Attendance
L.Gutay,O.Prokofiev, Y.Pishialinikov, N.Terentiev, S. Medved, G.Apollinari, N.Chester, A. Korytov, D. Earthly.

Agenda
Dave                        Latest Alignment Development
Sergei                      Cross-Talk Measurements on P2'
Giorgio                    ME23/2 Design Review
Laslo                       Wire QA/QC Measurements.

Latest Alignment Developments.
Dave gave a report on the alignment system and on the requirements on the monitoring of the chamber position. The requirements from the trigger group is that the strips be located with an error below 1 mm, which puts a requirement of approximately 0.25-0.5 mm on the location of the sensor, and 0.25-0.5 mm on the location of the strips in a chamber respect to the sensors (i.e. respect to the alignment pins).
The relative position monitoring is expected to track the position of the chambers to 0.1 mm. Dave described how he needs to bridge the anode electronics on the wide part of a chamber. However the proposal to reference the location monitors off the frame was considered rather risky, given the insufficient referencing of the frame to the chamber (they are related only in one point, at the position of the alignment pin). Nelson suggested the idea to locate the monitors off the top panel. Dave, Nelson and Farshid will evaluate this solution.

Long-range X-talk on strips.
Sergei described Adam measurement of the long-range x-talk among strips. He excludes the chip in which the signal develops (16 channels) and look at the charge on all the other strips relative to the calibration baseline (the x-talk signal is negative respect to the main signal). For the measurement of the signal, Adam looked at the signal charge after the baseline was corrected. The correlation between the x-talk charge and the signal charge is very clear, and the average value is -0.35% for the 4 planes in P2' with a 1 nF capacitor, and -0.25% in the two planes where the 2 nF capacitors where installed. Sergei also presented the interesting case of one pre amp that was switched off but still connected to the anodes wires (as opposed to all the other anode wires that were grounded through a 20 ohm resistor). In that case the x-talk was -0.85%, with no clear visible change for the layers with a 2 nF capacitor.

Design Review.
Giorgio presented the plan to reach operation readiness for panel cutting in Lab 8. The first step will be the Design Review, scheduled to take place on February 15.  The review committee is asked to :
" 1) Assess the Chamber Design Readiness for the ME23/2 chamber.
  2) Review the specific drawings of the ME23/2 chamber with emphasis on features related to panels machining and parts to be produced. "
The review will take place in ICB 2W, in the TD Headquarters, at 1:30, and is open to the EMU group.

Giorgio also presented the results on the direct measurement of the panels thickness (these are the 14 trial panels procured in October).  The thickness was measured with a deep-throath caliber at intervals of 6 inches, and reaching 1 foot inside the panel.  The average thickness was 624+/-4 mils, with a max. of 643 mils and a min of 617 mils. The thickness distribution is clearly skewed, in a direction opposite to our preliminary technical specifications (we observe 624+20-10 mils, while the preliminary specs where 625+9-19 mils).

Fiber Optics Based Wire Surface Imperfection Detector.
Laslo descried a reflectivity based system to monitor the quality of the wire. Based on the fact that at 640 nm, gold is 96% reflective, the expectation is that surface imperfections would dramatically change the reflected intensity. He described a simple experiment, where an He-Ne laser at 633 nm was used to shine a fiber, and the reflected light was observed by a SiPIN photo diode. He noticed the light decreasing by a factor of 2 when the wire was scratched.
Laslo then described a Fiber Support system, where a small 10 mm thick and 24 mm in diameter disk houses a number of fibers shining at a wire going through the center and reading back the reflected light.  He will construct a fiber transport system to test his idea on the "bad" wire he received from D0.