Daily and Long Term Variations of Out DoorGamma Dose Rate in Khorasan Province, Iran

摘要

In Iran before 1996, only a few hot spots had been identified, no systematic study hadbeen envisaged. Since then preparation of out-door environmental gamma radiation map of Iranwas defined as a long term goal in our center, at the same time simultaneous monitoring of out-door gamma level in Khorasan was also proposed. A Rados area monitoring system (AAM-90)including 10 intelligent RD-02 detector and all associated components were purchased. From 2003gradually seven stations have been setup in Khorasan. For all seven stations monthly average andone hour daily average on four time intervals have been computed. Statistically no significantdifferences have been observed. This is also true for monthly averages. The overall average doserate for present seven stations varies from 0.11μSv.h~(-1)for Ferdows, to 0.04μSv.h~(-1)for Dargaz.Based on our data, 50 minutes sample in any time interval is an accurate sample size to estimateout door Gamma dose rate.