To: J. Cook, D. Helms, W. Skinner
cc: Division (M7), FEL Coordination Group
From: F. Dylla
Subject: IR Demo Project Weekly Report, March 23-27, 1998
Date: March 27, 1998
FEL Management
Highlights of the week include the following: (1) successful
completion of the 38MeV electron irradiation experiments to prepare
three polarized ammonia targets for the Nuclear Physics program;
(2) initial check-out of some of the injector diagnostics.
On Tuesday, a package of information was forwarded to DOE-BES
that described present capabilities and near-term enhancements
of the IR Demo FEL for scientific investigations. The information
will be used by a working group of chemical physicists at next
week's ACS meeting in Dallas. A similar working group of physicists
interested in using the FEL for atomic, molecular and optical
physics is planned for April 7th at Jefferson Lab.
Installation Activities
The irradiation of the 3 GEN targets was successfully completed
early Monday morning. The GEN equipment was removed during the
day and beam was run to the injector dump that evening. The 2G
dump line was also reinstalled.
The gun cathode was aligned to within 6 sec. of arc of its desired
position. The drive laser with the 6 mm aperture was also realigned
to the gun cathode.
The gun cathode wafer was heat cleaned this week and a new cathode
made today in preparation for next week's attempt at high current
operation. It will be ready for Monday's startup of operations.
The optical cavity length was measured again this week. We have
performed a total of three different measurements of the cavity
length which agree to better than 100 microns. The FEL optical
transport lines were cleaned, installed, and aligned this week.
Pumping and leak checking is in progress.
The 180° bend magnet and vacuum chamber in the 3F region
is installed and under vacuum. The 180° bend magnet for
the 5F region is being rebuilt.
Two sets of wide aperture air core correctors were qualified for
first light operation. They will be installed tomorrow. The
first skew quadrupole will also be installed tomorrow for correction
cross-coupling after the 1/4 cryounit.
The new MPS is being installed and will be certified for 1mA operation
on Monday.
Convectron gauges were placed on the beam line at the 1G Dump
and just downstream of the X chamber for interlocking of isolation
valves.
The installation of grating over the helium transport lines was
started this week.
Commissioning
We discussed action items:
K. Mahoney presented the features of the new MPS and how it will
interface with operators and the machine. All valves are connected
to the MPS and are now being checked. An additional meeting was
held after the commissioning meeting to further resolve MPS details.
The FEL-MPS committee will meet Monday at 10:30 to review the
MPS for certification for 1 mA operation.
We had significant discussion of the plan and short term goals:
For several reasons the run for check-out of the Happek diagnostic
was postponed until next weekend. This will provide one week to
tune up the required beam for the tests. We need to provide high
current beam with an operational MPS for this experiment. 100
to 200 micro ampere is the required beam current, more if the
viewer will take it.
A scheduling meeting was held later in the day to resolve the
commissioning plan for this run. After MPS and BLM checkout,
we will attempt to push the beam current to the tune-up dump,
checking for beam loss and checking out diagnostic systems along
the way.
R. Li made a presentation on the current status CSR studies.
Li predicts that CSR can account for emittance growth of 7% ,
21% and 44% after the first optical, second optical and east arc.
We now have to develop experimental tests where the effects of
CSR can be enhanced or de-enhanced.
We discussed the issue of operation from the MCC. It was resolved
that we will look for near term opportunities to test operations
from the MCC.