Alpha Track Research Articles

Deep learning-based alpha particles spectroscopy with solid-state nuclear track detector CR-39

A novel approach for alpha particles energy spectroscopy utilizing a sophisticated deep learning machine learning algorithm is introduced. The approach we employ classifies the alpha particles trajectories on a CR-39 detector into six discrete energy levels: 0.5 MeV, 1.5 MeV, 2.5 MeV, 3.5 MeV, 4.5 MeV, and 5.4 MeV. Some 57 different CR-39 detectors were exposed to alpha particles of the stated energy levels using a241Am source. The dosimeters were then subjected to etching and imaging utilizing a Landauer Neutrak© system. A self-developed computer vision method was used to separate the energy-tagged alpha tracks from the CR-39 images. These tracks images were then inputted into an artificial neural network (ANN) algorithm for training. After completing the training, a test dataset was run to assess the algorithm's performance. An average accuracy rate exceeding 98% was attained across the six energy levels.This algorithm has the potential to enhance the precision of alpha particle dosimetry. Furthermore, once generalized to a continuous energy spectrum, as well as for other types of particles such as protons, this algorithm is anticipated to prove highly beneficial for analyzing the outcomes of various laser-driven high-energy particle experiments in general, and specifically for fusion experiments.

Nonlinear Calibration and Temperature Sensitivity of Makrofol Solid-State Nuclear Track Detectors for Radon Measurement

A key characteristic of a solid-state nuclear track detector (SSNTD) is that as more alpha tracks accumulate on the detector, the likelihood of track overlap will increase, making it difficult to distinguish individual events. This article presents the calibration of an in-house SSNTD using a Makrofol polycarbonate detector and electrochemical etching. The calibration employs a nonlinear log-logistic quantile function, which is nearly linear at low exposures but accounts for the reduced efficiency at high exposures due to overlapping alpha tracks. The function can be fitted to calibration measurements very accurately, eliminating systematic errors previously associated with the method at certain radon exposures. This article explores the uncertainties and detection limits associated with the calibration and outlines methods for their evaluation. Additionally, it includes a preliminary discussion on the method’s sensitivity to temperature.

Real-time particle visualization in an electric-cooled cloud chamber using machine learning

This paper presents the development and implementation of an electric-cooled cloud chamber designed to visualize alpha and beta particle tracks. Traditional cloud chambers rely on dry ice for cooling, which can be cumbersome and impractical for extended use. Our approach employs a Peltier device coupled with a commercial CPU cooler, providing a stable, large field of view, and long-lasting cooling environment. Additionally, we have integrated a real-time visualization system utilizing OpenCV and machine learning with TensorFlow. This system accurately identifies and labels particle tracks, enhancing the educational experience. The cloud chamber operates seamlessly with consumer laptops, such as the MacBook Air with an M1 chip, making it accessible and convenient for educational purposes. Initial qualitative results demonstrate the system’s effectiveness. Future work will focus on refining detection accuracy and exploring additional applications. This advancement not only improves the usability of cloud chambers but also offers new possibilities for interactive scientific education.

Determine the concentration of radon and uranium in different types of tea

ABSTRACT Radon is a radioactive element from 238U decay series which is naturally occurring and found in different concentrations in many biological formations. This radioactive gas rises from the sample and enters the homes and human lungs daily. The present study aims to determine the concentration of radon in 25 different types of tea collected from local markets in Kurdistan Iraqi region which are mostly consumed by the population because tea is one of the most food used in the form of cold and hot drinks in Iraq, so 25 samples of the most frequently traded tea have been collected from the market. Analysis of the concentrations of Radon-222 and Radium-226 for different types of household tea samples are very substantial for realising the comparative contributes of specific substances to the whole radon content set within the human body and his environment, which is the recommended limit for ICRP values (200–800) Bq.m−3. CR-39 detector was used to record the tracks of alpha particles released from radon content within the tea samples with PVC tube. The chemical etching NaOH solution 6.25 N was using at 70°C for 8 hours to enlarge and appear the alpha tracks, then scanned by microscope. The results showed that the lowest concentration of radon was 3.468 Bq.m−3 (TE11, 0.01%) found in Aero plane tea, while the highest value was recorded in Royal tea which was 123.467 Bq.m-3 (TE22, 8%) with an average value of radon concentration was 61.754 Bq.m−3. The obtained radon concentration levels in the samples were lower than the global permissibility limiting of exposure to radon were within the allowed limit value (200 Bq.m−3), also found to be lower than the (400 Bq.m−3) according to ICRP in foods; therefore, this will not form any risk on human being life.

Analysis of particles containing alpha emitters in stagnant water in Fukushima Daiichi Nuclear Power Station’s Unit 3 reactor building

Particles containing alpha (α) nuclides were identified from sediment in stagnant water in the Unit 3 reactor building of the Fukushima Daiichi Nuclear Power Station (FDiNPS). We analyzed different concentrations of α-nuclide samples collected at two sampling sites, the torus room and the main steam isolation valve (MSIV) room. The solids in the stagnant water samples were classified, and the uranium (U) and total alpha concentrations of each fraction were measured by dissolution followed by inductively coupled plasma mass spectrometry and α-spectrometry. Most of the α-nuclides in the stagnant water samples from the torus and MSIV rooms were in particle fractions larger than 10 μm. We detected uranium-bearing particles ranging from sub-µm to 10 µm in size by scanning electron microscopy–energy-dispersive X-ray (SEM–EDX) observations. The chemical forms of U particles were determined in U–Zr oxides, oxidized UO2, and U3O8 with micro-Raman spectroscopy. Other short-lived α-nuclides (plutonium [Pu], americium [Am], and curium [Cm]) were detected by alpha track detection, and the particles with α-nuclides was characterized by SEM–EDX analysis. α-nuclide-containing particles with several tens to several 100 µm in size mainly comprised iron (Fe) oxyhydroxides. In addition, we detected adsorbed U onto Fe oxyhydroxide particles in the MSIV room sample, which indicated nuclear fuel dissolution and secondary U accumulation. This study clarifies the major characteristics of U and other α-nuclides in sediment in stagnant water in the FDiNPS Unit 3 reactor building, which significantly contribute to the consideration of removal methods for particles containing α-nuclides in the stagnant water.

Effect of Heat Treatment on Alpha Track Profile of CR-39 Detector.

Effect of Heat Treatment on Alpha Track Profile of CR-39 Detector.

Alpha particle energy-range studies by a layer removal method in polycarbonate detectors for determining unknown ion energies

The aim of this study is to apply a “layer removal method” for alpha energy-range determination in polycarbonate detectors (PC) compared with SRIM software. This method is a precise chemical pre-etching process by which a layer of a certain thickness is removed from an exposed or unexposed PC detector surface before applying electrochemical etching (ECE). A group of 500 μm thick PC detectors was exposed to alpha particles of known fluence (∼1.0 × 104 alphas.cm−2) and ∼0.3–∼5.0 MeV energy range, followed by a pre-etching process at 12 different time intervals in 70% ethylenediamine solution. After the ECE process, alpha track density and diameter were determined. Track density versus removed layer thickness for each alpha energy follows a Bragg type peak after which approaching zero at a known removed layer thickness corresponding to the alpha range. The results also show a linear increase of the mean track diameter as the removed layer thickness increases for each energy. On the other hand, this study confirms a shift in the energy range registration by increasing the thickness of the removed layer. Using this precise method, an unknown energy can be determined by step-by-step thickness removal process until the track density approaches zero. In conclusion, the upper energy of ions emitted in a PFD can be determined. This method is a precise and simple method for ion energy-range determination studies for passive ion spectrometry.

The sensitivity of innovative techniques for measuring low levels of radon in the environment using passive detectors

In recent years, there has been a significant surge in interest in measuring low radon levels in the environment. These measurements are valuable, particularly for identifying radon priority areas as required by the European Council Directive 2013/59/EURATOM and for research related to climate change. Due to the limited sensitivity of existing radon detectors/monitors in addressing these challenges, substantial efforts have been devoted to developing new designs. This report compares the sensitivity of several innovative designs with that of existing passive radon monitors. These novel designs incorporate alpha track detectors, including large area low background detectors, with activated carbon fabric used as an efficient radon adsorber/radiator. Recent innovative solutions to mitigate the impact of temperature and humidity on detectors using adsorbers are also discussed. The background signal of detectors intended for use in these novel designs is examined, and their sensitivity is evaluated. The findings demonstrate that these novel designs have the potential to significantly enhance the sensitivity of long-term radon measurements, surpassing the detectors currently in widespread use by more than an order of magnitude.

Alpha particle spectrometry in fluorescent nuclear track detectors with an automatic 3D track reanalysis algorithm

The main obstacle to applying aluminum oxide doped with carbon and magnesium (Al2O3:C,Mg)-based fluorescent nuclear track detectors (FNTDs) in radionuclide therapy with alpha emitters is that it has not been known how to achieve an accurate and in situ dose assessment for in vitro cellular experiments. In this study, we developed an automatic 3D track reanalysis algorithm (ATRA) to analyze the alpha energy spectra in FNTDs. The algorithm provides an excellent track identification rate and an excellent track linking rate (0.961) without significant variations in various track densities. The algorithm also achieves a reliable track detection rate exceeding 0.927 for track densities at the level of in situ measurement, and it successfully measures the alpha energy spectra for obtaining the absorbed dose. We also confirmed that the track overlap clearly interferes with accurate track reconstruction for track densities beyond 1.5 × 106 tracks cm−2. We provided a correction equation that can be used to obtain the actual alpha tracks for high track densities; the equation may also correct estimations of absorbed doses due to alpha particles.

Radon exposure and its influencing factors across 3,140 workplaces in Spain

Indoor radon exposure increases the risk of lung cancer. Radon concentration in workplaces is regulated in EU countries, including Spain, based on a reference level of 300 Bq/m3. The objective of this study is to describe workplace radon exposure in Spain and its influencing factors. To do this, we collected long-term radon measurements with alpha track detectors in 3140 workplaces mainly located in radon prone areas. Radon concentration exceeded 300 Bq/m3 in 1 out of 5 workplaces. Median radon concentration was 107 Bq/m3 in radon prone areas, 28 Bq/m3 off radon prone areas, and 101 Bq/m3 globally for the complete sample. Our results indicate that excessive radon concentrations can be expected in radon prone areas at all floor levels, especially below ground. Floor level, working sector, and location significantly influence radon concentration. The highest radon concentrations were found in the Education & Culture sector, comprising schools, universities, libraries, or cultural centers. These results indicate that radon should no longer be considered a risk for marginal occupations, but a risk everyone has if located in a radon prone area. Immediate action, including radon testing and mitigation, is needed to protect workers in Spain against radon exposure. This is already mandatory since EU regulation for radon has been recently transposed in Spain. Competent authorities should enforce this regulation without further delay, and employers must address their responsibility and communicate with workers about this risk.

Comparison between etching techniques for solid-state nuclear track detector (CN-85) to develop alpha tracks

The present work aims to estimate and compare the etching parameters of Solid-state nuclear track detector (SSNTD) CN-85 with different etching techniques (Water bath, Ultrasound, Microwave, Oven and Plasma (Dry Etching)). CN-85 detectors were exposed in a direct contact to the sensitive face (notated face) for 15 s to alpha particles emitted from the radium-226 source (226Ra) of 4.87 MeV energy and 5 μCi activity. Small pieces with area (1 × 1) cm2 of CN-85 detectors were used. Using an optical microscope (model, N-200M). It has magnification of 400× to count the alpha tracks of CN-85 detectors. Tracks density and tracks diameters of CN-85 detector at different etching time from the five etching techniques were estimated. In addition, based on the experimental results, etching parameters related to the maximum track densities for CN-85 track detector are calculated. With etching efficiency value of ∼ 73%, microwave technique is the most efficient technique follow with plasma technique with (∼59%). The other three techniques had efficiencies three times less than microwave technique. Therefore, it can conclude that microwave etching technique is recommended for CN-85 detectors.

Experimental determination of alpha particle etchable track lengths in thermally treated CR-39 detectors demonstrates the existence of significant chemical changes

In the present work, a clear-cut determination of alpha particle track length in poly allyl diglycole carbonate (PADC) polymer-based nuclear track detectors NTDs (called CR-39) has been performed. We have applied the Over-Etched Track Diameter (OETD) method to determine the alpha particle etchable lengths in both non-thermally treated (pristine) and thermally treated CR-39 detectors. The diameters of etched alpha tracks in pristine and thermally treated CR-39 detectors have been measured as a function of etching time at different heating temperatures and times, using a 241Am radioactive source with alpha particles of specific energy of 5 MeV. This is the first-time etchable lengths of alpha particles have been determined in thermally treated CR-39 detectors. The results of the OETD method for the etchable lengths of alpha particles in non-thermally treated CR-39 detectors are in an excellent agreement with the previously published data and with the calculated lengths. On the contrary, the etchable lengths determined for thermally treated detectors are smaller than expected track lengths, the higher the heating times and temperatures. These results are discussed in the light of our understanding of the effects of thermal treatment in the polymer material that makes up CR-39.

Alpha Tracks Examination for Female Urine Samples who are Suffering from Urinary Tract Infections

Alpha Tracks Examination for Female Urine Samples who are Suffering from Urinary Tract Infections

Cold season dose rate contributions from gamma, radon, thoron or progeny in legacy mines with high natural background radiation.

In areas with high natural background radiation, underground cavities tend to have high levels of airborne radionuclides. Within mines, occupancy may involve significant exposure to airborne radionuclides like radon (222Rn), thoron (220Rn) and progeny. The Fen carbonatite complex in Norway has legacy mines going through bedrock with significantly elevated levels of uranium (238U) and especially thorium (232Th), and significant levels of their progeny 222Rn and 220Rn. There are also significantly elevated levels of gamma radiation in these mines. These mines are naturally chimney ventilated and release large volumes of air to the outdoors giving a large local outdoor impact. We placed alpha track detectors at several localities within these mines to measure airborne radionuclides and measured gamma radiation of bedrock at each locality. The bedrock within the mines shows levels up to 1900Bqkg-1 for 238U, 12000Bqkg-1 for 232Th and gamma dose rates up to 11μSvh-1. Maximum levels of airborne radionuclides were 45000Bqm-3 for 220Rn and 6900Bqm-3 for 222Rn. In addition, we measured levels of thoron progeny (TnP). In order to estimate radiation dose contribution, TnP should be assessed rather than 220Rn, but deposition-based detectors may be biased by the airflow of mine-draft. We present dose rate contributions using UNSCEAR dose conversion factors, and correcting for airflow bias, finding a combined cold season dose rate within these mines of 17-24μSvh-1. Interestingly, fractional dose rate contributions vary from 0.02 to 0.6 for gamma, 0.33 to 0.95 for radon and 0.1 to 0.25 for TnP.

Comparative Alpha Tracks Counting Using an Optical Microscope and a Spark Counter

Comparative Alpha Tracks Counting Using an Optical Microscope and a Spark Counter

Comparison of morphological characteristics for alpha tracks in CR-39 using different radon monitors

CR-39 is a solid nuclear track detector that is commonly used for long-term passive radon monitoring. For a specific incident particle, etching condition and type of CR-39, the morphology of the nuclear tracks in CR-39 varies with the energy and angle of incident particles. This study systematically compares the performance of six different passive radon monitors from the perspective of nuclear track morphology using both theoretical calculations and experiments. Based on different shapes of exposure chambers for these monitors, different strategies for dealing with incident α particles can be observed, especially for those emitted from deposited progeny on the inner wall. These characteristics contribute to the strengths and weaknesses of each monitor in terms of efficiency, uncertainty, robustness in measurement, and consistency of track morphology. The results of this study revealed that the optimisation of the radon monitor should be multidirectional and situation-oriented. It was expected to be helpful to improve radon measurement using these monitors.

A novel method for assessment of crowded plutonium alpha tracks

A novel method for assessment of crowded plutonium alpha tracks

AlphaCAMM, a Micromegas-based camera for high-sensitivity screening of alpha surface contamination

Surface contamination of 222Rn progeny from the 238U natural decay chain is one of the most difficult background contributions to measure in rare event searches experiments. In this work we propose AlphaCAMM, a gaseous chamber read with a segmented Micromegas, for the direct measurement of 210Pb surface contamination of flat samples. The detection concept exploits the readout capabilities of the Micromegas detectors for the reconstruction of 210Po alpha tracks to increase the signal-to-background ratio. We report here on the design and realization of a first 26 × 26 cm2 non-radiopure prototype, with which the detection concept is demonstrated by the use of a new algorithm for the reconstruction of alpha tracks. AlphaCAMM aims for minimum detectable 210Pb activities of 100 nBq cm-2 and sensitivity upper limits about 60 nBq cm-2 at 95% of C.L., which requires an intrinsic background level of 5×10-8 alphas cm-2 s-1. We discuss here the prospects to reach these sensitivity goals with a radiopure AlphaCAMM prototype currently under construction.

Radionuclide Content and Radiation Dose Rates of Uraniferous and Mineralized Granites at GV Occurrence in Gabal Gattar, Northeastern Desert, Egypt.

G. Gattar is located in the northern part of the Eastern Desert of Egypt, bounded by latitudes 26° 52´ - 27° 08´ N and longitudes 33° 13´ – 33° 26´ E and covers an area of about 178 km2. Eighteen samples, nine from uraniferous and nine from mineralized granites were measured radiometrically for 238U, 232Th, 226RaeU and 40K determination by Na-I detector and the radioactive minerals identified by alpha track method. Based on the petrography, radioactive mineral content and radioactivity, Gattarian granites were classified into uraniferous and mineralized granites. Uranium contents reach up to 229 ppm in the uraniferous granites and to 20300 ppm in the mineralized granites, which is extremely higher than the international limits. eTh/eU ratio of the studied uraniferous and mineralized granites show average ratios of 0.05 and 0.0044, respectively, which is extremely lower than the average of igneous rocks, suggesting uranium enrichment in reducing conditions. The uraniferous and mineralized granites U/Th ratios average are 62.23 and 4234.45, respectively, indicating that the studied two granitic types are considered highly productive rocks. The radioelements interrelations manifest that the distribution of radioelements not only magmatic but also related to hydrothermal redistribution of radionuclides associating with uranium deposition. The radiological hazard parameters, such as the dose rate (D), the annual effective dose equivalent (AEDE), radium equivalent activity (Raeq), external (Hex), internal (Hin) hazard indices and gamma index (Iγ) were estimated for these granites and compared with the international levels. Nearly, all the studied samples are to a great extent higher than the recommended permissible levels for all environmental parameters.

Measuring the Concentration of Radon Gas in Book Stores in Primary Schools in Diyala Governorate

In this research, the concentration of radon gas was calculated in the book store rooms of schools in Diyala Governorate, it was calculated by Solid State Nuclear Track Detectors (SSNTDS) when the detector (CR-39) was used, the detector was placed and suspended at a distance of 160 cm from the surface of the earth, and the detector was exposed for 30 days to record alpha tracks. The results of radon concentration showed that the highest concentration percentage was found in (Eishtar) school, which was equal to (84.896) Bq/m3, while the lowest value was recorded in (Habhib) school, which was equal to (11.242) Bq/m3, where the concentration rate was equal to (28.158) Bq/m3. When we compared our results with the global results, we found that the calculated radon concentrations are much less than the internationally permissible limits recorded by (ICRP), which were in the range of (200-300) Bq/m3.