2008 Volume 57 Issue 12 Pages 733-738
In order to develop a simple but reliable radiation detector for the general public, photon detection performances of radiation sensors have been studied in photon calibration fields and by Monte Carlo simulations. A silicon p-i-n photodiode and a CdTe detector were selected for the low cost sensors. Their energy responses to ambient dose equivalent H*(10) were evaluated over the energy range from 60keV to 2MeV. The response of the CdTe decreases markedly with increasing photon energy. On the other hand, the photodiode has the advantage of almost flat response above 150keV. The sensitivities of these sensors are 4 to 6 cpm for the natural radiation. Detection limits of the radiation level are low enough to know the extreme increase of radiation due to emergency situations of nuclear power plants, fuel treatment facilities and so on.