ICARE Radon Calibration Device

An aerodynamic calibration device called ICARE is briefly described. ICARE is currently being used at the Nuclear Research Center of Saclay in France for the certification of instruments employed in measurement of artificial radioactive particulate airborne contamination. ICARE is essentially a blower. Aerosols calibrated in size and labelled with ¹³⁷Cs or ²³⁹Pu are injected in the mainstream of the blower upstream of the test section. To extend ICARE's field of application to the case of instruments employed in measurement of ²²²Rn and of its decay products, a new line of injection has been designed and is under construction, in the frame of a contract financed by the European Community Commission. The main effort is presently oriented to-ward the development of a reliable ²²²Rn source, based on a solid deposit of ²²⁶Ra on organic fibers, and of a reference method for the measurement of ²²²Rn activity per unit volume of air. This reference is based on a modified version of standard containers being used in the French reference method for calibrated measurements of ¹³³Xe and ⁸⁵Kr by gamma spectroscopy.