The NBS radon-water standard generator

Abstract

NBS has completed the development of a transfer standard for radon-in-water measurements. This standard can be used to generate and accurately dispense radium-free 222Rn solutions of known concentration. It is based on an earlier and previously described prototype. The standard consist of a polyethylene-encapsulated 226Ra solution source in a small-volume accumulation chamber and an ancillary mixing and dispensing system which is partially automated with motor-driven syringes. The revised source configuration is more stable than the original prototype; and the mixing and dispensing system is more compact, rugged, and convenient. The standard generator was calibrated and certified in terms of the 222Rn concentration or total activity in an aliquot dispensed from the generator when a detailed operation procedure is adequately followed. The overall uncertainty of the calibration was estimated to be approximately ± 4%. © 1986.