-- BrendanKiburg - 05 Nov 2007

Brendan's original bad wire report

ePC2 has been disassembled in order to repair the broken wires. We have looked through run 11 for other hot spots / hot wires that we should check while the chamber is open.

Anode sectors should have 32 wires , I label the wires 1-32. As we go around, in the direction of increasing sector, I start with wire 1 and end with wire 32: Wire 1, Sector 1--Wire 32, Sector 1 -->Wire 1, Sector 2--Wire 32, Sector 2, etc...

Cathode sectors have 16 wires. The same convention is used.

Additionally, anode sectors are denoted with an A, while cathode sectors are denoted with a C.

See the attachment in http://www.npl.uiuc.edu/elog/mucap/run11/83 for the mapping. See also the explanations in andi.pdf.

Elog Date Run Anode I.Cath O. Cath Sector Wire Comment
69 08/14   2622     A5 19 During setup, hot spots
69 08/14     3375   C18 3 During setup, hot spots
388 09/09 53133 2622     A5 19 Part of hot spot
388 09/09 53133   3226   C8 14 Part of hot spot
388 09/09 53133     3862, 3863 C24 11,10 hot spot, coinc on 3863, singles on 3862
584 09/25 58369 2621-2623     A5 18-20 Wider spot on anode
584 09/25 58369     3863, 3864 C24 10,9 Wider spot on cathode
875 10/18       3796,3804,3808 C28 16,13,5 Could be electronics
875 10/18       3856 C25 1 Could be electronics
64 08/13       3809 C27 16 pulsed mode fine, clusters missing
64 08/13       3823,3824 C27 2,1 pulsed mode fine, clusters missing
64 08/13       3825 C26 16 pulsed mode fine, clusters missing

Andi's reports

Extraction of the "dead spot" wires

After consulting with Steven, I have determined how the mapping is setup and slightly tweaked the cathode settings Based on the Illinois analysis code, it appears the dead spot centered around z = +50 mm, phi = 3 radians corresponds to the following wires and sectors:

  • Anodes: 2701->2750 (Sectors A2, A1)
  • Inner Cathodes: 3242->3269 (Sectors C10 and C11, a little of C9)
    • wire 3242 has (z=+94 when phi = 2.8 and z=+191 when phi = 3.1)
    • wire 3269 has (z=-78 when phi = 2.8 and z=+19 when phi = 3.1)
  • Outer Cathodes: 3882->3912 (Sectors C23, C22 and C21 -- half of C23,C21, all of C22)
    • wire 3882 has (z=-102 when phi = 3.1 and z = -7.6 when phi = 2.8)
    • wire 3912 has (z=+84 when phi = 3.1 and z= +179 when phi = 2.8)

  • The peak of the intersection should be A2xC10xC22

  • ePC2 inefficiency:
    hepc2Efficiency.gif

  • The 2nd image comes from run 10. It shows the location of the anodes in question. The Inner Cathode 9-10 boundary has also been drawn. The inefficient lines are projections of the ePC1 cathodes, which are not parallel to the ePC2 cathodes.
  • By looking up the specifications of ePC2 from, http://www.npl.uiuc.edu/exp/mucapture/coll/epc2/Specifications.doc , I have determined that the blue lines represent the position of the cathodes:
    e.g. length of 800 and angle of 44.308 degrees means that the displacement along the circumference is 800* tan (44.308) ~ 781 mm
    Since the diameter of the inner cathodes is 632 mm, the displacement in phi over the length of the wire is 781/324 ~ 2.47 radians
    The blue lines have such a displacement in phi, whereas the inefficient "stripes" seem to be more like 4 radians.
  • Efficiency with sectors labeled:
    eff_wlines.gif

Topic attachments
I Attachment History Action Size Date Who Comment
PDFpdf andi.pdf r1 manage 131.9 K 2007-11-27 - 03:38 PeterKammel  
GIFgif eff_wlines.gif r1 manage 18.7 K 2007-11-29 - 22:37 BrendanKiburg Efficiency with sectors labeled
GIFgif hepc2Efficiency.gif r1 manage 37.8 K 2007-11-29 - 04:53 BrendanKiburg ePC2 inefficiency

This topic: Main > TWikiGroups > MuCapGroup > MuCapRun11 > DetectorRepair
Topic revision: r10 - 2007-11-30 - BrendanKiburg
 
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