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In the present work, the measurement of the 236U(n,f) cross section was performed, with reference to the 238U(n,f) reaction. The measurements took place at the neutron beam facility of the National Centre for Scientific Research "Demokritos" (Greece) and the quasi-monoenergetic neutron beams were produced via the 2H(d,n)3He reaction in the energy range 4–10 MeV. Five actinide targets (two 236U, two 238U and one 235U) and the corresponding Micromegas detectors for the detection of the fission fragments were used. Detailed Monte Carlo simulations were performed, on one hand for the study of the neutron flux and energy distribution at the position of each target, and on the other hand for the study of the energy deposition of the fission fragments in the active volume of the detector. The mass and homogeneity of the actinide targets were experimentally determined via alpha spectroscopy and the Rutherford Backscattering Spectrometry, respectively. The experimental procedure, the analysis, the methodology implemented to correct for the presence of parasitic neutrons and the cross section results will be presented and discussed.

Method for determination of plutonium isotopes in various environmental samples is presented. The separation and purification of plutonium is attained by extraction chromatography with triisooctylamine – polyethylene resin in nitric and hydrochloric acid media. Plutonium is measured by alpha-particle spectrometry after electrodeposition on a stainless steel disk. The analytical quality was checked by analyzing reference materials with different matrices from IAEA (Soil-6, IAEA-375, IAEA-384, IAEA-414) and NPL (AL-2009, AL-2010, AL-2011, AL-2013, AB-2014). The major advantages of the method are the low cost of the analysis, high radiochemical yields and high decontamination factors from the matrix elements, natural and man-made radionuclides.

The applicability of radon (222Rn) measurements to delineate non-aqueous phase liquids (NAPL) contamination in subsoil is discussed at a site with lithological discontinuities through a blind test. Three alpha spectroscopy monitors were used to measure radon in soil air in a 25,000-m2 area, following a regular sampling design with a 20-m2 grid. Repeatability and reproducibility of the results were assessed by means of duplicate measurements in six sampling positions. Furthermore, three points not affected by oil spills were sampled to estimate radon background concentration in soil air. Data histograms, Q-Q plots, variograms, and cluster analysis allowed to recognize two data populations, associated with the possible path of a fault and a lithological discontinuity. Even though the concentration of radon in soil air was dominated by this discontinuity, the characterization of the background emanation in each lithological unit allowed to distinguish areas potentially affected by NAPL, thus justifying the application of radon emanometry as a screening technique for the delineation of NAPL plumes in sites with lithological discontinuities.

The objective of this work was to prepare a novel substrate for the simultaneous concentration of actinides and sample preparation for alpha spectroscopy. Substrate preparation involved forming ultrathin films (10–180 nm) of quaternary amine anion-exchange polymers on glass and silicon by dip-coating. Samples were loaded by submerging the polymer-coated substrates into acidified solutions of 238Pu or natural water with elevated uranium concentrations. High resolution (25–30 keV) alpha spectra were acquired from these substrates under certain loading conditions indicating that through further development they may be a useful, inexpensive, and potentially field deployable platform serving national security and environmental sampling applications.

Samples of uranium contaminated dirt collected from the dirt floor of an abandoned metal rolling mill were analyzed for uranium using a sequential extraction protocol involving a series of five increasingly aggressive solvents. The quantity of uranium extracted from the contaminated dirt by each reagent can aid in predicting the fate and transport of the uranium contamination in the environment. Uranium was separated from each fraction using anion exchange, electrodeposition and analyzed by alpha spectroscopy analysis. Results demonstrate that approximately 77 % of the uranium was extracted using NH4Ac in 25 % acetic acid.

Anion-exchange polymer thin films (~150 nm) were coated onto silicon substrates and utilized for rapid concentration and radioanalytical analyses of actinide complexes (PuCl6 2−, Pu(NO3)6 2−). Batch uptake studies were performed using inductively coupled plasma mass spectrometry, liquid scintillation counting, and alpha spectroscopy. The thin film yielded rapid Pu uptake kinetics and an equilibrium constant (K d) of approximately 9060 L kg−1. The anion-exchange capacity of the films was determined to be 1.3 × 10−4 ± 1.1 × 10−5 eq g−1 using 36Cl uptake studies. Results indicated that the polymer films have great potential for utilization as a substrate for thermal ionization mass spectrometry and alpha spectroscopy.

Actinides can be measured by alpha spectroscopy (AS), mass spectroscopy or accelerator mass spectrometry (AMS). We tested a simple method to separate Pu and Am isotopes from the sample matrix using a single extraction chromatography column. The actinides in the column eluent were then measured by AS or AMS using a fluoride target matrix. Pu and Am were coprecipitated with NdF 3 . The strongest AMS beams of Pu and Am were produced when there was a large excess of fluoride donor atoms in the target and the NdF 3 precipitates were diluted about 6–8 fold with PbF 2 . The measured concentrations of 239,240 Pu and 241 Am agreed with the concentrations in standards of known activity and with two IAEA certified reference materials. Measurements of 239,240 Pu and 241 Am made at A.E. Lalonde AMS Laboratory agree, within their statistical uncertainty, with independent measurements made using the IsoTrace AMS system. This work demonstrated that fluoride targets can produce reliable beams of actinide anions and that the measurement of actinides using fluorides agree with published values in certified reference materials.

This paper describes a new analyte extraction medium called polymer ligand film (PLF) that was developed to rapidly extract radionuclides. PLF is a polymer medium with ligands incorporated in its matrix that selectively and quickly extracts analytes. The main focus of the new technique is to shorten and simplify the procedure for chemically isolating radionuclides for determination through alpha spectroscopy. The PLF system was effective for plutonium and uranium extraction. The PLF was capable of co-extracting or selectively extracting plutonium over uranium depending on the PLF composition. The PLF and electrodeposited samples had similar alpha spectra resolutions.

Different measurements of equilibrium equivalent concentration of radon progeny (EECRn) were obtained over a period of one year in indoor air of Physics Department at Minia University, located in the Upper Egypt. A method based on an alpha spectroscopy was used. Sartorius membrane filters (1.2 μm pore size, 25 mm diameter and its efficiency about 100%) were used as a collection media. Alpha activities were measured during and after air sampling by using surface barrier detector. EECRnvaried between 1.26 and 19 Bq m-3with an average value of 5.2 ± 0.46 Bq m-3. Unattached fraction was determined using a single stainless steel-wire-mesh screen (50% penetration for 4 nm equivalent diameter). A mean unattached fraction (fb) of 0.08 was obtained. Based on the obtained measured data values (fband EECRn), dose conversion factors were compared to epidemiology based value of 4 mSv/WLM for indoor air.

For radiation monitoring at the sites of such nuclear power plant accidents as Fukushima Daiichi, radiation detectors are needed not only for gamma photons but also for alpha and beta particles because some nuclear fission products emit beta particles and gamma photons and some nuclear fuels contain plutonium that emits alpha particles. In some applications, imaging detectors are required to detect the distribution of plutonium particles that emit alpha particles and radiocesium in foods that emits beta particles and gamma photons. To solve these requirements, we developed an imaging detector that can measure the distribution of alpha and beta particles as well as gamma photons. The imaging detector consists of three-layer scintillators optically coupled to each other and to a position sensitive photomultiplier tube (PSPMT). The first layer, which is made of a thin plastic scintillator (decay time: ~5 ns), detects alpha particles. The second layer, which is made of a thin Gd 2 SiO 5 (GSO) scintillator with 1.5 mol% Ce (decay time: 35 ns), detects beta particles. The third layer made of a thin GSO scintillator with 0.4 mol% Ce (decay time: 70 ns) detects gamma photons. Using pulse shape discrimination, the images of these layers can be separated. The position information is calculated by the Anger principle from 8×8 anode signals from the PSPMT. The images for the alpha and beta particles and the gamma photons are individually formed by the pulse shape discriminations for each layer. We detected alpha particle images in the first layer and beta particle images in the second layer. Gamma photon images were detected in the second and third layers. The spatial resolution for the alpha and beta particles was ~1.25 mm FWHM and less than 2 mm FWHM for the gamma photons. We conclude that our developed alpha–beta–gamma imaging detector is promising for imaging applications not only for the environmental monitoring of radionuclides but also for medical and molecular imaging.

The measurement of radon equivalent equilibrium concentration (EECRn) is very simple and quick technique for the estimation of radon progeny level in dwellings or working places. The most typical methods of EECRn measurements are alpha radiometry or alpha spectrometry. In such technique, the influence of alpha particle absorption in filters and filter effectiveness should be taken into account. In the authors' work, it is demonstrated that more precise and less complicated calibration of EECRn-measuring equipment can be conducted by the use of the gamma spectrometer as a reference measuring device. It was demonstrated that for this calibration technique systematic error does not exceed 3 %. The random error of (214)Bi activity measurements is in the range 3-6 %. In general, both these errors can be decreased. The measurements of EECRn by gamma spectrometry and improved alpha radiometry are in good agreement, but the systematic shift between average values can be observed.

This paper describes a new analyte extraction technique using polymer ligand film (PLF). PLFs were synthesized to perform direct sorption of analytes onto its surface for direct counting using alpha spectroscopy. The main focus of the new technique is to shorten and simplify the procedure for chemically isolating radionuclides for determination through a radiometric technique. 4′(5′)-di-t-butylcyclohexano 18-crown-6 (DtBuCH18C6) and 2-ethylhexylphosphonic acid (HEH[EHP]) were examined for plutonium extraction. Di(2-ethyl hexyl) phosphoric acid (HDEHP) were examined for plutonium and uranium extraction. DtBuCH18C6 and HEH[EHP] were not effective in plutonium extraction. HDEHP PLFs were effective for plutonium but not for uranium.

Cameras sensitive to ultraviolet light can be applied to detection of open alpha emitting materials. When absorbed in air, alpha particles generate radioluminescence light, which can be used for detection purposes, provided that background lighting levels are adequately low. In this study, three low-light sensitive camera technologies (CCD, EMCCD and ICCD) were utilized in a nuclear facility, and their performance in detecting alpha emitters was investigated. The results show that low read-out noise is essential for the detection of radioluminescence, as it allows short exposure times to be used. The ICCD was found to perform slightly better than the EMCCD in the field, while both cameras enable the detection of MBqlevel alpha activities in 100 s in the test configuration. Overall, the cameras and techniques used in this study are shown to be effective in detecting alpha emitters in a standard glovebox. This technology can be applied in the field of nuclear security, safety and safeguards, when remote detection of alpha emitters is required., JRC.E.7-Nuclear Safeguards and Forensics

An alpha–gamma coincidence spectrometer has been developed for the measurement of selected actinide isotopes in the presence of high beta/gamma fields. The system is based on a PERALS® liquid scintillation counter for beta/alpha discrimination and was successfully tested with both high purity germanium and bismuth germanate, gamma-ray detectors using conventional analog electronics.

Using calculation and SRIM simulations of alpha particle energy spectroscopy, we show that the initial energies and concentrations of alpha-emitting radioisotopes can be measured in-situ in a liquid environment. We quantify the effect on the alpha spectrum of reducing the thickness of the liquid source in front of the alpha particle detector as well as adding a cover material onto the alpha particle detector surface. In all cases, initial energies and concentrations are recoverable from the alpha particle energy spectra. By reducing the thickness of the liquid source, the contribution to the spectrum for low count rate, low energy radioisotopes can be revealed. However, adding a cover on the detector obscures the contributions of these radioisotopes.

The present study aims to use the α-spectroscopy at Nuclear Materials Authority (NMA) of Egypt. A radiochemical technique for analysis uranium isotopes was carried out for ten mineralized granitic samples together with the International standards RGU-1 (IAEA) and St 4 (NMA). Several steps of sample preparation, radiochemical separation and source preparation were performed before analysis. Uranium was separated from sample matrix with 0.2 M TOPO in cyclohexane as an extracting agent with a chemical yield 98.95% then uranium was purified from lanthanides and actinides present with 0.2 M TOA in xylene as an extracting agent. The pure fraction was electrodeposited on a mirror-polished copper disc from buffer solution (NaHSO 4 +H 2 SO 4 +NH 4 OH). Rectangle pt-electrode with an anode-cathode distance of 2 cm was used. Current was 900 mA and the electrodeposition time reach up to 120 min. The achieved results show that the chemical yield ranged between 87.9±6.8 and 98±8.6.

The medical gamma probe for radionuclide diagnostics based on LaBr3:Ce scintillation crystal and a silicon photomultiplier is described. Spectrometric characteristics of the detector are studied. The energy resolution is measured to be 3.6%at 662 keV and 10% at 140.5 keV. Technical parameters of the developed gamma probe are described. It is shown that it matches the best world analogues in the set of characteristics.

First measurements of natural surface and bulk 210Po specific activities for metals are reported. If covered with protective foils, the surfaces did not show indications of 210Po and the obtained upper limits are in the range of single mBqm-2. Weak bulk activities, in the range of 50 - 280mBqkg-1, were registered for Stainless Steel and Copper, while significant amounts of 210Po, ∼1.5Bqkg-1, were detected in Titanium. One special Teflon sample was investigated with respect to its bulk 210Po.

In 2012, D. K. Wehe and coauthors proposed a method of light yield amplification in scintillation detectors. A trivalent activator ion RE 3+ captures an electron produced by an incident particle in a scintillator and becomes a divalent rare earth ion RE 2+ . The scintillator is illuminated by laser photons that excite RE 2+ ions, which quickly de-excite and generate light photons. By cyclically excitation RE 2+ ions, one can obtain many light photons during any chosen accumulation time. Authors suggested that this method could remove the scintillation yield as a limiting factor of the energy resolution of scintillation detectors. This conclusion was based on the rather simplified theoretical examination of the pulse formation process in an amplified scintillator. In this work, the theory of branching cascade processes was applied to the description of the pulse formation process. The formulae for the energy resolution of an amplified scintillation detector and an ordinary scintillation detector were derived. From these formulae, it follows that the relative reduction in the energy resolution of the amplified scintillation detector with reference to the ordinary scintillation detector is less than a few percent.

Mixed fission and activation materials resulting from various nuclear processes and events contain a wide range of isotopes for analysis spanning almost the entire periodic table. This work describes the production of a complex synthetic sample containing fission products, activation products, and irradiated soil, and determines the percent chemical recovery of select isotopes through the integrated chemical separation scheme. Based on the results of this experiment, a complex synthetic sample can be prepared with low atom/fission ratios and isotopes of interest accurately and precisely measured following an integrated chemical separation method.

The decay time profile of vacuum ultraviolet scintillation induced by electronic recoils has been studied for liquid and gaseous xenon. The scintillation light from xenon excited by a gamma source was measured by using two vacuum ultraviolet sensitive photomultipliers, one for detecting scintillation and the other for counting photons of weak monochromatic light. The analysis results based on the time-correlated single photon counting method show that the time profile in the 176 nm scintillation decay curve for liquid xenon is consistent with a single exponential component and the decay time constant is 31.5±1.3 ns. This constant does not change significantly for pressure ranges between 90 kPa and 130 kPa. There is no emission wavelength dependence of the decay constant. The result corresponds to an average on electronic recoil energies up to 1.3 MeV.

Nuclear decay data measurements were performed in the frame of a EURAMET project. Two specific goals were addressed: (1) High-precision measurements of 238U alpha-particle emission probabilities and (2) experimental characterization of the shape of beta spectra using cryogenic detectors. In the paper, specific lessons learned from the metrological work are highlighted. This includes effects of source preparation on the quality of alpha and beta spectrometry, the influence of exchange effects on beta spectra and the use of a magnet system to eliminate coincidence effects by conversion electrons in alpha-particle spectra., JRC.D.4-Standards for Nuclear Safety, Security and Safeguards

Energy spectra of 210 Po were achieved by means of theoretical and experimental methods. The spectrometer which was consisted of a BC400 type plastic scintillation detector was used to obtain experimental energy spectrum of the alpha source. The theoretical alpha energy spectrum was also achieved by using FLUKA Monte Carlo (MC) program. The energy resolution values of both spectra were calculated. The performances of the methods were compared with

Radiochemical separation of americium, neptunium and plutonium was tested on model solution of evaporator concentrate sample for isolation of each of them for alpha-spectrometry analysis. A good chemical separation of radionuclides of interest from the matrix and interfering radionuclides is required, once the relatively small difference in alpha-particle energy makes it difficult to spectrometrically separate the peaks. This paper describes use of the molecular recognition technology product AnaLig®Pu-01 gel from IBC Advanced Technologies, Inc. to effectively and selectively pre-concentrate, separate and recover americium, neptunium and plutonium from model solution of evaporator concentrate samples from Nuclear Power Plant which belong to the most difficult matrices to analyse. The method is suitable for analysing highly contaminated samples of radioactive waste in a relatively short time. For counting the alpha activity of 241Am, 239,240Pu, 238Pu and 237Np ORTEC 576A alpha-spectrometer equipped with ULTRATM ion implanted silicon detectors (600 mm2 active area) was used. The spectra were processed by using the Alpha-visionTM 32-bit emulation software from the EG&G ORTEC company.

The purpose of this work was to determine polonium losses from a variety of sample types (soil, cotton fiber, and air filter) due to digestion technique, chemical separation, and deposition method for alpha energy analysis. Results demonstrated that yields from a perchloric acid wet-ash (87 ± 5 %) were similar to that from a microwave digestion (100 ± 7 %), but both were greater than the dry-ash procedure (38 ± 5 %). The polonium was separated from an SRM soil using an AG1X8 ion exchange column and deposited on a Ag disk with a recovery of 83 ± 7 % of polonium-209 (Po-209). Deposition yields without chemical separation averaged 90 ± 5 % of Po-209. The polonium-210 content was successfully measured in the three matrix types and quantitated using alpha spectroscopy.

We present a detailed report on the fabrication process of a metallic magnetic calorimeter (MMC). The MMC is configured in a planar geometry with a meander-shaped pickup coil covered with a Au:Er temperature sensor layer. The meander coil is used to apply a magnetic field to magnetize the erbium ions and to measure the magnetization change of the spin system. The MMC is designed to have a large area (1 mm\(^2\)) and 3 \(\upmu \)m thickness Au:Er layer, which is suited for large metal absorbers with a few nJ/K heat capacity in radionuclide analysis applications. The completed devices are used in alpha and Q spectrometries.

Using amorphous Carbon blended with Nickel (C/Ni) as electrodes for a polycrystalline diamond radiation detector (PC-C/Ni) was demonstrated previously as a novel technique to produce near-tissue equivalent X-ray dosimeters. In this project, we introduce the first characterisation of a (Chemical Vapour Deposited) single crystal diamond sandwich detector (with thickness of 0.4 mm) fabricated with this technique, labelled SC-C/Ni. To examine the performance of pulsed laser deposition (PLD) C/Ni as an electrode, alpha spectroscopy measurements and X-ray induced photocurrent measurements were studied as a function of the applied bias at room temperature and compared with those of the aforementioned PC-C/Ni. The alpha particle spectroscopy measurement data allows us to differentiate between electron and hole contributions to the charge transport signal, whilst the X-ray data was investigated in terms of dose rate-linearity, sensitivity, signal to noise ratio (SNR) and photoconductive gain. In the case of electron sensitive alpha induced signals, a Charge Collection Efficiency (CCE) higher than 90% has been observed at a bias of -40 V and 100% CCE at -300 V, with energy resolution of ∼3% for 5.48 MeV alpha particles. The sample showed very poor spectroscopy performance for hole sensitive signals up to 200 V. The X-ray induced photocurrents show a high SNR of ∼7.3 × 10³, an approximately linear relationship between the photocurrent versus dose rate and a sensitivity of 4.87 μC/Gy.mm³. The photoconductive gain of SC-C/Ni is calculated to be ∼20, this gain calculation might be explained by trapping effects as investigated in the alpha spectroscopy measurements.

In this project the steps taken toward the characterization, calibration and testing of two spectroscopy stations are presented. The first one is suitable for alpha spectroscopy, consisting of a large-window silicon surface barrier detector (SSB), a goniometric arm and a movable multiple source-holder inside a dark vacuum chamber. The second station contains two small-size, thin-window NaI(Tl) scintillators, and it is suitable for low-γ ray spectroscopy.

There have been developed several different methods for measuring radon concentration in water which are now widely used, such as: liquid scintillation counting, Lucas cell counting, gamma and alpha spectroscopy. However, as far as the radon measurements in carbonated water are concerned, there are some issues caused by the gas excess. The aim of our work was to develop a simple method for measuring radon concentration in carbonated water that can be used for in situ measurements. Nevertheless, we propose not one, but two methods for measuring radon concentration in carbonated water. Thus, the first one is based on Lucas scintillation cells, and can be used for on-site measurements, while the second one utilizes activated charcoal adsorption, and needs a setup laboratory for gamma spectrometry measurements. For the evaluation of the methods, we compared the results of the Lucas cell-Luk3C method and of the activated charcoal method, both for non-carbonated and carbonated water. The simplest method for radon concentration determination—Lucas cell method—was successfully applied to fourteen natural carbonated water samples from Borsec to Bilbor area. The radon concentrations obtained ranged from 5.6 ± 0.5 to 39.6 ± 4.0 Bq/L, with a mean of 15.9 ± 2.6 Bq/L, these values are lower than 100 Bq/L, the maximum value recommended by the World Health Organization.

Results of alpha spectrometric measurements performed deep underground and above ground with and without active veto show that the underground measurement of thick samples is the most sensitive method due to significant reduction of the muon-induced background. In addition, the polonium diffusion requires for some samples an appropriate selection of an energy region in the registered spectrum. On the basis of computer simulations the best counting conditions are selected for a thick lead sample in order to optimize the detection limit.

Uranium and plutonium were determined in the Tehua II-21 sediment core collected from the Gulf of Tehuantepec, Mexico. The analyses were performed using radiochemical separation and alpha spectroscopy. Activity concentrations of alpha emitters in the sediment samples were from 2.56 to 43.1 Bq/kg for 238U, from 3.15 to 43.1 Bq/kg for 234U and from 0.69 to 2.95 Bq/Kg for 239+240Pu. Uranium activity concentration in marine sediment studied is generally high compared with those found in sediments from other marine coastal areas in the world. The presence of relatively high concentrations of anthropogenic plutonium in the sediments from the Gulf of Tehuantepec suggests that anthropogenic radionuclides have been incorporated and dispersed into the global marine environment.

Liquid krypton has been used widely for electromagnetic calorimeters for charged particle and gamma ray detection above 100 MeV. Despite the significant price advantage of krypton over xenon, little work has been done with liquid krypton detectors for energies in the range 200 keV-12 MeV that is useful for applications involving neutron-induced gamma ray spectral analysis for isotope identification in elemental analysis. The presence of β decays arising from 85Kr (10.76-year half-life) combined with the 80 ns decay time of the dominant component of krypton scintillation light generates pile-up and reduces the photopeak efficiency of liquid Kr detectors. We discuss detector performance expected after careful optimization of the detector dimensions and doping the Kr with Xe to improve its scintillation light decay time characteristics.

The total reaction energy (Q) of individual nuclear decays was measured using microcalorimeters with transition-edge-sensor (TES) thermometers. For alpha-decaying actinides (e.g., U-235, Pu-239, Np-237, Am-241), Q is in the 4-6 MeV range. Nearly all of this energy goes into the relatively light alpha particle, and approximately 100 keV is left over for the much heavier, recoiling daughter atom. Alpha-particle energy spectroscopy with TES-microcalorimeters has shown the ability to simultaneously resolve peaks that overlap in conventional alpha spectroscopy, with resolution now less than 1 keV full-width-at-half-maximum (FWHM) at 5.3 MeV. For total reaction energy spectroscopy, we use the same TES design as our alpha detectors, but embed a small radioactive sample (of about 1 Bq) directly inside an absorber designed to capture all the emitted particles (alpha, recoil nucleus, electrons, X-rays) with near 100% efficiency. We have measured Q-spectra of alpha-decaying isotopes with spectral resolution of 2-3 keV FWHM. For some actinide analytical problems, the Q -spectrum is simpler than the alpha-spectrum: fewer peaks, further apart, and easier to quantify. We will discuss sensor design, methods for embedding radionuclides, and spectral data.

Solid State Nuclear Track Detectors (SSNTDs), CR-39™ type, are usually adopted in many applications in which it could be necessary to select tracks according to the incident alpha-particle energy; so several authors have argued that track parameters such as the major/minor axis being the most often reported, can be used to determine the alpha-particle’s energy. However, the use of these parameters only do an univocal result, for example the same axis length can be obtained for different combinations of incident angles and energies. We report on a track analysis performed by a semiautomatic system that classifies tracks according to two parameters, diameter length and mean grey level. This kind of analysis can give information about the track depth, that increases monotonically with the incident energy and angle of the alpha particle. Combining the information on the two parameters it is possible to determine univocally the incident alpha-particle energy values. In order to characterize CR-39 detectors according to the physical track parameters, detectors were irradiated, inside a vacuum chamber, by alpha particles at thirteen energy values, obtained by different mylar layers in front of a 241Am source. After the exposure the detectors were chemically etched to enlarge the tracks and then analyzed by means of a semiautomatic system, consisting on an optical microscope equipped with a CCD camera connected to a personal computer for image storage. A suitable routine analyzed the track parameters: diameter and mean grey level, allowing us to differentiate tracks according to the incident alpha-particle energy and then to individuate the discrimination factors for radon alpha tracks, when nuclear track detectors are applied in radon surveys.

A fluorescence-based alpha-gamma coincidence spectrometry approach has been developed for the analysis of alpha-emitting radionuclides. The thermalization of alpha particles in air produces UV light, which in turn can be detected over long distances. The simultaneous detection of UV and gamma photons allows detailed gamma analyses of a single spot of interest even in highly active surroundings. Alpha particles can also be detected indirectly from samples inside sealed plastic bags, which minimizes the risk of cross-contamination. The position-sensitive alpha-UV-gamma coincidence technique reveals the presence of alpha emitters and identifies the nuclides ten times faster than conventional gamma spectrometry.

A low budget radon monitor has been developed using silicon PIN diode. Sensitivity factor of this monitor is observed to be relatively high over the other similar monitors. This is achieved by incorporation of a hemispherical mesh in the sampling chamber, thereby accelerating the electro-deposition of charged polonium atoms on the detector surface. Its performance has been tested successfully against reference equipment.

Experiments in physics, Astro-particle physics and cosmology that require careful shielding against cosmic rays include dark matter searches, studies of radioactive decays, and neutrino detection experiments. The need for such shielding has motivated the construction of laboratory caverns in mines and adjacent to tunnels under mountains. There are currently about a dozen such laboratories, in existence or under construction, all in the Northern Hemisphere. A motivation has been made for the establishment of a Southern Hemisphere facility. In this paper a feasibility study of measurements of radon in air (using electret ion chambers and alpha spectroscopy), background gamma ray measurements (inside/outside) the tunnel using scintillator (inorganic) detectors, cosmic ray measurements using organic scintillators and radiometric analyses of representative rock samples for the establishment of such a facility in the South Africa is presented.

Alpha spectra were acquired with Quantulus 1220 liquid Scintillation Counter (LSC) and correlations among parameters, such as alpha particle energy, sample quenching, peak's centroid and resolution were established. The effect of quenching and factors such as types of counting vials, extractive reagents and composition of extractive scintillation cocktail on alpha spectral resolution, was experimentally studied.

In order to investigate the interaction between radon progeny and particles, an experimental campaign was carried out in a radon chamber at the Italian National Institute of Ionizing Radiation Metrology, quantifying the amount of attached and unattached radon daughters present in air, as well as the equilibrium factor in the presence of particles generated through indoor sources. A fixed radon concentration was maintained, while particles were generated using incense sticks, mosquito coils and gas combustion. Aerosols were characterized in terms of particle concentrations and size distributions. Simultaneously, radon concentration and attached/unattached potential alpha energy concentration in the air were continuously monitored by two different devices, based on alpha spectroscopy techniques. The presence of particles was found to affect the attached fraction of radon decay products, in such a way that the particles acted as a sink for radionuclides. In terms of sources which emit large particles (e.g. incense, mosquito coils), which greatly increase particle surface area concentrations, the Equilibrium Factor was found to double with respect to the background level before particle generation sessions. On the contrary, the radon decay product dynamics were not influenced by gas combustion processes, mainly due to the small surface area of the particles emitted. © 2016 Elsevier B.V.

A method was developed to produce a thin Polymer Ligand Film (PLF) using di(2-ethylhexyl) orthophosphoric acid (HDEHP) ligand for rapid extraction of plutonium. Ligands were incorporated into a polystyrene matrix to generate a smooth and durable surface for analyte extraction. PLFs were prepared with varying amount of ligands to find the optimimum ratio between the ligands and polymer structure to give best plutonium recovery. Also, the plutonium extraction is dependent on the concentration of nitric solution. This dependency was examined in the manuscript. The PLF samples were counted directly using alpha spectroscopy without any further chemical process to test the plutonium recovery. The alpha spectroscopy data shows that HDEHP based PLFs were effective in extracting plutonium from nitric acid solution. The surface characterization was performed with a scanning electron microscope (SEM) and digital autoradiography for defect examination of the PLF and plutonium distribution study, respectively.

Alternative method for determination of uranium isotopes in various environmental samples is presented. The method is based on total decomposition of the solid materials and preconcentration of liquid samples. The separation of uranium from interfering radionuclides and stable matrix elements is attained by liquid–liquid extraction with triisooctylamine/xylene in hydrochloric media. After the additional removal of stable iron by extraction with diisopropyl ether, purified uranium is electrodeposited on stainless steel disks and measured by alpha spectrometry. The analytical method has been successfully applied to the determination of uranium isotopes in water and bottom sediments from the rivers Danube, Ogosta and Tzibritza in Northwestern Bulgaria. The analytical quality was checked by analyzing reference materials with different matrices.

A rapid separation method has been developed which allows measurement of plutonium, americium and strontium isotopes in the high active sample from CBRN Training and Testing Centre in Zemianske Kostolany (Slovakia) with high chemical recoveries and effective removal of matrix interferences. This method uses different commercial products stacked AnaLig® Pu-02, AnaLig® Sr-01 and DGA® Resin cartridges from IBC Advanced Technologies and Eichrom Technologies. The method allows rapid separation of plutonium, strontium and americium using a single multi-stage column in the vacuum box (cartridge technology) with rapid flow rates to minimize sample separation time. The 239,240Pu, 238Pu and 241Am were determined by alpha spectroscopy, 90Sr was counted on TRICARB 2900 TR by Cerenkov counting of its progeny 90Y.

Uranium-233 (t 1/2 ~ 1.59E5 years) is an artificial, fissile isotope of uranium that has significant importance in nuclear forensics. The isotope provides a unique signature in determining the origin and provenance of uranium-bearing materials and is valuable as a mass spectrometric tracer. Alpha spectrometry was employed in the critical evaluation of a 233U standard reference material (SRM-995) as a dual tracer system based on the in-growth of 229Th (t 1/2 ~ 7.34E3 years) for ~35 years following radiochemical purification. Preliminary investigations focused on the isotopic analysis of standards and unmodified fractions of SRM-995; all samples were separated and purified using a multi-column anion-exchange scheme. The 229Th/233U atom ratio for SRM-995 was found to be 1.598E−4 (±4.50 %) using recovery-corrected radiochemical methods. Using the Bateman equations and relevant half-lives, this ratio reflects a material that was purified ~36.8 years prior to this analysis. The calculated age is discussed in contrast with both the date of certification and the recorded date of last purification.

In this article, the scintillation properties of 3-( p -toluidino)-5-phenyl-1- p -tolyl-1H-pyrrol-2(5H)-one as a Lactam is studied. m-xylene, cyclohexan, and ethanol are used as solutions, whilst, Anteracene and Naphthalene are used as secondary solvents. The influence of solvent on the scintillation efficiency is studied. The results show that the proposed material can be used as an organic scintillator but its efficiency for gamma spectroscopy is relatively low (∼5% of NE213 of similar size).

In the current work, alpha particle spectroscopy is investigated experimentally by utilizing the over-etched track lengths in the CR-39 detector. CR-39 samples were exposed perpendicularly to alpha particles emitted from 241Am with an energy ranging from 0.5 to 5.5 MeV. CR-39 samples were etched in 6.25 N NaOH at (70±0.5)°C for different durations. The track diameter and track length were measured under an optical microscope. The results show that, the energy-over-etched track length calibration curve is monotonic, in other words, the over-etched track length is a monotonic function in alpha particle energy. On the other hand, the energy-diameter calibration curve is degenerated, i.e. alpha track diameter is non-monotonic function in alpha particle energy. These results suggest that the CR-39 detector could be used as a wide range alpha particles spectrometer using an energy-over-etched track length calibration curve.

This paper describes new approaches to digestion, accurate separation and determination of americium in soil samples by alpha spectrometry. The soil samples were obtained from surface and at a depth of 40 cm in a residential area. They were digested on a hot plate or in closed vessels heated in a microwave oven. The effect of decomposition methods on accuracy and reproducibility has been investigated. An extraction chromatography column is used to separate the americium from other actinide elements and interfering substances in the soil matrix. Prior to the determination of very low amounts of americium (100 ng g−1), electrodeposition at a current of 800 mA and a plating time of 150 min in the pH range of 2–3 has been applied. The typical recovery of Am from the samples is 88 % when dissolution occurs in a microwave oven. This is higher than the typical recovery of 83 % that is observed when the samples are heated on a hot plate.

²²²Rn (radon) and ²²⁰Rn (thoron) progeny are known to interfere with determining the presence of long-lived transuranic radionuclides, such as plutonium and americium, and require from several hours up to several days for conclusive results. Methods are proposed that should expedite the analysis of air samples for determining the amount of transuranic radionuclides present using low-resolution alpha spectroscopy systems available from typical alpha continuous air monitors (CAMs) with multi-channel analyzer (MCA) capabilities. An alpha spectra simulation program was developed in Microsoft Excel visual basic that employed the use of Monte Carlo numerical methods and serial-decay differential equations that resembled actual spectra. Transuranic radionuclides were able to be quantified with statistical certainty by applying peak fitting equations using the method of least squares. Initial favorable results were achieved when samples containing radon progeny were decayed 15 to 30 min, and samples containing both radon and thoron progeny were decayed at least 60 min. The effort indicates that timely decisions can be made when determining transuranic activity using available alpha CAMs with alpha spectroscopy capabilities for counting retrospective air samples if accompanied by analyses that consider the characteristics of serial decay.

The main aim of this work was the preparation of samples with thorium content on the steel discs by electrodeposition for determination of natural thorium isotope by alpha spectrometry and secondary ion mass spectrometry and finding out their possible linear correlation between these methods. The analysis of the composition of surface was other aim of study. Discs were measured by alpha spectrometer. After that, alpha spectrometry discs were analyzed by TOF-SIMS IV, which is installed in the International Laser Centre in Bratislava. The integral and normalized intensities of isotope of 232Th and intensities of ions of ThO+, ThOH+, ThO2H+, Th2O4H+, ThO2 −, ThO3H−, ThH3O3 − a ThN2O5H− were measured. The linear correlation is between surface’s weights of Th and intensities of ions of Th+ from identified in SIMS spectra. We found out the chemical binding between thorium and oxygen and hydrogen on the surface of samples by SIMS method. Obtained intensities of ions 232ThO+, 232ThOH+, 232ThO2H+ prove the presence of oxidized forms of thorium in the upper layers of surface. The oxidized ions predominate in univalent form of thorium up to deep about 3,000 nm.