The 2F06 BPM was opened and mechanically checked this week. Two loose screws from an adjacent viewer were found and removed from the beam pipe.

The first light mirrors were installed this week in the optical cavity.

The stands and fixtures for the Happek interferometers were installed. Happek and his devices are scheduled to arrive Monday.

The metals group, led by a consortium of Armco, Virginia Power and Northrop Grumman installed its first apparatus in User Lab 3. Over the next month, utility and instrumentation hook- ups will be made. In User Lab 1, the first equipment for polymer studies shipped from DuPont was uncrated.

Commissioning Activities

On Monday we pulled the cathode from the gun. Visual inspection of the wafer revealed no debris, an observation that is favorable as compared to early February. A new wafer has been cleaned, anodized, and its outer periphery masked to cut down on beam halo. The new cathode was installed in the gun yesterday. Bake of the gun began today (Friday, 22 May 98). We are generally on track for resuming beam operations on 1 Jun 98, give or take a day.

There have been some hardware checks of the drive-laser RF system to ascertain phase drifts and amplitude noise. Nothing dominant has been found to date, but the process is continuing. We have put together a plan to model the drive-laser RF system and expect to complete the modeling in about a month.

The FEL systems are nearing completion. The CaF2 first-light mirrors were installed this week, and the FEL systems in the vault (notwithstanding that the wiggler is not installed there) are ready for lasing. Diagnostics in the Optical Control Room are nearly finished, and the supporting Laser Safety System will be installed imminently. In short, the Optical Control Room will be ready in two weeks or less. In parallel, both Labs 1 (Polymers) and 3 (Metals) are in process of being set up. Most likely the first user experiment will involve lasing on a polymer samples, but there will also be other options.

As noted above, beam operations are slated to resume 1 Jun 98. The general pattern of daily commissioning activities will begin as before: nominally day shift working through the metaprocedure, swing shift exercising the machine, and owl shift measuring beam quality. To expedite progress in establishing lasing-quality electron beam, we hope to evolve quickly to two shifts working through the Phase Space Setup Metaprocedure, with both of these shifts involving a diagnostics expert. The thrust will be to refine continually the Golden (Save/Restore) File without back-tracking until we have the electron-beam quality we need to lase. Then we'll put in the