MEMORANDUM

To: J. Albertine, D. Helms, W. Skinner

cc: Division (M7), FEL Coordination Group

From: F. Dylla

Subject: IR FEL Weekly Report: July 27-August 2, 1996

Date: August 2, 1996

Management

A summary presentation on the IR Demo FEL project was given at the FEL Program Review meeting held by the Navy High Energy Laser Office at NRL on July 30. The morning session was devoted to laser-materials damage and atmospheric propagation effects and the afternoon session was devoted to hardware topics including injector designs (LANL and Stanford) and system studies (NRL and Northrop Grumman).

On July 30-August 1, Northrop Grumman hosted a series of tours and discussion sessions on issues related to FEL development at the Northrop Grumman facilities in Bethpage, LI and Princeton, NJ. The meeting was hosted by the N-G Advanced Technology Development Center at these locations and included representatives from other company divisions at Rolling Meadows, IL, Sunnyvale, CA and Pittsburgh, PA. We found that there are useful hardware development activities on Favry-Perot interferometers, fly-wheel energy storage devices, and ceramic engineering that can be added to the existing collaboration with Northrop Grumman that supports FEL development at Jefferson Lab.

We mad preliminary plans to hold a workshop on the issues relevant to extrapolating the IR Demo to higher powers (~MW) on Sept. 24-25.

IR FEL Accelerator Systems

Detailed design of the transport line for the IRFEL's injector dump was started. The magnetic optics envisioned for the injector's transport line are well-suited for measurements of emittance and energy spread.

Detailed design of the transport line for the IRFEL's recirculation dump was also started. The preliminary design is encouraging in that it generates reasonable beam sizes at the dump.

Many more accelerator-subsystem schedules and plans have been added to the Web.

Injector Test Stand

We are presently holding to our revamped schedule for the Injector Test Stand. The vacuum bake of the gun and its beamline has started. A concerted effort has been initiated to procure improved ceramics and investigate an anti-field emission coating for the stem.

FEL Systems

Wiggler

A review was held of the magnetics design at the vendors on 7/29/96. The design of the main field structure, the magnetic materials, shimming techniques and the measurement approach were all found acceptable. Further work was desired in the end correction approach to reduce the possibility of beam offsets. Also required is an approach for dealing with errors due to the earth's field. A meeting to discuss mechanical design is scheduled for September 13 at the vendor's.

Optics

Orders were placed for the main optical cavity mounts which will be adapted to handle cooling, remote tuning and length control The engineering detail drawings for the optical cavity including these modifications to commercial hardware are to be complete early next week. Orders are also being written up for the raw pipe for the optical transport system.

Operations/Commissioning

Several schemes were considered for phasing the electron beam with the accelerating cavities for deceleration and energy recovery, and a promising scenario was adopted.

Facility

Work continued per schedule on the facility. Rebar was tied into the west half of the lower floor and wall joints early in the week. Despite a break in a 12" water main which flooded the excavation and 3" of rain on Wednesday and Thursday, concrete was poured on Friday to form 1/2 of the lower level floor before rains move in again. The major portion of the rest of the dig is complete and surveyed. Tie ins to the South Linac low conductivity water and main site electrical service have been scheduled for September 3 to coincide with a scheduled CEBA shutdown.