Next Meeting

Date: 29 Apr 99

Time: 1500-1600

Place: FEL Facility Break Room

Agenda for Next Meeting

• Status of shield design (Phillips/Biallas, 10 min)
• Status of apertured cesiator (Biallas, 15 min)
• Status of ion implantation (Biallas, Siggins, 10 min)

This Week's Attendees

G. Biallas, J. Gubeli, L. Phillips, T. Siggins, C. Sinclair, R. Walker

Discussion

T. Siggins gave a status report of the cathode wafer replacement. It is on schedule. The photoresponse prior to the bake was good. The cathode will be viewed after the bake and again after the HV processing. The cathode will be retracted back into the ball as far as possible during the HV processing even though this increases the voltage gradient at the lip next to cathode's normal position. The voltage will be increased gradually to see if this is a problem.

G. Biallas presented his hinged "saloon door" design for the cathode shield when it is retracted. Conceptually it looks good. Additional checks will be made for the guides, materials used, and thermal mass of the stalk.

G. Biallas reported the aperatured cesiator is in checking and will be ready for the machine shop by 29 April 1999. It should be ready for installation during this June's shutdown.

The status of the polishing of the 6" disks for ion-implantation studies is that all 6 disks we now have are of less than "best quality" and the polishing effort for these disks should be stopped. We have in house "best quality" material and it will be sliced up for the required samples. Additional "best quality" material will be ordered. Only the "best quality" machining and polishing procedures are to be used on these sample disks.

T. Siggins said that Ling Ling told him she would ion implant the sample disks, but that she is not interested in making the field emission measurements. C. Bohn needs to talk with Dennis Manos on this subject.

Closed Action Items

• Siggins: Record detailed wafer changeout plans on the two-week FEL scheduling board. Plan to do HV processing on shifts to save time. Status: Done.
• Siggins/Gubeli: Inspect test chamber for 6" plates and identify what is required to align the plates accurately. Status: C. Curtis can align them within 100 µm, if the glass viewing ports can be opened.
• Biallas: Procure four cross-forged steel plates for ion-implantation studies. Status: Canceled and replaced with a New Action Item below.
• Phillips/Biallas: Identify shield/shutter design for protecting the cathode wafer against ion back-bombardment during HV processing. Status: Done, as described in Discussion above.

New Action Items

• Biallas: Procure "best quality" (vacuum remelt) steel for the ion-implantation studies. Have JLab machine shop make the plates. (due 29 Apr 99)
• Bohn: Discuss with D. Manos how we can obtain the field emission data for the ion-implantation studies. (due 29 April 99)

Old Action Items

• Sinclair: Prepare procurement package for DLC-coated samples for Dylla's signature. Status: Based on the plate drawings, Biallas will get a quote. (due 29 Apr 99)
• Siggins/Biallas: Specify design of experiment to measure cathode temperature. (due date TBD)