What factor is critical when using the Beta Probe of the ADM-300?

The angle of the probe relative to the source is critical when using the Beta Probe of the ADM-300 because beta particles have relatively low penetration power and can be significantly affected by their interaction with the surrounding environment. When measuring beta radiation, the geometry of the setup is essential; if the probe is not positioned at an optimal angle relative to the contamination source, it may not accurately capture the beta particles emitted. This is because beta particles tend to scatter and are less likely to reach the detector if the angle is unfavorable, potentially leading to underestimations of contamination levels.

Moreover, positioning the probe at the correct angle ensures that the maximum amount of beta radiation is directed toward the detection area. This factor, combined with knowledge of the radiation’s characteristics and the specific application for which the probe is being utilized, plays a pivotal role in obtaining accurate and reliable measurements.

In comparison, while the depth of the contamination source, time duration of the measurement, and type of Geiger tube can influence measurements, they do not have the same direct impact on the efficacy of the probe's positioning for detecting beta radiation. Thus, the angle of the probe is paramount to ensuring accurate and effective radiation safety practices.