ISA meeting

Week 38, Sept. 15, 1998.

Status of the ring: The ring continued to run very well until we suffered an accident Thursday afternoon, when a window in the microtron broke. It was quickly fixed, but other leaks in the microtron dipole chambers developed, and a change of o-rings became necessary. These o-rings have been changed roughly once per year, because they are damaged by the very high levels of radiation. The intense use of the microtron for positron production has accelerated this process.
Both sets of o-rings have now been changed, and we are currently pumping again.
In spite of this, the ring has been in use every day since Sunday. The beam injected Sunday morning is still stored, and is used by two beamlines for alignment purposes.

The SGM II beamline saw its first beam yesterday, all the way up to the entrance slit. It will be opened up to the grating today, and degassing of the optical elements will start.

The SGM I had its motor changed successfully, and shows very good alignment. The middle grating is working quite well, but the intensity from the low- and high energy gratings is too low. The cause of this is still unknown.

The Onduline has been baked for a week, and now has 3*10^-10 torr in the interaction chamber, which is a little too high for the ultimate experiments. An ion beam has been through the interaction region.

The undulator is being used intensively, and the users vary the gap themselves. This has no noticeable effect on the beam or the lifetime, mainly because the beam excitation frequency is modified automatically to compensate for the small tune change induced by changing the gap.

The 1998 ISA Activity Report is now being put together, but several contributions are still missing. PLEASE get them as soon as possible to nh. The deadline for contributions was yesterday!

15/9 1998 nh+spm