Alpha particle spectroscopy is highly significant in technologies related to radioactivity, particularly in radiation safety and the study of natural radioactivity. On the other hand, tools capable ...of identifying and determining the energies of alpha particles are of great interest. Among these tools, Commercial Off-The-Shelf (COTS) instruments, which can be used for alpha particle detection, have gained significant importance due to their ease of use and low cost. In this study, alpha particle spectroscopy of a Ra-226 source has been performed using a commercial digital camera based-on a CMOS sensor. In order to determine energy spectrum of alpha particles emitted from the source, the performance of various edge detection algorithms was examined. An algorithm based-on local pixel changes was introduced and implemented. By comparing the run times of the algorithms, it was shown that the algorithm proposed in this article exhibited the shortest run-time. Additionally, a method for rejecting pile-up events to correct their destructive effects on the alpha particle energy spectrum was introduced and implemented.
•Alpha particle spectroscopy has performed by a digital USB camera.•The cooling system reduces the noise in the CMOS sensor.•A new and fast method for edge detection algorithm has been introduced.•A new pile-up rejection method has been applied.•The energy resolution improves by pile-up rejection algorithm.
Laser resonance ionization at the RISIKO 30 kV mass separator has been used to produce isotopically and isobarically pure and well quantified 222Rn emanation standards. Based upon laser-spectroscopic ...preparation studies, ion implantation into aluminum and tungsten targets has been carried out, providing overall implantation efficiencies of 40% up to 60%. The absolute implanted activity of 226Ra was determined by the technique of defined solid-angle α-particle spectrometry, where excellent energy resolution was observed. The 222Rn emanation coefficient of the produced targets was studied using α-particle and γ-ray spectrometry, and yielded results between 0.23 and 0.34, with relative uncertainty on the order of 1%. No dependence exceeding a 1% change of the emanation on humidity could be identified in the range of 15 %rH to 75 %rH, whereas there were hints of a slight correlation between the emanation and temperature. Additionally, and as expected, the emanation coefficient was found to be dependent on the target material as well as the implanted dose.
•Laser ionization ion implantation was used to implant 226Ra ions into metallic supports at an implantation energy of 30 keV.•Implantation efficiencies up to 60% were achieved.•The emanation of 222Rn from thus implanted 226Ra was investigated by gamma-ray- and alpha-particle spectrometry.•Emanation coefficients are well reproducible and deviate slightly from theoretical considerations demonstrating a target material dependency.•222Rn emanation from the sources is stable concerning relative humidity, but slightly dependent on temperature.
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•Functional Schottky barrier diodes based on 4H-SiC epitaxial layer were fabricated.•Typical reverse current of measured 4H-SiC diodes was below 3 pA/mm2.•Estimated Schottky barrier ...height was about 1.30 eV at room temperature.•Capacitance-voltage measurements revealed the doping concentration below 8 × 1013 cm−3.•Energy resolution of 20 keV was reached in detection of α-particles from 238Pu source.
Schottky barrier detectors based on a high-quality 4H-SiC epitaxial layer with varied thickness up to 70 μm were studied. The detectors had front-side circular Ni/Au Schottky contacts and a back-side full-area Ti/Pt/Au ohmic contact. Current-voltage characteristics in the reverse and forward directions of prepared detector structures were measured. The typical reverse current of the detector structure was below 50 pA at room temperature. The Schottky barrier height, series resistance and ideality factor were evaluated from the forward part of the current-voltage characteristics, and they were 1.3 eV, 1.33, and 638 Ω, respectively. Capacitance-voltage measurement of the detectors up to 600 Vwas also realized. This provided data to calculate the depletion width, concentration profile and barrier height. The lowest doping concentration of about 7 × 1013 cm−3 was determined. The spectrometric performance of the Schottky barrier detector structures was analyzed using an α-particle radioisotope source. The detector structures demonstrated a high energy resolution below 20 keV in the full width at half maximum for 5.5 MeV α-particles.
A new method for the determination of radium quartet (223,224,226,228Ra) in environmental samples by alpha-particle spectrometry with PIPS detectors is described. This uses 225Ra as yield tracer, in ...equilibrium at the beginning with 229Th. Thorium is removed from the sample by using AG1X8 anion-resin, and then radium isotopes are isolated and purified with a cation-exchange column Biorad AG50X8, verifying that Ac has been fully removed from the sample to ensure the good evaluation of the Ra yield (average decontamination factor > 92%). Finally, the counting source of radium is obtained by micro-precipitation with BaSO4. This method produces high spectral resolution (<35 keV), and quantitative Ra recoveries (>70%). In this new method, NH4Ac in 0.1 M HNO3 is used to remove the 225Ac contained in the sample in order to avoid its future spectral interference in the yield calculation. The method has been validated by using certified reference samples with known concentrations of radium isotopes.
•A new simplest method for radium quartet measurement was evaluated.•225Ra as isotopic tracer was used.•A depth study of 225Ra-225Ac separation was carried out.
Uranium isotopes
238
U,
234
U, and
235
U are alpha-particle emitters and can be directly measured by alpha spectrometry. To evaluate the accuracy of the determination of low concentration of U ...isotopes in water samples, six spiked water samples were analysed by extraction chromatography using uranium selective resin. The separated uranium isotopes were electrodeplated on a disc of stainless steel and were measured by an alpha spectrometer for the determination of radiochemical yield using
232
U isotopic tracer. Three certified IAEA reference water samples (IAEA-Cu-2010-03, IAEA-420 and IAEA-421) have been analysed for method validation. The measurement uncertainty sources were identified, and the combined standard uncertainty of the measurement has been determined. Although the activity of uranium isotopes in the certified reference samples was very low, the obtained results were reliable and were within the certified range with 95% confidence level. The characteristic limits (the decision threshold and detection limit) were calculated. The combined uncertainty of the results was mostly attributed to the count rates in the region of interest of the analyte and the tracer in the blank as well as in the sample spectra. Based on the results of the acceptance criteria including Z-score, u-test, trueness and precision, the used radiochemical procedure was found accurate and precise as well.
A low-cost total dissolution method for accurate determination of uranium and thorium isotopes in environmental samples (soil and sediment) was introduced, optimised and validated. The method ...included alkaline fusion based on sodium hydroxide (NaOH) and sodium peroxide (Na2O2), followed by sequential extraction chromatography separation and measurements with ICP-MS or alpha-particle spectrometry. The overall chemical recoveries for U and Th for the entire procedure were about 80% and 90%, respectively. The 238U contribution from partial dissolution of the nickel crucibles accounted for about 80% of the total background activity.
•Accurate and precise ICP-MS analyses of U and Th isotopes in environmental samples.•Optimised a low-cost total dissolution method based on NaOH and Na2O2 fusion.•Very good reproducibility for analysing 234U and 238U by alpha spectrometry.
In this study it is developed a model for the detailed and automatic study of the alpha-particle spectra coming from detection systems. The fitting of a typical shape of the alpha peak is performed ...by a Gaussian function for the right side of the peak and a sum of two Gaussian functions for its left tail. The model takes into account the entire spectrum background and, particular attention is posed to the analysis of overlapped peaks, background noise and peaks with low statistic counting. The effectiveness of the proposed model is supported by several tests.
•A model for the complete analysis of the alpha-particle spectra is presented.•The peak shape fitting model is based on the convolution of Gaussian functions.•The model provides adequate discrimination of overlapped peaks.•Spectra with background noise and low statistic counts are correctly handled.•Several tests prove the model effectiveness compared to an empirical method.
As known, the detector response function in the detection of alpha particles is characterized by the following distributions: electronic excitation and ionization, electron–hole pair statistics, and ...electronic noise contribution. The distribution due to the ionization–excitation process is of particular relevance, because it is not Gaussian and contributes essentially to the asymmetry of the alpha lines. For this work, we adapted the well-known code SRIM, to obtain and analyze the ionization/excitation distributions for alpha-particles in silicon, in a wide range of energies from 0.5 to 10 MeV. These curves were later well-fitted to a function corresponding to the convolution of a Gaussian with exponentials truncated in the low-energy zone of the distribution. A detailed study about the dependence of all the fitting parameters on energy was performed. The parametrization carried out in this work can also be an useful tool to generate the corresponding ionization–excitation curves required in the task of reproducing real alpha-particle spectra.
•Analysis of I/E distributions for alpha-particles in Si was performed.•I/E distributions well-fitted to the convolution of a Gaussian with two exponentials.•Dependence of the four fitting parameters (σ,τ1,τ2,η) on energy was studied.•Dependence on energy of the maxima displacements was analyzed.•Dependence on energy for the resolution (FWHM) was also evaluated.
•First time a sequential method for Sr-90 and Po-210 was developed.•A low quantification limit was obtained combining lyophilisation and acid leaching.•The method was applied to seafood samples.•The ...method was fully validated through certified reference materials and intercomparison exercise.•Good chemical yields were obtained.
The latest EU Council Regulation 2016/52/Euratom updates the emergency limits on radionuclides in foods including 210Po and 90Sr, two of the most important radionuclides for radiological dose from the ingestion pathway. A novel and straightforward method has been developed for sequential determination of 90Sr and 210Po in food samples using ultra low-level liquid scintillation counting and alpha-particle spectrometry. For 90Sr analysis, the method makes use of stable strontium as yield tracer, and 210Po is determined through self-deposition using 209Po as a yield tracer. The quantification limit for this method is 25.0 and 2.0Bqkg−1 for 90Sr and 210Po, respectively. The proposed radiochemical separation can be completed within 2days for a batch of 12 samples. The radiochemical procedure was validated by its application for the measurement of IAEA certified reference materials, and through participation in a national intercomparison exercise. Results are also presented in seafood from the Mediterranean coast.
In order to compare alpha-particle and gamma-ray spectrometry, the activity concentrations of 235U, 238U and 226Ra in samples of coal, slag and fly-ash from the thermal power plant “Nikola Tesla A”, ...Serbia, were determined by these two methods. Methods were compared and discussed from the point of view of its precision, difficulty to apply and complexity. Gamma-ray spectrometry was performed with HPGe (High Purity Germanium) spectrometer, while alpha activity was measured by PIPS (Passivated Implanted Planar Silicon) detector. For the alpha-particle spectrometry, the chemical procedures applied were chromatographic resin extraction for uranium isotopes and micro-coprecipitation for 226Ra. Thin alpha sources were prepared by electrodeposition and filtration through polypropylene membrane filter for uranium determination, while filtration technique was performed for radium sources. For the evaluation of the statistical difference between individual measurement results obtained by application of two methods Z - test was used. In order to evaluate the difference between two methods used, paired samples t-test and F-test were applied. Results show that there is no statistical difference between two methods used and that gamma-ray spectrometry is a valid alternative to time consuming alpha spectrometry.
•Comparison of alpha-particle and gamma-ray spectrometry was performed.•Sample preparation methods for alpha-particle and gamma-ray spectrometry were described.•Individual results were statistically compared by using Z-test.•Paired samples t-tests and F-test were used to compare these spectrometric methods.
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