Study on calculation of detector flux with Monte Carlo methods

Monte Carlo techniques mostly being used for calculating detector flux are, the first is that the track-length is record when particle goes through the detector, the second is that small detector is approximately regarded as a point, then doing the calculation of point flux using relevant method, the third is that the position of point is sampled uniformly in the detector, the statistical result of sampled point flux is computed as the detector flux, the fourth is the forced directing detector method. In most practical cases, two kind of detectors, spherical and cylindrical detector, are often used, this paper mainly studies the third and the fourth method of statistical estimation for calculating spherical and cylindrical detector flux. The corresponding computer program have been accomplished and put into MCNP-3B. Testing results indicate that new approaches are more effective than the original MCNP methods. (author)