Minutes Run IIB Silicon Sensor Meeting, March 13, 2003

These minutes can be found at:
http://d0server1.fnal.gov/projects/run2b/Silicon/www/smt2b/Documentation/minutes/minutes_Mar13_03.html  

 

Agenda

ü      News / Status                                                   George / Marcel 

ü      New Analogue Cables                                      Frank Lehner

ü      Update Flux Normalization                               Tim Bolton

ü      Status Layer 0/1 sensor tests                             Regina Demina

ü      Comparison test results with  HPK                    Sergey Korjenevski

ü      Plan for layer 0/1 PRR                                      all   

 

News / Status   (George, Marcel)

o       The Production Readiness Reviews for the outer layer sensors was held the previous week on March 6, 2003. The committee members are Nicola Bacchetta, John Ellison (chair), Bruno Gobbi, Ron Lipton, Hartmut Sadrozinski, Steve Worm. The initial feedback from the committee was that the results presented were adequate, but that the level of quality and understanding of the results ought to be significantly improved. You can find all the material presented at the Review at
http://www.physik.unizh.ch/~lehnerf/dzero/prr/prr_l2.html

Analogue Cables        (Frank Lehner)

o       http://d0server1.fnal.gov/projects/run2b/Silicon/www/smt2b/Documentation/minutes/dyconex_status_march2k3.pdf 

o       Frank brought a new batch of 40 analogue cables from Dyconex. Please note that this is an in-kind contribution from the University of Zuerich. These cables are of superior quality. There are no shorts or opens in the cables. The trace width is slightly larger than our specification: 19 microns rather than 15-16 microns. Pitch is 91.5 microns. An initial look at the capacitance of the traces shows 0.34 pF/cm averaged to both neighbors with in addition 0.17 pF/cm to lower cable for a total capacitance of 0.51 pF/cm for cable stack plus ~10% for higher orders. The ANSYS calculation by Kazu obtained 0.47 pF/cm for 200um spacer with dielectric constant of 2.0 ( we have ~2.5).

o       Dyconex also has a proposal for laminating the cables. They produced a special ‘mesh’ cable, which are kapton cables with holes of radius 60 mm. The cables come in three varieties: hole-distance 190, 210 and 230 mm, which corresponds to an er ~1.95, 2.2 and 2.45. All mechanical details need to be understood before we can decide to accept this lamination proposal. We should aim for finalizing the analogue cable design sometime in June.
  

Update flux Normalization     (Tim Bolton)

o       http://d0server1.fnal.gov/projects/run2b/Silicon/www/smt2b/Documentation/minutes/TB_Radiation Test Status.pdf 

o       A main issue during the sensor PRR was the flux normalization. The results from the irradiation tests gave a value for a of 1, whereas the expected value is 3. An error was made in the normalization to area. The area of L1 sensors was used rather than the area of the Layer 2 sensors, which gives a factor of 2. A set of cross checks was made at KSU

o       Flux calculation from Faraday cup was cross checked and found to be okay.

o       Fluence will also be independently measured using a Cu foil.

o       The hypothesis of the protons “channeling” through the Si was studied by positioning the sensors at an angle. No effect observed.

o       Hardness parameter k uncertainty. A value of 3.87 from a model calculation was used, though there is some indication from the Montreal group that a slightly lower value for k is preferred.

o       Work will continue.

 

Status Layer 0/1 Sensor Test Results    (Regina Demina)

o       See March 20 presentation and below

 

Comparison Test Results with Hamamatsu Results           (Sergey Korjenevski)

o       http://d0server1.fnal.gov/projects/run2b/Silicon/www/smt2b/Documentation/minutes/irrad_results_dec2002.htm

o       There are 15 ELMA layer 1 sensors. Of these, 4 are mechanical, 7 are from the first batch and 4 from the second batch. Three Hamamatsu sensors were irradiated (sensor # 7, 11 and 12 I believe). They were irradiated to a flux of about 0.8E12 1MeV neutron equivalent. All sensors are type inverted, although the inversion point is not clear. Studies of leakage current are in progress. One HPK sensor showed an anomalous number of bad strips (>50 strips) and will be remeasured.

o       The grading of the two vendors, ELMA and HPK, gave an overall electrical grade of 1.33 to ELMA and 1.9 to HPK. The sensor with the bad strips is the only sensor that receives a grade less than 2.

 

Link to the Run IIb silicon page
http://d0server1.fnal.gov/projects/run2b/Silicon/www/smt2b/smt2b.html

Links to minutes archive
http://d0server1.fnal.gov/projects/run2b/Silicon/www/smt2b/Documentation/Minutes/minutes_silicon.htm