Fault studies showed no measureable dose rates in the adjacent control room. Both the control room and laser room are shielded by concrete. The klystron produced some measureable x-ray dose rates within several feet of the unit. The maximum electron energy of 10 MeV was chosen specifically so that activation of beam-line components by photoneutrons would not be a concern. The threshold for the production of neutrons by gamma-bombardment of nitrogen is 10.55 MeV, and 15.67 MeV for oxygen. The accelerator safety envelope includes a maximum integrated beam current of 220 nanoamperes for eight hours. Typical operating conditions are 20 nc/pulse at 10 hertz for an average beam current of 0.2 microamperes. Maximum dose rates measured near the target stations were approximately 0.5 Sv/h (50 rem/hr). Doors to the target room are interlocked with the electron beam such that inadvertent entry causes the interlock system to disable beam production by interlocking both RF power and laser emission.
The AGS started its heavy ion program on schedule April first. The program will run for one month, then switch over to protons beginning June first. The High Energy Physics program is scheduled to run uninterrupted until January of 1998 when preparations for RHIC commissioning will begin. It has been several years since the AGS has run more than a few months of protons without a scheduled maintenance period. One of our concerns will be the failure of key magnet elements in high radiation areas which may result in significant dose being received during repairs. We have factored this into our ALARA goals for this year. The addition of a beam scraper in the main ring later in the year may alleviate this concern by causing much of the activation to be "collected" at a single point which is removed from the more travelled areas of the ring. It is hoped this will lower the residual dose rates from the extraction elements.
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