[en] The response of a storage photostimulable phosphor imager system has been studied using alpha- and beta-particle point sources, large area sources, and with environmental soil samples previously characterized for radionuclide content. Alpha-particle radiation can easily be differentiated from other radiations. Furthermore, for thin sources, alpha-particle-emitting radionuclides can be differentiated from each other. A number of other response characteristics of the system are also described

[en] This document describes the alpha-particle calibration services offered by the Radioactivity Group of the National Bureau of Standards (NBS) (Scheduled Calibrations; 43030C and 43040C; formerly 8.2H and 8.2I). The fundamental measurement quantities are defined, the measurement approach is described (or reviewed), and the operating procedures are described from the point of view of the calibration technician or metrologist. The measurement uncertainties, and how they are estimated, are described. Methods for maintaining and assessing quality control, e.g., international comparisons, MQA programs, etc. are also briefly reviewed

[en] Two alpha-particle counting systems for the measurement of large-area sources were developed at the National Bureau of Standards. The systems and their characteristics are described. One system uses an internal-source proportional counter and the other measures sources external to the counting volume through a thin aluminized mylar window. The internal system is used to measure sources in the lower-activity ranges. These calibrated sources are then used to establish the efficiency of the external counter used to measure the higher-activity sources

[en] In 1973 the National Bureau of Standards (NBS) distributed three calibrated test solutions to interested laboratories. Two of these solutions each contained nine gamma-emitting radionuclides that the participants were asked to identify and quantify. The third solution contained ⁸⁹Sr and ⁹⁰Sr-⁹⁰Y, and participants were asked to perform a quantitative radioactivity analysis of the mixture. The results reported by all of the participating laboratories are given here. Most of the activity values reported for the mixed gamma-emitting solutions were within plus or minus 20 percent of the corresponding NBS values, but less than half of the laboratories reported ⁸⁹Sr and ⁹⁰Y activity values both of which were within plus or minus percent of the NBS values

[en] The authors are currently engaged in a program to determine the potential of resonance ionization mass spectrometry (RIMS) for ultrasensitive isotopic measurements and for the determination of certain nuclear properties (e.g., spin and magnetic moment) of rare isotopes. The RIMS process has been under development for the past 5 yr or so as a technique for ultrasensitive elemental analysis. In RIMS, conventional mass spectrometry is combined with resonant laser ionization to provide sensitive, selective detection of elemental species. The resonance ionization process can achieve (by virtue of enormous resonance enhancement) nearly unit efficiency ionization of a selected elemental species. The mass spectrometer provides mass-specific (more precisely, mass-to-charge ratio specific) detection of the ion with near unit efficiency. Recently, RIMS was used to detect 1000 ⁸¹Kr atoms in a background of 10⁷⁸⁰Kr and ⁸²Kr atoms and 10¹² atoms of other elements. It has also provided part-per-billion sensitivity in the measurement of gallium in solid silicon

[en] The development of traceability in low-level radioactivity measurements is discussed. The role that the development of large quantities of natural matrix standards can play is also discussed. (author)

[en] Individual papers are processed separately for the data bases

[en] This report describes results of the first year of a program that will enable the Nuclear Regulatory Commission to improve, demonstrate, and document traceability of its measurements to the national physical measurement standards for ionizing radiation. The principal actions being taken are: (1) characterization of the response of thermoluminescence dosimetry systems used for routine surveillance of nuclear facilities; (2) type testing and characterization of portable survey instruments; and (3) implementation of routine quality assurance services which will demonstrate that regulatory measurements are sufficiently consistent (in agreement) with national measurement standards. During the year, some tests of the TLD system were performed as specified in American National Standard N545-1975, specifically uniformity, reproducibility, dependence of exposure interpretation on the length of the field cycle, energy dependence, light dependence, and moisture dependence. The energy dependence of five portable survey instruments was determined for exposure to photon radiation, and a chamber for exposure to gaseous sources of beta radiation was designed and partly built. The four laboratories which calibrate portable survey instruments for NRC inspectors were invited to participate in measurement quality assurance interactions with NBS, and all expressed a desire to do so

[en] An intercomparison study of low-level ²³⁷Np determination in artificial urine samples has been carried out. The purpose of this study was to find the present open-quotes optimalclose quotes method available for use in a routine in vitro radiobioassay program for occupationally exposed workers. Four synthetic urine samples with differing ²³⁷np concentrations were prepared: (1) mBq kg^-1 of ²³⁷Np; (2) 3 mBq kg^-1 of ²³⁷Np with natural uranium, ²³⁹Pu and ²⁴¹Am as interferences; (3) 50 mBq kg^-1 of ²³⁷Np; and (4) a matrix blank. The solutions were submitted to 10 alpha-particle and 10 inductively-coupled plasma-mass spectrometry (ICP-MS) laboratories of which six and four laboratories, respectively, returned results. Two laboratories performed assays using both techniques. The radiochemical method of choice used ²³⁹Np as the tracer which utilized a combination of coprecipitation and anion-exchange separation. The best results obtained by ICP-MS were comparable with the most accurate results obtained by alpha-particle spectrometry but not any better. Alpha-particle spectrometry measurements overall gave consistently better agreement with the known values

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