Determination of Fluorine in NBS Coal and Coal Fly Ash by Proton Induced Gamma Ray Emission and Spark Source Mass Spectrometry

Abstract

Fluorine concentrations in US National Bureau of Standards standard reference materials 1632a (coal) and 1633a (coal fly ash) have been determined by proton induced gamma ray emission (PIGME) and spark source mass spectrometry (SSMS) using the method of standard additions. Good agreement was obtained between the two techniques with no significant bias. The mean values for 1632a and 1633a were ± 18 mg kg^?1 and 109 ± 11 mg kg^?1 respectively.     

Etude Des Teneurs En Cuivre,Zinc, Et Arsenic Dans La Poudre De Lait Par Activation Neutronique

Abstract

Copper, zinc and arsenic have been determined in dehydrated milk powder by neutron activation analysis. Irradiation 13 of ashed milk powder in a flux of 10¹³ thermal neutrons per second per sq. cm. was followed by: elution through an anion exchange resin; solvent extraction of copper with dithizone into a chloroform phase; precipitation and subsequent redissolution of arsenic as As₂, S₃ and as a polysulfide, respectively. The determinative step involved gamma ray spectroscopy of the isotopes Zn⁶⁷, Zn⁶⁵, Cu⁶⁴ and As⁷⁶.     

Estimation of plutonium present in 200 litre waste drums containing high amount of beta gamma activity

The segmented gamma ray scanning system developed for the assay of plutonium present in 200?L waste drums was modified for the estimation of gram amounts of plutonium in the presence of high beta gamma activity. A multi gamma ray source of ¹⁵²Eu having?~1?mCi activity was used for the determination of attenuation correction factors for high count rate drums. Dead time corrections were applied to arrive at the corrected count rates for all the gamma rays. Present study has shown that the estimation of?~1?g of ²³⁹Pu in a waste drum can be carried out in the presence of ¹³⁷Cs up to an activity level of 20?mCi.     

Beta decay of the fission product Sb and a new complete evaluation of absolute gamma ray transition intensities

The radionuclide ¹²⁵Sb is a long-lived fission product, which decays to ¹²⁵Te by negative beta emission with a half-life of 1008 day. The beta decay is followed by the emission of several gamma radiations, ranging from low to medium energy, that can suitably be used for high-resolution detector calibrations, decay heat calculations and in many other applications. In this work, the beta decay of ¹²⁵Sb has been studied in detail. The complete published experimental data of relative gamma ray intensities in the beta decay of the radionuclide ¹²⁵Sb has been compiled. The consistency analysis was performed and discrepancies found at several gamma ray energies. Evaluation of the discrepant data was carried out using Normalized Residual and RAJEVAL methods. The decay scheme balance was carried out using beta branching ratios, internal conversion coefficients, populating and depopulating gamma transitions to ¹²⁵Te levels. The work has resulted in the consistent conversion factor equal to 29.59(13) %, and determined a new evaluated set of the absolute gamma ray emission probabilities. The work has also shown 22.99% of the delayed intensity fraction as outgoing from the 58 d isomeric 144 keV energy level and 77.01% of the prompt intensity fraction reaching to the ground state from the other excited states. The results are discussed and compared with previous evaluations. The present work includes additional experimental data sets which were not included in the previous evaluations. A new set of recommended relative and absolute gamma ray emission probabilities is presented.     

Determining trace amounts of nickel in plant samples by neutron activation analysis

Neutron activation analysis of plant samples for trace amounts of nickel has applications in various fields. Landsberger and Robinson (Trans Am Nucl Soc 102:187–188, 2010) found their measurement of the concentrations of nickel for different NIST reference materials to be significantly greater than the certified values when measuring nickel from the 810.8 keV gamma ray that comes from ⁵⁸Co from the ⁵⁸Ni(n,p) reaction. They determined that this overestimation was due to a significant interference by the presence of ¹⁵²Eu at 810.5 keV, and presented a method for correcting this interference. Their method involved a long thermal irradiation and correction of gamma ray counts based on the 1,408 keV belonging to ¹⁵²Eu. This paper presents an alternative approach, which involves irradiating the samples with epithermal neutrons, which suppressed the ¹⁵²Eu to the point of being negligible for samples with low levels of europium. Both methods were determined to work well for the identification of nickel concentrations by neutron activation analysis.     

Sulfur determination in coal by 14 MeV neutron activation analysis

A procedure involving the irradiation of coal samples with 14 MeV neutrons and subsequent gamma-ray spectrometry of the irradiated sample for the estimation of solfur in coal, has been outlined. The samples were irradiated with 14MeV neutrons from a Cockroft-Walton type generator for one minute and then subjected to gamma-ray spectrometry for another minute using an automated transfer cyclic system. Ten such cycles were repeated for accumulating events under the 2130 keV gamma ray photopeak belonging to³⁴P (T=12.4 s) produced by the³⁴S(n, p)³⁴P reaction for assessing the lower level of detection, LLD, of Sulfur. Interferences due to the presence of other elements in coal were also determined. Sulfur can be determined at LLD of 0.25% in coal provided a 5 g sample of the coal is irradiated with a neutron flux of 5·10⁹ n·cm⁻²·sec⁻¹ assayed with a gamma ray spectrometer having a large hollow core Ge(Li) detector and an anti-Compton shield.     

Monte Carlo simulation of PGNAA system for determining element content in the rock sample

The element content in rock sample can be determined by prompt gamma ray activation analysis technology. The neutron distributions under the conditions with different moderating materials, moderator size and distance from neutron source to lead-out hole were simulated using Monte Carlo method, and then the optimal structure parameters to get the highest thermal neutron flux was obtained. The PGNAA system with optimal parameters based on ²⁵²Cf neutron source was founded. In addition, the rock and element standard samples were irradiated by thermal neutron in this system. Moreover, the element content was calculated by processing gamma ray spectroscopy recorded, and it is in agreement with result of XRF method.     

Application of INAA complementary gamma ray photopeaks to the homogeneity study of a mussel candidate reference material

Homogeneity study is one of the steps in reference material, RM, characterization. Due to its inherent characteristics, Instrumental Neutron Activation Analysis, INAA, is an analytical technique of choice for homogeneity testing. An interesting possibility is the use of complementary gamma ray photopeaks to confirm INAA homogeneity test results. In this study, the use of the complementary gamma ray photopeaks of ^110mAg, ⁸²Br, ⁶⁰Co, ¹³⁴Cs, ¹⁵²Eu, ⁵⁹Fe, ¹⁴⁰La, ²³³Pa (for Th determination), ⁴⁶Sc and ⁷⁵Se radionuclides was investigated in the between bottle homogeneity study of a mussel candidate RM under preparation at IPEN–CNEN/SP. Although some photopeaks led to biased element content results, the use of complementary gamma ray photopeaks proved to be helpful in supporting homogeneity study conclusions for the new RM under characterization.     

Neutron and gamma ray doses from a 252Cf brachytherapy source in a water phantom

Axial and radial doses of Neutrons and gamma rays from an Isotron ²⁵²Cf Brachytherapy source were calculated in a Water phantom using Maienshein’s prompt fission gamma rays data and Maxwellian neutron energy spectrum. It was observed that neutron dose due to the source casing thickness does not contribute significantly to the total dose. Further the calculated secondary gamma ray dose rate is very small compared to the calculated primary gamma dose rate. Neutron and secondary gamma ray dose calculated in this study agree with the published data. Results of this study will be presented here.     

Study of naturally occurring radioactive material (NORM) in top soil of Punjab State from the North Western part of India

The concentration levels of ²³⁸U, ²³² Th, ⁴⁰K and ¹³⁷Cs in top soils of State of Punjab located in the North Western part of India were measured using conventional low background gamma ray spectrometric setup as well as Compton suppressed gamma ray spectrometric setup. The radioactivity level of ²³⁸U and ²³²Th was found to vary between 15 Bq/kg and 27 Bq/kg and between 16 Bq/kg and 57 Bq/kg respectively. The radioactivity level of ⁴⁰K was found to vary between 266 Bq/kg and 799 Bq/kg. The mean radioactivity level of the NORM in general was found to be similar to what is expected as a result of their normal abundance.     

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.     

Study of the isomeric ratios in photonuclear reactions of natural Selenium induced by bremsstrahlungs with end-point energies in the giant dipole resonance region

We have determined the isomeric ratios in ⁷⁴Se(γ, n)^73m,gSe and ⁸²Se(γ, n)^81m,gSe photonuclear reactions of natural Selenium induced by bremsstrahlungs with end-point energies in the giant dipole resonance region. The investigated samples were irradiated at electron accelerator Microtron MT-25 of the Flerov Laboratory of Nuclear Reaction, Joint Institute for Nuclear Research, Dubna, Russia. The gamma spectra of the samples irradiated were measured with spectroscopic system consisting of 8,192 channel analyzer and high-energy resolution (180 keV at gamma ray 1,332 keV of ⁶⁰Co) HP(Ge) semiconductor detector Canberra. The GENIE2000 (Canberra) computer program was used for data processing. The results were discussed and compared with those of other authors.     

Neutron beam preparation with Am–Be source for analysis of biological samples with PGNAA method

Material analysis with prompt gamma neutron activation analysis (PGNAA) requires a proper geometrical arrangement for equipments in laboratory. Application of PGNAA in analysis of biological samples, due to small size of sample, needs attention to the dimension of neutron beam. In our work, neutron source has been made of ²⁴¹Am–Be type. Activity of ²⁴¹Am was 20 Ci which lead to neutron source strength of 4.4 × 10⁷ neutrons per second. Water has been considered as the basic shielding material for the neutron source. The effect of various concentration of boric acid in the reduction of intensity of fast and thermal components of the neutron beam and gamma ray has been investigated. Gamma ray is produced by (α, n) reaction in Am–Be source (4.483 MeV), neutron capture by hydrogen (2.224 MeV), and neutron capture by boron (0.483 MeV). Various types of neutron and gamma ray dosimeters have been employed including BF₃ and NE-213 detectors to detect fast and thermal neutrons. BGO scintillation detector has been used for gamma ray spectroscopy. It is shown that the gamma and neutron radiation dose due to direct beam is of the same magnitude as the dose due to radiation scattered in the laboratory ambient. It is concluded that 14 kg boric acid dissolved in 1,000 kg water is the optimum solution to surround the neutron source. The experimental results have been compared with Monte Carlo simulation.     

Monte Carlo simulation of Cu,Ni and Fe grade determination in borehole by PGNAA technique

A prompt gamma neutron activation analysis borehole logging method for copper, nickel and iron grade estimation is proposed. The performance of the method was simulated by MCNP5 code. Based on the theory of neutron–gamma distribution on the borehole condition, the BGO scintillator and ³He neutron tube are adopted to record gamma ray spectrum and thermal neutron simultaneously, and least square method is used for the characteristic gamma ray counts calculation in the high energy range. The results of detection limit of metal grade in borehole condition indicate that the effectiveness of this logging method.     

Statistical assessment of radiological data of tiles collected from Jordan

ABSTRACT

In this present study, activity concentration of natural radionuclides such as ²²⁶Ra, ²³²Th and ⁴⁰K were determined using gamma ray spectrometer based on High Purity Germanium (HPGe) detector in ceramic tiles collected from Jordan. The average activity concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K were found to be 63.75 ± 24.12, 93.65 ± 13.89 and 180.9 ± 45.69 Bq.kg^?1. respectively. Using activity concentration of ²²⁶R, ²³²Th and ⁴⁰K, the radiological parameters such as radium equivalent activity (Ra_eq), Criteria formula (CF), absorbed dose rate (D_R), annual effective dose rate (H_R), activity utilisation index (AUI), external hazard index (H_ex), international hazard index (H_in), alpha index and gamma index (I_γ) has been calculated to assess the radiation hazards in the Tiles. The calculated average value of all radiological parameters is less than the recommended limit. The calculated values of annual effective dose rate (H_R), show that about 30% of the samples exceeded the recommended limit of 1 mSv.y^?1. Moreover, multivariate statistical techniques such as Pearson correlation, factor and cluster analysis were performed between the radioactive variables to know the existing relation between them.     

Determination of Germanium in Zinc by Differential Cathode Ray Polarography

Abstract

A differential cathode ray polarographic method is described for determining traces of germanium in zinc and its compounds. The germanium was previously extracted with carbon tetrachloride from the sample solution in hydrochloric acid. After reextraction with water the germanium content was determined polarographically in 1.4 M perchloric acid ? 5.10^?2 M pyrogallol. The detection limit was 0.0012 μg/ml, allowing to detect about 4 ppb of germanium in zinc using 5 g samples.     

Gamma ray spectra and sensitivities for 14 MeV neutron activation analysis

The purpose of this study was to define experimentally the sensitivity of determination for 63 different elements by 14 MeV neutron activation, with a 150 kV Cockroft-Walton accelerator at a neutron flux of 2·10⁸ n·cm⁻²·sec⁻¹ on the sample. The obtained gamma ray spectra are given, and the origin of the photopeaks observed are explained. A maximum irradiation time of five minutes was used as a convenient experimental limit to obtain the maximum sensitivity, considering, however, that the tritium target life is limited, and that the time to perform an analysis has to be reasonable. The practical use of 14 MeV neutron activation analysis is demonstrated by the detection limits obtained.     

The isomeric ratios in photonuclear reactions of natural barium induced by bremsstrahlungs with endpoint energies in the giant dipole resonance region

We have determined the isomeric ratios in ¹³⁰Ba(γ, n)^129m,gBa, ¹³²Ba(γ, n)^131m,gBa and ¹³⁴Ba(γ, n)^133m,gBa photonuclear reactions of natural barium induced by bremsstrahlungs with end-point energies in the giant dipole resonance region. The investigated samples were irradiated at electron accelerator Microtron MT-25 of the Flerov Laboratory of Nuclear Reaction, Joint Institute for Nuclear Research, Dubna, Russia. The gamma spectra of the samples irradiated were measured with spectroscopic system consisting of 8192 channel analyzer and high-energy resolution (180 keV at gamma ray 1332 keV of ⁶⁰Co) HP(Ge) semiconductor detector Canberra. The GENIE2000 (Canberra) computer program was used for data processing. The results were discussed and compared with those of other authors.     

Study of the isomeric ratios in photonuclear reactions of natural holmium and lutetium induced by bremsstrahlungs with endpoint energies in the giant dipole resonance region

We have determined the isomeric ratios in ¹⁶⁵Ho(γ, n)^164m,gHo and ¹⁷⁵Lu(γ, n)^174m,gLu photonuclear reactions of natural holmium and lutetium induced by bremsstrahlungs with end-point energies in the giant dipole resonance (GDR) region. The investigated samples were irradiated at electron accelerator Microtron MT-25 of the Flerov Laboratory of Nuclear Reaction, Joint Institute for Nuclear Research, Dubna, Russia. The gamma spectra of the samples irradiated were measured with spectroscopic system consisting of 8192 channel analyzer and high-energy resolution (180 keV at gamma ray 1332 keV of ⁶⁰Co) HP(Ge) semiconductor detector Canberra. The GENIE2000 (Canberra) computer program was used for data processing. The results were discussed and compared with those of other authors.     

Determination of zinc in geological samples using Compton suppression with thermal and epithermal instrumental neutron activation analysis

The determination of Zn in geological samples using instrumental neutron activation analysis is usually done using the ⁶⁴Zn(n,γ)⁶⁵Zn reaction and its 244 day half-life. However this analysis has proven to be potentially difficult. This is due to its relatively low neutron absorption cross section and gamma ray intensity, and the relatively high neutron absorption cross section and gamma intensity of ⁴⁶Sc, which has an energy peak that is only 5 keV greater than ⁶⁵Zn. The use of a high resolution detector makes it possible to differentiate between the ⁶⁵Zn and ⁴⁶Sc photopeaks peaks. However, the dominating ⁴⁶Sc gamma ray can even make peak fitting routines unsuccessful in the proper determination of ⁶⁵Zn. The use of a Compton suppression system suppresses the ⁴⁶Sc peak, which has two coincident gamma-rays, and this greatly improves the ratio of the height of the ⁴⁶Sc 1120.5 keV photopeak to the ⁶⁵Zn 1115.4 keV photopeak. Irradiating the sample with epithermal neutrons also improves the measurement since ⁶⁵Zn has a higher cross section for epithermal neutrons rather than thermal neutrons, whereas ⁴⁶Sc has a higher thermal cross section. Another technique to determine zinc is the use of ⁶⁸Zn(n,γ)^69mZn reaction with its 13 h half-life using epithermal neutrons and Compton suppression INAA. However, the 438 keV gamma ray of ^69mZn has no interference with any adjoining photopeak. A critical comparison of these two methods is given.