Two soft X-ray cameras(KJ5) have been constructed for the D-T phase of JET operation. The active Si detector elements are placed within a substantial radiation shield made mainly from barytes concrete. The initial part of the DTE1 experimental programme has provided an opportunity to assess the operation of this diagnostic. The results show that the shield and detectors are working as expected and that the system will continue to work well when the highest power levels are reached. A comparison is made with the signals from an unshielded detector.