computing
2006
Updated on Thu, 2007-01-04 14:57. Originally created by potekhin on 2006-10-10 14:42. Under:
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| AuAu 200 GeV central | rcf1289 STARSIMUpdated on Tue, 2006-10-10 14:34. Originally created by potekhin on 2006-10-10 14:34. Under:Starsim Production Geometry TagsUpdated on Mon, 2009-11-30 16:01 by testadmin. Originally created by perev on 2006-10-10 14:06. Under:This page was merged with STAR Geometry in simulation & reconstruction and maintained by STAR's librarian.
OFC West possible distortionUpdated on Tue, 2006-10-03 18:20. Originally created by genevb on 2006-10-03 17:39. Under: There remains a possible distortion due to a potential short in the OFC west as well. We see a bimodal pattern of 0 or 80 excess nanoAmps coming out of the OFC West field cage resistor chain (it has been there since the start of the 2005 run). That corresponds to a 0.38 MOhm short (420nA = 2 MOhms). The corresponding distortion depends on the location of the electrical short. The plot shown here is the distortion in azimuth (or rPhi) at the outermost TPC padrow near the sector boundaries (r=195 cm, the pads are closer to the OFC near the sector boundaries) due to such a short between different possible field cage rings:
In terms of momentum distortion, a 1mm distortion at the outermost padrows would cause a sagitta bias of perhaps about 0.5mm for global tracks (and even less for primary tracks), corresponding to an error in pt in full field data of approximately 0.006 * pt [GeV/c] (or 0.6% per GeV/c of pt). This is certainly at the level where it is worthwhile to try to fix the distortion if we can figure out where the short is. It is also at the level where we should be able to see with the lasers perhaps to within 50cm where the short is. Just as a further point of reference, the plot for radius = 189cm, corresponding to the radius of the outermost padrow in the middle of a sector (its furthest point from the OFC) can be found here.
This possible distortion remains uninvestigated at this time.
Gene Van Buren Update on 2006 issuesUpdated on Wed, 2006-09-06 11:01. Originally created by genevb on 2006-09-06 10:53. Under:FINDINGS: BeamLine position does move with SpaceCharge(+GridLeak) correction. Here I plot the BeamLine constraint as a function of turning on the SpaceCharge correction 10% at a time:  The cause appears to be the Minuit Vertex Finder exhibiting something like a (x,y) = (0,0) bias which gets worse when the distortion corrections are not proper. To demonstrate this, I plot the beamline position as reconstructed using SpaceCharge,GridLeak,ShortedRing-corrected data (left) and uncorrected data (right). The center point in each plot is the "as-is" reconstructed beamline x and y intercepts. I shift all the hits in the TPC by +/-0,1,2 mm in x and y and re-calibrated the BeamLine for each shift. The blue dots represent those shifts given to the TPC hits, while the arrowheads point at the value that comes from the calibration for the respective shifts. Some bias appears to remain even with the calibrations in place, but the bias is clearly stronger for uncorrected data. 
 In this case, the uncorrected data is actually using calibrations as they were in June when the BeamLine calibration was originally done: no SpaceCharge, and only a partial Shorted Ring correction. A few more things can be learned from the data by excluding sections of the TPC. In these plots, I show sector positions as they are in the TPC, divided into 12 supersectors with inner (padrows 1-12) and outer (padrows 14-45) subsectors. Each bin then represents the y-intercept of the beamline when I EXCLUDE the vertices which have any tracks passing through that part of the TPC. I include in text below the plot the y-intercepts for the minimum and maximum shown in the plots, and for the FULL TPC (not excluding any vertices). I can exclude some sectors simultaneously too. EAST IS ON TOP, WEST IS ON BOTTOM (unless I tied east and west exclusion together, so I only show one plot). The disc in the center of each plot represents the FULL TPC position for comparison. First, using the corrections as they were in June, one can clearly see the effect caused by uncorrected SpaceCharge:
In FullField data like this, SpaceCharge makes tracks rotate clockwise when viewed along the positive axis. So SpaceCharge-distorted tracks at positive x tend to want a higher vertex position, while ones at negative x want a lower vertex position. Therefore, excluding vertices which use tracks at positive x from uncorrected data will effectively lower the average vertex position, and vice versa for negative x. The uncorrected data is dominated by SpaceCharge, so both halves of the TPC look pretty much the same. With Shorted Ring and SpaceCharge corrections as they were in July (SpaceCharge calibration had been done without the final Shorted Ring corrections), one can see that we were probably slightly over-correcting for this data, but not by much as the minimum and maximum were both within ~300 microns of using the whole TPC. With the SpaceCharge+GridLeak re-calibrated using the final Shorted Ring corrections in place, the fully corrected plot now appears as in the August-corrections column above. The max-min diff has gone from 310 microns to 220 microns! And the west tpc (bottom) looks essentially flat: there is no distortion apparent in the beamline from the west TPC! The east still shows some remnant distortion. This could be due to either more SpaceCharge in the east than west, or due to not-quite-complete corrections of the shorted ring in the east TPC. Either explanation is viable. These graphs also demonstrate that there is unlikely to be much contribution from misalignment of TPC (sub)sectors. We can remove azimuthally symmetric distortions like our standard SpaceCharge+GridLeak and the Shorted Ring by tying together (excluding at the same time) opposing (in phi) subsectors of the TPC:  Full TPC y = -0.259742 +/- 0.002232 Minimum y = -0.263744 Maximum y = -0.243980 Here I think it is of interest to notice that the major cause for altered beamline in the east TPC is from the outer subsectors at 3 and 9 o'clock. Shorted ring distortions are primarily an inner sector effect and should not show up in this plot anyhow. This means that it is more likely to be due to additional ionization in the east TPC over the west. We can also analyze the horizontal determination of the beamline.  Full TPC x = -0.009712 +/- 0.002242 Minimum x = -0.018511 Maximum x = 0.000031 Again, more distortions in the east TPC. Overall max-min diff here is only 185 microns! It's curious that this is not symetric about 6 and 12 o'clock. Tying opposing subsectors shows something else:  Full TPC x = -0.009712 +/- 0.002242 Minimum x = -0.015330 Maximum x = -0.002258 Both the east and west show something at 5 and/or 10 o'clock (and a bit at 4/10) contributing (minutely - were talking on the order of below 100 microns) to the horizontal position of the beam. dAu photon embedding detailsUpdated on Wed, 2006-12-27 16:31. Originally created by starembed on 2006-08-30 08:30. Under:
AuAu200 photon embedding detailsUpdated on Wed, 2006-12-27 16:29. Originally created by starembed on 2006-08-28 07:52. Under:
LPP group (Dubna) activitiesUpdated on Wed, 2006-12-27 16:34. Originally created by starembed on 2006-08-28 01:32. Under: This page is intended to provide embedding progress for soft-photon
study conducted by PPL (Dubna, JINR) group in Russia.
Run 6: Issues with 2006 BeamLine calibrationUpdated on Wed, 2009-03-18 18:00. Originally created by genevb on 2006-08-22 19:15. Under:From the beamline constraint calibration which has been done for the BeamLine constraint calibration for p+p 2006, there is some reason for concern over the relatively larg
Getting site information from VORSUpdated on Thu, 2007-01-11 10:01. Originally created by stargrid on 2006-08-21 18:04. Under: VORS (Virtual Organization Resource Selector) provides information about grid sites similar to GridCat.
You can find VORS information here.
Run VII preparation, meeting #3 -00-00
Thursday, 1 January 1970 , at 00:00 (GMT), duration : 00:00
STAR HBT phone meeting -00-00
Thursday, 1 January 1970 , at 00:00 (GMT), duration : 00:00 From Skype call +99008275548848 1-605-475-8500 (long distance costs apply). Calling from Europe, call In Belgium: 070 35 9987 In France: 0826 100 275 In Germany 01805 00 7646 In Ireland: 0818 270 032 In Italy: 0848 390 172 In Switzerland: 0848 560 152 In UK: 0870 738 0760 (national rate charges will apply). Enter Conference Room Number : 5548848
STAR HBT phone meeting -00-00
Thursday, 1 January 1970 , at 00:00 (GMT), duration : 00:00 From Skype call +99008275548848 1-605-475-8500 (long distance costs apply). Calling from Europe, call In Belgium: 070 35 9987 In France: 0826 100 275 In Germany 01805 00 7646 In Ireland: 0818 270 032 In Italy: 0848 390 172 In Switzerland: 0848 560 152 In UK: 0870 738 0760 (national rate charges will apply). Enter Conference Room Number : 5548848 STAR HBT phone meeting -00-00
Thursday, 1 January 1970 , at 00:00 (GMT), duration : 00:00
STAR HBT phone meeting -00-00
Thursday, 1 January 1970 , at 00:00 (GMT), duration : 00:00
STAR HBT phone meeting -00-00
Thursday, 1 January 1970 , at 00:00 (GMT), duration : 00:00 From Skype call +99008275548848 In the US, call 1-712-432-4000 Calling from Europe, call In Austria: 0820 400 01562 In Belgium: 0703 59 984 In France: 0826 100 266 In Germany 01805 00 7620 In UK: 0870 119 2350 Enter Conference Room Number : 5548848 STAR HBT phone meeting -00-00
Thursday, 1 January 1970 , at 00:00 (GMT), duration : 00:00 From Skype call +99008275548848 In the US, call 1-712-432-4000 Calling from Europe, call In Austria: 0820 400 01562 In Belgium: 0703 59 984 In France: 0826 100 266 In Germany 01805 00 7620 In UK: 0870 119 2350 Enter Conference Room Number : 5548848 STAR HBT phone meeting -00-00
Thursday, 1 January 1970 , at 00:00 (GMT), duration : 00:00 From Skype call +99008275548848 In the US, call 1-712-432-4000 Calling from Europe, call In Austria: 0820 400 01562 In Belgium: 0703 59 984 In France: 0826 100 266 In Germany 01805 00 7620 In UK: 0870 119 2350 Enter Conference Room Number : 5548848
STAR HBT phone meeting -00-00
Thursday, 1 January 1970 , at 00:00 (GMT), duration : 00:00 From Skype call +99008275548848 1-605-475-8500 (long distance costs apply). Calling from Europe, call In Belgium: 070 35 9987 In France: 0826 100 275 In Germany 01805 00 7646 In Ireland: 0818 270 032 In Italy: 0848 390 172 In Switzerland: 0848 560 152 In UK: 0870 738 0760 (national rate charges will apply). Enter Conference Room Number : 5548848
STAR HBT phone meeting -00-00
Thursday, 1 January 1970 , at 00:00 (GMT), duration : 00:00 From Skype call +99008275548848 1-605-475-8500 (long distance costs apply). Calling from Europe, call In Belgium: 070 35 9987 In France: 0826 100 275 In Germany 01805 00 7646 In Ireland: 0818 270 032 In Italy: 0848 390 172 In Switzerland: 0848 560 152 In UK: 0870 738 0760 (national rate charges will apply). Enter Conference Room Number : 5548848
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