Study of calculation and correction method of detection efficiency of the volume source

MCNP programme can be used to simulate detection efficiency of high pure germanium detector that measures a volume source at certain position. However, Mathematics model of detector and source cannot be established perfectly, so the result of calculation has some error. To get accurate calculation result, the result must be corrected. The authors have considered various factors that influence the result, and established an expression to correct the calculation result, and then, compared the calculation result after correction with experiment result and result of the other programme (ISOCS). The authors concluded that MCNP programme is efficient way to simulate the detection efficiency of the volume source by correction. (authors)