Attendance
L.Gutay,O.Prokofiev, A.Bujak, Y.Pishialinikov, G.Smith, R.Evans, N.Terentiev, S. Medved, G.Apollinari, N.Chester, D.Nothacker, A. Korytov (by video).

Agenda
Adam                      Resolution Studies in  P2'.
Dave                       Gas System Proposal for MP9
Ron                         Interactions with Plascore
Yuri                        Cordex Measurements on P3
Oleg                       HV Status of P2',P3 and Aging Test Chamber

Resolution Studies in P2'.
Adam presented some results coming from his resolution studies for P2'. He fits a line through 5 of the six points in a plane (as measured by the strips) and computes the average residual. When the residual is plot as a function of the location along the chamber (he uses the scintillator counters to define such a location) if the planes are perfectly aligned to each other, then the residuals are supposed to average to zero and lay on an horizontal line.

As a function of anode position, Adam observes lines where the average residual is ~ 100 microns, with slopes of the order of 100 microns/meter. This shows that the individual planes needs an additional correction to obtain a perfect alignment among themselves.

Finally Adam presented a series of curves which give the average strip resolution as a function of position of incidence on a given strip. When the particle hits the center of the strip, the resolution is at its worse (ranging from 200 to 800 microns along the length of the chamber, from the thin to the wide grooves). When the particle hits between strips, the resolution is at its best (~100 microns) irrespective of the strip width.

MP9 Gas System.
Dave presented a proposal for a gas system in MP9. The system would be similar to what we have in Lab 7 at the cosmic test and what would be setup in UF and UCLA. Dave considered a system that could switch the FR4 off, for the initial chamber purging, to turn it on later for HV training and test measurements.  The system Dave described would cost around 10k$.  Of the 2 mixing system that Dave described (constant pressure and constant flow) the second is preferable, since it would allow any number of chambers to be connected to the output manifold. However the MKS flow controllers presently used are not factory calibrated on CF4. Dave mentioned that the Mathelson controllers are calibrated for CF4.
Dave went also through some gas estimates, which indicated that at 200 cc/min we would have to change gas bottles twice/month, which is acceptable from the operational point of view.
Finally Dave indicated a possible problem with the presence of silicone oil in copper tubes, and his preference for stainless-steel pipes.

Plascore Situation.
Ron described the situation with Plascore. Fermilab is procuring 4 carbon steel platens to provide Plascore with better tooling (the platens presently used by Plascore are anything but flat). The platens are machined according to Plascore drawings. Fermilab is also providing flat support to allow Plascore to cool the panels in a flat condition after their manufacturing.

P3 Measurement on the Cordex.
Yuri described his work on the measurement of strips and marks position done on the Cordex, a Coordinate Measurement Machine used by the Fermilab inspection group.
The accuracy of the machine is 5 microns (0.2 mils). Yuri defined a system center on the hole used for the alignment pin and measured the position of the grooves respect to their theoretical position derived from the engineering drawings. He described the impressive number of measurements done to define the position of the grooves. The machine was scanning across a groove, measuring the x-y-z position of the surface of the panel in approximately 60 points. In this way Yuri was able to define the center of the groove (and its location) very precisely. He noticed that the grooves are straight lines to the level of 2 mils, which is very good. However, when measuring the absolute position of the grooves, he determined that the first groove (groove #1) was precisely at its theoretical position, groove #41 (a groove in the center of the panel) was shifted by approximately 100 microns (4 mils) while groove #80 (the last groove in the panel) was shifted by 200 microns (8 mils) respect to the theoretical position. There appears to be a systematic error in the machining of the Gerber cuter that is being further investigated.
Finally Yuri presented a scan across the full width of the panel, showing the groove depth variation, ranging from 3 mils to 10 mils, due to the known local  "bumps" and "valleys" in the panels.

HV Status of P2', P3 and Aging Test Chamber.
The aging test chambers can hold 4.5 kV.
P3 can reach 4.4 kV in all the chamber. A number of segments can go higher to 4.5 or 4.6 kV.
P2' can reach 4.2 kV in all the chamber. One segment has the wires misplaced respect to the center of the plane, and cannot go any higher. 5 of the 6 segments in the narrower section of the chamber can only reach 4.3 kV before corona develops. The present theory is that the corona develops on the first wire segment, where some wires are placed of the gas holes at the bottom of the anode panels. Further investigation will clarify the issue.