To: J. Albertine, D. Helms, W. Skinner
cc: Division (M7), FEL Coordination Group
From: F. Dylla
Subject: IRFEL Weekly Report Sept. 16-20, 1996
Date: September 20, 1996
Plans are completed for next week's MW Workshop which will be
hosted by the Laboratory on Sept. 24-25th. We expect approximately
35 attendees from outside organizations. The workshop was organized
by Alan Todd of Northrop Grumman.
The August monthly report for the IR FEL Demo project was forwarded
to the Navy and DOE on Sept. 20. The first installation planning
meeting was held on Sept. 20 with WBS managers and representatives
from the installation teams to begin coordination of the installation
tasks in the FEL building. Detailed lists of tasks and labor
estimates are being reviewed with the goal of optimizing the use
of labor and minimizing the conflicts with the support of the
CEBAF accelerator operations.
A design review for the optical cavity is scheduled for next
week on Sept. 26
Injector Test Stand
- Injector commissioning activities included the following:
1) We fully inserted the cathode into the gun and were able to run
with laser light being extracted from the analyzing port.
2) We remeasured the photocathode quantum efficiency after one
week and measured 3.2%. This is down from 5.6% measured Monday.
3) We had problems with a small vacuum leak in the lightbox which
subsequently sealed itself. To better coordinate subsequent
activities in the ITS and avoid potential disruptions of the run
schedule. a work permit system has been instituted.
4) Problems which appeared in the drive laser's ability to deliver
high power were potentially attributed to a suspected problem
with the heater unit for the SHG crystal which should be rectified
with a replacement available next week from the manufacturer.
5) Optical-path alignment was completed to a point at which beam
operations could proceed. More measurements on the surrogate
system are still needed for system signoff.
- The rf interlock for the drive laser was installed and checked
out. This interlock is designed to prevent rf-induced Q-switching
of the laser, and thereby solves the problem that lead to damaging
a doubling crystal during the week of 19 August.
- The buncher cavity and its water skid are now installed in
the test cave, and its Temporary Operational Safety Procedure
is signed off. Soon we will test the buncher at power.
- Fabrication of the cryounit progressed to the point of installing
the end cans, i.e., closing up its cryostat.
- All of the hardware tests associated with cryomodule-klystron
operation at 8 kW have been successfully completed. Plans are
to provide this capability for first light provided we can procure
the necessary power supply in time. Specifications for the power
supply have been developed and submitted to our procurement office
for dissemination to potential vendors. Negotiation with vendors
will commence shortly.
- An analysis was initiated to explore whether higher-power klystrons
might significantly ease the rf-control requirements and procedures
for the cryomodule in the presence of energy recovery.
- The design of the multislit aperture (for transverse emittance
measurements of the 10 MeV electron beam) and its mounting is
- Specifications and costs of bridging components for the cryomodule's
cryostat are being iterated with potential vendors in an effort
to keep costs down.
A successful review of the mechanical design for the IR wiggler
was held last week (Sept. 13) at the vendor (STI). Final drawings
for fabrication approval should be shipped to us next week.
Material was prepared for next week's review of the optical cavity
on Sept. 26. Modeling efforts are continuing for the thermal
distortion of the mirror substrates using both sapphire and silicon
substrates. Support labor was provided to support ITS operations
Considerable progress has been made on the "10 MeV set-up
procedure" for the FEL injector and its dump line. A bulletized
version of the procedure will soon be posted to WWW.
Concrete was poured this week in the injector pit area and
part of the ceiling in the West end of the building. We provided
the contractor with a signed drawings indicating all penetrations
for FEL related utilities and hardware.