# MEMORANDUM 

**To:** Distribution

**From:** F. Dylla

**Subject:** FEL Upgrade Project Weekly Brief - October 4-8, 2004

**Date:** October 8, 2004

**Highlights:**

This week we hosted a major review of the Navy funded FEL program at
Jefferson Lab on Wednesday and Thursday.\
The review topics included a summary of the 10 kW campaign and the
planned three year program for the Navy (FY05-07) for performance
testing and operation of the 10 kW FEL and development of key hardware
for 100 kW FELs.\
We were pleased that all but one of our external review panel members
could attend the review, in addition to our program officers from ONR
and NAVSEA.  We would like to take this opportunity to thank our review
panel members who have devoted considerable time and effort to advising
us on the design, fabrication and commissioning of the 10 kW Upgrade
over the past four years since the project was initiated in June 2000.\
Despite all the activities of this review week, installation and
check-out activities continued at a high level as we near the end of
this shut-down period.\
Highlights of the week\'s accomplishments include:

\- installation of the new short wavelength (1-3 micron) electromagnetic
wiggler\
- successful hot check-out of all the RF systems for both the injector
and linac

> \- successful heat clean ,cesiation, and HV conditioning of the
> photogun

\- continued progress on the installation of the optical transport
system

**Management:**

We completed preparations for, made presentations at, and survived the
drama of our third Navy panel review in the last 9 months.\
Five white paper proposals were submitted to the JTO for FEL technology
development on Monday. We are also collaborating on a couple of
proposals by other institutions.\
The project monthly report for August for the Army funded THz project
was submitted to the DOE and Army program offices.  The project monthly
financial report for September was prepared for ONR.

**WBS 4 (Injector):**

The DC Photocathode gun is ready to provide beam for FEL ops. The
anodized GaAs wafer was heat cleaned on Monday. On Tuesday we made a
cathode with 6.5% QE. On Thursday we performed cathode high voltage
conditioning successfully. No evidence of field emission from the
cathode was observed.

This is the second cathode we made on the anodized wafer installed under
vacuum back on May of this year. The first cathode delivered 940
Coulombs of charge with 6 re-cesiations. We expect longer lifetime for
this second cathode after fixing a very hard to detect leak in the gun
gate valve flange.

Gun HVPS - Is operational with some drift observed in the current
readings.  The Conditioning Resistor was cleaned again without much
change in the current drift.  The electronic boards will be cleaned next
week to try to improve the drift.

**WBS 6 (RF)**

RF - Hot checkout of all RF systems continued this week.  Several small
problems have been found and corrected.  The Quarter was RF processed to
Drive High gradients.  Window and waveguide \"washing\" was performed
for several hours to improve the vacuum and load handling capabilities. 
This process will continue next week also to improve all zones.

 

**WBS 8 (Instrumentation):**

The new valves for the 0G diagnostics development station and the
additional 4F valve to aid in optics work were connected and tested
through the control system to the Machine Protection System. There is
still more work to be done but the connections that prevent burning
large holes in things has been done. Test fixtures to readily test these
were also built.\
   Continued work on the beam viewer system. An additional control box
was built for VBV3F00 to aid in beam viewer alignment for the 3F region
viewers   Much time was spent in the 0F, 1F, 2F region in final focusing
and aligning viewer cameras and repairing air lines due to other
installations. The cameras in the 1G Dump have been exchanged for new
ones, and those viewers have also been re-aligned.  Final alignment of
3F06, 3F07, 3F09 and 3F04 will commence next week. Additional camera
lenses have been ordered.\
   Both Arc string 165 kW box supplies along with the Injection,
Extraction 5kW string box supplies were powered on earlier in the
week to begin shake out.  A punch list is being complied as we started
to turn on the magnetic transport system. The Injector (FL05B13) trim
rack was also powered up and debugged successfully in order to support
the Gun group.\
   Considerable progress was made on the new LPSS.  The vendor spent a
couple of days here assisting us in configuring the new LPSS Master LC
CPU, Ethernet and Control Bus modules. Connection to the additional
safety viewer will be made next week. The new IClass card readers are
here and work continues in converting the data base to work with the new
system. The tentative date for LPSS certification is Oct. 21.

**WBS 9 (Beam Transport):**

## W80 Wiggler 

• We use two probes to get a complete characterization of the wiggler.
One of the probes had developed a 12 Gauss offset, spoiling our proof
runs. We calibrated the offset, subtracted it from the data and were
able to continue with all six proof runs. Steve certified the wiggler
for use. It was installed Wednesday.

***Installing the EM Wiggler and Decompression Chicane to Reduce
Downstream THz***

•    The wiggler and its chamber was installed and aligned

• We started the process of taking the "tops" off the 4 GW dipoles in
the chicane in order to install the chamber.

• The Vacuum Group leak checked the chamber and we installed the
Synchrotron Light Port and its internal mirror, which will provide a
check on the position of the beam when setting the strength of the
chicane. The chamber will be baked over the weekend.

• Installation of low conductivity water piping was completed.

***Sextupole (SF)***

•   The requisition was generated for signature, the
specification/statement of work was signed and the final numbers were
put on all the drawings.

***UV Branch Line***

• The specifications for ordering the replacement GW Dipoles remain in
checking.

**WBS 11 (Optics):**

Progress occurred in the following areas:\
***Cryomirror:\
***We did a verification of the LN2 flow rate with the setup we\'ve been
using.  The flow rate over 23 min was just over 1 L/min.  The dewars,
subcoolers, cryolines and mirror were removed in preparation for the
installation of the 2.8 micron mirrors next week.

 ***2.8 and 1.06 micron mirrors:\
*** We\'ve received our 2.8 micron mirrors.  We are rapidly putting them
through our metrology checks.  So far, so good.  We received a quote
from a vendor of known low-loss coatings and are proceeding with the
procurement.\
***Scraper outcoupler:\
***No news since the last report. \
***Other activities:\
***Optical power meter readouts we no longer need downstairs were
removed from that region.  The turning mirror cans to the OCR have been
mechanically aligned.  We received our turning mirrors (minus the one
with the hole in it) and they are going through metrology.  Mounting
them to the cooling plates starts next week.  The collimator lite has
been mechanically assembled.  The stand for it arrived and we will
install it early next week.  Shield covers for the optical components
have been fabricated.  Progress continues on the OBPM system, and on a
fast scanning autocorrelator.

**Terahertz Project:**

This week we assembled one of the safety shutter/viewer assemblies.  We
received the re-polished mirrors (M2, M3 and M4) back from the vendor.
We received the conditioning mirror vacuum chamber and 2 of the 5
polarizing grids.  Work commenced on assembling the beamline components
in Lab 3.