EFFECT OF VARIATION IN THE AMBIENT TEMPERATURE ON THE NIST ENCAPSULATED 222 Rn EMANATION STANDARD SOURCE

The effect of ambient temperature variation on radon emanation fraction from NIST standard source was studied using a newly constructed chamber. The results indicate that, the effect of decreasing the temperature rather than the certified value ( at 21 ± 3 °C) has a considerable effect on decreasing the radon emanated from the source. On the other hand, the radon emanation fraction factor of the source is tendentious to the unity when the temperature was increased to more than 30 °C. The effect of the accumulation time on the radon emanation is very exhibiting whatever the temperature decrease.