ISA meeting

Week 17, April 21, 1998.


Status of the ring: The last week of electron run 1/98 went well. During the last days of the run, the bunch length was measured. At 150 mA, it is more then three times larger than expected, at 60 mA about twice as large, and with 30 mA in the ring, we measure the expected bunchlength of 0.6-0.7 ns. In addition, we found that even with a large current, the bunches are short for a few minutes following an injection. We will continue these measurements in electron run 2/98. A small influence on the bunch length of the phase-modulation of the RF-frequency was also observed.
The ring is now being modified for ion operation. The laser chamber has been mounted instead of the undulator chamber, and the ion cavity will be mounted today, such that baking can start tomorrow, if the control system is ready by then.

Electron run 2/98 will start in August, so now we should start thinking about modifications, such that everything can get ready for the next changeover in week 29-31.

The onduline group last week observed a change in photon beam position in the reaction chamber with varying undulator gap. This cannot be observed on electron beam by the ring pickups, so there may be an alignment problem in the monochromator.

The Microtron will have its new cooling system mounted next week. At the same time, the machine will be realigned and trimmed in an attempt to get back to the good old days, when we routinely had 10mA/1µs pulses.

The new control system is being checked during this changeover. TW reports, that everything is moved to the new system, including the ramping system. It will be changed back to the old system before the ion run starts, because crucial parts are still missing, especially for running electron cooler experiments. So far, no problems have been found.

The EBIS problems, concerning two HV-supplies, have been fixed, and we are now ready to attempt simultaneous injection and extraction of a separator beam. Just now, we are fighting electrical noise from the RF source. As soon as that is under control, we will continue the commissioning.

21/4 1998 NH + SPM