This standard is the responsibility of the Accredited Standards Committee N42 on Radiation Instrumentation.Committee N42 delegated the development of the standard to its Subcommittee N42.1. Drafts were reviewed by Committee N42, Subcommittee N42.1, and other interested parties, and the comments received were utilized in producing the standard as finally approved and discussed. Performance criteria contained in this standard were tested for applicability under the sponsorship of the US Department of Energy and the US Nuclear Regulatory Commission. The standard was approved by Committee N42 letter ballot of February 6, 1989.