Johnson Matthey TRACERCO T401, User Manual, Page: 22 / 26

10 Hints for Radiation Contamination Monitoring

Hold detector probe 2mm from the surface being measured. This provides conditions which most
closely reflect those used when calibrating the probe.

Avoid contaminating the face or head of the probe during operation.

Wherever possible, check that the monitor is working before use by placing it adjacent to a known
test source.

Alph a part icles are h e avil y a tte nu ate d b y wa ter. Mo n itor in g a wet surf ace containing
alpha emitting radionuclides will dramatically reduce the observed count rate relative to dr y
conditions. In the worst case scenario, all alpha particles will be absorbed before being
detected by the probe. A similar, though less pronounced problem may be encountered when
measuring nuclides which emit weak beta particles.

Use the optional extension arm for the detector probe when monitoring above head height
or the internal surface of pipes, vessels or ventilation ducts.