Status of the ring: The leaking ion-pump feed-through found last Tuesday in corner 2 was replaced the same day, followed by a bake-out until Wednesday night and there was an accelerated beam Thursday afternoon, although we were bothered by another (short) power cut on Thursday. Yesterday and again this morning we had 130 mA beam accelerated. The venting of the ring vacuum system in corner 2 also led to a degradation of the lifetime. It is, however, improving again, and now the lifetime is 14 hours at 110 mA.

The microtron, and the ring injections, do not seem to suffer from the intense use of it by the positron group. The o-rings in the main dipoles have, however, started to leak again without magnetic field. This could be due to the higher radiation exposure. The o-rings will have to be exchanged, when the present electron run is finished. In the future, we should exchange these o-rings with more radiation-resistant o-rings, which however will need fabrication of a new vacuum chamber.

The second motor on SGM I will be exchanged this week.

The horizontal mirror in SGM II has been mounted and baked, and the grating is presently being installed in its mount.

has been proposed to extend the present synchrotron radiation run by two weeks, for several reasons. Apparently there are no objections to this change, and we plan to fix this schedule next Tuesday unless serious objections are received before then.

250898 SPM