Calculation of leaked electromagnetic field in gallery of klystron of NSRL

The HF microwave leak in the gallery of klystron of NSRL affects microwave communication greatly. In order to reduce electromagnetic radiation field a nd to restrain electromagnetic noise, it is necessary to locate the noise s ource. But for the complicated leaked field, it is difficult to locate the noise source. We can measure the leaked field and calculate it, so as to lo cate the radiant noise source and study the method of reduction the electro magnetic noise. This article gives the method and formulas of calculating o f electromagnetic field, and also On-the-spot contrast test.