GTS meeting 11 10 15

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  • The configuration to be tested: Pure alumina (white) R30 insulator + Shed with full electrode assembly and GaAs wafer on puck # 4.
  • Phil and Yan completed the vacuum bake to 250C for ~ 40 hour over the weekend. Gun chamber ion pump controller reads ~0.5 nA.
  • John installed the R350kV(HVPS side)-R30(Gun side) cable. Procedure is being written by Carlos.
  • The anode is connected to a pico-ammeter through an over-current protection circuit installed by John. The pico-ammeter is in the GTS control room.
  • Rad monitors are connected, but some do not work.
  • TV signal for monitoring turbo pump pressure is operational in GTS control room.
  • Carlos, Bubba and Yan will start HV conditioning Wednesday Nov 11th after establishing maximum values for HVPS current trip limits based on experience with previous test of white R30 insulator + Shed with dummy ball that reached 375kV w/o breakdown, albeit with significant field emission.
  • A pre-HV checklist is being developed now that the chamber is flanked by two gate valves, one with a 4-1/2" viewport, and the other one connecting the cathode preparation chamber. That is the way to say: " This is not a vacuum viewport breaking facility" .
  • Presently, FGTSLOG is in the "retired" category, but we can still make entries, just a matter to find it in DTLite. T. Larrieu proposes to move it to the LERFLOGS under LGTSLOG.
  • The other ball electrode is back from Barrel Polishing, the results are promising. Bubba is optimistic about making this process work. Some markings are from the original surface, some others are from the barrel polishing procedure itself. Bubba will contact the vendor to request procedure (recipe) and itemized list of components and supplies needed to do the job.