# MEMORANDUM 

**To:** Distribution

**From:** F. Dylla

**Subject:** FEL Upgrade Project Weekly Brief -- July 28 -- August 1,
2003

**Date:** August 1, 2003

**Highlights:**

This week, prior to shutting the machine down on mid day Monday for a
high level Marine Corp tour and an NRC inspection, we were able to
recirculate electron beam in the FEL Upgrade. The ease of this initial
operation was a good sign of the state of the recirculation hardware and
the skill of our chief FEL commissioners, Dave Douglas and Steve Benson.
Beam operations resuming today after the completion of the 3-day Navy
sponsored High Power FEL workshop, with the day being spent on injector
set-up.

**Commissioning:**

On last Friday we went through the injector setup procedure.  After
carrying out the procedure, the beam spots were ratty and the energy
spread out of the injector was large.  After some searching we found a
new phase set point that gave nice spots and a small energy spread out
of the injector.  This set up still needs to be optimized but it is a
good starting point.  On Monday we used this setup to phase the linac
and thread the beam through to the re-injection point of the linac. 
After checking out the functioning of the steering and focusing magnets
we tried to match to the linac.  Made some progress but had to shut down
for the Marine and NRC tours.  No beam running again until today when we
continued injector set-up.

**Management:**

A majority of the senior members of the FEL team attended this week's
Navy High Power FEL Workshop held at the Applied Physics Laboratory in
Laurel, MD.

We were pleased to see over 200 attendees at the workshop from the Navy,
contractors, and the National Labs and Universities involved in FEL R&D.
We presented six (6) papers ranging in scope from a FEL Upgrade project
summary to details on relevant SRF, optics, beam transport and
cryogenics technology. The key results from the workshop from our
standpoint were the recognition and support shown by ONR and JTO for FEL
technology development, and the interests shown by the operational Navy
(NAVSEA and PEO Carriers) in the long term development of FEL hardware
for Naval applications. Working Group summaries from the workshop should
be available by 6-10 weeks.

We offer our congratulations to Alan Todd from AES who had the
complicated chore of organizing and running this important event.

We received incremental funding for the start of two FY03 JTO projects
this week: (1)

\$127k of \$276k requested to implement the first optical transport line
from the upgrade to the users labs so that lethality measurements can be
started at the 10 kW level; and (2)

\$175k of \$369k requested for the first phase of studying damage
resistant IR optics for high power FELs.

On Monday July 28, we had a briefing and tour for the staff of Brig.
General Richard Zilmer. The General was unable to attend at the last
minute but his staff led by Lt. Col. Wassink spent

2 hrs at the facility and promised to arrange a return visit for the
General. The group was accompanied by our Marine representatives to the
JTO: Major Steve Redifer and Franz Gayle.

Following the Marine Corp visit, the FEL facility was inspected by the
NRC. We received excellent marks on our radiation control and management
procedures (as did CEBAF).

**WBS 4 (Injector):**

Continued manufacturing parts for the second electrode structure.
Fabricated and polished the new mount for the ion implant system for use
with the support tube. Started polishing the first niobium electrode for
test in the field emission test stand.

Gun HVPS - Capacitors were added to the Master drive unit to help reduce
a 2 MHz noise source in the measurement stack. The buffer amps in the
I&C chassis were changed to a better quality Op Amp to greatly reduce
the noise with a one stack configuration. It will be checked with the
two stack configuration as soon as schedule permits

**WBS 6 (RF):**

RF - Checked attenuation factor for the Quarter\'s probe attenuators.
They had not changed from their previous values of 2.9 dB. RF was run a
few hours every day to maintain its good operational condition. The
SOP\'s for the Buncher and Linac HVPS are in draft form. The Buncher
updated SOP was sent out for comments.

**WBS 8 (Instrumentation):**

In spite of the time lost to the Navy workshop much was accomplished in
preparation to run the FEL in full power mode. The systems and
documentation are in the final revision for certifying that we are ready
to run the accelerator in CW mode - with electron beam powers
approaching 1 megawatt!\
   

The Machine Protection System (MPS) software is being updated, a high
level EPICS screen is being created that will interpret the machine
configuration data from the MPS system and present the user with a
\"prioritized list\" of what machine elements are limiting the machine
from entering into the higher modes of operations. This will be a VERY
user-friendly screen that should eliminate ALL the current confusion in
setting-up the machine from the perspective of satisfying the MPS.\
   

All changes to the Drive Laser Pulse Controller (DLPC) are complete and
the system is ready for beam operations to resume tomorrow. Changes have
also been made to the Drivemaster Screen. Software readback of the
\"Current Allowed Beam Mode\" from the DLPC has been made available to
EPICS as well as a \"DLPC TRIP\" flag bit to indicate the condition
where the DLPC has detected a violation of the beam mode restriction
that must be resolved. These system readbacks have been included in the
current controls screens. They can be found on the MPS/FSD main screen.
The following list details the current Pulse Controller Interlocks
implemented due to current Beam Mode definitions: BEAM MODE 0: No beam
allowed, all interlocked devices engaged. \* ND2 Filter engaged \*
MPS/Operation Shutter Held Shut \* EO Cell Gate Inhibited BEAM MODE 1:
Ceramic Viewer Mode (2Hz, 100us, 9MHz w/ ND2) \* ND2 filter permanently
engaged \* MPS Shutter and EO cell gate interlocked to 0.05% Pulsed Duty
Factor \* Micropulse Frequency Interlock restricted to \<= 9.36 MHz BEAM
MODE 2: Standard Tune-Up Mode (2Hz, 250us, 4Mhz) \* ND2 filter free to
insert and retract \* MPS Shutter and EO cell gate interlocked to 0.08%
Pulsed Duty Factor \* Micropulse Frequency Interlock restricted to \<=
4.68 MHz BEAM MODE 3: High Power Pulsed Lasing (i.e.. 2Hz, 800us, Any
Micropulse Freq.) \* ND2 filter free to insert and retract \* MPS
Shutter and EO cell gate interlocked to 0.2% Pulsed Duty Factor \* No
restrictions on Micropulse Frequency except for 75MHz operation not
allowed BEAM MODE 4: Uncommissioned \* equivalent to Beam Mode 0 - no
beam allowed - BEAM MODE 5: Uncommissioned \* equivalent to Beam Mode
0 - no beam allowed - BEAM MODE 6: Uncommissioned \* equivalent to Beam
Mode 0 - no beam allowed - BEAM MODE 7: FULL POWER MODE (No
Restrictions) \* ND2 filter free to insert and retract \* MPS Shutter
able to open and close freely \* EO Cell Gate unsupervised and
unrestricted \* Micropulse Frequency Selection unrestricted (Latch
High/75MHz permitted and CW beam as well as any combination of Pulse
Repetition Rate and Pulse Width (or Duty Factor). BEAM MODE 7 is also
achieved when the GUN HVPS interlocks (\"HVPS OFF\" and \"Gun NOT ON\")
are made up as is always the case when we are in \"RESTRICTED ACCESS\".
This is also referred to as MPS BYPASS MODE. BEAM MODE 6 (BLM commission
mode) has been programmed into the DLPC firmware but is currently
disabled until the MPS check-out is complete since it is a CW mode.
Also, note that the 37.425 MHz micropulse frequency option is not active
at the time due to an omission in the pulse controller design. We are
currently working to implement the solution.

   

The background subtraction function (on the Linux IOC framegrabber)is
proving to work very well.  After further testing of the interface, the
complexity of the logic was increased to create a better understanding
for the user about when the system is processing or ready.  The IOC has
been causing some problems as far as disconnecting channels.   This has
caused a need to test this area and also brings up the idea of better
security against this.  A potential fix is to allow the user the ability
to restart the program by invoking a script.  Several ideas are being
considered.\
   

The High Reflector (HR) & Output Coupler(OC) Buffer Board was assembled
and tested OK.  Progress was made on the RTD and Analog chassis for the
OC. This will complete all *known* optical instrumentation (through to
EPICS).\
     

Provided support to Nimel Theodore for testing of his High Voltage
Transformer for material processing.\
  

Corrected problems with 2nd Arc Power Supply MPS status and the MPS
current limits on the Injector Dipole magnet.  This was changed to
correct linearity problems as well as false trips.  Wiring was completed
for the 1G dump trim magnets. Effort continued on the fabrication of the
GC magnet power supplies.\
  

Completed the installation, alignment and checkout of the dump viewers. 
Continued installation of the SLM\'s at 2F06, 2F09 and 4F00. A rough
draft of the MPS Certification Procedure has been written and is out for
review as is a procedure for BLM testing. All magnets with dual power
supplies have been identified and labels are being made.  A LOTO
procedure for magnets will be out early next week. The calibration of
the current monitoring cavities against the 2G electron beam done has
been done. For the few data points we have at only a few hundred
microamps the readout looks to be close to or better than one percent.\
   

A lot of time this week was spent preparing for the up coming OSHA
inspection.  There are still several minor issues that need to be
resolved, i.e. extension cord use and cleanliness/housekeeping.

**WBS 9 (Beam Transport):**

#### Dipoles

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

• The magnet assembly continues, main coils are mounted and hoses are
being custom made for the lead connections. Wang NMR has repaired and
shipped the shorted GG coil.

• With the end of fabrication, we are having both Bosma (GYs) and
Process Equipment (GX & GQ) send their excess inventory of JLab
supplied, 1006 steel slabs back to JLab.

***Multipoles:***

[Trim Quadrupole (QT) / Vertical Arc Corrector (GC)]{.underline}

• The new, isolated, 4-quadrent power supplies for the GC Correctors
were started by Jim Coleman.

***Octupole (OT)***

• Process Equipment is shipping one each of left-over 1006 steel slabs,
style 12 & 14 directly from their inventory to New England Technicoil
for their production of the Octupole cores.

**WBS 11 (Optics):**

We took the opportunity this week to prepare for upcoming safety
inspections. Housekeeping was addressed, and new permanent electrical
wiring was installed in the drive laser clean room. Measurements were
done to determine the throughput of the drive laser optical train --
these will be analyzed today. Work progresses on various optical
diagnostics enhancements. Work was performed on the ultraviewer system.
Work was done to raise the output of the Nd:YAG laser used in the mirror
test stand. We received the 10.6 micron HR mirror that was sent to the
vendor for recoating.   We have been working with the Mechanical
Engineering group on the UV optical transport system and optical beam
positioning system.

***Operations/other activities:***

A solenoid-driven optical shutter was added to the laser alignment
assembly located near the backleg of the accelerator. It can be
controlled from the Control Room. This allows operators to check
centering of the beam against beamline center. The mechanical shutter
used as an EO cell replacement failed and the spare was installed. The
failed unit is being returned to the factory for repair. Michelle Shinn
attended the Navy Workshop and gave three presentations.