Report from BESSY
Friday 10/24 10 pm - Sunday 10/26 5 pm
Brad Wargelin, Tim Norton, Robert Austin

Confuration: SSD_X on SX700, SSD_5 on 12-20 (white beam)


Notes:


SRF/QE(E) Measurements on SX700 beam line

We were nearly ready to run, but then BESSY lost beam current when trying to reduce beam current from 3ma to 40ua. By around 01:00 UT, we were ready to start up, but during alignment of the ssd with the SX700, we found a large apparent nonuniformity in the SSD_X response, but this was due to a high LLD threshold setting on the ratemeter SCA (set to approximately match the LLD of the SSD MCB). The SCA LLD was reduced from 0.41V to 0.21V, and the count rate started to make more sense.

Measurements listed as: runID, CMDB-ID, Energy Rate, Comments (rate, etc ..)

Repeat some at lower rates to separate higher orders and pileup.

[<--BJW, TJN-->]

Reinject to do high energies.


17:33 closed gate valve on SSD_5, refilled detectors with LN2

18:00 started aligning detector for white light measurement.

BESSY fits to the SX700 QE(E) measurements resulted in the following window thicknesses:

10-26-97 @02:00 (Central European Time), the clocks were moved back one hour, so I had to relive 01:00 bis 02:00.

[<--TJN, RJA->]


White light measurements with SSD_X

Relative aperture sizes

Measurements listed as: RunID, CMDB-ID, apsize, Comment

The 5000AL25 aperture was used to check the rate for the 5000AL125 aperture. The rate was always too high (obviously). By the time this error was noticed, the rate with the 5000AL125 aperture was only 700 Hz - we will have to skip the ABS QE measurements until after the next injection.


QE uniformity map

All measurements performed at a beam current of 3.0nA, and a rate of 1200Hz

Measurements listed as: runID, CMDB-ID, X(um), Y(um), itime





Relative aperture sizes

Measurements listed as: RunID, TRW-ID, apsize

SAO computer 80 seconds ahead of PTB current monitor computer.

[<--RJA, BJW-->]


Absolute QE/Counting Rate Linearity

Measurements listed as: RunID, TRW-ID, ratemeter rate, dead time corrected rate, collect time, current


QE/Spectral Response Function of SSD_X on SX700



Listed as: RunID CMDB-ID Energy Rate Time


Absolute QE---25-um Al filter

Measurements listed as: RunID, CMDB-ID, ratemeter, dead time corrected rate, collect time


QE/Spectral Response Function of SSD_X on SX700

Measurements listed as: RunID, CMDB-ID, Energy, Rate, Time



Testing concluded at 6:00pm on Sunday October 26. We ftp'd the last data files and logs to PTB and SAO and packed up by 11:00pm ..... back to the hotel to pack and sleep .... we all have flights out in the morning.



Notes

During run 500514, after adjusting the PC server monitor so everything fit on the screen---the monitor is messed up so that the top, bottom, and right edges are cut off whenever the PC is rebooted, which means that the easily-forgotten info on #requests and #clients can't be seen---BJW noticed that the ssd_5 MCB CPU Busy light was flashing at several Hz, and the PC server requests tally was also incrementing at a few Hz, with more clients (2 or 3) than the number of MCB display windows (1). Since we were running SSD_X, this didn't interefere, but over the next couple hours several things were checked, none of which had any effect on either the PC server or MCB:

During run 500620, after 1800 of 2000 seconds had elapsed, the spectrum display started over and the run progress display showed that iteration 15 of 40 was in progress! There were also messages in the launch window indicating that run 500495 was in progress. What apparently happened is that run 500495, an Icing test from 4 days previous, had not aborted properly when it was stopped and was lurking in the background, hammering on one or the other MCB. Eventually it escaped from limbo and nuked the active process. I aborted the old process--again--and continued with run 500621, but the PC and MCB started going nuts again, so after one iteration of 500621 had finished I rebooted the Sun and then the PC. That seems to have exorcised the ghost run.