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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. [ABSTRACT FROM AUTHOR]

Abstract: Different methods such as full spectrum DPM (FSDPM), dual isotope estimation and inclusion methods were studied for the activity quantification of 3H and 14C in dual beta labeled samples using liquid scintillation analyzer. A standardized Packard tritiated water was used as tritium source and 14C activity was standardized by CIEMAT/NIST method and compared with the results obtained by the above three methods. Minimum detectable activity was 2100dpm/l for 3H and 1200dpm/l for 14C with a counting time of 300min. The accuracy of the results obtained was found to be within ±10% for 3H: 14C activity ratios 1:1, 1:2, 2:1, 6:1, 9:1, 13:1 and 18:1. [Copyright &y& Elsevier]

Abstract: The CIEMAT/NIST efficiency tracing method using 3H standard was implemented at Radiation Safety Systems Division, Bhabha Atomic Research Centre (BARC) for the standardization of 131I radioactive solution. Measurements were also carried out using the 4π β–γ coincidence counting system maintained as a primary standard at the laboratory. The implementation of the CIEMAT/NIST method was verified by comparing the activity concentration obtained in the laboratory with that of the average value of the APMP intercomparison (). The results obtained by the laboratory is linked to the CIPM Key Comparison Reference Value (KCRV) through the equivalent activity value of National Metrology Institute of Japan (NMIJ) (), which was the pilot laboratory for the intercomparison. The procedure employed to standardize 131I by the CIEMAT/NIST efficiency tracing technique is presented. The activity concentrations obtained have been normalized with the activity concentration measured by NMIJ to maintain confidentiality of results until the Draft-A report is accepted by all participants. The normalized activity concentrations obtained with the CIEMAT/NIST method was 0.9985±0.0035kBq/g and using 4π β–γ coincidence counting method was 0.9909±0.0046kBq/g as on 20 March 2009, 0h UTC. The normalized activity concentration measured by the NMIJ was 1±0.0024kBq/g. The normalized average of the activity concentrations of all the participating laboratories was 1.004±0.028kBq/g. The results obtained in the laboratory are comparable with the other international standards within the uncertainty limits. [Copyright &y& Elsevier]

Abstract: Alpha specific activity of 243Am was determined using pulse shape discrimination in liquid scintillation spectrometry. 238Pu, 36Cl and 239Np (purified from 243Am) were used for obtaining the spillover of alpha/beta particles into the beta/alpha channels, respectively. Synthetic mixtures of 241Am/243Am were prepared. Using the alpha-specific activity, weights of the stock solutions used and the half-life of 241Am and 243Am isotopes, the expected 241Am/243Am atom ratios in the mixtures were determined and compared with those obtained by thermal ionization mass spectrometry (TIMS). An agreement of about 1% was obtained between the 241Am/243Am atom ratios determined by the two methods. This shows that liquid scintillation counting with pulse shape discrimination can be used for 243Am determination with an accuracy better than 1%. [Copyright &y& Elsevier]