Alpha Monitoring - doe-hdbk-1113-98_reaffirm_2005

DOE-HDBK-1113-98

Radiological Safety Training for Uranium Facilities

Module 104 Internal Dose Control

in respiratory protection requirements, he or she should not enter the

work area until the conflict is resolved and the appropriate respiratory

protection equipment is available.

Special Radiological Surveys and Techniques for Contamination

Monitoring

i. Alpha Monitoring

As workers at a uranium facility, you will likely perform self-

monitoring for the presence of radioactive contamination.

If you recall from the general characteristics of uranium, it primarily

decays by emitting an alpha particle. Many uranium decay products

also decay by emitting alpha particles.

Alpha particles are highly charged and will only travel about 2 inches

in air. Alpha particles are also stopped by the dead layer of skin. This

means that alpha particles external to the body are not a health

concern. It also means that alpha particles are hard to detect because

the detector must be close to the source of the material emitting the

alpha particle.

There are many detector types available for detecting alpha

contamination. Two of the most commonly used types are scintillation

detectors and gas proportional counters. A thin window Geiger-

Mueller (GM) detector, such as a pancake probe, will also detect a

small portion of the alpha radiation emitted.