IR FEL Monthly Report for February 1997
Navy IR Demo Contract WBS Elements
WBS 1 Project Management
February 1997 was the eighth full month for the IR Demo project
funded by the Navy.
The IR FEL Demo project through the month of February 1997 has
a total of $4,209k (less SRF and building) of cost performance
scheduled. The work performed through the current period is $3,524k
or 44% complete of 52% scheduled. The actual cost accrued through
the current period is $3,649k. This results in a schedule variance
of -$685k (an increase of $71k) and a negative cost variance of
$126k. The net change in the cost variance is -$298k, going from
a positive $172k to a negative $126k.
The building construction schedule in the performance reporting
schedule is less aggressive than the actual contract schedule.
In the performance schedule the contractor remains essentially
on schedule. However, we expect BOD #2, occupancy of the second
floor, will be 2-3 weeks behind schedule. The building is being
reported as $23k behind schedule and $48k undercost.
The performance measurement reporting system for the project was
reviewed in preparation for the January monthly report. Using
the secondary peg points with dollar values below the previously
reported primary peg points ($100 K or more in value) significantly
improved the cost performance data for the project. A previously
reported negative cost variance was an artifact of taking credit
for only primary peg points. The January monthly report was completed
and distributed on Feb. 28th
The DOE Basic Energy Sciences Program Office held a review of
the IR Demo project and the Jefferson Lab FEL program on Feb.
23-25. The review was co-chaired by the Navy (John Albertine)
and included six external reviewers. The review team gave the
project excellent marks for the execution of the Demo project
to date. A draft report is expected from the Team early in March.
Dylla and Helms have been invited to DOE-BES headquarters on
March 6th to discuss continued interactions with BES.
A draft Field Work Proposal for FY98-99 support of the IR Demo
User Facility was forwarded to the DOE-BES Program Office for
comments.
A draft report from the meeting of MTAC on December 18 was received
from SURA. Comments were returned to SURA and the Navy HEL Office.
The committee urged the Jefferson Lab team and our industry collaborators
to work with the Navy Program Office to strengthen the long-range
plan for further discussions with Navy officials and congressional
staff.
It was decided to defer all 10 MeV injector operations with electron
beam to the FEL Facility, and to concentrate activities in the
Injector Test Stand (ITS) toward maturing the technology for the
photocathode gun and establishing reliable operations of the gun.
Complete testing of the cryounit without electron beam will also
take place in the ITS as originally envisioned. Plans are to
move all gun and injector hardware to the FEL Facility starting
1 June. These injector activities preserve the milestone of installing
all hardware in the Facility by 30 Sept. 97.
At the SPIE Conference on High Power Lasers held in San Jose on
Feb. 11-15, G. Neil presented a talk on modeling of the optics
for the IR Demo. M. Shinn gave a status paper on the IR Demo
Project. Related papers were given by J. Albertine, J. Cook,
A. Todd, and M. Kelley.
On Friday, 7 Feb., C. Bohn presented a colloquium at the Naval
Postgraduate School entitled "Collective Effects in Electron
Beams for High-Power Free-Electron Lasers" and participated
in discussions of a tutorial nature on coherent synchrotron radiation
(CSR). The following Monday, 10 Feb., Bohn attended a meeting
at SLAC concerning research and development for the Linac Coherent
Light Source (LCLS), where he presented a talk entitled "Survey
of Jefferson Lab's IRFEL and Coherent-Synchrotron-Radiation Studies".
CSR experiments planned for the IRFEL are also of high interest
to the LCLS, as was highlighted in discussions at the meeting.
WBS 5.0 Instrumentation & Controls
Beam Instrumentation: The beam position monitor mechanical contract
was awarded to Breezes Precision Boring. The terms call for 60
day delivery, a visit was made 2/28/97 to discuss the details
for the assembly. The vendor will have all of the required materials
in house by March 3, there has been ample work completed to assure
the delivery on April 18. There are three tasks sub-contracted
out: the stress relieving, EDM cutting of the stripline slots,
and the electropolishing of the subassembly. These will be tracked
to assure timely completion.
The beam viewer assemblies were received Feb. 27. A sample will
be leak checked and connected to an RGA (residual gas analyzer)
to assure proper procedures were used during the cleaning and
assembly. These 13 devices have been delivered complete to minimize
the draw on internal manpower.
The M56/M55 system is progressing well, the modulator chassis
is complete, receiver chassis is being debugged and the firmware
is being developed. The two cavities required should be complete
in late April or early May.
The multislit emmitance monitor parts are now complete, the 52
slits (two devices; 13 each horizontal and vertical arrays) were
successfully machined to +/- 2 microns. These devices will now
proceed to assembly. The software has been tested by using PARMELA
output as a signal and viewing with the CCD camera that will be
used in the accelerator. Due to the deferred 10 MeV testing this
device may be tested as a part of the expanded 350 KeV+ test plan.
It is desirable to complete as much system checkout as possible.
Personnel Safety System: A review date of April 1 has been set
for the Personnel Safety System Review. This review will also
cover the Laser Safety System (LSS) used to interlock each of
the optical labs. The PSS racks have been relocated to Zone 15.
This will make the connection to the Main Control Center (MCC)
much easier.
Machine Protection System: The procurement for the Argonne system
is proceeding, we have single pieces of this hardware in house
to facilitate the software efforts. Discussions are ongoing to
define the different states of machine operation and how this
interfaces to the drive laser controls.
Controls Hardware: The computer procurement award was delayed
due to discount confusion between Jefferson Lab and Hewlett Packard.
This has been resolved with delivery scheduled for April 21.
The detailed VME & CAMAC crate assignments are being finalized
as well as the cable database for installation.
Software: Excellent progress is being made on all of the systems.
By deferring the 10 MeV beam tests the software resources will
not need to be diverted to the injector test stand, this will
further enhance the timely completion of the systems needed for
commissioning.
DC Power: The order was placed for the remaining two 100 Amp
chicane power supplies. The delivery is expected to be six months
(this will be tracked closely). The trim racks are nearing completion,
cable assemblies will be fabricated in the service building to
connect the 32 channels per rack to the termination blocks located
in the tunnel. This will reduce the time required to install
the system once the FEL building is available.
Vacuum System: The cable database is nearly complete, the rack
layouts are finished and the detailed crate design is proceeding.
The 50 beam line ion pump controller (BLIPC) printed circuit
boards are complete and being tested. This board was re-laid-out
from the old artwork and assembled off site. The next boards
due are the gate valve controller cards.
WBS 6 Cryogenic Distribution
Quad transfer line installation is complete. All linac transfer
line modules are fabricated and have all been placed in the linac.
Welding will start after confirmation from survey and alignment
that the positions marked for the location of the transfer lines
are correct. Fabrication of the sleeve supply and return transfer
lines are nearly complete; just the final leak tests remain.
Detail design of the field flex can should be complete by 3/10;
most of the required parts have been procured. We have started
installation of the gas lines at the CHL. All procurements for
instrumentation and control are complete. Fabrication of the
cryogenic distribution system is 65% complete.
WBS 7 Beam Transport
The electron beam optics of the machine in the optical chicane
region were changed slightly to allow the space for the shielding
in front of the optical collimator. The shift does not affect
clearance to other features of the optical cavity or the design
of the dipoles.
For dipoles, the bidders received solicitations for the optical
chicane dipoles as design work continued on the remaining reverse
bend, 180 degree and injection/extraction dipoles
At the Magnet Test Stand, 304 stainless steel qualified as the
vacuum chamber material of choice after tests in the prototype
dipole. The prototype trim quad underwent detailed magnetic
measurements which require extensive analysis over the next weeks.
The prototype sextupole went through preliminary magnetic characterization
with the conclusion that we will need field clamps, but the basic
design is sound. In the opinion of L. Harwood, exact pole tip
shape will need further work, but fabrication and installation
can proceed.
The first article of the main quads arrived from the vendor.
It passed magnetic tests.
A kick-off meeting was very productive for design of the stands
for magnetic elements downstream of the cryomodule.
For the vacuum system, the differential pump station was signed
off and design of the vacuum chambers in the remaining first light
regions started. Substantial portions of the vacuum hardware
have been ordered.
The review of the dumps was held on the on February 5. Several
issues involving protection of dumps or the collimator that are
not designed to withstand the full beam intensity or an odd beam
distribution were identified and require further study.
WBS 8 RF Systems
The chopper system was operated with its new software in both
the CW and pulsed modes. In the CW mode, the cavity can only
take 100 watts before the pressure becomes excessive. The stainless
steel outer conductor of the drive probe is the suspected problem
even with cooling fins. In the pulsed mode, the cavity has received
380 watts without a vacuum problem.
New software for the quarter cryounit was successfully tested
this month. The tests for the mechanical tuners will be tested
after the quarter cryounit is cold.
The spare 50 kW klystron did not pass its acceptance tests. It
appears to have developed a vacuum leak and will have to be returned
for rework.
Hipotronics still expects to deliver the first unit of the 225
kW variable DC power supply in May 1997, but there has been little
evidence of progress. A trip to the vendor is in order. The
design review is tentatively scheduled for the latter part of
March.
The installation schedule for the FEL building is approximately
50% in place and starting to be helpful.
WBS 9.2 Injector Move
The purchase order for the high voltage tank fabrication was awarded.
Delivery is scheduled to be in mid-May.
The purchase order for the laser clean room fabrication was awarded
to Clean Air Technology. It is scheduled to be complete by June
1.
Work continued on injector layout design. About 50% of the design
work is complete.
WBS 9.4 Wiggler
Sent out requests for quotation on the wiggler vacuum chamber
tubing. The vacuum chamber support design is 60% complete.
STI Optronics has completed all the mechanical components for
the wiggler. Some parts still have to be anodized. Assembly
has begun on the supports. STI Optronics has received and measured
most of the magnets from Shin-Etsu. The uniformity of the magnets
is excellent. The final set of magnets is due around March 10.
Final magnet measurements are now scheduled for early April.
WBS 9.6 Optics
During February, activities concentrated on completing the designs
for the optical transport and diagnostics. The turning mirrors
("mirror cans") and diagnostic pickoff drawings were
signed and are in Procurement. The redesigned collimator did not
pass our initial internal review, and is being redesigned. We
completed the drawings for installation of the optical transport
pipe; with installation occurring sometime in March. Procured
parts continued to come in, major acquisitions were the ion pumps,
the linear stage, and the monochromator/spectrograph. Software
development for the optical cavity controls continues. With much
of the optical cavity fabrication complete, we are beginning to
assemble the parts to check for fit. The Mach-Zehnder interferometer
is being reassembled on a small (19" x 23") optical
breadboard for testing with an 8 m separation between the folding
mirrors and the beamsplitters.
ITS
The photocathode drive laser was operated in support of transverse
emittance measurements. The IR and SHG powers were quite stable.
The divide-by-two electro-optic modulator, with it's new lithium
niobate crystals was installed and found to steer the beam to
an unacceptable degree. It was returned to the manufacturer, repaired,
and when installed, found to handle the nominal 20 W of IR without
problems. We are having problems matching sufficient rf into
the modulator to get good modulation, and are working this issue.
We could not duplicate last Summer's locking of the laser's phase
to the master oscillator, although performance was acceptable
for the initial longitudinal measurements. The rf group is looking
into the problem.
Injector, SRF, Facility, and Other
Activities Outside Navy IR Demo Contract
Injector Test Stand (ITS)
The month's activities were focused on three areas: reconfiguring
the experimental beamline of the gun to permit both transverse
and longitudinal phase-space measurements, acquiring the components
necessary for upgrading the gun to operate at photocathode stand-off
voltages of at least 350 kV, and developing warm ceramic windows
for use at 50 kW on the injector cryounit. In addition, we received
the spare 50 kW klystron and began running it through a series
of acceptance tests. Also, the software and screens for the cryounit
were successfully tested, and the software for the mechanical
tuners was installed.
We succeeded in reconfiguring the experimental beamline of the
gun and readying the gun for renewed operation at 250-300 kV stand-off
voltage. The existing ceramic stack was processed to 320 kV,
and all of the components and software for the beamline were checked
out. We turned on the gun, producing low power electron beam
at 250 keV, and began commissioning the new experimental beamline.
We checked out the magnets, the drive laser and its upgrades,
the diagnostics and rf systems, and we also completed hardware
checkout of the new diagnostics, light-box harp, and aperture.
Good extinction ratios were also achieved of unwanted ghost pulses
from the drive laser.
We then started 24-hour operation of the photocathode gun at 250
keV, running three full days during the last week of February.
In conjunction with gun operations, we aligned the drive laser
to the photocathode, hard aperture, and camera in the test cell
to permit laser-beam analysis. In general, the drive laser was
brought back to a fully operational state. We also recesiated
the cathode and brought it back up to several percent quantum
efficiency. Subsequently, we made about 20 measurements of transverse
emittance to verify the performance of the new hardware in the
beamline and the reproducibility of measurements taken last November,
and to quantify the effect of the rf kicker cavity on the beam.
No effects were observed which are directly attributable to the
kicker cavity. The kicker cavity itself was commissioned to perform
as required for longitudinal measurements.
We also vigorously pursued the acquisition of a cathode support
tube with field-emission-resistant coating, and new high-voltage
ceramics coated for uniform resistivities in the range 5-100x10^9
ohms. These are components that will be used to upgrade the gun
to operate at higher stand-off voltages. We received the coated
cathode support tube from FM Technologies. By month's end, Lawrence
Berkeley Laboratory had successfully produced two coated ceramic
cylinders using ion implantation, and they were in process of
shipping the ceramics to Jefferson Laboratory.
Development of warm ceramic windows for use in high-rf-power operation
of the cryounit proceeded slowly due to technical difficulties
with the ring-resonator test stand used to certify these windows.
Thus, not only did we upgrade the test stand, but also we developed
a new window-test resource based on using one of the 50 kW klystrons
to supply rf power to the window test fixture. It allows parallel
testing of warm windows in both the resonant ring and ITS cave.
By month's end, the resonant-ring test stand had been run with
a single warm window and with no vacuum in the system. The window
was exposed to rf power up to 50 kW with no breakage. A second
window was in testing. Qualification of the 50 kW rf system for
window testing was imminent.
WBS 3 Cryomodule
There was, and continues to be, considerable activity toward qualifying
warm windows for the injector cryounit. The resonant ring test
facility was reconfigured to replicate more closely the vacuum
conditions at the window that would prevail during cryounit operation.
It was run with a single warm window and with no vacuum in the
system. The window was exposed to rf power up to 50 kW with no
breakage. This result supports our hypothesis that artificially
high vacuum conditions during testing was the cause of limited
window performance. At month's end, a second window was in testing.
Testing with vacuum awaited further rework of the vacuum test
fixture, with first experiments anticipated for early March.
In addition, the 50 kW rf system was also configured with a waveguide
for window testing in parallel with the resonant ring tests.
First experiments with the 50 kW system were also anticipated
for early March.
A final internal review of the cryomodule design and existing
test results from the injector cryounit was held on 19 Feb 97.
No show-stopping issues were identified.
Cryomodule production proceeded generally on schedule. The first
cryomodule cavity pair was assembled, and it finished testing
during the last week of February in the Vertical Test Assembly.
Preliminary analysis of the data was favorable. Gradients were
10 MV/m or higher with little or no field emission evident. The
second cryomodule cavity pair is scheduled for assembly during
the first week of March.
WBS 2 Beam Physics
Plans were documented for experiments to measure transverse-emittance
growth from coherent synchrotron radiation (CSR) in the bunch
decompressor following the wiggler location, and in the first
recirculation arc. As currently envisioned, the emittance measurements
will involve quadrupole magnets and viewers at the wiggler location
(with the wiggler removed), downstream of the bunch decompressor,
and in the back leg (which has a multiplicity of measurement systems).
Parametric investigations of the influence of bunch charge, bunch
length, bunch momentum spread, transverse bunch size, and transverse
emittance at entry to the bending systems are all envisioned.
We anticipate being able to start taking CSR-related data around
the turn of the calendar year. In addition, theoretical work
continued toward the goal of developing a good algorithm for doing
numerical many-particle simulations that include CSR.
As required, simulations were done to finalize specifications
for beam-transport components. For example, detailed tracking
studies were completed that resulted in a decision to retain the
beam scraper and the establishment of its specifications. A second
example is a series of simulations of the FEL injector to explore
the sensitivity of its performance to the fields of the injection/extraction
dipole magnets. This study generated guidelines for the resolution
of magnet measurements that will be done as part of the acceptance
tests for these magnets once they are received.
WBS 4 Commissioning/Operations
In light of the schedule for producing a new ceramic stack for
the gun, we renewed consideration of a deferral of all 10 MeV
experiments to the FEL Facility, and ultimately decided to do
so. This permits us to do gun development through 1 Jun. 97,
as well as thoroughly test the injector's cryounit without beam,
and then commission the full injector with beam starting in Sept.
97. It preserves the milestone of installing all hardware in
the FEL Facility by 30 Sept. 97, and also relieves some stress
on the Laboratory's labor resources in achieving this milestone.
Moreover it enables us to improve greatly our confidence in the
photocathode gun. The principal disadvantages of the deferral
are delays in commissioning and debugging some components of the
injector hardware with beam, but these are offset by the advantage
of allotting time to work on the gun, the highest-risk subsystem
of the FEL.
A new procedure was developed for setting the momentum in the
arcs using the air-core corrector magnets that are already part
of the baseline design of the arcs. The procedure was posted
on www as part of the "arc 1 setup procedure".
Plans were documented for experiments to measure transverse-emittance
growth from coherent synchrotron radiation (CSR) in the bunch
decompressor following the wiggler location, and in the first
recirculation arc. As currently envisioned, the emittance measurements
will involve quadrupole magnets and viewers at the wiggler location
(with the wiggler removed), downstream of the bunch decompressor,
and in the back leg (which has a multiplicity of measurement systems).
Parametric investigations of the influence of bunch charge, bunch
length, bunch momentum spread, transverse bunch size, and transverse
emittance at entry to the bending systems are all envisioned.
We anticipate being able to start taking CSR-related data around
the turn of the calendar year, an activity that will likely occur
in the course of commissioning the accelerator and recirculation
loop.
We considered whether to retain the electron-beam scraper in the
first recirculation arc and decided to do so. It will localize
the potential loss of particles with large energy offsets, as
might be produced as a result of the lasing process in the wiggler.
Likewise, it provides a nice diagnostic of the wings of the longitudinal
phase space emanating from the wiggler, making it a valuable
tool for FEL experiments. Specifications were established that
permit the scraper to serve as an excellent energy-distribution
and halo diagnostic, as well as in its nominal machine-protection
role.
A series of sensitivity studies was done by way of numerical simulations
as part of developing detailed specifications for the magnet measurements
envisioned for the injection-line dipole magnets. The basic plan
is to procure these magnets, measure them to now-specified accuracies,
and then do follow-on computer modelling that incorporates measurement
results to optimize the resultant electron-beam dynamics. There
are no significant difficulties anticipated with this approach.
Facility
The month's effort in the facility was focused on getting the
steel frame for the upper level completed. Work started in the
beginning of the month in the lobby area but by month's end the
frame was covering the entire upper level. This sets the stage
for the addition of the wall panels to enclose the structure and
adding the roof deck. Roof decking and second floor decking in
the lobby area was completed. The HVAC compressors were set on
their pads and electrical hookup of the main switchgear initiated.
The set of completed cryogenic transport lines were transferred
to the Facility in preparation for the lengthy installation process.
Jefferson Lab personnel initiated the LCW piping installation
effort. Schedules were reviewed in a monthly meeting with the
contractor. The contractor was sent a get-well letter reminding
them that there is a $1500/day penalty on not achieving beneficial
occupancy of the second level by Mar 15, 97. The contractor admits
to a 3-week schedule slip against the March 15 contractual BOD
2 (upper level). This was primarily caused by problems with one
of their subcontractor's miscalculations on the framing. It now
appears the upper level will not be fully dried in until the third
week of April. The delays in BOD will affect the equipment installation
schedule upstairs, cause more work to occur in the summer, and
press the availability of installation personnel to keep the schedule
on track.
Upcoming Meetings and Reviews
AVS Workshop: Contamination Measurement and Control, Jefferson Lab March 26-27, 1997
Navy Laser Safety Meeting, Jefferson Lab, April 15-17, 1997
Navy High Energy Laser Office Project Review, Jefferson Lab, April 15, 1997
SURA Board of Trustees Meeting, Washington, April 16-17, 1997
SURA Maritime Technical Advisory Committee, June 10-11, 1997
SURA Science and Technology Review, July 15-17, 1997