Patent ID: 7456405

Claim:
A method for detecting a presence of artificial radiation comprising: measuring a plurality of radiation particle counts using a plurality of counters, each counter having a corresponding distinct energy threshold level; calculating a radiation dose rate based upon the radiation particle counts of the plurality of counters; comparing the radiation dose rate with the radiation particle counts from one of the plurality of counters to generate an energy deviation result, the energy deviation result indicating a presence of artificial radiation when the energy deviation result falls outside of a threshold value range, the threshold value range defined by a first threshold value and a second threshold value, the first threshold value greater than the second threshold value; wherein the step of comparing comprises forming a ratio of the radiation particle counts from one of the plurality of counters with the radiation dose rate to generate the energy deviation result; and wherein calculating the radiation dose rate comprises summing weighted radiation particle counts from each of the plurality of counters, weighting of the radiation particle counts for each of the plurality of counters based upon the energy threshold level associated with each of the plurality of counters.