Neutron activation in EBT-P

Neutron activation due to photoneutron production in the lead shields proposed to protect the EBT-P superconducting coils from excessive x-ray heating was investigated. The photoneutron flux distribution in various EBT-P structural components was calcualted for typical upgrade operating conditions using a standard twodimensional transport model (TWOTRAN). Activity levels were then evaluated for major structural materials using activation cross sections tabulated in the GAMMON library. Activation dose rates in the device enclosure following several days of 8h/day upgrade (90GHz) operation were found to be about6 mrem/h, decaying to <0.25 mrem/h in about3 days. This requires radition monitoring of all personnel entering the device enclosure during this time, but should not generally restrict ''hands on'' access to the device. There is thus no strong motivation to replace lead with another shield material; however, it may be desirable to borate the enclosure walls in order to reduce the effect which impurities might have on activity levels