Li Detector Research Articles

Determining the thickness of a thin aluminum sheet using the transmission measurement of X-rays with varying energies: A comparative analysis between calibration curve fitting and artificial neural network approaches

This study proposes an innovative configuration for thickness measurement based on X-ray transmission, intending to improve the precision of measuring thin aluminum sheets. In this configuration, an activation sample containing Zr, Sb, and Ba elements is irradiated by 59.54 keV gamma rays emitted from three 241Am radioactive sources with a total activity of 1.78 GBq. Subsequently, the activation sample emits fluorescent X-rays at energy levels of 15.78 keV (Zr-Kα1,2), 17.67 keV (Zr-Kβ1), 26.36 keV (Sb-Kα1,2), 29.73 keV (Sb-Kβ1), 32.2 keV (Ba-Kα1,2), and 36.38 keV (Ba-Kβ1). These X-rays are collimated into a narrow beam, which then penetrates through an absorbing sample, and is ultimately recorded by a Si(Li) detector. Two different approaches are investigated to determine the thickness of absorbing samples including Calibration Curve Fitting (CCF) and Artificial Neural Network (ANN). The CCF approach requires constructing linear calibration curves for establishing the relationship between lnR (R is the ratio of the peak areas in measurements with and without absorbing sample) and the thickness of the absorbing sample at each X-ray energy level. The sample thickness is then determined by calculating a weighted average of the measured thicknesses associated with all analyzed energy levels. This approach requires in-depth understanding of radiation physics and proficiency in X-ray spectrum analysis. Meanwhile, the ANN approach uses raw spectra obtained by the Si(Li) detector to predict the thickness of aluminum sheets, facilitating analysis without requiring human intervention. The reliability of these approaches is evaluated through experimental measurements on aluminum sheets with thicknesses ranging from 0.064 cm to 1.074 cm. The results indicate that using X-rays with many different energies leads to superior accuracy in thickness measurements compared to using X-rays with a single energy. Besides, both the CCF and ANN approaches yield relative deviations of less than 3% between the predicted and reference thicknesses. It is important to emphasize that the ANN approach represents a promising solution for automated analysis without the intervention of experts.

Determination of Transmission Factors and γ-Ray Linear Attenuation Coefficients of Some Construction Materials Mixed with Ulexite and Borax

In the study, transmission factors (T) and linear attenuation coefficients (μ) of some construction materials (briquette, sand, marble, paint, adobe, soil, and lime) mixed with ulexite and borax are measured with energy dispersive X-ray fluorescence spectrometer for 59.5 keV energy by using a Si(Li) detector. Ulexite and borax were added to the samples at a rate of 25, 50, and 75 percent. Results are presented and discussed in this paper. Measurements made on these construction materials with technological importance will create new use areas

COeCO: A new [formula omitted]-delayed conversion-electron spectroscopy setup for low-energy ISOL beams at the ALTO facility in Orsay

A new β-decay station, COnversion electrons Chasing at Orsay (COeCO), has been developed at ALTO to perform conversion electron spectroscopy studies of neutron-rich nuclei produced by photo-fission of a uranium carbide target. It is based on the collection of a low-energy ISOL beam on a mylar tape, and the transportation of the electrons emitted by the produced radioactive source through a magnetic field induced by two copper coils, towards a cooled Si(Li) detector. In this article, a detailed description of the new decay station and its components is given. The magnetic field induced by the coils was measured and compared to simulations performed with the COMSOL® software. The efficiency of the detection setup was estimated using a 207Bi and a 152Eu source as an off-line commissioning. Finally, the results obtained with a 96Rb radioactive beam for the on-line commissioning are presented.

Rapid method for determining elemental composition in oxide powder sample using Rayleigh-Compton scattering technique

This study presents an innovative approach utilizing gamma scattering techniques to precisely determine the composition percentage in a two-component oxide compound. The experiment involved a 241Am gamma-ray source emitting 59.54 keV radiation and a Si(Li) detector to capture Rayleigh and Compton scattering signals from oxide powder samples. These samples were meticulously prepared by blending Pb3O4 and ZnO, with Pb3O4 proportions ranging from 0% to 100%. To ensure accuracy, eleven standard samples were employed to generate standard curves for the Rayleigh-Compton ratio. The key finding of this research was the calculation of composition percentages for the four samples under investigation, derived from experimental data and the standard curve. Validation against reference materials revealed a minimal relative deviation of approximately 1.0% when estimating the Pb3O4 ratio, showcasing the precision and potential applicability of this method in material science and analysis.

The LSU-Argonne conversion electron spectrometer: A new detector for the X-Array and SATURN decay station

A new conversion electron detector has been commissioned at the ATLAS/ CARIBU facility at Argonne National Laboratory. The LSU-Argonne Conversion Electron Spectrometer (LACES) is a LN2-cooled Si(Li) detector system designed to be incorporated into a decay station that comprises the dedicated HPGe clover array with a box geometry (X-Array) and the Scintillator and Tape Using Radioactive Nuclei (SATURN) device. This integration enables simultaneous measurements of conversion electrons and gamma-rays in decay experiments, yielding novel information on transition multipolarities, electric monopole transitions, and isomeric states that decay mostly via conversion electrons. A measurement of the energy resolution of LACES yielded 2.3-keV FWHM at 975 keV for electrons and 1.3-keV FWHM at 75 keV for X-rays. A detailed study of the absolute detection efficiency (at 5 mm from the source) was performed, where this quantity was determined experimentally in the range of electron transition energies between 25.5 keV and 1047.8 keV and subsequently simulated using the GEANT4 code. Measurement and simulations are found to be in excellent agreement. A precise characterization, for this type of detector system, of the absolute detection efficiency for such a wide energy range is reported for the first time.

Investigation and optimisation of a lithium-drift silicon detector using Si–Li structure and bidirectional diffusion and drift techniques

Abstract The research relevance is predefined by the continuous development and improvement of radiation analysis methods and the need for more efficient and accurate detectors for various applications. This research may improve the sensitivity and resolution of Si(Li) detectors, which is important for scientific and industrial research as well as radiation safety monitoring. The research aims to analyse and improve the performance of a Si(Li) lithium-drift silicon detector. The methods used include an analytical method, classification method, functional method, statistical method, synthesis method and others. The results of the two-sided observation of lithium diffusion in silicon monocrystals provided valuable information about the characteristics of the process and its dependence on the method of silicon production. A large-diameter detector detection mode was found to be important for optimising the production of such detectors. The diffusion process in monocrystalline silicon produced by the shadowless zone melting method is relatively fast. This means that lithium ions penetrate the material rapidly and spread evenly throughout its volume. This fast diffusion process can be useful for detectors that need to respond quickly to incoming signals. It was found that in monocrystalline silicon produced by the Czochralski method, there is a delayed penetration of lithium ions.

Detection of Precious Trace Metallic Elements in Charnockite Composition by PIXE Technique

The geochemical analysis of the middle Z precious metallic trace elements of the charnockite mineral composition was obtained by using proton induced X-ray emission at 3 MeV with a Si (Li) detector. Compared with other experimental nuclear analytical techniques like EPMA, XRF, and NAA, proton induced X-ray emission is used to detect with good accuracy and precision in the case of trace precious metals like Mo, Nb, Ru, Rh, and Ag, etc., in charnockite mineral composition due to the cross-sections with 3 MeV protons and good agreement. But peak resolution problems of K-X-rays of low Z and L-X-rays of the above elements which were presented in charnockite analysis must be solved and also change the detector parameters to obtain exact values in traces of the above elements in parts per million.

Efficiency and resolution characterisation of a high-resolution bent crystal X-ray spectrometer using ray-tracing simulations

We report the characterisation of the efficiency and resolution of a high-resolution bent crystal spectrometer under Johannson geometry, using ray-tracing simulations. The spectral resolution is measured experimentally from electron-beam and fast ion-beam interactions with thin solid foils. The X-rays emitted by target atoms as well as projectile ions are studied. The results of the ray-tracing simulations are in very good agreement with the beam-foil spectroscopy experiments. The geometrical factors affecting the resolution are also discussed in detail. We also characterise the detection efficiency of the spectrometer by simultaneous measurements of X-rays using a semiconductor detector, i.e. Si(Li) detector, with known detection efficiency. These results are also compared with the ray-tracing simulation results.

An experimental study on chemical shifts and X-ray intensity ratios

In this study, full widths at half maximum (FWHM), asymmetry indexes, chemical shifts (ΔE) and Kβ-to-Kα X-ray intensity ratios of some pure metals (Mn, Fe, Cu and Zn) and some of their oxidized compounds (Mn2O3, Fe2O3, Fe3O4, Cu2O3 and ZnO) were investigated. The samples were excited by 59.54 keV photons emitted from a241Am radioisotopes source and characteristic K X-rays emitted from the samples were counted by a Si(Li) detector. The results have shown that the Kβ-to-Kα X-ray intensity ratios, asymmetry indexes, chemical shifts and full widths at half maximum (FWHM) values can change with sample sizes.

Transformation of ICEBall to fIREBall for conversion electron spectroscopy

Conversion electron spectroscopy is a valuable tool in nuclear structure studies, but the complex spectra resulting from the high density of levels in the spectra of heavy nuclei make it difficult to extract the most beneficial information from singles measurements. This work reports on the transformation of ICEBall, which was a mini-orange spectrometer that was used in coincidence with various Germanium detector arrays, to the improved fInternal conveRsion Electron Ball (fIREBall) spectrometer for the improved measurements of E0 transitions and conversion electron coefficients. A combination of FreeCAD, COMSOL, and Geant4 simulations were implemented to optimize the geometries for the magnet filters used in the spectrometer to significantly improve the efficiency of electron collection in the energy range of interest 200 keV-1 MeV. The array of six mini-orange Si(Li) detectors are to be replaced with six new, thicker Si(Li) detectors. Experimental tests reported here show a peak improvement in absolute efficiency from 2.8% to 5.3% for the 482 keV K electron line in 207Bi for a single magnet filter and detector pair.

Using the gamma spectrometry method to determine the concentration of radon in samples of mineral radon water

The results of a study on the choice of the optimal measurement geometry, measuring capacity and method of sealing the measuring capacity for determining the concentration of radon-222 in samples of mineral radon water are presented. Studies of radon water samples were carried out in laboratory conditions on a stationary gamma spectrometer based on a semiconductor Ge(Li) detector. The concentration measurements in the samples were carried out in accordance with MVI. MN 3421-2010 “Methodology for measuring the volumetric and concentration of gamma-emitting radionuclides on gamma spectrometers with semiconductor detectors” for standard plastic vessels “Denta, 0.1 l” and “Marinelli, 1 l”, and glass containers with a volume of 0.5 l with lids for twisting and seaming. The results of the research showed that the leakage of radon from a glass container with a metal lid for sealing is minimal. This method of sampling and sealing the measuring vessel makes it possible to increase the accuracy of the presented measurement results by reducing the corrections for sample preparation when calculating the expanded measurement uncertainty. A glass container with a volume of 0.5 l with a metal cap for seaming was used to measure the concentration of radon in samples of mineral radon water taken from wells and a drinking fountain of the Radon sanatorium of Belagrozdravnitsa JSC (Dyatlovo District, Grodno Region). The concentration range was 760–2100 Bq/kg. The selected measuring container, the method of its sealing and the measurement geometry can be used for future measurements of the radon concentration in samples of mineral radon water taken in the sanatoriums of the Republic of Belarus.

An Experimental Study on the Measurement of Gamma-Ray Linear Attenuation Coefficients with Transmission Factors for Ispir and Kızılcahamam Dry Bean

In the present work, the gamma-ray linear attenuation coefficients (µ) and transmission factors (TF) were measured for Erzurum Ispir dry bean (IDB) and Ankara Kızılcahamam dry bean (KDB). Photons of the Am-241 point source with an energy of 59.54 keV, an Energy Dispersive X-Ray Fluorescence Spectrometer (EDXRFS), and a Si (Li) detector were used in the experiment. As a result, it was observed that the average transmission factor of Erzurum İspir dried beans was higher than that of Ankara Kızılcahamam dry beans, and the average linear attenuation coefficient was smaller. This means that Ankara Kızılcahamam dry beans absorb more gamma rays than Erzurum İspir dry beans, that is, they interact more with gamma rays.

Levels of a select group of trace elements in scalp hair of schizophrenics by PIXE

The levels of ten trace elements in the range Ca to As in the scalp hair of schizophrenics were analyzed using Particle Induced X-ray emission (PIXE) technique. Thirty males and females with a confirmed diagnosis of schizophrenia and an equal number of age-matched controls of both genders were chosen. The samples were excited with a proton beam of 2.5 MeV and spectra were scanned by a Si (Li) detector. The findings revealed a statistically significant difference in the concentration of six trace elements (Ca, Zn, Se, Mn, Fe, Ni, and Cu) in scalp hair of schizophrenia patients compared to controls, implying a disruption in the homeostasis of these elements. A plausible correlation of this imbalance with the etiology and pathology of schizophrenia is discussed.

K shell fluorescence parameters of some elements at 59.54 keV: Experimental and theoretical results

Kα, Kβ and total K X-ray fluorescence cross-sections, K shell fluorescence yields, Kβ/Kα X-ray intensity ratios, K shell level widths, K shell life times, K to L shell vacancy transfer probabilities, K shell jump ratios, Auger electrons emission ratios and excitation factors for some elements in the atomic number range 22 ≤ Z ≤ 48 have been investigated. A Si(Li) detector and Am-241 annular radioactive source were used in the measurements. The obtained experimental data were crosschecked with theoretically calculated results and other available experimental results from the literature. It was observed that there is a good agreement between them within experimental uncertainties.

Investigation of coherent/Compton scattering differential cross section ratios in Cu alloys as depending on chemical environment and scattering angle

In this study, seven alloys with a nominal composition of (CuO2)0.5 M0.5 (M = Fe, Co, Ni, Cu, Zn, Y, and Nb wt%) were produced via the powder mixed method. Alloys and pure metals were excited with 59.54 keV photon energy emitted from Am-241 radioactive source at 25°, 35°, 45°, 55°, 65°, 75′ and 85° scattering angles. The spectra of the coherent/Compton peaks were obtained by Si(Li) detector. First of all, chemical shift, (ΔE) peak energies, (E) asymmetry index (As) and full width half maximum (FWHM) values were found in the Compton/Coherent scattering spectra obtained depending on the scattering angle and the chemical environment of the transition metals. Then the ratios of the Coherent/Compton scattering differential cross-section (dσcoherent/dσCompton) were obtained experimentally. The experimental dσcoherent/dσCompton ratios of the selected 3d-4d transition metals were found to be compatible with the data in the literature. Asymmetry and chemical shifts were observed in almost all samples, especially in Compton peaks, with increasing scattering angles. The chemical shifts of Compton and Coherent peaks of the alloys were found in the range of 1–932 eV. The experimental dσkoherent/dσCompton ratios for the alloys obtained by adding Fe, Co, Ni, Cu, Zn, Y, and Nb to Cu2O were found as 0.697, 0.689 0.678, 0.698, 0.736, 0.755, 0.798, 0.835 at 45° scattering angle, respectively. It has been determined that the experimental dσcoherent/dσCompton ratio for each alloy increases with increasing atomic number, while it decreases with increasing scattering angle.

Double Sided Drift Method Reduces the Effect of Crystals' Inhomogeneity to Si(Li) Detector's ElectroPysicsal Characteristics

Double Sided Drift Method Reduces the Effect of Crystals' Inhomogeneity to Si(Li) Detector's ElectroPysicsal Characteristics

ELEMENTAL CONCENTRATION OF PACKAGED MEALS (BAKED AND EXTRUDED GOODS MADE USING COMPOSITE CEREAL-PULSE FLOUR) PROCURED AT DEBRE TABOR MARKETPLACES IN ETHIOPIA

The elemental analysis of packed food items which is collected in Debre Tabor markets, Ethiopia namely Pasta, Macaroni, cookies, biscuit, wheat bread, white teff injera, Red teff injera, barley so, barleycorn and maiz bread samples were carried out using EDX spectrometer. An X-ray beam was used to excite each sample and spectra were recorded with a high-resolution Si(Li) detector. The data analysis was carried out by software. Trace elements P, K, Na, Cl, Mg, Ca, Fe, Al and Zn were estimated, and elemental concentrations were determined. To get the exact results of the present study the analysis repeats three times.

Precise conversion electron intensities of low energy gamma transitions for efficiency calibration of electron detectors

Precise energies and relative intensities of gamma transitions and conversion electrons in the electron capture decay of 153Gd have been determined independently with our well-tested and optimized gamma and electron spectrometers - a large-volume (60 cc) HPGe detector and a mini-orange electron transporter paired to a Si(Li) detector, respectively. The experimental internal conversion coefficients of the gamma transitions in 153Eu have been determined using Normalized Peak to Gamma method and compared with the theoretical values adopted by Nuclear Data Sheets to assign multipolarities of all the transitions. The precise internal conversion electron intensities of the low energy transitions can be used as standards for calibration purposes of electron detectors and spectrometers.

Statistical investigation of the large-area Si(Li) detectors mass-produced for the GAPS experiment

The lithium-drifted silicon (Si(Li)) detector developed for the General Antiparticle Spectrometer (GAPS) experiment features a thick (∼2.2 mm) sensitive layer, large (10 cm) diameter, and excellent energy resolution (∼4 keV for 20–100 keV X-rays) at a relatively high operating temperature (approximately −40 °C). Mass production of GAPS Si(Li) detectors has been performed to construct a large-volume silicon tracker for GAPS. We achieved the first success of the mass production of large-area Si(Li) detectors with a high (∼90%) yield rate. Valuable datasets related to detector fabrication, such as detector performance and manufacturing parameters, were recorded and collected during the mass production. This study analyzes the datasets using statistical methods with the aim of comprehensively examining the mass production and to gain valuable insight into the fabrication method. Sufficient uniformities of the performance parameters (leakage current and capacitance) between detectors and strips are found, demonstrating high-quality and stable mass production. We also search for correlations between detector performance and manufacturing parameters by using data-mining techniques. Conventional multivariate analysis (multiple regression analysis) and machine-learning techniques (regression tree analysis) are complementarily used, and it is found that the Li-drift process makes a significant contribution to the performance parameters of the finished detectors. Detailed investigation of the drift process is performed using environmental data, and physical interpretations are presented. Our results provide valuable insight into the fabrication methods for this kind of large-area Si(Li) detector, and encourages future projects that require large-volume silicon trackers.

Development of Tincal based polypropylene polymeric materials for radiation shielding applications: Experimental, theoretical, and Monte Carlo investigations

Samples of new polymeric material based on polypropylene doped with various Tincal concentrations have been developed. The prepared samples are coded PT1, PT2, PT3, and PT4. The structural characteristics of the produced polymeric materials were investigated using X-ray diffraction (XRD) and Raman Spectroscopy. The obtained materials' shielding capacity was studied in terms of mass attenuation coefficient and half-value layer. The mass attenuation coefficient was experimentally estimated using a high-resolution Si (Li) detector and a multichannel analyzer with multiple variable sources, and the findings were then compared with the Phy-X/PSD and MCNP algorithms. The existence of two bands at 2.770–2.830 cm−1 and 1.405–1.455 cm−1 in the Raman spectra can be attributed to CH2 vibration modes. Due to the increased density of the sample, Tincal enhancement with greater ratios has a beneficial influence on linear attenuation coefficient (LAC) values. This led the samples to be sorted in the following order: PT1<PT2<PT3<PT4 in terms of LAC. The greatest half value layer (HVL) values for PT1 were found to be between 0.876 and 41.24 cm. Furthermore, the PT4 values were the lowest, ranging from 0.491 to 32.291 cm at 0.015 and 15 MeV, respectively. The obtained results introduced the PT4 sample as the best shield against gamma rays among all prepared samples.