06/04/97 Update

Lastest PEP-II Commissioning

Since our last note in May, PEP-II commissioning has continued at a good clip. Here is the latest as of Wednesday morning June 4:

The HER vacuum system was completed all around on Saturday May 31.

Sunday June 1 was used to finish last minute details.

On Monday June 2, a 9 GeV electron beam was reestablished. Since the power supplies for the IR2 insertion quadrupoles were not ready, a temporary IR lattice was generated to "drift" the beam through IR2 without the insertion quads. By 9 pm on Monday the beam was to back to IR2 (1/3 of the HER) as in May and starting to emerge from IR2. By 11 pm the beam was seen on loss monitors and beam position monitors in IR6 (another 1/3 of the ring).

By 4 am on Tuesday June 3 beam was seen at the end of one full turn in the HER in IR10. There seemed to be an "obstruction" near IR6 which caused some beam losses and required steering and quadrupole adjustments. By 11 am on Tuesday a start of a second turn was seen. The injection kickers were energized and the injection DC bumps adjusted. By 12 noon a full second turn and a part of a third was seen. One turn lattice measurements were also taken.

This morning Wednesday June 4 access has been taken to investigate the IR6 "obstruction" and to finish work on the insertion quadrupole power supplies. We plan to have the hardware ready to store beam by the end of today.

The near term plans for the HER are to 1) generate many turns, 2) capture the beam with the RF system, and 3) inject several bunches. We intend to do HER studies most of the month of June. Also, the two kilometers of positron extraction line and bypass line are ready for beam tests and we have been given permission recently by the safety committees to do so. Positrons tests will begin as soon they fit with the SLC positron program.

We are very pleased with the commissioning progress so far. Many thanks to all the people from the three laboratories (LBNL,LLNL, and SLAC) and our review committees who have worked so hard to get us this far. Your hard work has paid handsomely. Many thanks again.

Cheers, John Seeman

Suggestions to: John Seeman

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