). At greater off-axis angles, photons were incident on the side of the detector cartridge and generated secondary radiation from photon interactions in the cartridge materials that subsequently registered MCP counts.

The measurement of Absorption edge parameters of the L III edge of pure elements Hg, Tl, Pb and Bi along with their compounds HgCl2, HgO, HgF2, TlCl, Tl2O3, PbCl2, PbF2, Pb3O4, BiF3, BiCl3 and Bi2O3 has been done using EDXRF technique. In the present measurements 241Am (59.54 keV) radioactive source of activity 100 mCi along with CANBERRA make cryo-cooled Si (Li) detector is used. The measured results are compared with theoretically calculated values from FFAST version 2.1 (Chantler et al., 2005) and shows good agreement with each other within experimental uncertainties within 3.5%. It is observed that the values of absorption edge parameters of the LIII edge depends slightly on the chemical environment and shows almost constant behaviour with effective atomic number ( Z eff )

Radioisotope Technology has proven its suitability as a diagnostic tool for troubleshooting Industrial distillation columns. In packed bed distillation columns, the coking phenomenon is likely to occur inside the packing (solid) through which a liquid is flowing. The aim of the proposed work is to try to address the coking phenomenon as a challenging issue in petrochemical industry by combining or integrating sealed radioactive source techniques and radiotracer techniques. The results correspond respectively to tests using two radioisotopes with gamma scanning technique and radiotracers. In the first approach the structural characteristics of a laboratory constructed distillation column have been investigated by using the Gamma scanning technique which consists in using a 60Co as a gamma ray sealed source associated to a NaI(Tl) detector. The second approach by radiotracers consists of an injection of an appropriate quantity of a specific radiotracer (99 mTc) at the inlet of the process and studying its presence in the column. According to the results, it was concluded that the radiotracer method may be a good approach for detecting the presence of coke in case of liquid flow through solid packing in distillation columns.

Laser-based particle accelerators have been an active field of research for over two decades moving from laser systems capable of one shot every hour to systems able to deliver repetition rates in the Hz regime. Based on the advancements in laser technology, the corresponding detection methods need to develop from single to multiple use with high readout speed. Here, we present an online compact tracker of particles using scintillators with nine resolvable energy levels and a spatial resolution of 3.6 × 3.6 mm2 over the whole active area. This paper describes the design and construction of the detector, which is based on pixellated scintillators embedded inside an absorber matrix. The scintillator pixels are fiberoptically coupled to a camera system for online readout and analysis. Calibration with a radioactive source and first experimental data measuring laser accelerated ions at the PHELIX laser at GSI, Darmstadt, Germany, are presented and discussed.

β + particles from 22 Na radioactive source were detected using the low-cost photodiode BPW21 (P-N Junction Diode). Kurie plot has been carried out. The present study indicates that it can be used as a detector for beta particle detection.

This work describes and shows data from a prototype instrument designed to sample transitory gamma rays resulting from stockpile stewardship testing. The required instrumentation needs to be large, sensitive, low cost, and have the ability to measure pulse widths as narrow as 5 ns (or less). The natural material for an instrument to meet these criteria is an organic scintillator. In order to cover a large area and reduce the overall cost of the detection system (material and electronics), one approach would be large pixel elements to cover an array of a few square meters. Unfortunately, this approach will not provide the accuracy required for these experiments as large volume scintillation detectors broaden the intrinsic full-width at half maximum (FWHM) of the scintillation light pulse due to delays introduced by internal reflections within the scintillator volume. We devised an approach to mitigate these broadening effects from large volume detectors, while remaining at a low cost. Our detectors consist of a bundle of extruded plastic scintillation bars, readout by wavelength shifting fibers that pipe the scintillation light to a fast light readout device. In this paper we describe the detector unit and assembly procedure, the fast photomultiplier tube (PMT) and readout electronics, as well as data from the laboratory with a radioactive source and cosmic-ray muons. Additionally, we show results from a detector unit tested at the NRL Mercury pulsed power facility. The concluding section discusses the path forward for this instrument and possible improvements for a field-deployable system.

Based on The National Electrical Manufacturers Association (NEMA), using the AMINE software to construction of sinograms and using a positron emission source of 22Na, were made calculations to determine the spatial resolution of a ring array system of phoswich detectors of positron emission tomograph included in the CLEAR PET-XPAD3/CT prototype for small animals, made in the laboratories of CCPM and whose project is led by the research group ImXgam. The radioactive source 22Na of approximately 9 MBq of activity, with spherical shape and diameter of 0.57mm is immersed in a plexiglas disc that was located at the geometric center of tomographic system with a Field of View (FOV) of 35 mm in the axial and transverse directions. Displacements of radioactive source were performed on the three cartesian axes and was rebuilt a sinogram for each axis. The shape of sinogram allows describe the correct position and the maximum efficiency of each detector. Subsequently, was carried out a scanning in each one of three spatial axes taking enough distance to cover the dimensions of radioactive source. Data for each phoswich detector were recorded. The process was repeated for other axes and then radioactive source was centered with respect to the FOV and were calculated FWHM (Full Width at Half Maximum) and FWTM (Full Width at Tenth Maximum) values and performing statistics of these values with parabolic fitting, the latter setting allows to obtain parameters of spatial resolution of system.

The present work, an important application of Compton scattering, is aimed at presenting the use of a NaI(Tl) scintillation detector for the estimation of concentration (density), fluid-fluid interface level and presence of a foreign body (Al) in fluids. The measurements are made using a well collimated gamma photon beam, having energy of 662 keV, from 137 Cs radioactive source. The scattered gamma photon flux is detected by a NaI(Tl) scintillation detector (dimensions 51 mm in diameter and 51 mm in thickness) placed at a scattering angle of 110° relative to the primary gamma ray beam. This method is quite sensitive to detect changes in concentration (density) of the order of 0.0153 g/cm 3 in a given aqueous solution. Furthermore, the interface level and position of a foreign body in heterogeneous fluids are observed by monitoring changes in the recorded scattered intensity. The estimated fluid-fluid interface level and the level up to which the presence of a foreign body is detected is close to actual value.

Double-sided silicon strip detectors (DSSSD) are commonly used for event-by-event identification of charged particles as well as the reconstruction of particle trajectories in nuclear physics experiments with stable and radioactive beams. Intersecting areas of both p- and n-doped front- and back-side segments form individual virtual pixel segments allowing for a high detector granularity. DSSSDs are employed in demanding experimental environments and have to withstand high count rates of impinging nuclei. The illumination of the detector is often not homogeneous. Consequently, radiation damage of the detector is distributed non-uniformly. Position-dependent incomplete charge collection due to radiation damage limits the performance and lifetime of the detectors, the response of different channels may vary drastically. Position-resolved charge-collection losses between front- and back-side segments are investigated in an in-beam experiment and by performing radioactive source measurements. A novel position-resolved calibration method based on mutual consistency of p-side and n-side charges yields a significant enhancement of the energy resolution and the performance of radiation-damaged parts of the detector.