CESR Tuning - 2 beam current limit in 9t,5 bunches Got up to 496 ma. S

Vacuum - During machine studies, lost 330 mA positron beam, and opened the Q3E/B3E joint leak badly. The pressure went up as high as 1e10-2 torr. Tighten the flange a little, and we were able to get all the ion pumps on. Flashed B3E/W, SB3E/W and ISP E/W TiSPs. S

Inflector not ready due to synch vacuum trip. Get Trouble Panel alarm 17 also. See Extremely high (off the chart) vacuum only at T27 MPX. Rapped on PIG gauge, and pressure readout changes from greater than 10**-3 torr to 2x10**-5 torr. Replace MPX card, get same pressure. Cold cathode gauge AT THE SAME LOCATION says pressure is 10**-6. So we have a bad PIG gauge. Unplugged the HV PS for T27 PIG gauge to disable alarm and get inflector ready. S

Linac RF - Replaced another new Maxwell capacitor which blew apart in Modulator 6. S

Began processing Linac RF test section. LS1 and parts of L0 are roped off or gates are locked up, and signs are posted. Only running Modulators 1 and 8 which power section 1 and the test section in L0 on top of synchrotron (because of reduce cooling capability - cooling tower for Linac/Synch/Exp 85 deg water is partially shut down). Quickly ran up to 3 MW (out of ~16 MW maximum). Lots of vacuum action, and processing slowed at about the 4 MW level. So far, maximum is 11 MW (with lots of VSWR's and vacuum action).

Modulator #3 klystron filament overcurrent. Bypassed interlock. W

Feedback - LONGITUDINAL THRESHOLDS, FEEDBACK CAVITY: Measured 9x5 and 9x4 single and two beam thresholds for various states of feedback cavity port termination. See 360 mA 2 beam threshold with all ports terminated, versus 300 mA threshold with 3 ports terminated and 3 open. No effect seen in the 9x4 2 beam threshold. These observations are consistent with cavity placement, which doesn't provide sufficient gap between electrons and positrons at the present location. F

Measured longitudinal instability "thresholds" for the remaining 9x4 bunch spacing for single and two beams. 9x4 spacing other than 1,2,3,4 have significantly higher two-beam "thresholds" (from 380-410 mA), which are higher than 9x5. Also saw several times (with two-beams) that the excited lines went away as more electron current was added. Continued filling was then limited by RF. This effect was quite reproducible (and was seen also in 9x5 two days ago). So it seems the more current the better! S

CESR Magnets - temperature - Q01E. access confirmed that main 4 of Q01E is in fact periodically running overtemp. S

CESR RF - Modified the "SRF control signal combiner" in the west transmitter. It now inhibits switching from field to reflected power regulation if the tuning angle error is less than 1 V and if the field is greater than 10 kW. Otherwise, the output is the greater of the field or 90% of the reflected power. Q

Pulse processed W1 with forward power up to 200 kW. F

Temporarily reduced the west RF amplitude regulator integrator reset delay by 2, to about .5 ms. This appears to have fixed the beam killer/quench trip problem. However, it seems that the cavity amplitude loop bandwidth is a little too high, so there is some overshoot on turnon. F