To: Attendees

From: Fred Dylla

Subject: Gun Ceramic

Date: December 12, 1996

cc: C. Sinclair

A meeting was held on Dec. 11 to discuss the path forward on the gun ceramic.

The group (noted below) decided the following:

Guiding Principle: We will change only one parameter at a time; therefore, we will install a coated central stalk in the existing stack assembly

1. Check adhesion of FM Technologies coating on ss samples after several 600°C cycles.

2. In parallel to 1., get a new stalk coated (high field region only); coat witness samples simultaneously.

3. Install new stalk in old ceramic stack.

4. Proceed in parallel to complete both new ceramic stack assemblies; including brazing

a. HiTemp coated ceramic,

b. ion-implanted ceramics.

Note #1: We will decide in January which assembly (a or b) to fully assemble because only one mid-voltage ring presently exists.

Note #2: We should strive to have coated stalk ready to assemble in existing stack by the first week of January.


R. Legg

T. Siggins

F. Dylla

C. Bohn

G. Neil

L. Phillips

R. Walker

G. Biallas

Note added 13 December 1996:

The stalk to be coated is only finished at the 15 micron level in the areas outside the area to be coated. The 15 micron finish is probably not adequate to support the fields in these areas (though they are lower than in the high-field region) without excessive field emission. Thus, we decided to coat the entire tube, rather than simply the high-field area. It was deemed less laborious and time consuming to coat the whole tube than to polish the whole tube down to a 1 micron, as opposed to 15 micron, finish.