Tuda logbooks General E1104 ISACII E1195 E1103 E1147 S1287 S1203 S1233 S1284 S1447 23Na(a,p) S1540 S1381  S1847 Catania

S1287

Fields marked with * are required Entry time: Wed May 25 03:15:44 2011 Author*: Type: - please select - Routine Other Category: - please select - General Other Subject: <p>Summary at start of run</p> <p>Read through the runbook and end of run summar and the situation appears to be:</p> <p>1. The check of the tune showed it was OK, although a bit of beam (or halo) clipping 4mm collimator</p> <p>2. There are some changes to the gas filling scheme - Jamie should be present for the next one.</p> <p>3. Evidence that the gas pressure is dropping slowly - need to watch this</p> <p>4. Trigger is Coinc.OR.SS_2.OR.PD.&nbsp; Rate at this is 200/s at 4epA (50/50 Coinc and S2_2)</p> <p>5. Suggestion we could increase the beam a factor of two to get back to the same coinc rate.</p> <p>&nbsp;</p> <p>Analysis.&nbsp; Looking at the rates I see:</p> <p>Running at 66 pnA and see about 4,000/s triggers and 3,200/s accepts. Scaler 9 over 40,000/s.</p> <p>Looking back in run book the max trigger accept rate we see is about 3,800/s.&nbsp; Could double beam and gain only</p> <p>modest increase on accepted rate, but at cost of faster damage of detector.&nbsp; Suggest we run</p> <p>like this for a bit and make sure all is well.</p> <p>&nbsp;</p> <p>Took a look through the spectra.&nbsp; All ADCs OK, but no TDC signals.&nbsp; Checked past saved runs.&nbsp; There up</p> <p>to run 98.&nbsp; The next saved on disc is run 104 and they aren't there.&nbsp; Nor in any saved runs after this.</p> <p>Looked at electronics and reason clear as the module providing the TDC trigger (lower section of a</p> <p>429 unit) has no input.&nbsp; Eventually determined that it would make sense if this unit was operating</p> <p>in 2 x 8 mode rather than what it is currently set on (4x4).&nbsp; Switched this over and now working OK.</p> <p>Assume this was changed inadvertently during all the work on the chamber yesterday.</p> <p>&nbsp;</p> <p>0300.&nbsp; Running again and all ADC and TDC spectra make sense.&nbsp; Off for a cup of tea.</p> Encoding: HTML   ELCode   plain   Suppress Email notification          Resubmit as new entry Attachment 1:

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