Application of particle induced gamma-ray emission for non-destructive determination of fluorine in barium borosilicate glass samples

Barium borosilicate glass (BaBSG) is proposed as a potential candidate for vitrification of nuclear waste generated from thoria based nuclear reactors. Along with fission products, activation products and many inactive chemicals, like fluorine in the form of HF are expected to be present in the dissolver solution with nuclear waste. As vitrification occurs at high temperature, it is important to quantify fluorine in BaBSG. Due to its complex matrix, most of the wet chemical and nuclear analytical methods encounter problems in the estimation of fluorine. Particle induced γ-ray emission (PIGE) method has been standardized for non-destructive determination of fluorine contents in BaBSG samples utilizing measurement of prompt gamma-rays from ¹⁹F (p, p’γ) ¹⁹F reaction. Experiments have been carried out with thick pellet targets prepared in cellulose matrix using 4 MeV proton beam from the folded tandem ion accelerator at BARC, Mumbai. For obtaining current normalized count rate of interest, beam current variation was monitored by the Rutherford backscattering spectrometry (RBS) method as well as by the in situ approach using an externally added element sensitive to PIGE. In this paper standardization of PIGE methods for F determination, validation of methods using synthetic samples, and application to BaBSG samples are reported.     

Determination of the elemental distribution in a sample using neutron induced gamma-ray emission tomography

The factors that affect accurate, quantitative results to be obtained by neutron induced gamma-ray emission tomography are stated. The technique, which is a combination of neutron activation analysis with computerised gamma-ray emission tomography, would be enhanced by the use of multiple detector assemblies, in geometrical configurations, which simultaneously record the gamma-rays emitted and improve detection efficiency. Developments in the past few years in positron emission tomography (PET) where scanners made of single scintillation block detectors, cut into smaller segments, to form individual crystal detector elements and packed in ring around the radioactive object, are discussed. The coincident detection efficiency for annihilation photons and cascade gamma-rays for such systems are considered and the possibilities of carrying out NIGET with coincident gamma-ray tomography are explored whilst indicating some of the limitations. This is an area which requires further, intense investigation and has an impact on a wide range of applications, particularly in the biomedical field.     

Determination of total fluorine in five coal reference materials by proton-induced gamma-ray emission spectrometry

The direct non-destructive proton-induced gamma-ray emission (PIGE) technique with a germanium detector was applied to the determination of total fluorine concentration in five coal reference materials (BCR 40, NIST 1632b, NIST 1635, SARM 20 and USGS CLB-1). Duplicate analyses were made from five randomly selected bottles of each coal. Individual data are presented and some problems (calibration, proton stopping power, effects of sample heating by the proton beam, background estimation) which were encountered during this study are discussed. Sensitivity and reproducibility of the determinations, and homogeneity of the coal samples with respect to fluorine contents by analysis of variance were investigated. The present data are also compared with the few published values for these reference samples, including other PIGE data. The use of synthetic standards and spiked samples in the present study suggested that the PIGE method was more accurate than other techniques.     

Radium determination in soil samples using a gamma-ray coincidence spectrometer

A technique for the assay of radium by detection of coincident γ-radiation is evaluated. The sensitivity of various counting modalities is compared. The influence of finite sample size and density is discussed. Interference from other natural radioactivities is investigated and it is shown that a two channel arrangement is sufficient to take this into account.     

Determination of fluorine in geological samples using accelerator derived neutrons

A fast, neutron activation analysis technique is described for the determination of fluorine in geological samples. The method utilises the reaction¹⁹F(n,α)¹⁶N for the determination. However, it avoids the interference reaction from oxygen which produces the same radionuclide since the neutrons are derived from the bombardment of beryllium with 3 MeV deuterons. The maximum energy of the neutrons so produced is well below the threshold for the competing oxygen reaction. The results indicate that the method gives acceptable accuracy over the range of a few tens ppm to several percent fluorine content using suitable standards. Sample analysis time is only a few minutes allowing the analyses of large numbers of samples per day.     

Determination of thorium concentrations in soil and sand samples using instrumental neutron activation analysis

Thorium along with its daughter products present in the soil is one of the major contributors to the external gamma dose in the environment. To establish the dose levels, quantification of thorium contents in soil samples is very important. As a part of pre-operational environmental radiological surveillance, a total of 23 soil and six sand samples were collected from different locations around the proposed nuclear power plant site of Jaitapur, Maharashtra. Thorium concentrations in these samples were determined by instrumental neutron activation analysis (INAA). Samples were irradiated with neutrons in Apsara reactor at a neutron flux of?~5?×?10¹¹ cm^?2 s^?1 and radioactive assay was carried out using high resolution gamma ray spectrometry. Relative method of INAA was used for quantification of thorium utilizing 311.9?keV gamma ray of ²³³Pa, the daughter product of ²³³Th. The concentrations of thorium in the soil and sand samples were in the ranges of 4.0?C18.8 and 1.2?C6.2?mg?kg^?1 respectively.     

Determination of primordial radionuclide concentrations in UAE groundwater using high-resolution gamma-ray spectrometry

Journal of Radioanalytical and Nuclear Chemistry - Groundwater is the most valuable resource in arid regions, such as UAE. Estimations of natural radionuclide concentrations are important to...     

Analytical use of alpha-source induced gamma-ray emission

Summary A non-destructive multi-element method based on nuclear reactions and Coulomb excitation induced by alpha-sources and the measurement of prompt gamma-rays is described. The method is suitable for light and medium Z elements and is particularly sensitive to light elements. The experimental set-up necessary for the prompt measurements is quite simple. With 0.34 mCi ²⁴¹Am source, the sensitivity of the method is discussed for the light elements Li, Be, F and Na. The influence of sample size, air pressure etc. on the thick target yield has been investigated. Monte-Carlo calculations have been performed to study the modification of the isotropic behaviour of the alpha-source due to the protective covering and to calculate the average energy loss. The lithium determination in some minerals has been carried out.

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Analytische Anwendung der -induziertcn -Emission

Zusammenfassung Eine zerstörungsfreie Multielement-methode, die auf Kernreaktionen und Coulombanregung induziert durch -Quellen beruht, sowie die Messung prompter -Strahlung werden beschrieben. Die Methode eignet sich für leichte und mittelschwere Elemente und ist besonders empfindlich bei leichten Elementen. Der für Promptmessungen notwendige experimentelle Aufbau ist recht einfach. Die Empfindlichkeit der Methode bei Benutzung eines 0,34 mCi starken ²⁴¹Am-Präparats wird für die leichten Elemente Li, Be, F und Na diskutiert. Der Einfluß von Probengröße, Luftdruck usw. auf die Ausbeute eines dicken Targets wurde untersucht. Monte-Carlo-Rechnungen wurden ausgeführt, um die Modifizierung der isotropen Abstrahlung der Quelle durch deren Schutzabdeckung zu studieren und um den mittleren Energieverlust zu erhalten. Eine Li-Bestimmung in einigen Mineralen wurde durchgeführt.

     

Chemical speciation of chlorine in atmospheric aerosol samples by high-resolution proton induced X-ray emission spectroscopy

Chlorine is a main elemental component of atmospheric particulate matter (APM). The knowledge of the chemical form of chlorine is of primary importance for source apportionment and for estimation of health effects of APM. In this work the applicability of high-resolution wavelength dispersive proton induced X-ray emission (PIXE) spectroscopy for chemical speciation of chlorine in fine fraction atmospheric aerosols is studied. A Johansson-type crystal spectrometer with energy resolution below the natural linewidth of Cl K lines was used to record the high-resolution Kα and Kβ proton induced spectra of several reference Cl compounds and two atmospheric aerosol samples, which were collected for conventional PIXE analysis. The Kα spectra which refers to the oxidation state, showed very minor differences due to the high electronegativity of Cl. However, the Kβ spectra exhibited pronounced chemical effects which were significant enough to perform chemical speciation. The major chlorine component in two fine fraction aerosol samples collected during a 2010 winter campaign in Budapest was clearly identified as NaCl by comparing the high-resolution Cl Kβ spectra from the aerosol samples with the corresponding reference spectra. This work demonstrates the feasibility of high-resolution PIXE method for chemical speciation of Cl in aerosols.     

The distribution of fluorine and other elements in teeth using proton induced reaction analysis techniques

Proton induced gamma-ray emission (PIGE) and proton induced X-ray emission (PIXE) analysis was employed to investigate the distribution of the concentration of fluorine and ten other elements along sections of teeth samples, extracted from eight individuals. These sections which included the bulk of dentine and enamel were scanned using a proton beam of 250 m diameter. Rutberford backscattering spectra were also collected in order to obtain information about the concentration of major elements and to correct for matrix inhomogeneities.     

Determination of radiostrontium in soil samples using a crown ether

A simple and rapid method has been developed for the separation and determination of total radiostrontium in soil. The method consists of three basic steps: oxalate precipitation to remove bulk potassium, chromatographic separation of strontium from most inactive and radioactive interferences utilizing a crown ether (Sr. Spec, EIChroM Industries, Il. USA) and oxalate precipitation of strontium to evaluate the chemical yield. Radiostrontium is then determined by liquid scintillation counting of the dissolved precipitate. When 10 g samples of soil are used, the sensitivity of the method is about 10 Bq/kg. The chemical yield is about 80%. The separation and determination of radiostrontium can be carried out in about 8 hours.     

Application of proton induced X-ray emission to the qualitative and quantitative analysis of iodine in biological samples

Particle-induced X-ray emission (PIXE) was applied to evaluate the loss of volatile elements such as iodine in biological samples. The analytical quality of the method is comparable or better than spectrophotometry, which is currently believed to be the most reliable for iodine determination. The temperature dependence of volatility loss of trace iodine was characteristic, and the feature was divided into three temperature regions. The first one, ranging from room temperature to 200 °C, showed only a slight loss below 20% on drying; the second stage, between 200 °C and 350 °C, where carbonizing processes became prominent, showed a remarkable loss up to 50%; the last one, beyond 350 °C, was accompanied by a considerable loss of iodine (more than 80%) with ashing. Even in the analysis using low temperature ashing with oxygen plasma, the loss of iodine observed was considerable (nearly 80%). The significance of these findings by PIXE in trace analysis is noted to improve analytical quality of volatile elements, such as iodine in biological, medical and also environmental fields.     

Elemental concentrations in geochemical reference samples by neutron capture prompt gamma-ray spectroscopy

A facility for neutron capture prompt gamma-ray activation analysis, installed on a curved thermal neutron guide at the ILL High Flux Reactor, is described. Elemental sensitivities for B, Sm and Gd have been measured. The performance of the facility has been assessed by the measurement of these trace elements in eleven USGS geochemical reference samples and comparison of the results with existing values. Preliminary concentrations of B, Sm and Gd are also reported for twelve French GRS.     

Determination of hydrogen in rock samples by neutron-induced prompt gamma-ray analysis

Prompt gamma-ray analysis was applied to determine hydrogen in geological samples. In order to obtain accurate values, blank values were estimated and subtracted. Samples were dried to constant weight in an oven. Helium gas was introduced into the sample box to purge the air containing moisture during the measurement. Hydrogen contents in some geochemical standard samples were determined and highly reproducible values were obtained.     

Determination of nitrogen and fluorine in air-dust samples by photon activation

Summary Air-dust samples with masses of 12 mg each were analysed instrumentally for their nitrogen and fluorine content by photon activation. The samples were irradiated with photons of maximum energy,E _max=15MeV. The nuclear reactions¹⁴N(, n)¹³N and¹⁹F(, n)¹⁸F give two positron emitters. The positrons react with electrons, emitting annihilation radiation. The 511-keV peak of the annihilation radiation of¹³N and¹⁸F is measured simultaneously and the decay curve is taken. The half-lives of 9.96 and 109.7 min allow a quantitative separation. By choosingE _max=15 MeV for the activation we eliminate interference from carbon and oxygen. The activation threshold for the n,-reaction of carbon is 18.72 MeV and for oxygen 15.67 MeV, while the activation threshold for N is 10.55 MeV and for F 10.44 MeV. The detection limit for the instrumental method is 4g for both nitrogen and fluorine.

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Die Analyse von Stickstoff und fluor in Luftstaubproben durch Photonenaktivierung

Zusammenfassung An Luftstaubproben von 12 mg Masse konnte der Gehalt an Stickstoff und Fluor durch Photonenaktivierung zerstörungsfrei bestimmt werden. Die Proben wurden mit Photonen einer Energie von E_max=15 MeV bestrahlt. Die 511-keV-Linie der nach¹⁴N (, n)¹³N und¹⁹F (, n)¹⁸F entstandenen Nuklide wurde simultan gemessen und die Zerfallskurve aufgenommen. Die Halbwertszeiten 9,96 und 109,7 min liegen so weit auseinander, daß eine quantitative Trennung möglich ist. Durch Wahl der Aktivierungsenergie treten keine Störungen durch Sauerstoff und Kohlenstoff auf, da die Aktivierungsschwellen für die, n-Reaktionen von C bei 18,72 MeV und von O bei 15,67 liegen, während sie für N bei 10,55 MeV und für F bei 10,44 MeV liegen. Die Nachweisgrenzen liegen beim zerstörungsfreien Verfahren bei 4g für N und für F.

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Presented at the 8th International Microchemical Symposium, Graz, August 25–30, 1980.     

Simultaneous determination of low Z elements in barium borosilicate glass samples by in situ current normalized particle induced gamma-ray emission methods

Particle induced gamma-ray emission (PIGE) method using 4 MeV proton beam was utilized to analyze two types of barium borosilicate glass (BaBSG) samples for quantification of concentrations of low Z elements. The in situ current normalization method was applied in the analysis of eight samples containing varying concentration of F along with Si, B and Na. Charge normalized PIGE method was applied to determine concentrations of above low Z elements including Li and Al in samples having simulated nuclear waste from reprocessing of thoria spent fuel. Synthetic samples and NIST SRMs were used for method validation.     

Determination of selenium in animal tissue samples using radioisotope induced X-ray fluorescence

A summary of sources of background affecting gamma-ray spectrometers and methods for eliminating each are discussed, along with practical cost/benefit ratios. Background contributed by samples generally defines practical levels for system background. The practical bottom line can be obtained for relatively modest costs. A realistic bottom line is attained in underground systems when the major contributions to the background come from cosmogenically produced⁶⁸Ge and double-beta decay of⁷⁶Ge in the detector. The true bottom line is reached with isotopically enriched detectors that eliminate these two chemically inseparable radioactive impurities. Data from isotopically enriched detectors are presented.     

Elemental composition of hypertrophic scar and normal skin tissue using proton induced X-ray emission

Hypertrophic scars are a particular type of scar that can form after any type of dermal trauma. They are unsightly, red and elevated above normal skin level. At present no-one knows why these scars form and what form the treatment should take. Full thickness hypertrophic skin tissue as well as full thickness normal skin samples, obtained form the Restoration of Appearance and Function Trust (RAFT), Institute of Plastic Surgery, Mount Vernon Hospital, were analysed, using simultaneously both PIXE and RBS, with a 2 MeV proton beam. The epidemis was compared to the dermis on both normal and scarred tissue, and each was compared to the other, to see if there were any variations in elemental composition. In all the samples C, N and O detected by RBS and P, S, Cl, K, Ca, Fe detected by PIXE were found, In the majority of samples Zn and Cd were found, and in a few samples Sn was determined. Significant differences in concentrations, for the elements P, S, K and Cd, between the epidermis and dermis in both hypertrophic scarred and normal skin tissue were found. A difference was also detected between elemental concentrations in normal and scarred skin for the elements Ca, P, S, Fe and Cd.