# MEMORANDUM 

**To:** Distribution

**From:** F. Dylla

**Subject:** FEL Upgrade Project Weekly Brief - October 31 - November 4,
2005

**Date:** November 4, 2005

**Highlights:**

This week we continued to work through our punch list as we interleave
the

close-out of shut-down activities with machine start-up activities.
Specific accomplishments during the week included:

> \- both optical cavities are now under high vacuum
>
> \- we are going through the final wiggler alignment procedures; the
> chamber alignment was completed and the final wiggler alignment is
> scheduled for next week when the adjacent vacuum work is completed
>
> \- the optical transport system to Lab 1 has been pumped down
>
> \- RF operation in the first and second cryomodules has been checked
> out during 2^nd^ shift runs
>
> \- we also put a shift into additional operation of the injector and
> confirmed that the emittance diagnostic (the "multi-slit") is
> operating properly
>
> \- work remains on the 3^rd^ cryomodule which had its second window
> replaced today after diagnosis of a flange seal problem by the SRF
> crew. It had just passed initial leak test as of this writing.
>
> \- the shielding blocks behind the FEL vault access door were
> re-installed today in preparation for resumption of full beam ops

Next week we hope to complete the alignment and vacuum activities and
devote more operational time to tuning up the injector

**Management:**

We prepared FY05 summary and FY06 planning documentation for discussions
with ONR on our cost-performance reporting system.

Gwyn Williams and Fred Dylla attended the American Vacuum Society
meeting in Boston of which Fred is the Chair of the Board of Trustees
and Gwyn serves on the Executive Board of the Surface Science Division. 
The meeting presented many opportunities to meet FEL users and discuss
research opportunities.\
\
During these Boston trips, Fred Dylla gave a talk on the FEL Program at
MIT's Center for Accelerator Science and technology (CAST) and Gwyn
Williams gave a talk at MIT's Lincoln Laboratory on the JLab high power
THz source.  This meeting was attended by over 100 LL staff and
scientists and business development managers from local companies, and
aroused a high level of interest in applications of THz for security
applications.

**WBS 4 (Injector):**

This week we received the coil for sputtering a NEG coating on the gun
vacuum chamber. We also moved to our lab the IR Demo Gun vacuum chamber
for testing the NEG sputtering system. We also ran beam for injector
setup centering the beam through the buncher and the solenoid and tested
the functionality of the new QJ/VT0F03 downstream of the unit. More work
is needed to thread the beam through the unit.

**WBS 5 (SRF):**

The third harmonic cavity for the 100 mA injector module has completed
its initial chemistry cycle and will go through heat treatment today.
Initial TVA testing is scheduled to begin early next week. A new RF warm
window is being designed and procured through AES to accommodate the
higher power requirements associated with the change from 30mA to 100mA.

The requirements for the two all metal warm valves have been specified
and budgetary costs have been collected. This information has been
passed onto AES for procurement.

A status meeting was held at the vendor's site regarding the procurement
of the fundamental power couplers (FPC). AES personnel were present
during this meeting which included discussions specific to the
fabrication and schedule of the four FPC's. Delivery is expected mid
December.

The design of the beam pipe section between the gun and the cryounit is
proceeding along with a goal of achieving high vacuum and minimizing
particulate contamination.

The tooling design modification for the cavity tuner apparatus is
complete and signed off. Procurement of the parts needed for this
modification shall begin next week.

**WBS 8 (Instrumentation):**

The majority of this week was spent working with the vacuum folks to
rework the beam viewers with new silicon flags. The 3F region was
reinstalled and ran into some issues with lighting and focusing on the
newer flags. Student version of work: \"It seems as though the upstream
cameras are lighting the cameras downstream from them. (i.e. 3F05 can
actually be seen well when 3F01 is on). When this does not happen, the
viewer that is trying to be focused/aligned is too dim in this region to
see. However, upstairs in the control room the image isn\'t so bad,
which is strange because the image on the TV in the vault goes through
the same epics that the control room does\...:scratches head: With the
new targets in it seems like there either needs to be more light on the
viewport or the LED\'s need to be farther away from the viewport so they
scatter more light onto the target as opposed to scattering it in the
ring surrounding the target and into the beampipe. In fact since we are
putting a 1000 angstrom gold mask on a polished silicon wafer we are
facing the old problem of looking at a mirror. These features have been
resolved. (chuckle). Five new cameras were also fabricated with the new
CCD elements. As far as the silicon flags are concerned they will likely
be changed again when the holy grail of OTR materials are developed. The
requirements are three fold: 1. Must be thin to minimize the radiation
created when inserted; 2. must be flat and mirror-like; 3. must have
fiducials to calibrate frame grabber system. One plan which is in the
works is to coat the 250 micron silicon wafers (50mm dia.) with 5
microns of Cubic Boron Nitride (CBN) (or diamond) then etch the silicon
out of the middle, leaving the outer frame as a support then deposit a
gold mask for fiducials. A company; \'Le Bond\' near Atlanta has agreed
to try their tool coating techniques on our wafers.\
   Three sets of BPM Electronics have been installed and are working
properly through EPICS, with the embedded IOCs.  Some initial operation
data has been taken while the injector was being setup for operations. 
Understanding how these electronics operate with the FEL is the next
major step in developing this system.  Currently some design changes are
being looked into for more remote functionality as far as rebooting the
IOC and remote programming. We also updated the database and sequencer
for the new Coldfire BPM. The other 5 BPMs are ready to install. The
Coldfire chips for these 5 BPM are coded and programmed, and the
databases were built too. So we total have 8 new Coldfire BPM, and all
the diagnostic screens are created.\
   The Beam Viewer Crate backplane is nearing completion, some minor
changes were made to accommodate the control cards design.  These
changes are being corrected and then the board will be ready for quotes
and ordering.  The Control Card design is making progress, EECAD is
currently working on the schematic of the card.  The firmware has been
verified to fit in the PLD under the current layout with room for
expansion.  Some measurements have been made on the crate to ensure that
the boards dimensions are correct.   The reversing switch boards have
been ordered and will be ready for installation next week.  Some final
parts are being ordered so the switches will be ready for operations
next week.  The new dump monitor pcbs are being populated at this time
for testing before several are built up.  The enclosure documentation
for these electronics has been completed and signed off.  These will be
ordered as soon as possible.\
   The design continues on for the general purpose I/O card.  More
functionality is being incorporated into the design to take advantage of
the Coldfire\'s functionality.  The parts that will need to deal with
the Coldfire directly are being chosen so the software design can
begin.  Other details for protecting the inputs and outputs to the
Coldfire are being looked at as well.  The pin assignments are nearing
completion for the card and more of the electronics design will begin
once that is completed.\
   The software for the minimum gap of the wiggler was changed from
16.5mm to 17mm. The firmware minimum gap will be updated next week. The
EPICS sequencers for the K value conversions are still under
development. Next week the software focus will be on completing and
testing the EPICS wiggler controls as well as setting up a new IP
address for the\
controller.\
   We are currently trying to wrap up the framegrabber upgrade. Also
researching JCA (Java Channel Access) for potential use on future
control system applications. This would include its user interface, data
processing, and channel access capabilities. JCA maybe the solution to
bridging the gap between the control system and database tracking.\
   Progress has been made this week on video system maintenance. Not all
of the video system outputs have been recommissioned since the system
was upgraded. The optics team has developed a Lab-view program which
controls a single video switcher card (F0253). This is an ideal upgrade
to our IOC based testing setup. We are working towards setting up a new
PC/Lab-View based Video Switcher Test Area. A USB-CanBus interface has
been ordered.\
   Progress has also been made in developing EPICS tools which work with
the Configuration Control Database. This will allow us to automate
information updates with the database from the EPICS screens that we are
so familiar with. The goal is to move away from \"web-page\"
interfaces.\
   Installation of a new fabrication/machining station in the FEL I&C
trailer also began this week; this station will contain a drill press,
vice, hole punch, and several other pieces of hardware which will cut
the layover time for fabrication of new chassis panels and increase the
productivity and efficiency of the group. This relocation effort is in
part motivated by the injector test stand work in the FEL building.

**WBS 9 (Beam Transport):**

***Sextupole (SF)***

• Production measurements revealed that though the high harmonics were
very small, the sextupoles have a quadrupole component that is beyond
specification. Magnet test tried torquing the bolts and this changed the
value of the quadrupole. They also tried removing the field clamps to
get a feeling on their contribution. We will evaluate the data today. In
the mean time we put the original sextupoles back into the 2nd Arc.

***Replacement Chicane Dipoles (GW)***

• The remaining two units in at Magnet Test, awaiting the testing of
Sextupoles before the GWs get measured.

***UV Line***

• STI's has tested all the QX quads and they should be picked up Monday.
We are working on getting another lab to test two of these quads
absolutely on their test stand.

• Meanwhile, quads are not tested and girder assembly remains on hold.

• The NEG Pump cartridge holder design for the second corner UV chamber
is on hold.

#### UV Wiggler Progress

• No progress on the new wiggler vacuum chamber until new funding is
available.

***Down period issues for the IR portion of the FEL***

• The QJ/VT magnet was fixed by changing the lead configuration.

**WBS 10 (Wiggler):**

The wiggler chamber, having been straightened last week, was
leak checked this week.  A damaged conflat seal was repaired but
the chamber would not come down in pressure.  The vacuum crew decided
to bake the chamber to get accumulated water out of it.  Once this was 
done the chamber was reinstalled and aligned.  The final hookup of the
vacuum chambers must be done before final wiggler alignment is carried
out.  This should be done by early next week.\
The UV wiggler measurements should restart next week now that the
QX measurements are nearly done.

**WBS 11 (Optics):**

***FEL mirrors:\
***The HR and OC assembly\'s hot nitrogen purges were terminated and
pumpdown commenced.  With the activation of the new NEG pump on the HR,
this assembly went quite well.

***Other Activities***

With work on the optical cavity assemblies complete, attention turned to
the optical transport system (OTS).  The OTS was aligned to User Lab 1
(UL1) following test firings of the fast valve.  Optics were installed
and aligned in the lab cassettes and turning cans and Brewster windows
in UL4 & 6.  In-vacuum wiring was completed or repaired in the UL2 & 4
lab cassettes.  We anticipate pumping down and starting a hot N2 purge
of this long section of beamline by COB today, the first time it\'s been
pumped down in 4 years.  I&C pulled cables for the PZTs in each optical
cavity assembly so the driver electronics could be moved to the Control
Room.  This will speed troubleshooting and commissioning of the fast
feedback part of the OCMMS.  A new support for the X-ray cube was
designed that permits access to the OCMMS apertures and exterior
electronics and lasers.  For the THz pump probe design; the AD9850
Direct digital synthesizer board was brought up with a clock at 50 MHz.
The accompanying configuration software was used to achieve phase
synchronized outputs down to 1Hz. The 1 GHz ultra low phase noise op amp
board was received (spec\'ed at -120 dBc/Hz at 100 MHz and

1 KHz deviation).  The drive laser optical transport was aligned to
properly illuminate the photocathode.  The Injector could then produce
beam, as is reported elsewhere.  Work on the advanced drive laser
continued, with an emphasis in characterizing the phase noise.  For the
master oscillator, the value read out by the synchronization electronics
was as low as 260 fs.  Measurements using the RF group\'s
newly-assembled system yielded a value of 400 fs.  (Both are better than
the 1ps spec.)  Nevertheless, we would like to understand the difference
in values.  Then we will characterize the phase noise of the entire
laser system.  Work to synchronize this laser to the accelerator RF and
to transport a high quality mode to the photocathode progresses.  The
extended range NIR camera was received, and we\'ve started evaluating it
(It appears to give very detailed images), as well as determining how to
install it so it can view the surface of the optical cavity mirrors.  

Chris Behre (the current Safety Warden) coordinated the safe handling
and use of KOH in UL5. 

Michelle Shinn presented two JLab proposals to a panel of experts
assembled by the Joint Technology Office (JTO) in Albuquerque. She also
answered questions as to the role JLab will play in fulfilling work
proposed by two industrial firms.

Joe Gubeli wrote a status report on User Lab 4.  The outgassing test
chamber is undergoing some redesign, it is now to be made out of 8\"
diameter pipe. This is to allow a simpler design for custom heat
jackets. David Hardy completely disassembled the new turbo pump to fix
all of the leaks that happened during the bake out last week. When Dan
Oprisko finishes the new chamber and bellows the apparatus will be
reassembled and baked out.

**Terahertz:**

This week we ordered optical components for the imaging experiment, and
continued discussions regarding a new superconducting transition edge
detector, which should be able to detect individual pulses at 75 MHz.