Difference between revisions of "Minutes-8-30-2012"
(→Production) |
|||
| Line 24: | Line 24: | ||
- Wire frames: Chris will put the resistors on the first PCB set next week. Then we will start laminating the wire plane #29, we have a frame for it. The other three G10 wire frames will come from the machine shop in ~2 weeks. Fernando and Bill confirmed that the new PCBs can be used. | - Wire frames: Chris will put the resistors on the first PCB set next week. Then we will start laminating the wire plane #29, we have a frame for it. The other three G10 wire frames will come from the machine shop in ~2 weeks. Fernando and Bill confirmed that the new PCBs can be used. | ||
| − | - Roger got quotations from Allflex and Flexible Circuits, the two Minnesota companies that made the cathode foils and the rigid-flex assemblies. According to Allflex they have material for 18-19 foils and we asked for 20. We will need the foils for some of the cathodes on package #2. Based on Dave's estimations for the refurbishment of the first package and then completion of the fourth one, we will need the foils sometime in November-December. In any case it's better to submit the PR now and contact Eugene to use funds (~$ | + | - Roger got quotations from Allflex and Flexible Circuits, the two Minnesota companies that made the cathode foils and the rigid-flex assemblies. According to Allflex they have material for 18-19 foils and we asked for 20. We will need the foils for some of the cathodes on package #2. Based on Dave's estimations for the refurbishment of the first package and then completion of the fourth one, we will need the foils sometime in November-December. In any case it's better to submit the PR now and contact Eugene to use funds (~$26K) from FY12. |
== Cathode corrosion == | == Cathode corrosion == | ||
| + | - The last test with the vacuum chamber: we had a sample with Viton+Apiezon, three O-ring pieces across a strip using the strong (red) clamp and keeping it for one week at high temperature and humidity, the longest time so far. The picture of the sample is linked above: copper changed color everywhere except at the place where the Apiezon was applied. Several dark lines are visible at the O-ring positions. Two on the sides are darker, probably they took the main pressure from the clamp, in the middle we see | ||
== Conductive tape studies == | == Conductive tape studies == | ||
| + | |||
| + | - Vlad did the same ball counting studies as before, but with another cathode (#4, one of the worst: top of former package #1) this time using improved technique in removing the conductive tape and measuring the resistances. The correlation between the resistances and the ball numbers is much more evident now (profile plot above). Again we have about 0.5-2 Ohms per ball and all the resistances above several Ohms (~10-15%) can be explained by loose contacts between the balls and the cathode traces. The highest resistance on this cathode was 50 Ohms. | ||
== Engineering == | == Engineering == | ||
Revision as of 12:19, 31 August 2012
August 30, 2012 FDC meeting
Contents
Agenda
- Production Construction Tracking (Dave)
- Cathode corrosion
- Recent test results: [1]
- Conductive tape studies: [2], [3], [4],[5], [6] (Vlad)
- Engineering (Bill)
- Cathode strong-backs
- Electronics (Chris, Nick)
- PCBs
- Third package tests FDC E-log (Beni)
- TDR, pages 132-145 (Lubomir)
- Other
Minutes
Participants: Fernando, Bill, Dave, Elton, Simon, Chris, Vlad, Beni, and Lubomir
Production
- Dave: working on all the cathodes for package #1. Using the new tool to hold the cathodes flat, two cathodes moved to tables and the cards are being glued there. Will have cathodes for the first, second, and third cells by next Tuesday, next Thursday, and next next Tuesday respectively. This is assuming one cathode per day, which is limited by the tools that we use now.
- Wire frames: Chris will put the resistors on the first PCB set next week. Then we will start laminating the wire plane #29, we have a frame for it. The other three G10 wire frames will come from the machine shop in ~2 weeks. Fernando and Bill confirmed that the new PCBs can be used.
- Roger got quotations from Allflex and Flexible Circuits, the two Minnesota companies that made the cathode foils and the rigid-flex assemblies. According to Allflex they have material for 18-19 foils and we asked for 20. We will need the foils for some of the cathodes on package #2. Based on Dave's estimations for the refurbishment of the first package and then completion of the fourth one, we will need the foils sometime in November-December. In any case it's better to submit the PR now and contact Eugene to use funds (~$26K) from FY12.
Cathode corrosion
- The last test with the vacuum chamber: we had a sample with Viton+Apiezon, three O-ring pieces across a strip using the strong (red) clamp and keeping it for one week at high temperature and humidity, the longest time so far. The picture of the sample is linked above: copper changed color everywhere except at the place where the Apiezon was applied. Several dark lines are visible at the O-ring positions. Two on the sides are darker, probably they took the main pressure from the clamp, in the middle we see
Conductive tape studies
- Vlad did the same ball counting studies as before, but with another cathode (#4, one of the worst: top of former package #1) this time using improved technique in removing the conductive tape and measuring the resistances. The correlation between the resistances and the ball numbers is much more evident now (profile plot above). Again we have about 0.5-2 Ohms per ball and all the resistances above several Ohms (~10-15%) can be explained by loose contacts between the balls and the cathode traces. The highest resistance on this cathode was 50 Ohms.
![[1]](http://www.jlab.org/Hall-D/detector/fdc/corrosion/2012-08-30_09.26.58.jpg){kind=link}