Floor Probe/Contamination Monitor (NE Model FLP3D) Test and Evaluation Report

A floor contamination monitor model FLP3D manufactured by Saint-Gobain Crystals and Detectors UK Ltd. was tested at Oak Ridge National Laboratory. The purpose of the test is to evaluate the monitor's performance as a mobile instrument capable of detecting alpha and/or beta contamination that may exist on a flat surface such as a floor. The monitor consists of a large area scintillation probe (600 cm2) and a rate meter mounted on heavy-duty wheels with a 22 mm separation between the monitored surface and the probe. Performance was evaluated under normal and severe environmental conditions in terms of temperature and humidity variations, and exposure to RF and magnetic fields. Sensitivity measurements were also made to determine the probe's efficiency for detecting alpha and beta contamination. The overall performance of the floor monitor is considered satisfactory under the various environmental conditions with no major problems observed. The monitor is approximately 50% efficiency for 90Sr/90Y with the source placed in contact with the detector's protective grille (0 mm) and at a distance of 22 mm. However, in its present physical configuration, the floor monitor is inefficient in detecting alpha contamination due to the 22 mm separation between the surface to be monitored and the detector's surface. The alpha detection efficiency can be enhanced to a reasonable vale by redesigning the brackets holding the heavy-duty wheels to reduce the height between the surface to be monitored and the surface of the probe to a few millimeters. For use at ORNL, this change is recommended