# MEMORANDUM 

**To:** Distribution

**From:** S. Benson for F. Dylla

**Subject:** FEL Upgrade Project Weekly Brief -- November 3-7, 2003

**Date:** November 7, 2003

**Highlights:**

Good progress was made in hot checkout this week. All magnets, including
the new GY were run for long periods without problems. The MPS was
checked out and reconfigured for the new magnets. The drive laser power
was greatly increased. All RF systems are functional and zones 1 and 4
are running smoothly at gradients above those required. Vacuum problems
delayed zone 4 commissioning but repairs had that zone up and running by
Thursday.

Two problems arose this week. One was a radiation shielding
configuration problem that surfaced. This problem, which prevents us
from running beam, has been corrected and awaits Radiation Control Group
signoff. We expect to be able to run beam on Monday. The second problem
is infrared sensor trips in RF zone 2. Though all cavities are capable
of running at their "drive high" values, six cavities trip off after a
short time with IR sensor trips. The IR sensor measures the temperature
rise in the RF warm window. We are now calibrating temperature
measurements of the window to see if the new windows, which are ceramic,
are exceeding safe operating levels.

**Commissioning:**

On Monday the final water connections were made to the newly installed
GY magnet, final alignment was carried out, and the vacuum ion pumps
were started.

On Tuesday we brought up magnets and RF. The injector RF and the magnets
came up smoothly. One bad shunt module was found and some wiring
problems with the MPS system were identified. Zone 2 came up smoothly to
7 MV/m in all cavities. Zone 4 came up with more difficulty. The helium
pressure seemed high. Commissioning was stopped on Zone 4 when an ion
pump failed. Also on Tuesday, we found that some local shielding on our
insertable beam stop was missing. We installed a table to support the
shielding and sought guidance from the radiation control group on the
thickness of the shielding.

On Wednesday the ion pump was repaired and it was found that the
cryomodule guard vacuum was poor. A turbo pump was placed on the module
and normal cryo operations were restored. During the zone 4 repairs we
worked on bringing up the gradients in zone 2. Two cavities came up to
drive high values. The other six cavities tripped with and IR sensor
indication before reaching drive high gradients.

On Thursday we brought zone 4 up to full gradient operation and ran for
a while to improve waveguide vacuum levels. In parallel we looked at the
RF windows using an IR camera. The camera indicated uniform temperature
on the window. Unfortunately we had to look through a window that had
not been calibrated. Calibration of the camera is ongoing.

Friday we took some more data on waveguide temperature vs. RF power and
soaked zones 1n and 4 for several hours. We also finished installation
of the beam stop shielding.

**Management:**

This week we received an additional \$300k of funding from ONR to
continue the FEL commissioning effort to cover interim funding needs
until the FY04 MOA between ONR and DOE is implemented.\
\
We have scheduled a review of the AFRL funded UV FEL program on Nov.
25th for our AFRL program manager, John Eric.  Henry Helvajian who
supervises the Aerospace Corporation sub-contract for the UV FEL project
will also participate.\
\
On Monday Nov. 3rd, Dr. Ray Orbach, the Director of DOE\'s Office of
Science visited  Jefferson Lab for our annual review of our
institutional plan.  With regard to the FEL Program, Dr. Orbach was
pleased to note the establishment of FEL program funding by the Navy in
the FY04 budget and the Navy\'s intent of a continuing commitment for
involvement of Jefferson Lab in this program.  We thank Michael
Deitchman and Gil Graff for sending a strong letter of intent from ONR
to Jefferson Lab prior to this important review.\
\
George Neil attended a workshop this week at the Barking Sands Naval
Reservation in Hawaii at the request of Navsea to begin the process of
developing plans for a potential high power FEL test facility for the
Navy.  We congratulate George for his completion of the New York City
Marathon in 3hrs and 15 minutes on Sunday in preparation for his long
plane trip to Hawaii.\
\
Fred Dylla presented a paper at this week\'s 50th International
Symposium of the AVS in Baltimore which summarized a half century of
development of vacuum science and technology for particle accelerators,
magnetic fusion devices and gravity wave observatories. The paper was
published in a special 50th anniversary issue of the Journal of Vacuum
Science and Technology (JVST) that was edited by Fred and Paul Redhead
(of the Canadian National Research Council).\
\
Gwyn Williams helped to organize a workshop held this week  (Nov. 5th)
at BAE Systems in Manassas, VA to discuss the future of x-ray
lithography. Attendees which included representa-tives from industry,
DARPA, academia and NRL discussed the need to re-establish facilities
where x-ray lithography can be used to demonstrate sub 100nm
capabilities. If sufficient industrial interest is generated, Jefferson
Lab may be asked to re-commission the Helios synchrotron. Such a
re-commissioning effort would help fund additional lab space and
injector test capability in the existing FEL facility.

**WBS 4 (Injector):**

The W&M ion-implant system is back in operation. The electrostatic
design of a ring (similar to the ground ring on the actual electron gun)
for the HV test stand is complete. This ring will be installed in the HV
test stand chamber for testing the field emission suppression coating on
the curved surface of a tube. Sketches are pending final approval before
requesting fabrication to the machine shop.

**WBS 5 (SRF):**

[FEL03 status:]{.underline}\
Work continues apace. The heat shield is on and remaining plumbing and
fit-up details are being worked out. This was the first heat shield made
of this type and had a number of issues that had to be reworked based on
SL21 experience. The thermal intercepts to the nitronic rods are
currently being fitted. The space frame has appeared in the assembly
area and is being prepared for installation around the cold mass, either
this week or next.

**WBS 8 (Instrumentation):**

This week began with a glimmer at the end of the shut down tunnel but
after a few days it looked as if it were a train coming. The calorimeter
that was to have been installed last week had accidentally been
contaminated with oil. The system was completely broken down and
returned to the test lab for cleaning. Ralph Afanador and his crew got
the job turned around in one day. By Wednesday morning it had been
reassembled and turned back to the optics group for another (last one)
round of bake, leak check, and installation. The week ended by setting
up RTD thermometers on the zone 2 SRF cavity windows. These new ceramic
windows are capable of running at higher temperatures than the old poly
ones. Unfortunately, it looks like they may have to.\
  

The horizontal and vertical dump raster power supplies were pulled due
to a failure one day before Isabel toured the lab. This failure was
tracked down to an electrolytic cap that had been installed backward and
finally shorted. Both boards were thoroughly inspected, realigned, and
put back into service. We also took the opportunity to write a complete
testing and troubleshooting procedure.\
  

The accelerator vacuum also sucked, but not in the way we had wished.
The ion pump at 0F06 needed shock treatments; pumps are hi-potted to
clear \'whiskers\' which make the vacuum appear higher than it really
is. The treatment worked. The cryomodule in zone 4 had the beamline ion
pump fail, preventing RF operation. This was solved by adding a pump to
the roughing port (sort of like having a third arm transplanted to the
middle of your back).\
  

The new video/AMS switcher is moving from the debug & developmental
stage to one of operations. The physical layer of the CAN bus
communications from the IP pack in the IOC to the digital I/O of the
crosspoint chassis board (F0253) is fully tested and now works. In the
process, we discovered a PCB layout issue that will need to be corrected
for future boards. For our prototypes, however, we have modified the
board to allow the CAN circuit to operate properly. With the physical
layer of the CAN communications working properly, we have been able to
successfully switch video across the board, however, only the first 16
inputs are switching. Currently, we are reviewing the code embedded in
the crosspoint board which is responsible for generating the serial data
which switched the signals. We expect there may yet be a subtle error
keeping the second half of the systems inputs from mapping to the
outputs. DC power for the 1st Arc GG path length corrector has been
completed. Installation of the 1st Arc dipole shunt, shunt resistor and
thermal interlocks have been completed and are ready for Ops. MGC2F07
chassis has been completed and testing is in progress. This is the third
of four GC power supplies. All of the magnet power supplies have been
run and are ready for operations. Since the DY is no longer needed it
has been remove from the Machine Protection System (MPS) and the
firmware has been modified to reflect the changes. This has also been
fully tested.\
  

Efforts on the frame grabber project were directed toward researching
the errors received by the IOC running the software. There seems to be a
problem with the UDP messages being sent. A test plan has been developed
to find out if the problem is associated with only one of the IOCs. The
rest of the week was spent researching for background knowledge of
uClinux, the embedded linux that\'s going to be used for the ColdFire
linux IOC project.\
  

Progress has been made on the design and fabrication of the calorimeter
chassis.  This houses a heater control board, and temperature readouts
for the two RTDs and two zener diode thermometers. Fabrication of both
the rear and front panels and wiring harness\'s have been completed.
Airlines were installed on the HR_PM5K and HR_J50 solenoids. Installed
and began testing of the 2F06 chimney viewer. Installation of SLM5F02
periscope has been completed and tested. The current/voltage calibration
of the Charge/Dump Current Monitors is complete.  Both channels were
satisfactorily checked for frequency response as well. They respond to a
couple tenths of a % over the range from 0.1 to 10 mAmp.

**WBS 9 (Beam Transport):**

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

• For the recently installed GY in the first arc, we hooked up the power
leads, attached the vacuum chamber to the other chambers and pumped
down, installed the cooling water connections, shunt system and the
synchrotron light diagnostic periscope. It is ready to run. Final
alignment showed little movement from the initial alignment, indicating
good stability on the part of the refurbished CERN adjuster cartridges.

[SF Sextupoles]{.underline}

• Mel Gonzales of the electrical CAD group is nearing the end of
revising the drawings of the SF Sextupole design. The specification to
match the drawing package was finished and will be checked by another
engineer.

**WBS 11 (Optics):**

This week\'s work (including Friday afternoon) on optical and
optics-related subsystems could be summarized as \"in process\".  A
careful study of the sources of vibration-induced angular jitter was
performed Friday afternoon and Monday, and is proving to be invaluable
in better understanding what we are measuring with the OCMMS
position-sensitive detectors.  Pinhole leaks on the inner circumference
of the holder slowed progress on the new outcoupler mirror.  Another
braze cycle takes place today, using some new paste-based brazing
material that was just received.  We have a plan \"B\" in place, should
need to install an outcoupler arise before it is fixed.  On Monday we
discovered that the bake calorimeter was ruined by the presence of oil. 
We (I&C and Optics) had to start over, starting with parts, connecting
hoses, and the pump cart being cleaned.  Through the course of the week
we then had a set of vacuum pump cart problems (on two separate pump
carts!) that prevented us from reinitiating a bake of the calorimeter. 
We should be able to start it later today.  A newly refigured and coated
10.6 micron HR mirror was received from the vendor late last week. 
Metrology revealed that its ROC was made to the OC mirror specification,
-16 m, so it was returned for rework.

 

The drive laser lamps were replaced in preparation for renewed
operations.  Overall throughput was checked, and found to have improved
by 35%, mostly due to the installation of the new EO modulator. This
will give us increased operation time between recesiations. 

**Terahertz Project:**

A 10mm diamond window has been installed at the FEL in place of the
quartz window and the Nicolet Impact-400 Michelson interferometer has
been re-commissioned once more to allow THz measurements to take place
once beam is re-established.  The bill of materials for the beamline
vacuum components is complete and in line with the proposal.  AES is
currently designing M1 and M2 (=M3=M4) after a brief hiatus. Preliminary
price estimates for the mirrors are being obtained.  This process is
necessary in case small design changes significantly affect final costs.