Management

Highlights for week: (1) successful FEL contract close-out meeting with the Navy and (2)
(hopefully) successful completion of the cathode changeout procedure for the FEL gun.

On April 26-27, we had a contract close-out review for the Navy/DOE 1997 Memorandum
of Agreement which covered FEL commissioning and fabrication of the second FEL
cryomodule. Attending for the Navy were: John Albertine (Chair), Joung Cook (NRL) Mike
Gouge (ORNL/SPAWAR), and Bill Colson (NPS). The review committee was impressed
with the project performance during the contract period and will forward a close-out report to
the Navy and DOE.

Letters of invitation were sent out to over 10 representatives from FEL User Groups
requesting presentations at the June 17-18 LPC workshop.
 

FEL Installation/Maintenance Activities

The vacuum and rf systems were extensively checked, and some maintenance was done on
the former. The organization of the Analog Monitoring System was also reworked and
improved. The Laser Safety System for User Lab 3 (the "Metals Lab") was checked out this
week.
 

FEL Commissioning Activities

High-voltage processing after the installation of the new cathode wafer was done this week,
although it proceeded more slowly than hoped. Most of the processing took place with the
cathode wafer retracted from the ball to preserve its quantum efficiency. We decided to stop
processing late last night and do a short overnight heat clean of the wafer so we could cesiate
and check the gun today. We are unsure whether the gun will come up to voltage because
some relic field-emission activity was taking place at 430 kV in the precesiated gun. At this
writing (Friday, 30 Apr 99, 1445), we know the quantum efficiency of the cathode is quite
good compared to the last few post-processed wafers. A cathode scan is being done, and
when it is finished, we will try to bring the gun up slowly to 330 kV. If we are successful,
commissioning activities will resume in earnest on Monday morning.

B. Yunn completed a parametric study of the machine versus gun voltage. The study
involves PARMELA simulations of the beam up to the wiggler. Yunn found that electron
beam of sufficiently good quality can be delivered to the wiggler with gun voltages as low as
250 kV. To do so, however, requires a new setup of the injector and linac. Our hope and
plan is to bring the gun to 330 kV so we can start with the saved setups from the previous
run. Nonetheless, it is good to have an alternative available.