MULTIPLE TYPE RADIATION DETECTION UNIT

PURPOSE:To enable highly accurate measurement with reduced effect due to noises by a method wherein radiation detection elements are divided into subdetection groups to detect radiation using the highest level signal thereamong. CONSTITUTION:A plurality of radiation detection elements 1 are arranged to fit the size of an object to be inspected and divided into subgroups having a specified number each. Precounter 4 composing a detection unit are connected to a CPU5, a RAM6 and a ROM7 through a data bus 8. The CPU5 performs computa tions and processings in the following patterns (a) and (b) group by group to calculate the count of the net radiation. (a) the count is measured with respective counters without radiation source and the results are stored into a RAM6. (b) the count is measured likewise with a radiation source and the results are stored into the RAM6. Data is outputted corresponding to the subgroup indicating the max. net value.