Right Arm top VDC status

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User name Jack

Log entry time 23:35:06 on April 22, 2009

Entry number 267418

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267422 04/22/09 23:58 Jack No, I think things will be fine (sorry, I'm tired)

keyword=Right Arm top VDC status

The VDCs on the Right Arm have been set to zero volts and must remain at that voltage. Earlier today I checked the VDCs for gas leaks and found a leak on the top gas window of the top VDC, the one we just replaced. It is leaking at an old repair I did a long time ago. The good news is that with - 3700V on the cathodes the gas window appeared to have a small, comfortable, outward bow to it. This was with the exhaust of the chamber connected to the exhaust tubing. Gas flow through the chamber is comparable to the flow through the bottom chamber, though slightly less. So, I don't think things should be fine. I had to remove the carbon fiber covers and the aluminum foil over the gas window. After the leak was localized I put the aluminum covers back on top of the VDCs. We ran the VDCs to -4000V and took some cosmics data. Vince has posted this already in the halog. Vince set the HV to zero volts and it must remain there till I repair the leak tomorrw. The repair will take about 6-8 hours, the RTV will need to cure before gas pressure is re-applied to the VDC.