**MEMORANDUM**

**To:** Distribution

**From:** F. Dylla

**Subject:** FEL Upgrade Project Weekly Brief -- March 10-14, 2003

**Date:** March 14, 2003

**Highlights:**

This week we pushed ourselves closer to start-up of first light tests
and completion of the high power hardware with a few ups and downs: (1)
we started transmitting alignment laser light down the optical cavity
axis to begin the cavity length calibration process; (2) the gun innards
started to go back together as we moved toward final steps of
repolishing our ball electrode and voltage conditioning of the gun
ceramic assembly; (3) as we continued to put RF power onto the SRF
system for fine tuning and conditioning, we opened up a leak in one of
the external RF widows in the injector cryounit that will require a
replacement that is already underway; (4) we made good progress on
qualifying 3 of the remaining 5 magnets in the 2^nd^ recirculation arc.

We are looking forward to hosting our annual FEL Users Meeting and Laser
Processing Consortium Workshop next week on March 19-20.

***Commissioning Activities:***

[Electron Beam Transport System:]{.underline}

One of the two remaining GQ dipoles for the second recirculation arc was
qualified and is ready for installation; the second GQ started
qualification measurements on Thursday. We are holding to our plan of
having these dipoles and associated vacuum chambers installed by
April 1. The large 180 degree bend dipole for the 2^nd^ arc was fully
re-assembled after extensive rework by our competent machinists and
magnetic qualification began today.

**Special Meeting Notices:**

[FEL Users and Laser Processing Consortium Workshop: March 19-20,
2003]{.underline}

Our annual users meeting will be held on March 19-20 at the CEBAF Center
Auditorium at Jefferson Lab. This meeting is open to anyone interested
in past and planned future use of the FEL User Facility for basic,
applied and mission related R&D. The preliminary agenda for this meeting
will be posted on the JLab WEB site next week.

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

At Jefferson Lab (ONR invitees only)

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

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

**Management:**

We made final preparations for next week\'s FEL Users Meeting and LPC
Workshop on March 19-20. The meeting will also include concurrent
meetings of the FEL Program Advisory Committee (FEL-PAC) and the
Industrial Advisory Board.

On Tuesday, March 11, we attended a review of the NSF sponsored
Industry-University Research Center on laser manufacturing that is led
by the Old Dominion University in the Applied Research. We had the
opportunity after the review to show the attending NSF officials the FEL
Facility.

Today we hosted visitors from several DOD departments who requested a
tours of the FEL Facility.

**WBS 4 (Injector):**

We are approaching the final polishing steps on the cathode ball (\<9
micron diamond paste). We started to re-assemble the many components
that get installed within and beyond the cathode stalk. They have all
been cleaned and the sub assemblies will be pre-baked. We finished the
bakeout of the gun assembly minus the electrode structure and started
high voltage conditioning of this structure.

**WBS 6 (RF):**

We continue to use some second shift time to put RF power on the buncher
and SRF systems. During RF conditioning and calibration of the injector
cryounit on Wednesday evening we opened up a leak on one of the warm RF
windows. This window was removed on Thursday and replaced with a pumped
blank-off, and the warm up of the cryounit was begun to enable a new
window to be installed next week. We will be analyzing why the window
developed a leak.

**WBS 8 (Instrumentation):**

Commissioning efforts continued on the DY ARC, Injection and Extraction
magnets and power supplies. Field polarity checks were completed for the
trim and quad magnets up to MQX4F09 (temporary dump). Assistance was
given in Magnet Test to get a supply sufficient to run the DY through
full hysteresis. - Thanks to EES & Roger Flood!

Re-aligned ITV1F04 thru ITV1G00 for MAX Video input. Cable terminations
continued for the SLM\'s in the 1st Arc and completed checkout of the
Ultraviewers and Insertable mirrors for the HR and OC. Checkout of the
software for the SEE BPM\'s is in progress.

MPS/DLPC integration: The drive laser is currently using the original
DLPC chassis and Con-Optics Model 305 chassis to do interlocked pulse
selection. We are now beginning to commission the new VME based system.
This main focus now is to test the synchronous countdown board and get
the duty factor measurement board tested. This week has been spent
writing the Altera code for the duty factor measurement card.

The new analog interface board for the gun HVPS is in, stuffed and is
being checked out. This will be commissioned after the gun HV tests on
Monday. A test fixture was built for testing the optical cavity encoders
locally at the cavity.

**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.

• The first arc 180 degree magnet (DY) (and the temporary linac
spectrometer magnet on the same circuit) were powered to the maximum of
220 A and remote operation was proven.

• The temporary diversion dipole at the end of the optical cavity, used
for pulsed operation was powered to 74 A instead of the expected 100 A
because the power supply requires a more resistive circuit. We will
connect two of the IR Demo's DU, Injector dipoles in series with the
magnet for full current operation.

***Dipoles***

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

• No progress.

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

• We found from our work with the Work around GW above that more
resistance is needed in the injector and extractor strings. We will use
the same work around of using surplus DU magnets.

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

• The machinists of the shop did a very competent job of putting the
first dipole together, installing the new field clamp micro adjusters
that copied the functionality developed for the GX/GQ Dipoles. The
machine shop welder re brazed two fittings that leaked when low
conductivity water was turned on. The magnet was powered up. The
machinists are starting to commission the measurement apparatus.

• We found that the two main power supplies installed in the Test Lab
don't have the voltage capability to run the magnet to full field.
Fortunately we installed a third surplus supply as a "work-around" for
the Physics magnets before the CEBAF shutdown. With the addition of the
proper computer control, we will use it to commission the magnet.

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

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

• The two GQ magnets passed preliminary qualification measurements with
field integral uniformity of ± 0.7 parts in 10,000 (Spec is ± 1.0 parts)
and field integrals that match within 3 parts in 10,000 (Specification
is 10 parts in 10,000). David Douglas still has to verify the
qualification using his Integrals along the beam path methods.

• Wang NMR shipped the replacement GX coil and it should be received
today.

• The first of the two remaining GX dipoles was placed on the test stand
and measurements were started.

***Quadrupoles***

[Trim Quad (QT)]{.underline}

• The additional coils to modify the remaining two Trim Quadrupoles
(QTs) for the second arc to add the vertical corrector function (GC)
were added by Jim Breeding of the Jlab Shop. The function will be
verified in tests next week.

***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) are being
made by Hiroyuki Toyokawa and we will attempt to install the coils on
the third Optical Chicane Dipole (GW) today.

• Robin Wines issued the sketches for a saddle shaped, air core vertical
corrector in the optical chicane. Jeff Dail of the JLab Shop drew up his
fixtures and will be making them next week.

**WBS 10 (Wiggler):**

We ran the power supplies for the wiggler through several hysteresis
cycles this week and rechecked the ability to ramp the wiggler strength.
Everything worked fine. The trim card which had been giving us problems
now functions perfectly. We also did some stress testing of the system
by tripping the wiggler supply while monitoring the voltage on the trim
supplies. A trip from 130 Amps led to a voltage of 2.5 volts on the trim
supply. This is not enough to cause any problems.

**WBS 11 (Optics):**

Over the weekend, we terminated the purge on the OC assembly and pumped
it down. It\'s running on its ion pump, and the vacuum is slowly
improving. The insertable mirror assembly after the outcoupler was also
checked for contamination, finding none, it was pumped down and its ion
pump started. The grout used to maintain the position of the diagnostics
girders was painted with epoxy paint to eliminate dust, and the region
where the alignment optics placed enclosed with clear, heavy plastic
sheeting. We pumped the 4F electron beamline down to a level sufficient
to get the ion pumps working. They hadn\'t been used since the old
machine was decommissioned, so, they are rather noisy, but that is a
minor issue, but created some opportunities to learn more about the
vacuum system. At the time this report was written

(\~ 14:00), we have a clear path between the optical cavities, and are
setting up the alignment system (ultraviewers) to align the OC mirrors.
We\'ve been operating the y axis motors on both assemblies to lubricate
the leadscrews. While doing this, the OC motor failed. While replacing
it with a spare, the encoder readback failed. We\'ve still not resolved
why the encoders of a second motor failed, so we will contact the
vendor. In the meantime, we will run the motor and have a camera on the
feedthrough shaft to provide visual confirmation of motion. Once we can
move the OC leadscrew remotely, we\'ll move on to installation of the
laser and optics for the other ultraviewer. The I&C group connected our
LSS shutter and diagnostic shutter (an insertable mirror to view
spontaneous emission from the wiggler) to the controls system.

Alignment of one OCMMS optical assembly is essentially complete and it
will be installed next week. The grout around the optical cavity vacuum
vessels will be painted this weekend.

***Other activities:***

We worked on preparing presentations for the LPC meeting next week.