Radioactivity calibrations with the "4π" Gamma ionization chamber and other radioactivity calibration capabilities

Abstract

The calibration and related measurement services of the National Bureau of Standards are intended to assist the makers and users of precision measuring instruments in achieving the highest possible levels of accuracy, quality, and productivity. NBS offers over 300 different calibration, special test, and measurement assurance services. These services allow customers to directly link their measurement systems to measurement systems and standards maintained by NBS. These services are offered to the public and private organizations alike. They are described in NBS Special Publication (SP) 250, NBS Calibration Services Users Guide. The Users Guide is being supplemented by a number of special publications (designated as the "SP 250 Series") that provide a detailed description of the important features of specific NBS calibration services. These documents provide a description of the: (1) specifications for the service; (2) design philosophy and theory; (3) NBS measurement system; (4) NBS operational procedures; (5) assessment of measurement uncertainty including random and systematic errors and an error budget; and (6) internal quality control procedures used by NBS. These documents will present more detail than can be given in an NBS calibration report, or than is generally allowed in articles in scientific journals. In the past NBS has published such information in a variety of ways. This series will help make this type of information more readily available to the user. This document (SP 250-10), NBS Measurement Services: Radioactivity Calibrations with the "4it" Gamma Ionization Chamber and Other Radioactivity Calibration Capabilities, by J. M. Calhoun, is the tenth to be published in this new series of special publications. It describes the use of the NBS "4tt" gamma ionization chamber to measure the activity of gamma-ray-emitting radionuclides against national standards (see test numbers 43010C and 43020D in the SP 250 Users Guide). It also reviews NBS capabilities for making direct radioactivity calibrations. Inquiries concerning the technical content of this document or the specifications for these services should be directed to the author or one of the technical contacts cited in SP 250. The Center for Radiation Research (CRR) is in the process of publishing 21 documents in this SP 250 series, covering all of the calibration services offered by CRR. A complete listing of these documents can be found inside the back cover. NBS would welcome suggestions on how publications such as these might be made more useful. Suggestions are also welcome concerning the need for new calibration services, special tests, and measurement assurance programs

Source self-attenuation in ionization chamber measurements of 57Co solutions

“…Measurements were made using the following ionization chambers: the NIST secondary standard 4πγ ionization chamber "A" (ICA) (Calhoun 1987); the Vinten 671 (VIC) (Woods et al 1983); AtomLab models 400 (AL-400) and 500 (AL-500); and Capintec models CRC-15, CRC-15R, CRC-35R, CRC-25PET, and CRC-1.8atm (The 1.8-atm chamber from Capintec is the basis of their CRC-PC dose calibrator.). For the ICA, measurements were made relative to the response on a radium-226 reference source, #50.…”

Standardization of 68Ge/68Ga Using Three Liquid Scintillation Counting Based Methods

“…Ampoule A1 was measured in the NIST-maintained radionuclide activity calibrators (“dose calibrators”) and the NIST “4π” γ IC [ 13 ] to allow for the determination of calibration factors in this specific measurement geometry. The solution in A1 was then diluted by a factor of about 200 through two serial gravimetric dilutions, giving two additional ampoules, A1D1 and A1D2 .…”

A Review of NIST Primary Activity Standards for 18F: 1982 to 2013

“…The NIST pressurized ionization chamber “A” has been used since the 1960s to maintain activity standards via calibration factors (K-values, vide infra ) [ 83 ]. Details of the chamber and its operation have been discussed in a recent publication that addressed the ramifications of the discovery of a slow drift in the height of sample placement resulting from a slipping positioning ring [ 84 ].…”