Interference from Radon - hdbk1113cn10147

DOE-HDBK-1113-98

Radiological Safety Traning for Uranium Facilities

Module 104 - Internal Dose Control

When performing personnel monitoring it is very important to keep the

detector (i.e., the probe) close to the surface being monitored and to

move the detector slowly. If the detector is not held close to the surface

being monitored, the alpha particles may not reach the detector. If the

detector is moved too quickly across the surface, the electronics in the

instrument will not have time to respond to indicate the amount of

radioactive contamination present.

The general method for personnel scanning for alpha contamination is to

scan at appro ximately 2 inche s/ sec at a dis tance of appr oximately

inch. For personnel scanning for beta contamination, it is recommended

to scan at 2 inches/ sec at a distance of inch. However, the surface

being surveyed (i.e., soil, building surfaces, equipment, personnel), the

scanning speed, and the instrument response time will determine the

level of contamination that can be detected.

Failing to survey properly can have the same results as not surveying at

all. Contamination may go undetected and may be tracked out of the

radiological area. Once outside the radiological area, the contamination

may be transferred from surface to surface. This transfer of

contamination could result in uranium ending up inside your body, the

body of a co-worker, or even the bodies of your family members and

friends. The potential for spreading undetected contamination should

always be kept in mind when perfor ming self-monitori ng.

iv.

One of the problems encountered when monitoring for contamination is

interference from radon and its decay products.