Difference between revisions of "Minutes-7-19-2012"
From GlueXWiki
(→Agenda) |
|||
Line 18: | Line 18: | ||
= Minutes = | = Minutes = | ||
− | Participants: Bill, Dave, Eugene | + | Participants: Bill, Dave, Eugene, Nick, Chris, Simon, Beni, Vlad, and Lubomir |
== Production == | == Production == | ||
− | - | + | - The wire frames that are not installed yet are listed in the Construction Tracking (page 1) linked above. We need two wire frames to finish package #4. Frame #2 is ok but has been deadened with 6cm diameter which is for the first two packages. #28 can be used, initially the dark current was higher but went down to 350nA. #3 could be the other candidate but the current increased after two days of testing, will continue with the tests over the weekend. |
− | + | ||
− | - | + | - All these chambers show elevated dark current, maybe due to the same reason. On one of them (#6), on one HV sector (#1) we removed the current limiting resistors connected to the sense wires on the HV board: the dark current remain almost the same. We concluded that the current leakage is on the HV board, and more precisely on the positive HV trace. This trace has a section running on the back side which we suspect is causing the problem due to proximity to the Rohacell and the gold plated area on the back of the board. End of October 2011 we found that these traces are causing noise on the strips and we started coating them with conformal coating. |
− | - | + | - Several options were considered: 1) to put #28 and #3 in the fourth package and finish it, 2)To try to fix two of the boards and use them in the fourth package, 3) to wait for the spare parts to build four new wire frames and use two of them in the fourth package. So far we excluded option #1. Since 2) and 3) will take time we decided to close the fourth package with four cells, take it out of the installation fixture and put there the first package for refurbishment (we did all this right after the meeting). |
+ | |||
+ | - One way to fix the trace (Bill) is to cut the wire frame from the back in the Rohacell region ( Casey has done this once), another way (Dave) is to bypass the trace on the back side and make cable connection on the top. We decided to go with the later, but for that we have to mill a natch | ||
- Third package: 10 ground clips (first article) finally arrived and we tested them on the package. They have a bite of ~12.5mm and we asked for 11mm, that's why we have to bend them a little, but other than that they worked fine. Casey put already them on one cell and is looking for a way to bend them in a standard way, using a press. This is not a big deal and we decided to go ahead with the production of the rest of the clips, instead of waiting another month. Tina and Dave put the labels on all the pre-amps for the third package. | - Third package: 10 ground clips (first article) finally arrived and we tested them on the package. They have a bite of ~12.5mm and we asked for 11mm, that's why we have to bend them a little, but other than that they worked fine. Casey put already them on one cell and is looking for a way to bend them in a standard way, using a press. This is not a big deal and we decided to go ahead with the production of the rest of the clips, instead of waiting another month. Tina and Dave put the labels on all the pre-amps for the third package. |
Revision as of 18:50, 19 July 2012
July 19, 2012 FDC meeting
Agenda
- Production Construction Tracking (Dave)
- Fourth package status and spare wire frames (Lubomir, Vlad)
- Third package preparation
- Grounding scheme (Vlad)
- Engineering [1], [2], [3], [4], [5] (Bill)
- Electronics (Chris, Nick)
- Gas system (Beni, Bill)
- Pipe outgassing, gas detector aiging
- Gas mixture (Lubomir)
- Test set-up in 126 (Beni)
- Other