Determination of the emanation properties of powder materials by means of the NE 1501 detection unit

A method has been developed for the determination of the specific radon exhalation rate of powdered materials by using the TESLA NE 1501 detection unit. The radon released is transferred quantitatively into a TESLA DS 401 M Lucas-type scintillation detector and its activity is evaluated with an NZQ 605 T measuring system. For a detector with the backround reading of 0.004 s-1 and calibration constant of 2.4 s-1 Bq-1 and for background and sample counting times of 1 hr (sample mass 50 g), the detection limit for the specific radon exhalation rate is 4.2x10-11 Bq g-1 s-1. Using the method described, the specific radon exhalation rate can be rapidly and selectively determined for environmental samples such as fly ash, coal, building materials, soil, sediments, biological samples, etc. (author). 4 figs., 3 tabs., 7 refs