A beta radiation detector which is capable of reliably detecting beta radiation emitted from a surface. An electrically conductive signal collector is adjustably mounted inside an electrically conductive enclosure which may define a single large opening for placing against a surface. The adjustable mounting of the electrically conductive signal collector can be based on the distance from the surface or on the expected beta energy range. A voltage source is connected to the signal collector through an electrometer or other display means for creating an electric field between the signal collector and the enclosure. Air ions created by the beta radiation are collected and the current produced is indicated on the electrometer or other display means.
The present invention generally relates to the detection of radiation, and, more specifically, to the detection of beta particle radiation. This invention was made with Government support under Contract No. W-7405-ENG-36 awarded by the U.S. Department of Energy. The Government has certain rights in the invention. For the safety of individuals, the detection of beta particle radiation is of extreme importance in any location where radioactive materials are handled. In the past, the detection of beta radiation from surfaces has been accomplished primarily through two types of monitors. The first involves the use of swipes or smears taken from surfaces to detect loose surface contamination. These samples are analyzed remotely. This technique offers good sensitivity for loose contamination, but is slow, relatively expensive, and dependent on the skill of the individual acquiring the samples. This type of radiation sampling is also subject to missing portions of the contamination. The second technique involves chemical analysis of samples to determine the tritium content of materials. This technique is physically destructive of the sample, and is very slow and expensive.