IR FEL Monthly Report for December 1996
Navy IR Demo Contract WBS Elements
WBS 1 Project Management
December 1996 was the sixth full month of activities for the IR
Demo project funded by the Navy. With respect to the planned
accrual of project cost by December ($3009k), $1939k of work was
accrued which accounts for 24% of the project completed. The
actual costs accrued through December totals $2459k. This results
in a negative schedule variance of $1069k ( an increase over November
of $161k) and a negative cost variance of $520k (an increase of
$303k). The largest portion of the schedule variance ($533k)
remains in the Optics System which we expect to recover by April
without impact on the total project schedule.
The Beam Transport and I&C WBS elements are expecting to complete
several overdue pegpoints in January which will improve the variances.
For the $3.5M FEL User Facility Building, the building construction
performance reporting schedule is less aggressive than the actual
contract schedule. In the performance schedule the contractor
has gone from ahead of schedule to essentially on schedule due
to weather and Christmas break delays in December. (However,
the contractor schedule is now two weeks behind). $2136k of actual
cost for the building has been accrued and the Facility is 57%
complete.
John Albertine and Fred Dylla presented a requested briefing to
the Navy Studies Board on Dec. 10 on the Navy High Energy Laser
Program and the status of the kilowatt Demo.
A presentation was given to a Metals Fabrication working group
at Newport News Shipbuilding on Dec. 9 about possible interactions
with the Jefferson Lab FEL program.
At the first meeting of SURA's Marine Technical Advisory Committee
held on Dec. 17-18, the committee was given presentations on the
status of the Navy's High Energy Laser Program, the Jefferson
Lab's 1 kW Demo and the MW FEL Workshop. An initial report from
the committee is expected next month.
A meeting was held on Dec. 19 with R. Marianelli (DOE-BB), and
D. Lehman (DOE Construction Project Office) to review the preliminary
agenda and list of potential reviewers for the Feb. 24-25 DOE-BES
review of the Jefferson Lab FEL program.
The top level design drawing for the IR FEL was frozen as of Dec.
20. All subsequent changes will be subject to a change control
process.
WBS 5.0 Instrumentation & Controls
Beam Instrumentation: The BPM review was held on Dec. 4. The
review close-out is scheduled for Jan. 9. Of the two families
of detectors; stripline & buttons, the prototype stripline
detector is being modified to eliminate an unwanted resonance
at 1455 Mhz. These will be ordered in Jan. once the design is
approved. The buttons are on order and should be delivered in
late Feb. or early March. The additional SEE electronics will
be ordered in Jan. Two channels of BPMs will be installed on
the Injector Test Stand (ITS) for operation and testing beginning
the end of April. This testing will be focused more on the software
than the hardware. The shielded beam viewer contract is late
by a few weeks, delivery will be the end of Jan. rather than in
mid-December. The video system for operations from the CEBAF Main
Control Room (MCC) has been purchased, a similar system for analog
signals is being investigated. The bunch length monitor from
University of Georgia (Happek) continues to make good progress.
Happek has redesigned the mechanics for a smaller foot print
for ease of mounting and maintenance. A student from Happek's
group has begun to write the required software to enable the measurement
to be a single step operation. He has visited Jefferson Lab in
Dec. and will return in Jan. for further training. The path length
monitor cavities are being fabricated. All parts for the receiver
chassis have been procured and construction should begin mid-Jan.
Fabrication of the modulator chassis is complete and testing
of the unit will begin promptly.
Personnel Safety System: Procurements are proceeding, 90% of
the hardware has been delivered. The four racks are about 65%
complete. These are being built in the end of the north linac.
The final design review has not yet been held.
Machine Protection System (MPS): The Fast Shut Down (FSD) and
bare Machine Protection System (MPS) printed circuit boards from
Argonne should arrive in Jan. Work continues on the modifications
to the Beam Loss Monitor boards.
Control System Hardware: The purchase requisition for computer
components was not submitted in Dec.; this will take place in
early Jan. The requisition for network hardware did get submitted
and signed. The overall layout and design continues.
Control System Software: Progress continues to be made, software
group is working on the priorities for both FEL and work scheduled
for the CEBAF machine.
DC Power: The trim rack fabrication is 80% complete. Drawings
with magnet nomenclature are being finalized, following this the
cable databases will be setup. We are preparing to purchase the
50 Amp power supplies.
Vacuum Controls: The ion pump power supplies are 60% complete.
The ion pump power supply control card has been laid out and
is being prototyped. The vacuum control boards are being fabricated
by an outside vendor. The crate design has begun.
WBS 6 Cryogenic Distribution
Quad transfer line installation is under way. The 2K supply,
2K return and shield supply are welded. These circuits are being
leak tested. Parallel construction of the linac return transfer
line modules #2,3,4 is progressing well. # 3 is 95%, #2 and #4
are 25% complete. Detail design of sleeve transfer lines and
the Field Flex can is progressing. Detail design of the gas lines
is complete. Installation of the Gas lines in the linac has started.
Most of cryogenics procurements are complete. The only major
procurements left are for the field flex can and these should
be started in January.
WBS 7 Beam Transport
General: We froze the top-level machine drawing, established
a Lattice Review Committee, and formally instituted a change-control
process. The lattice is designed to provide a high-brightness
electron beam for lasing and high acceptance for energy recovery
in keeping with the goals of the IRFEL Program. These goals are
to generate first light (requiring nominally 38 MeV, 1.1 mA cw
electron beam without energy recovery), followed by high-power
operation (requiring nominally 42 MeV, 5 mA cw electron beam with
energy recovery), and during commissioning, to investigate effects
of space charge and coherent synchrotron radiation on the electron-beam
dynamics. A second cryomodule can be added to boost the beam
energy to 75 MeV without affecting the design or placement of
the second recirculation arc.
The pace of the System, continued to accelerate as more personnel
were assigned to the task by engineering. However it is still
lagging behind schedule with the outstanding peg points not taken.
(Design of quadrupoles and dipoles) Reducing the cost from increases
in scope still remains an issue.
Dipoles: Work concentrated on refining the design of the three
styles of Recirculation Dipoles. Most importantly, a mu metal
pole with a Purcell gap between the metal and the magnet iron
worked to bring the field flatness within specification within
the central area of the dipole. Also, thicker field clamp was
successful at bringing the length vs. excitation to nearly within
specification by eliminating saturation effects. At month's
end, the close out of the magnet review remained illusive as our
customer, the accelerator physicist revealed that his testing
of the lattice proved that his requirements applied to a wider
aperture than previously appreciated and we mutually realized
the his flatness specifications continued unabated throughout
this wide aperture beyond the ends of the magnet. (as if the
magnet were infinitely wide) Additional tests on the prototype
were planned to explore how wide the magnet has to be on the ends.
The Northrop Grumman designer has brought the Optical Chicane
Dipole Design Package to the checking stage with the above improvements
and the requirements packages were being prepared for the Reverse
Bends and Pi Bends.
The designs of the injection and extraction dipoles were firmed
up further. All the measurements on the prototype dipole are
now directly applicable to this other class of dipole.
Quadrupoles & Sextupoles: The order for the Weak Quadrupoles
was placed and should be received on schedule. The prototype
trim quadrupole is still awaiting measurement and evaluation.
The prototype sextupole parts were received.
Vacuum: The Injection Line X Chamber was partially signed off
for fabrication. Design on stands and girders for the Beam Transport
part of First Light continued to lag. Work continued on interfacing
the baked system to the non-baked system in the injector region.
Continued emphasis was placed on determining final quantities
of commercial parts so that orders could be placed.
We started a parallel effort to design the girders in the back
leg. The receipt of parts for this one design with many multiples
will maintain a steady flow of work for installers during the
installation period.
Installation: Work on definition of the cable tray continued
and the major load of cable tray was ordered and received. The
low conductivity water systems were defined by the Engineering
Department.
WBS 8 RF Systems
The ITS test cave was changed over for the 350 MeV experiment.
The final alignment of the beam line components will be finished
today. The Quarter cryomodule was moved into the cave off-axis.
All of the 10 MeV stands that are possible to install at this
time are in and aligned. The RF system was interfaced and tested
with the Personnel Safety System for the ITS. The contract was
placed for the 225 KW variable DC power supply. The first unit
is due 1 June 1997. The final version of the RF software was
tested this month for the Drive Laser and Buncher. The Chopper
will use the Buncher code with the water skid by-passed and different
download files. The state machine and other signals for the Quarter
cavities are defined and code is to be tested in January.
WBS 9.2 Injector Move
Drawings for the high voltage power supply tank were signed off
by Dec. 20. Work continued on injector area layout. Suggested
changes in the sprinkler positions were submitted to the building
contractor. We are still awaiting budgetary quotes from vendors
for a new clean room.
WBS 9.4 Wiggler
The mechanical support design is at the 90% level. The optical
bench is being purchased. Northrop Grumman agreed to do the detailed
design work for the vacuum chamber and chamber supports. The
poles for the wiggler are complete at STI Optronics. All other
parts are being machined. The magnet blocks for the wiggler have
been delayed until late January. The current schedule for final
wiggler measurement is mid March.
WBS 9.6 Optics
December marked the beginning of the optical cavity assembly fabrication.
We are targeting to complete most procurements and fabrication
by the end of March. Major procurements mentioned in last month's
report, in particular, the sapphire optical cavity mirrors, were
obligated this month. We received the tubing and the gate valves
for the optical transport system. We received estimates on windows
and mirrors, and will begin the procurement process next month.
We enhanced the prototype cavity length diagnostic's functionality
by replacing the micrometer on the translation stage with a New
Focus Picomotor, a type of stepper motor we will use on the photocathode
drive laser as well as in the optical transport system. It has
been interfaced through Labview, and implementation in EPICS looks
straightforward.
Injector, SRF, Facility, and Other
Activities Outside Navy IR Demo Contract
Injector Test Stand (ITS)
This month we worked on enhancements to the photocathode drive
laser system. We added an optical pick off to a Brewster window,
allowing us to monitor the laser's spatial profile at a position
equivalent to the photocathode. We believe we have traced the
problem in the output power stability to CuCl contamination of
the cooling water by the pump. The contamination was due to the
corroding away of the electroless nickel plate coating on the
bronze volute. We will conduct tests with a new volute in early
January.
In early December, we finished taking the full set of 250 keV
transverse-emittance measurements that were originally planned.
We also took a set of data at 300 keV, and it scaled with voltage
per theoretical expectations. On 5 December we shut down the
gun and began installation activities related to the 350 keV experiments
and to the full 10 MeV injector. This included inserting the
cryounit, beam dump, and assorted stands and girders, into the
test cave. It also included installing the beamline for the 350
keV experiments, as well as working to upgrade the photocathode
drive laser and its optical transport system. Installation activities
stayed on schedule.
Resistance data on the new coated ceramics unambiguously indicated
that the coating offers no significant improvement in electrical
properties, with the exception that both the new and original
ceramic coatings still provide for significant suppression of
secondary electron emission from the ceramic surfaces by lowering
the secondary emission coefficient of pure alumina. Otherwise,
the chief benefits of the new ceramics are a lower propensity
to crack or puncture, properties that arise as a consequence of
the higher percentage of glass phase. These findings motivated
a change in plans for upgrading the gun. Specifically, we decided
to coat a new cathode-support tube with a coating known to be
resistant to field emission, use it to replace the tube presently
in the gun, and keep the existing stack in the gun. In parallel,
we will construct two new high-voltage ceramic stacks, one using
two of the new ceramics, and another using two new ceramics with
an ion-implantation coating. These stacks will then be stored
should they be needed in the future. The upgraded gun is now
projected to be completed in late January, and operations should
then resume in mid-February.
A detailed draft of the goals and plans for the 350 keV experiment
was prepared. For the goals, we consider that we must: (1) achieve
"nominal" beam parameters for FEL operation, (2) achieve
stable operation at 350 kV, and (3) develop a procedure to reproduce
beam conditions using only diagnostics that will be in the FEL
injector. We also consider that we should: (1) attempt operation
at >350 kV, (2) perform beam-parameter studies to understand
the physics of the gun, and (3) make emittance measurements versus
solenoid settings. If done properly, the parametric studies would
satisfy all other goals except operation at voltages >350 kV.
Given that the "musts" are achieved, the breadth and
depth of our experimental program will ultimately be weighed against
schedule considerations.
WBS 3 Cryomodule
HOM Load copper parts received for production run. Quality assurance
and inspection of parts is ongoing. We are scheduled to be producing
HOM loads the first two weeks of January. This will delay the
start of cavity pair assembly from the scheduled start of 2 January
1997. Cavity pair assembly will start when HOM loads are available.
Cryounit and cryomodule parts punch lists are being generated
to ensure availability of all small piece parts. Cryounit helium
vessels are schedule for modification in house in January. Final
rework of the return end can for cryomodule assembly is underway
and is schedule for completion in January.
Review of production and assembly documentation is ongoing. New
HOM assembly procedures will be developed during January production.
These procedures will be a substantial rework of existing documentation.
Cryomodule assembly schedule is still on track with the delay
in the start of cavity pair assembly. This requires the parallel
cryounit assembly similar to that performed during CEBAF cryomodule
production.
WBS 2 Beam Physics
The top-level machine drawing was frozen on 20 December, at which
time a Lattice Review Committee was formed, and a change-control
process was formally instituted. The lattice is designed to provide
a high-brightness electron beam for lasing and high acceptance
for energy recovery in keeping with the goals of the IRFEL Program.
These goals are to generate first light (requiring nominally
38 MeV, 1.1 mA cw electron beam without energy recovery), followed
by high-power operation (requiring nominally 42 MeV, 5 mA cw electron
beam with energy recovery), and during commissioning, to investigate
effects of space charge and coherent synchrotron radiation on
the electron-beam dynamics. A second cryomodule can be added
to boost the beam energy to 75 MeV without affecting the design
or placement of the second recirculation arc. Details at the
subsystem level are generally fluid, i.e., not yet frozen, but
any changes at the subsystem level that affect the lattice are
now subject to review by the Lattice Review Committee. Various
updates of analyses related to particle tracking in the revised
lattice are underway.
An analysis was done of the droop in, and stability of, the rf
system that could be expected from beam loading associated with
pulsed 1.1 mA operation with the 8 kW klystrons. Both the rf
and beam should be stable. However, there will be some energy
spread and phase slip imparted to the electron bunches that must
be considered in developing the technique for measuring the momentum
spread.
Further simulations were done to explore the influence of accelerator
settings on beam properties at the wiggler entrance. There is
not a problem in finding settings to achieve desired combinations
of bunch length and momentum spread at the wiggler. In the coming
months, we plan to use a combination of analytic techniques and
simulations to devise suites of settings that minimize complications
in commissioning the machine, i.e., transitioning from first-light
current to full-power operation.
WBS 4 Commissioning/Operations
A first draft of the procedures for first-light turn-on of the
FEL was written. In addition, several sets of candidate accelerator
settings to support generation of first light were proposed based
on numerical simulations of the electron-beam dynamics. We have
begun the process of iterating the development of the turn-on
procedure against the numerical simulations to refine the overall
process for first-light commissioning.
We compiled a comprehensive list of software-development tasks
needed to support every phase of the IRFEL, from the upcoming
350 keV experiments in the ITS all the way through a complete
machine operating in support of the user facility. The list was
presented to, and coordinated with, the Accelerator Division's
software group to aid their resource planning.
We began to plan specific CSR experiments using the IRFEL. Plans
for the experiments will be folded into the overall commissioning
plan for the machine, and emittance diagnostics for these studies
are already part of the diagnostic suite under development.
Facility
The first coat of paint was put on the accelerator enclosure this
month. This set the stage for commencement of mounting of u channel
for the mounting to air and LCW pipes on the wall which was also
completed in the initial accelerator area. Surveyors put in their
monuments for establishing the building grid. The contractor
finished hanging the main HVAC duct and most lighting conduit.
Piping for compressed air feed is being installed. Outside the
fill has been going in at a rapid pace in the interfloor area
and penetrations were then positioned and prepared for hooking
to the next level in most of the floor. That effort is about
80% complete. Simultaneously with that effort the foundations
were prepared for pouring of the floor in the loading dock and
entrance lobby. The truck ramp was completed. The contractor-proposed
placement drawing of the sprinklers was marked up to accommodate
the actual placement of hardware and cable trays and returned
for construction.
Despite these efforts the contractor fell behind near the end
of the month when local sand pits shut down delaying completion
of the interfloor filling. The pouring of the second level floor
and erection of the metal frame work was 2 weeks behind at the
end of the month. This delay is not impacting the access or installation
activities on the lower level but increased attention will be
required to ensure that it doesn't affect the second beneficial
occupancy. The contractor requested relief on Beneficial Occupancy
Date 1 due to excessive rain. That was expected to be granted
for berming activities and pouring of the utility room pad provided
no additional slip is indicated in Beneficial Occupancy Date 2.
Upcoming Meetings and Reviews
Laser Processing Consortium Workshop Jan. 21-22, 1997
SPIE High Power Light Source Conference Feb. 8-14, 1997
DOE Basic Energy Science Review Feb. 24-25, 1997