Difference between revisions of "Minutes-5-23-2013"

From GlueXWiki
Jump to: navigation, search
(→‎Agenda)
Line 15: Line 15:
 
= Minutes =
 
= Minutes =
  
−
Participants: Casey, Bill, Dave, Chris, Simon, Beni, and Lubomir.
+
Participants: Bill, Eugene, Glenn, Chris, Nick, Simon, Beni, and Lubomir.
  
 
== Production ==
 
== Production ==
  
−
- Spare package: interestingly the second cell with wire frame #6 showed the same problems as with wire frame #3 before: no signals on chan.1, point source of noise in one of the middle wires and glow discharge (sudden increase of the current on both sense and field wires). The difference is that the source of the noise was at the end of the wire (as picked up by the strips), and also that the glow discharge disappears when removing some of the cathode cards. All this was pointing that the problems are caused by the tip of the wire sticking out of the solder.
+
- Spare package: On Friday all the channels of cell #2 were tested and worked fine. Over the weekend the cell tripped from time to time. After we identified one HV sector (28 wires on the side of big wire numbers) that trips, we opened the package for a third time. In addition we noticed that the dark current goes down when removing one of the pre-amps in the same area at the signal side of the wires. There we found one suspicious soldering that was fixed. At the other side of the wires we found a small epoxy ball that was removed. After some additional cleaning of the wires in this area we closed the package again. It is being flushed with gas since Tuesday and will be checked on Friday.
−
As for chan.1 we looked at the previous wire frame #3 and found the HV resistor for wire #1 had a crack. On Tuesday we opened the top cell (with the help of Mark Bear) and found exactly what we expected. The cracked resistor was replaced, the solder pad re-flowed to cover the wire, and then we closed the package. Will start testing it on Friday afternoon; Dave will bring the NIM power supply that we share with the magnet people. The two wire frames #3 and #6 were done at the same time by the same people using same tools, obviously this explains the similarities in their problems.  
+
  
−
- At the beginning of next week (most likely Tuesday) we will install two new cells (wire frames #27 and #28). The last two cells will have thicker spacers. We discussed what kind of holes we want to drill on these spacer rings to have the same pressure in the cells. The best is to have separate flow controller for the last two cells and to regulate the flow so that there's no big pressure difference between the cells. Bill propose to use a simple plastic part used in fans to spread the air. It will be mounted inside the spacer rings.
+
== Update on the corrosion test at MePhi ==
  
−
== Installation ==
+
- Vlad finished the test with 6 EPDM samples at 100degC at 100% humidity. The results are similar to what he got before with two samples. All the simples died between 6 and 24 hours. Now with higher statistics he estimates the activation energy to be 0.35+/-0.07 eV (consistent with the literature). Assuming the same chemical reaction for the Viton corrosion (just that Viton contains less amount of Sulfur) we estimate 1055 +/- 211 days live time at room temperature, but at 100% humidity. We don't know how to extrapolate the humidity down to 50%. It would be good to place O-ring samples outside of the packages to be tested whenever the FDC is taken out from the magnet for some maintenance.  
−
 
+
−
- Mock-up: Casey adjusted and connected all the eight rails of the two carts at Blue Crab, now we can continue with the test putting the packages on the cart. Before that (next Wednesday) Casey with the help of Bill will make one of the inter-package spacers to install it between two of the packages.
+
  
 
== Engineering ==
 
== Engineering ==

Revision as of 17:06, 23 May 2013

May 23, 2013 FDC meeting

Agenda

  1. Production Construction Tracking
    • Spare package status
  2. Update on the corrosion test at MePhi results (Lubomir)
  3. Engineering (Bill)
    • Cooling system status and tests
  4. Electronics (Chris, Nick)
  5. Full electronics tests FDC E-log (Beni)
  6. Other


Retrieved from "https://halldweb1.jlab.org/wiki/index.php?title=Minutes-5-23-2013&oldid=47631"