1 / 18

Transfer Line Studies

Transfer Line Studies. James N. Bellinger University of Wisconsin-Madison 12 December 2008. Summary. No Cocoa yet Hand fits show relative rotation among Endcap disks Can identify backwards DCOPS. Description. 6 Transfer lines at 60 degree intervals around the outside of the detector

kylene
Download Presentation

Transfer Line Studies

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Transfer Line Studies James N. Bellinger University of Wisconsin-Madison 12 December 2008

  2. James N. Bellinger 12-December-2008 Summary • No Cocoa yet • Hand fits show relative rotation among Endcap disks • Can identify backwards DCOPS

  3. James N. Bellinger 12-December-2008 Description • 6 Transfer lines at 60 degree intervals around the outside of the detector • 12 DCOPS on each Transfer line • 4 on each Endcap • 4 on selected MABs • 2 Lasers on each Transfer line • Call them the Plus and Minus lasers • 72 DCOPS in all, with 144 readings • Oriented so the 1/3 CCD pair measure Rφ, 2/4 pair measures radius

  4. James N. Bellinger 12-December-2008 Problems • A few DCOPS were unreadable • Sometimes LV to Barrel DCOPS was off • Lasers were shadowed in places: no signal • Laser direction not always adjustable

  5. James N. Bellinger 12-December-2008 Layout YB-2 YB-0 YB+0 YB+2 Laser Laser ME-4 ME+1 ME+2 ME+3 ME+4 ME-3 ME-1 ME12

  6. James N. Bellinger 12-December-2008 Cocoa Model of Transfer Lines • Is not ready yet.

  7. James N. Bellinger 12-December-2008 Data Selection • From CRAFT run • Select interval with field at 3.8T in which laser directions don’t drift much • Select interval with field off ditto • (CRAFT data taking was two runs: would have been a single run if the power hadn’t failed) • Plot the distribution of mean values subject to quality cuts • Background area <300000 pixel x counts • Signal area>0 and <500000 • Sigma >39 pixels and < 220 • Mean>0 pixels and < 2048

  8. James N. Bellinger 12-December-2008 Endcap-only study • For each magnetic field state • For each Endcap, use the laser at that end • For each Transfer line, use the 4 DCOPS • Reorient the CCD information to match DCOPS mounting • For each CCD, fit the means at the 4 DCOPS and find the residuals • Average the residuals of opposite pairs of CCDs • Interpret these residuals as displacements of the DCOPS and plot them

  9. James N. Bellinger 12-December-2008 Plus Endcap DCOPS displacements Vectors plotted to show dX Ring diameter is not relevant Largest vector has length given in the title Vectors at center average of rest, to estimate disk displacement

  10. James N. Bellinger 12-December-2008 Minus Endcap DCOPS displacements ME-1 and ME-2 show relative rotation about .5 mrad ME-1 and ME-2 show relative dislocation of about 3mm

  11. James N. Bellinger 12-December-2008 Change with field Change in relative displacement with field is mostly radial ME+3 and ME+2 move oppositely (EXPECTED!) The disk YE+2 bends, and the DCOPS positions are cantilevered

  12. James N. Bellinger 12-December-2008 Change of Raw Beam Positions ME-4 ME-3 Difference between field on and off for Minus endcap at each station, as a function of position (φ) around the disk. ME-4 next to laser: little change ME-3: about 3mm ME-2: about 3mm ME-1: about 8mm ME-2 ME-1

  13. James N. Bellinger 12-December-2008 Connecting Across • Select data from 16-August • Not all profiles are usable • For Transfer Line 1, only connect with Up/Down CCD data (Rφ) • Both lasers reach across for Line 1, so I can compare their results directly

  14. James N. Bellinger 12-December-2008 Example of Transfer Line Profiles CCD0 CCD0 data reaches across, but CCD1 gets blocked somewhere CCD1

  15. James N. Bellinger 12-December-2008 DCOPS orientations This one is odd: data suggests other direction DCOPS directions aren’t the same along a line

  16. James N. Bellinger 12-December-2008 Deviations from Linear Fit • 10 Stations had data for Up/Down CCDs (not always both of the pair) for both laser beams • Estimated laser tilt • Averaged CCD values if both present • Corrected for laser tilt if not • Fit for each laser and plotted the deviations from the fits

  17. James N. Bellinger 12-December-2008 Oddity RMS=3.3mm Difference is huge at this point. If I assume the DCOPS is backwards, the points fit very well. RMS=1.0mm Difference in deviations found using Plus and Minus laser fits

  18. James N. Bellinger 12-December-2008 Conclusions • When the beam is unobstructed we can get useful information out of the system • Once mounting variations are understood we’ll have a better measure of the resolution of the system

More Related