Determination of gross alpha beta surface contamination by handheld equipment

Contamination of surfaces by solid material may occur by spillage of powders, by contact between the surface and radioactive material, by the drying of radioactive liquids and solutions on the surface of the material, or by deposition from airborne radioactive material. Surface contamination may also occur by sorption of radioactive gas such as tritium, or vapor such as tritiated water. A potential radiological hazard arises from the presence of radioactive surface contamination. It can become airborne and subsequently may be inhaled, or it may be transferred by contact to the hands and subsequently to food and ingested, or it may penetrate the intact skin or enter an open wound giving rise to an internal radiological hazard. The presence of radioactive contamination at levels, which may not be a health hazard, may interfere with experimental work, leading to erroneous low-level counting results, or cross-contamination of radiochemical experiments. In this study we present the results of international comparison organized by IAEA Vienna, Austria for the tree samples spiked with unknown Alpha and Beta Activity. The source used as alpha emitter was Cm-244 and the beta emitter was Sr-90. The measurements of surface contaminated samples after calibration of the system are done with SAB-100 probe for measurement of surface contamination designed to be used with any CSP survey meter. Its phoswich scintillation detector with 100 cm2 detection area makes it an ideal tool for direct measurement of alpha and beta emitters. The high sensitivity of the system for the determination of the Gross Alpha and Beta activity makes sure detection of low values activity of samples. Our laboratory results are: for sample 01 (beta) Aβ=(1.09±0.12) Bq/ cm2 and Aβ (IAEA)=(1.21±0.01) Bq/cm2: for sample 02 (alpha) Aα=(0.69±0.07) Bq/ cm2 and Aα (IAEA)=(0.71±0.09) Bq/cm2; for sample 03 (mix alpha and beta) Aα=(0.35±0.04) Bq/cm2 and Aα (IAEA)=(0.37±0.04) Bq/cm2; Aβ = (0.76±0.08) Bq/ cm2 and Aβ (IAEA)=(0.6±0.07) Bq/cm2. As it seems our results are in good agreement with reference values given by IAEA (International Atomic Energy Agency).