1 HBD Update Itzhak Tserruya DC meetingJune 10, 2009 June 10, 2009

Most Recent Scan Anlz: H=0.0ppm, O=0.3ppm Trans: H=0.0ppm, O=0.0ppm %Int. Trans (Fit: nm)=100.0% %Int.Trans. (Data: nm)=102.2% Anlz: H=6.8ppm, O=3.3ppm Trans: H=31.6ppm, O=4.1ppm %Int. Trans (Fit: nm)=88.4% %Int.Trans. (Data: nm)=92.6% Anlz: H=4.1ppm, O=1.3ppm Trans: H=27.6ppm, O=4.5ppm %Int. Trans (Fit: nm)=89.3% %Int.Trans. (Data: nm)=95.3% Ever since the flow rate was increased to ~4lpm just before the start of the run, the ppm values in both arms have remained more or less stable. 2June 10, 2009

Transmittance History 3June 10, 2009

4 Present status WEST: All 10 modules up and running in a very stable mode since the beginning of the run. EAST 8 modules running in a reasonably stable mode since the beginning of the run. 1 module very unstable (EN4) 1 module disabled (ES1) since the beginning of the run. Has a short between the mesh and the top GEM. Not clear what happened LeCroy HV PS We still have some problems with one of the LeCroy PS which induces from time to time a trip in the quartet of modules that it supplies. Seems to behave better over the last week.

5 June 10, 2009 Gain stability - West

6 June 10, 2009 Gain stability - East

7 June 10, 2009 Run-9 history: West WS1 WS2 WS3 WS4 WS5 WN1Dead short on Top GEM repaired on March 3 WN2 WN3 WN4 WN5 Summary: one short in one module  0.2 % loss of acceptance

8 June 10, 2009 Run-9 history: East ES1Disabled since March – Short between mesh and Top GEM ES2Bottom dead short - repaired on March 3 ES3Middle dead short - March 3 Bottom dead short - June 4 ES4 ES5 EN1 EN2 EN3 EN4Middle dead short found during assembly Middle second dead short - March 12 Bottom dead short - April 1 Top partial short – May 12  dead short May 27 Bottom additional partial short – May 12  dead short May 27 EN5Bottom dead short - March 12

9 June 10, 2009 Run-9 history: Summary Summary West: one short in one module  0.2 % loss of acceptance Summary East: ES1 disabled  2.6% loss of acceptance ES2 1 ds  0.2 % loss of acceptance ES3 2 ds  0.4 % EN4 5 ds  0.9 % EN5 1 ds  0.2 % Total 4.3 % acceptance loss Clear difference in the behavior of the West compared to the East reflecting the much better assembly procedure used for the West detector.

10 June 10, 2009 Run-9 history: Summary (II) Check for possible aging effects: two GEMs from the East arm, randomly chosen among those that were found to be perfect in the initial test back in December 2008, were retested on May 12, 2009 and found to be perfect with no sign of any aging effect.