NBS (National Bureau of Standards) Measurement Services: Radioactivity Calibrations with the '4 pi' Gamma Ionization Chamber and Other Radioactivity Calibration Capabilities

摘要

The paper describes the use of the NBS 4 pi' gamma ionization chamber - an instrument which provides an indirect method of comparing the activity (decays per second) of gamma-ray-emitting radionuclides with national standards for a routine calibration service by the National Bureau of Standards Radioactivity Group. A description of the chamber's construction and characteristics, the operational procedure, and the associated equipment is included. A description of NBS capabilities for direct radioactivity calibrations is also presented. Many of these capabilities are used to establish calibration factors for the '4 pc' gamma ionization chamber.