Next Meeting

Date: 15 Apr 99

Time: 1500-1600

Place: FEL Facility Break Room

Agenda for Next Meeting

• Status of apertured cesiator (Biallas, 15 min)
• Status of ion implantation (Biallas, Siggins, 10 min)

This Week's Attendees

G. Biallas, C. Bohn, R. Evans, J. Gubeli, K. Jordan, L. Phillips, T. Siggins, C. Sinclair

Discussion

Plans for the upcoming wafer change in the FEL gun were outlined and are delineated on the FEL 2-week scheduling board. Plans include: masking the wafer, testing the wafer's QE prior to high-voltage processing, HV process to a quiet 510 kV and then run the gun at 330 kV, and defer deciding on the duration of heat cleans until we see how well the preliminary steps go.

We had a detailed discussion about ion implantation. T. Siggins wisely suggested we reserve a pair of 1-micron- polished plates as a control on the experiments, i.e., measure their FE properties without ion-implanting them. We will have two other pairs of plates. One pair will be polished to 1 micron and ion implanted; the second pair will be polished to 9 microns and ion implanted. Testing these plates and comparing to the control should tell us much. After we are finished with the control pair, they will be sent out for application of DLC.

In testing a pair of plates, great care is needed to position them accurately (parallel to one another) in the test chamber. We did not solve the problem at this meeting other than to offer two ideas. First, if some material is used as an alignment aid, it must not neither scratch the surface of the plate nor leave a residue. Second, perhaps the Lab's alignment crew can help out. Siggins, possibly with J. Gubeli, will check the test chamber and see what is involved.

Status of the plates is: D. Bullard is polishing the first pair, having one at 9 microns already and starting on the other. There is not much extra time needed to go from 9 microns to 1 micron. The four other plates are still being machined.

G. Biallas presented the latest top-level design of the apertured cesiator. It will provide an acceptably vigorous cesium flux; Biallas and C. Sinclair have come to closure on the flux calculation. The Committee decided to go ahead with this design. Next step is to have J. Smith do the detail drawings (about 2 weeks), then build it, then test it. Estimated time to installation: 2 months.

C. Bohn will be away from the Lab during most of the next two weeks, so the next formally scheduled Committee meeting is 15 Apr 99. Informal discussions will surely take place in the interim.

Closed Action Items

• Biallas/Sinclair: Resolve discrepancy in the calculation of cesium-deposition rate with focused cesiator design. Status: Have come to agreement on flux calculation, as mentioned in discussion above.
• Biallas: Arrange for fabrication of additional 6-inch sample electrodes. Status: Four plates are in machining.
• Siggins: Polish the spare cathode ball to 1-micron fineness. Status: Completed this week; ball will be shelved until needed.

New Action Items

• Siggins/Gubeli: Inspect test chamber for 6" plates and identify what is required to align the plates accurately. (due 2 Apr 99)

Old Action Items

• Sinclair: Prepare procurement package for DLC-coated samples for Dylla's signature. Status: Unknown; package was to have been passed to Dylla by now.
• Siggins/Biallas: Specify design of experiment to measure cathode temperature. (due date TBD)
• Dylla: Ascertain feasibility of low-cost "load lock" for cathode-processing experiments in the ARC. Status: No progress due to lack of funding. (due date TBD)
• Siggins: Begin scanning gun data and, with D. Gilchrist's help, compiling information into an electronic logbook. Status: No progress. Bohn called V. Bookwalter this morning to appeal for her attention.