**MEMORANDUM**

**To:** Distribution

**From:** F. Dylla

**Subject:** FEL Upgrade Project Weekly Brief -- March 17-21, 2003

**Date:** March 21, 2003

**Highlights:**

Highlights for the week included: (1) conditioning of the gun ceramic
stack assembly up to

430 kV; (2) qualification and installation prep for 3 of the remaining 5
dipole magnets in the 2^nd^ recirculation arc; and (3) successful
turn-around of the injector cryounit by the SRF crew after last week's
warm window problems.

***Commissioning Activities:***

[Electron Beam Transport:]{.underline}

Two GQ's and 1 GX are ready for installation on Monday. The 2^nd^ GX
magnet and the last magnet to complete the 2^nd^ recirculation arc (GY)
are both on the measurement stands.

[Optical Systems:]{.underline}

Commissioning of the optical cavity assemblies continues. The diagnostic
system that monitors the outcoupler optical cavity was moved into place.

[Instrumentation and Controls:]{.underline}

All trim magnet power supply systems for all installed magnet systems
were exercised. A problem in the gun HVPS was diagnosed as a beating
problem between the two 5 mA stacks.

One stack was disconnected to allow the successful high voltage
conditioning of the gun ceramic stack assembly.

[Photoelectron Gun:]{.underline}

Successful conditioning of the ceramic stack assembly and high voltage
transmission line of the gun to 430 kV.

**Special Meeting Notices:**

[FEL Upgrade Cost and Schedule Teleconference: March 24, 2003 :
0800]{.underline}

(ONR invitees only)

[FEL IR/UV Upgrade Semiannual Review: April 9-10, 2003]{.underline}

At Jefferson Lab (ONR/AFRL/DOE invitees only)

**Management:**

This week we hosted our annual FEL Users Meeting and Laser Processing
Consortium Workshop on March 19-20. It was a successful and well
attended meeting. We had 113 registrants (71 from universities, 28 from
the National labs and 13 from industry). The program is listed on our
web site and we will be adding copies of the presentations. In parallel
with this meeting, the joint UVA/NSU/JLab IGERT program sponsored by NSF
was held. This brought more than 20 student posters to the meeting on
laser-materials related science and technology.

We also held meetings of the FEL Program Advisory Committee and the
Jefferson Lab Industrial Advisory Board during the User meeting.

We prepared a project status report and financial reports for the ONR,
NAVSEA and DOE Program Offices as background material for a conference
call scheduled for Monday morning.

**WBS 4 (Injector):**

The support electrode is ready for re-installation. The ball electrode
is on its final polish step and will be ready next week when we begin
final step of the electrode re-assembly. The internal parts of the
electrode structure have all been re-cleaned, and the complicated
structure behind the stalk assembly has been re-assembled in a separate
vacuum test stand so that the high surface area bellows and wire
assemblies can be partially outgassed before the final assembly. While
this electrode preparation has been going on, we have been voltage
conditioning the remainder of the gun assembly after a full bakeout
cycle was completed last week, and have brought this assembly up to 430
kV as of this writing (1715hrs, March 21), which is the required
overhead for operation at our nominal gun voltage of 350 kV At this
point we are projecting bakeout of the full gun assembly with the
electrode structure during the first week of April and re-start of gun
commissioning by mid- April.

**WBS 6 (RF):**

In the process of testing the injector cryounit last week, we developed
a leak in one of the warm rf windows. The cryounit has since been warmed
up, both windows replaced, and the cryounit cooled down to 4K. We are
coordinating cool down to 2K with a needed cool-down of a cryomodule in
the main accelerator next week, and then this system will be returned to
operability.

**WBS 8 (Instrumentation):**

Effort continued on the shunt hookup for the Wiggler and Optical Chicane
magnets. Communication cabling for the transport system shunts have been
pulled in and are being terminated. The last trim rack (3F region ) is
in commissioning. Wiring of the 896 power supplies continues.

Beam viewers 3F04 - 3F09 have been re-aligned for use with Max Video. A
half rack has been installed next to the High Reflector which will house
instrumentation and controls ports for Optics use.

The final punch list for the 4F vacuum region is underway. This includes
installing the three position mirror assembly for the Happek device. The
Happek is used for optimizing (minimizing) bunch length at the wiggler.

The firmware programming for the duty-factor calculation board \[for the
dlpc/mps system\] is ready to be embedded and tested. The duty factor
calculation board has been built and is ready to be programmed and
tested.

A Quarterly EH & S inspection was conducted on Tuesday. With few
exceptions, we came through with flying colors. A list of items being
tracked will be available early next week. One noted problem is the
ongoing water leaks at both ends of the tunnel. Repeated attempts by
Plant Services to plug the leaks have been unsuccessful. Also repeated
attempts to keep one of the safety system doors from sticking and
preventing the maglock from energizing, have failed. We need to elevate
our concerns for these two annoying problems.

**WBS 9 (Transport):**

***Work Arounds***

Substitution of IR Demo 180° Bend (DY) for the Upgrade 180° Bend (GY) in
the First Arc and installation of a GW beyond the Optical Klystron as a
diverter-to-the-dump magnet

• In order to add more resistance to the circuit, we are working to
connect two of the IR Demo's DU, Injector dipoles in series with the
temporary diversion dipole at the end of the optical cavity. This will
allow the magnet power supply to deliver the required 100 A.

***Dipoles***

[Optical Chicane Dipoles (GW)]{.underline}

• No progress.

[Injector Dipoles (DU/DV)]{.underline}

• No progress

[Arc 180 Degree Dipoles (GY)]{.underline}

• The machinists of the JLab Shop continued their very competent job as
they commissioned the measurement apparatus for the GY dipole. They
refurbished the probe motion mechanism that allows both circular
(through the arc) and straight (for measuring the ends) motion. They
aligned the apparatus to the magnet within .003 inches.

• The machinists made a new probe holder for the two NMR and two Hall
probes that move to seven positions across the width of the good field
region. These readings will match the series of readings taken on the
similar, one meter radius, Pi Bend (DY) dipoles of the IR Demo. The
transverse distance between readings will be 50 % larger in order to
accommodate the wider 8 inch wide good field region. Fortunately this
pattern of readings allows the use of the spreadsheet developed for the
DY measurement. Ken Baggett, who is on loan from the Alignment Group,
finished massaging the spreadsheet to bring it up to date for GY
measurements.

• Measurement of the GY started. After battling control problems and
safety paperwork, Bill Merz, Kevin Jordan and Tom Hiatt got the newly
installed 66 KW power supply to respond to control commands. This supply
has the current and voltage capability to fully test the GY.

• Wang NMR continued potting the coils for the second dipole.

[Arc Bend & Reverse Bend Dipoles (GQ, GX)]{.underline}

• The second last GX magnet passed preliminary qualification
measurements with core field matching the first GX to 1.5 parts in
10,000. Specification is 10 parts in 10,000.

• Tests of the final GX Dipole started this week. We were able to do
this because replacement GX coil from Wang NMR arrived in time. The JLab
Shop machinists again helped us out, taking the GX dipole apart and
replacing the leaking coil and putting the magnet back together. Note,
because the coil was partially made from recycled copper from the first
GY coil its dimensions were 0.25 inches too wide. In a very quick
maneuver, the machinists removed that amount of material from the inside
of the small return leg and replaced it with a shim plate on the outside
of the return leg. This should have no effect on field quality.

• Installation of the two GQ dipoles and one GX could have started on
Thursday but a combination of heavy rain and critical work in bringing
the CEBAF accelerator back up from the down period prevented Neil
Wilson's crew from doing this work. Installation is scheduled for
Monday.

***Quadrupoles***

[Trim Quad (QT)]{.underline}

• The vertical corrector function (GC) in the two Trim Quadrupoles (QTs)
for the second arc was verified. They will be installed on Monday.

***Sextupole (SF)***

• No news.

***Octupole (OT)***

• The order is ready to be placed anticipating the next batch of
commissioning money.

***Correctors***

• The coils for the horizontal optical chicane corrector (GZ) were made
by Hiroyuki Toyokawa and he installed them in the third Optical Chicane
Dipole (GW). He is working on the connection of the series of parallel
wires into form the coils on the magnet.

• Jeff Dail of the JLab Shop completed the fixtures for making the GA
vertical corrector and will start winding as soon as we get the epoxy.

**WBS 11 (Optics):**

We worked late last Friday to install a motor with a working encoder and
pumped down the vacuum vessel over the weekend. This put us back on
track to run the leadscrews of both the HR and OC, so as to initiate the
in-vacuo lubrication process we previously demonstrated on the HR
assembly. In the process, we discovered that some of the stepper motor
drivers had been changed, and certain parameters didn\'t match what the
software was indicating. The I&C group swung into action and helped get
that straightened out. We then found that the drag torque on the OC was
quite high, and finally resulted in the stepper motor shaft slipping on
the flexible bellows coupling clamp. We had a fixture made to measure
the torque in-situ(without venting the vacuum vessel), and we\'ll use it
to determine what\'s wrong and fix it. We also made plans to modify the
flexible bellows coupling and the motor shaft to accept a pin to make
the coupling more robust. We worked to get the ultraviewer mounted near
the HR assembly aligned and working. By midweek, we were aligned to the
OC. In the process, we confirmed that the clips that retained the mirror
on the ultraviewer were pressing too hard on it, and we were aberrating
the beam. New clips have been designed and submitted for fabrication.
We\'ll have them early next week, and will install them while vacuum
work is being conducted on the beamline. The OCMMS optical assembly that
monitors the OC was moved into position. The HR OCMMS optical assembly
is being assembled and aligned, and will be moved into the vault next
week.

We received word that the oscillator for the advanced drive laser, a
custom system built by Time-Bandwidth Products, will be delivered and
installed in the beginning of April. The laser appears to be exceeding
the specified output by almost a factor of two. Once it is installed and
qualified, we look forward to receiving follow-on funding to purchase
the amplifiers for the laser in order to complete the laser system.
Several of us gave presentations at the LPC meeting. We assisted the
Hall C installation staff by loaning them a 6\" gate valve.