Minutes Run IIB Silicon General Meeting,
These minutes can be found at:
ü News / Status George / Marcel
ü Washington Meeting Summary-Electrical Marvin Johnson
ü Washington Meeting Summary-Mechanical Bill Cooper
ü Readout Update Andrei Nomerotski
ü Frequency Dependence of the Interstrip Capacitance and the Full Matrix Scan Bob McCarthy
ü Database Update Eckhard von Toerne
News/Status (George, Marcel)
o A Director’s Review of the Run IIb Detector Upgrades has been scheduled for June 3-5. The schedule for the review calls for one hour of silicon presentations and all L3 managers should prepare a 15 minute presentation which will be included in a binder for the reviewers.
have received responses from
o Lower limit specification on depletion voltage is accepted
o Hamamatsu prefers mask alignment tolerance of ±2mm and their default sensor numbering scheme
o Hamamatsu proposes to include a polysilicon resistance monitor in the production deliveries
o Hamamatsu reports flatband voltage of 1.5V
o Second prototype SVX4 wafers arrive at Fermilab tomorrow (May 16)
o Two L0 hybrids have been received and meet mechanical specifications
o Partial Operational Readiness Clearance for the hybrid and module test stands has been signed.
o The revision 3 Purple cards have arrived at KSU
o Orders for the High Voltage supplies and probe station have been placed by Cinvestav
o Prototype Aluminum box for radiation monitor has arrived at Fermilab
o PLEASE BE SURE TO KEEP US INFORMED OF YOUR TRAVEL AND VACATION PLANS
Washington Meeting Summary (Marvin and Bill)
o There was a meeting at the University of Washington on May 5 and 6 primarily focusing on grounding for the inner layers. Marvin and Bill provided a summary of the meeting.
o Marvin emphasized that we are trying for low inductance coupling between the hybrids and the sensor support structures and between the various parts of the support structures
o Multiple connections
o Wide thin traces
o Solid ground plane is unnecessary, ground mesh is adequate
o Avoid floating conductors
For Layer 0 we need to short out the capacitance formed by the HV board on the sensor and the carbon fiber support structure. The kapton mesh pieces that we have designed and prototyped will be used for that. For the hybrid support structure, one needs to have a good connection between the sensor ground to the hybrid with low inductance. Foreseen is the use of six kapton mesh strips on only one side of the hybrid.. The cooling lines need to be grounded as well, which can be achieved with conductive epoxy.
for achieving these goals have been identified,
discussed and are being worked on by the
o A point of concern that was raised was the RTD’s. The RTD cables will run all the way to the junction cards and capacitive filtering should be provided so that no noise is introduced through these cables. No conceptual plan for the RTD filtering exists as of yet.
o Jim reported that four Layer 0 ELMA sensors have had 0.5 mm cut from each long edge (the guard ring remains intact) in order to have nominal Hamamatsu size L0 sensors available. Two of those sensors were “mechanical”, and two were “electrical” grade. Those sensors were tested prior to cutting, and will be tested again after cutting.
Readout Update (Andrei)
o Andrei provided a very nice summary of the status of the readout, and the details are available at http://d0server1.fnal.gov/projects/run2b/Silicon/www/smt2b/Documentation/Minutes/SiReadout_status_051503.pdf
o Marvin pointed out that the current plan is not to dice any of the SVX4 wafers until after they have been tested.
o Andrei reported that the SVX4 shows relatively little sensitivity to the PARST signal (beyond the first few pipeline cells after PARST on the bench. There was some discussion of the possibility of attempting to check the pedestal as a function of pipeline after the PARST for the SVX2 at a test stand to determine whether the ground problems that are apparent in the assembled system are also apparent on the test bench.
o Andrei noted that there are urgent tasks that are not getting attention such as comparisons between the sensor and module test results, and we are planning to build electrical staves soon, so it would be good to get the appropriate modules burned in, in the very near future. Someone should start to systematically perform the quality assurance of the silicon modules.
o Bob reported on the observed unusual frequency dependence of the interstrip capacitance measurements (with a peak around 1kHz) on sensors. He has verified that he does not see the same effect using the same setup on a bare capacitor. The symptoms are also not bias voltage dependent or dependent on the level for the measurement. Details are available at http://d0server1.fnal.gov/projects/run2b/Silicon/www/smt2b/Documentation/Minutes/Silicon_Testing_freq_matrix_scan_050803.doc
o Bob noted that he was not currently using any specifically designed hold down mechanism during probing of the sensors, and Regina suggested that he should indeed be restraining the sensors during probing.
o Bob also noted that while using the matrix they are switching the bias off between measurements for each strip, and the L0 sensor was measured in four hours in this mode. It was agreed that the sensors can remain biased during all measurements.
o The final temperature and humidity controls are not yet installed at the Stony Brook probing site.
o Bob showed results of coupling capacitance measurements that included two groups of three channels at more that twice the average values. This seems to indicated shorted Aluminum strips on the sensor. It was recommended that these measurements be repeated and that the sensor be visually inspected to see of the Aluminum strips are indeed shorted for three adjacent strips.
Status of Database (Eckhard)
o Eckhard was unable to make his presentation because the meeting ran into overtime, but you can view his prepared slides at http://d0server1.fnal.gov/projects/run2b/Silicon/www/smt2b/Documentation/Minutes/database_may15.ppt
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