IR FEL Monthly Report for September 1997
Navy IR Demo Contract WBS Elements
WBS 1 Project Management
September 1997 was the fifteenth full month for the IR FEL Demo
project funded by the Navy.
Cost Performance Scheduling
We have expanded the discussion of cost performance/scheduling
in this monthly report, which is the last month of the IR Demo
Construction project.
The IR FEL Demo project through the month of
September 1997 has a total of $8,083k (less SRF and the building)
of performance scheduled. The work performed through the current
period is $7,766k or 96% complete versus 100% scheduled. The
actual costs accrued through September totals $7,674k. This results
in a negative schedule variance of $317k and a positive cost variance
of $92k.
As of the end of September 1997, $8,061k has
been costed and/or obligated ($7,674k in actual costs and $387k
in current obligations). The project was completed and closed
out at $8,061k or $21k under the budgeted cost. The customer
was billed for all costs to include the outstanding obligations.
These outstanding commitments will be followed through to completion
in monthly reports through December 1997.
Management
The official milestone date for the completion of the IR Demo
construction project was Sept. 30. This milestone was defined
as completion of the FEL User Facility with installed FEL hardware
ready for start of commissioning. The FEL project team thanks
all the Jefferson staff, contractors, and collaborators who have
helped us reach this important milestone. Readers of this report
know that some installation activities will remain after the Sept.
30 milestone, however, these tasks have been staged to not impede
start-up of commissioning activities.
The IR Demo Construction Project Close-Out Review was held on
Oct. 2-3. The review was attended by the staff and management
of the Navy High Energy Laser Office, the DOE Site Office, Adm.
(ret.) Ted Parker (representing SURA's Maritime Technical Advisory
Committee), and Bill Colson from the Naval Post Graduate School.
The review agenda included a summary of the technical, cost,
and schedule status of the IR Demo construction project (which
was officially completed on Sept. 30th), and also included discussions
of the plans for commissioning and initial operation of the FEL.
On Oct. 3, a workshop was held on FEL optics development and
implications of coherent synchrotron radiation on FEL design.
On Sept. 4, F. Dylla met with BES Chemical Sciences Program Management,
Bob Marianelli and Andrew DePristo, at DOE-BES headquarters.
The first nine IR FEL pre-proposals were delivered for review
by BES.
On Sept. 11, Bob Marianelli and Eric Rohlfing from the DOE-BES
Program Office, and Dan Lehman from the DOE-ER Construction Management
Office visited the laboratory to review the progress on the IR
Demo project and discuss future DOE interactions. Eric Rohlfing
is reviewing the BES pre-proposals in Chemical Sciences that were
submitted to DOE on Sept. 4. BES management requested the project
commissioning schedule and a listing of current and potential
university collaborators (particularly at the local universities).
We also discussed the options available for extending the IR
Demo wavelength range. Of particular interest to BES is the mid-to-far
IR range because of the scientific applications noted in the 1994
NAS Study. Note: that the IR Demo with the present 42 MeV linac
can deliver long wavelength radiation to approximately 25 mm.
A brief white paper on the wavelength upgrade options available
to the IR Demo will be prepared for BES.
H. Grunder and F. Dylla made a presentation on Sept. 10 to SURA
Executive Committee on the status of FEL program. A related discussion
concerned possible involvement of the SURA Materials Council with
FEL User Lab proposals and sponsorship of a proposed workshop
on Laser Processing in January 1999.
Jefferson Laboratory's annual Science and Technology Review was
held Sept. 17-19 as a required component of SURA's contract with
DOE to operate the laboratory. Three review team members of seven
that paid particular attention to the FEL Program presentation
were John Galayda (Advanced Photon Source), Erik Johnson (BNL)
and Steve Laderman (Hewlett Packard Laboratories). Good marks
were received on the execution of IR Demo construction project,
including resolution of issues that were identified at the mid-project
DOE review in February. The recent attention given by the FEL
Program Management was encouraged to continue to develop basic
science applications which complement the existing industrial
and Navy applications.
F. Dylla and a number of LPC collaborators attended a workshop
on Sept. 21-24 called "Atomic, Molecular and Optical Physics"
sponsored by the DOE-BES Program Office. In working sessions
on low field, high field, and surface phenomena, the potential
use was noted of 3rd and 4th generation light sources (including
specific mention of the Jefferson Lab FEL).
On Sept. 23, Jefferson Lab hosted the Virginia Technology Council,
which included discussions of continuing support of the FEL User
Facility and Applied Research Center in the Commonwealth's "Technology
Blueprint" being prepared by CIT and the Council.
Jim Cox, Chairman of the ODU Physics Dept. visited the week of
Sept. 5 to discuss interactions with the FEL program, particularly
new members of the ODU atomic physics faculty.
On Sept. 15, Tony Favale and Alan Todd from Northrop Grumman visited
the laboratory to discuss continuation of our collaborative R&D
activities for next year.
WBS 5.0 Instrumentation & Controls
Regarding instrumentation and control systems:
All of the beam viewers and BPM's and the multi-slit from the
gun to the injector dump were installed and wired up. The system
checkouts continuethe BPM and viewer software will be ready in
mid-October. The back leg girders have also been completed.
The wide chamber beam viewers had a problem with the threads cut
for the turnbuckle; the left hand thread pitch was off slightly
causing the turnbuckle used for alignment to wobble. These are
being re-cut in the Jefferson Lab shop. The 4-channel BPM filter
banks are arriving and being installed. These are required to
interface the stripline BPMs to the recycled 4-channel electronics.
The (prototype) VME buffer board for the video multiplexing of
the beam viewers (and laser monitors) is complete and documented.
This is now being used to commission the EPICS software and control
screens. The initial beam test does not require the mux but it
may be ready.
The PSS (Personnel Safety System) system has been certified, which
includes the accelerator enclosure and access control. The peripherals
are added as needed; the gun high voltage power supply, laser
PSS shutters and the high power DC supplies are connected but
the RF systems are not. These systems will be included when the
RF commissioning is complete. At this point, the RF systems are
being run into shorts and are not connected the SRF cavities.
The ODH (Oxygen Deficiency Hazard) monitoring system has also
been certified. These safety systems are recertified semi-annually.
The beam dump LCW (Low Conductivity Water) system and associated
instrumentation is being fabricated and tested. The controls
for the dump skid (pump & polisher) are complete and operational.
Each of the three beam dumps and the beam scrapers have identical
instrumentation and the control chassis are nearly complete.
The insertable dumps also require an interface chassis for each.
The water system has been checked for leaks but has not yet been
filled with clean water.
The vacuum system is operational through the control system.
The controls have been tested for all devices that have been installed
in the tunnel. The connections to the MPS (Machine Protection
System) still has to be tested as well as the fast valve logic.
The design review was held for the MPS. There is a list of issues
to be addressed but nothing that will hold up operations. The
CAMAC version of the beam loss monitors will be used for the beam
operations this fall, The new VME version will be operational
for operations following the January CHL (Central Helium Liquifier)
shut down. The CAMAC FSD (Fast Shut Down) boards are being used
for the RF interface to the "P1" line. This is the
beam inhibit in the event an RF system shuts down due to an interlock
fault. This prevents uncontrolled beam loss due to a change in
energy. System level design continues defining the devices associated
with the four beam modes and the four machine modes.
The AMS (Analog Monitoring System) continues to make progress,
both the backplane and the buffer boards are ready for assembly.
The buffer boards will be sent out for fabrication once the first
article is tested and accepted. One hold up is the delay in shipping
of one of the card-edge connectors. We are working this but delivery
looks like early Nov. The analog-to-fiber chassis arrived but
the frequency response falls short of 1 MHz. This unit is used
to transmit the AMS signals to the MCC (~.5 km). The frequency
response within the FEL building should be flat to over 20 MHz.
The DC power trim racks have been powered up and checked for the
locations where magnets exist in the tunnel. The large box supplies
and the chicane supplies have been checked out and operated into
loads using EPICS. The magnets in the injector have been run
through the control system and have had their field polarity checked.
Control cables for the optical transport and mirror cans are in
place. The cables are being terminated and tested as the devices
arrive. The access control hardware for the user lab Laser Safety
Systems is arriving and being checked out. Magnetic locks are
being installed as well as the PLCs. The installation is proceeding
slowly due to the lack of manpower, this will change in October
as the tunnel will be locked up at ~15:00 each day for commissioning
activities. The smart card entry software and database was contracted
out and is progressing well. This will be ready for an operational
test by early November.
The Hewlett Packard workstations and X-Terminals are all on-site
and are being set-up in the building. There has been a problem
logging into the new servers with the X-terminals, this is being
worked with HP. The workstations should be operational by mid-October,
these have been delayed because of conflicts with personnel supporting
the CEBAF systems. The software for high voltage conditioning
of the gun is being tested, this will allow hands-off gun start-up.
The controls interface for operating the high voltage power supply
from the control room are complete. The voltage and current read
backs are connected through EPICS and patched to the table top.
These signals are also available on the projector for ease of
viewing.
WBS 7 Beam Transport
The system is at 91% of budgeted cost of work scheduled. Of 27
dipoles magnets, 8 are installed, the remainder are in assembly
or measurement. Of 55 quadrupoles and sextupoles, 36 are ready
or installed and the remainder are in fabrication or measurement.
Of 65 (low dollar value) correctors and air core skew quadrupoles,
12 are on hand or installed with the remainder mostly in fabrication
due in October. Most stands and girders are installed. Most
of the vacuum system is installed with the outstanding arc chambers
on hand but awaiting resolution of a magnetic welds issue. Of
6 dumps and one scraper, 2 are installed and 4 are on hand. The
inner workings of the scraper is still in design. Of the power
supplies and cabling, all DC supplies are installed with AC supplies
for 3 raster magnets and cable connection still in process. Of
utilities, LCW mains and air lines and nitrogen lines are installed
with connections in process.
Three issues are outstanding. In the dipole area, fringe fields
from injection and extraction chicane dipoles need to be shielded
from adjacent 10 MeV beam lines. We are studying this problem
with TOSCA finite element model. In the sextupole area, the pole
tips still need final definition and subsequent machining. This
shape will be obtained with measurements on the prototype. In
the vacuum system, as stated earlier, welds on beam chambers for
one style of reverse bend (DQs) and the 180 degree dipoles (DYs)
drive field uniformity slightly out of specification. We are
studying multiple options such as: install as-is, brazing, replacing
local weld with inconel and local annealing
Remaining Installation Work can be summarized:
Assemble 6 dipoles, finish 8 quadrupoles and complete fabrication of 53 correctors
Measure and install the above plus 16 in-process magnets.
Weld and install arc vacuum chambers and their vacuum electronics and controls.
Hook up cabling, LCW cooling and instrument air.
We substantially met the goal of having the required hardware
in place (on site) by September 30 for start-up of commissioning.
WBS 8 RF Systems
In the Injector, zone 1, the RF systems for the buncher and quarter
cryomodule were successfully tested into waveguide shorts under
local control. They will be operated under software control next
month. The Master Oscillator installation is complete. The new
divide by 40 chassis is installed. Preliminary tests of the phase
stability with the drive laser system were started and look good.
In the Linac, zone 2, testing of the low level RF control system
was halted to concentrate on the Injector zone. The full cryomodule
was aligned and cooled to 2°K. The second spare 50 kW klystron
was again tested unsuccessfully. High body current was the problem.
The klystron is to be shipped back to the vendor next month.
The first Hipotronics 225 kW variable DC power supply was successfully
tested with a small load. The second unit will be repaired next
month. The location of the buncher water skid was moved again
due to space requirements of other equipment. Buncher testing
will be done in October. The assembly and preliminary testing
of the 500 kV high voltage power supply and transmission system
was done this month. Additional modifications and testing are
scheduled for October. Modified software for the Injector and
Linac was installed and partially tested. Additional cleanup
work remains for October.
WBS 9.2 Injector Move
All injector subsystems before the quarter cryounit were essentially
complete by months end. The high voltage power supply was operational
up to the conditioning voltage of 420 keV. Enough of the optical
transport line was installed to deliver light from the drive laser
to the cathode. The RF systems were installed to begin commissioning
of the buncher cavity. All magnets and diagnostics before the
cryounit were installed and tested. Finally, 350 kV beam was
run at low current to the first viewer. After the cryounit, the
beamline was complete with the exception of dipoles. The RF systems
for the cryounit are completely installed and are in final check
before final waveguide hookup and commissioning.
WBS 9.4 Wiggler
The wiggler vacuum chamber was welded and straightened to within
the required stay-clear envelope. It was then successfully fitted
up into its support. The wiggler viewers were completed and assembled.
Final assembly and installation will be carried out when all
parts are cleaned and checked for particulate.
WBS 9.6 Optics
This month, the right angle valve for the upstream optical cavity assembly passed particulate and vacuum tests and was installed. The 5.5 in. calcium fluoride window used for the Brewster window on the output coupler side of the cavity was clamped in its holder without incident. These components were installed on the assembly, completing it, save the insertable pellicle assemblies. These will be installed next month. We ran tests to see if the optical cavity mirror holder could be replaced without disturbing the alignment, and found that we could, within the accuracy of the measurement (~ 0.5 mrad). Discussions with the two optics companies producing cavity mirrors resulted in plans for them to send their test plates to China Lake for calibration. It appears we will have the next iteration of first light optics available for metrological testing before the end of next month.
The rest of the components for the mirror cassettes were awarded this month. The vacuum components needed to make the bodies began arriving this month. Assembly will begin in November, with installation beginning no later than December. Procurement of insertable dump hardware began this week. It is on schedule for a December installation. The cameras monitoring the FEL optical transport system mirrors were assembled in their holders, installation will occur in October.
The drive laser was operated approximately 70 hrs to check out
the new divide-by-40 hardware and associated electronics. Phase
drift was controlled very well; the error signal was no more than
0.4 deg. peak-to-peak. Drift was quite low, about +/- 0.1 deg.
Minor problems with control of the hardware were resolved, and
the suite of laser beam controls (minus the rf controls) was successfully
moved to FELSRV. We also completed installation and alignment
of the mirror cans and telescope box for the drive laser optical
transport system (OTS). A red He-Ne in the drive laser clean room
transmitted by the OTS enters the light box, but is not centered
on the photocathode. We plan to complete the alignment in early
October. A green He-Ne (Gre-Ne) laser was installed on the light
box stand and was aligned to transmit a beam onto the photocathode.
Once calibrated, this setup provides a convenient check of the
photocathode quantum efficiency. This laser system was used to
produce photoelectrons during the recommissioning of the gun.
Injector, SRF, Facility, and Other
Activities Outside Navy IR Demo Contract
INJECTOR TEST STAND
WBS 3 - CRYOMODULE
Linac Cryomodule
The injector quarter cryomodule and linac cryomodule have been
prepared for commissioning. This will occur in October as soon
as the FEL schedule allows. Commissioning is expected to be routine.
Warm Windows
The quarter cryomodule 50 kW warm RF windows are still in fabrication.
As soon as metalized ceramics are in-house we will assemble three
additional windows, bringing our inventory to four.
WBS 2 -- BEAM PHYSICS
Detailed analysis of the longitudinal emittance data from the
350 kV gun experiments conducted over the last weeks of the Injector
Test Stand Program is now essentially complete. The analysis
strongly suggests that there was an error in the measurement of
the bunch charge for the long pulse, high current setup. Specifically,
simulation (PARMELA) results closely match the phase-space data
if the input bunch charge is 175 pC rather than the 135 pC measured
with the picoammeters. Accordingly, we will pay special attention
to bunch charge measurements as we commission and operate the
gun in the FEL Facility. It is difficult to infer a precise value
for the rms longitudinal emittance in the ITS experiments because
the measurement is dominated by uncertainties caused by finite
slit size. However, an upper bound is 44 keV-deg at 175 pC bunch
charge, which compares favorably with the 50 keV-deg required
at the wiggler, although if the upper bound is close to the real
value, there is little margin. Nevertheless, all indications
are that gun operations at 350 kV produce an electron beam with
phase-space properties that meet requirements. The analysis is
documented in Jefferson Lab Tech Note 97-006 dated 24 Sep 97.
Work continued toward specifying the RF phases in the injector.
Space-charge forces, because they are nonlinear and dynamic,
complicate the task of determining the transfer matrices. Our
approach is to determine the matrices for the RF elements numerically
and do multiparticle statistical simulations to study the overall
system sensitivity to RF phase. Using PARMELA is the most likely
avenue.
The impact of off-normal performance of the injector and full
linac is under further consideration because the respective electron-beam
energies affect procedures for RF phasing and for setting up the
electron-beam transport system. In particular, performance of
the injection/extraction (DV) dipole magnets is sensitive to the
cryounit performance. We are pondering how to maximize the variability
of the beam-transport system for "5 mA, 42 MeV" performance
in view of uncertainties in the ultimate linac performance. There
is less, but not negligible, concern with "1.1 mA, 38 MeV"
first-light beam.
We also continued working toward a simulation code that includes
noninertial forces in bends due to coherent synchrotron radiation.
The latest technical detail to be resolved was the adaptation
of leap-frog integration to transitions between straight trajectories
and curved trajectories, where without care it is possible to
"hop" a particle onto a "wrong" trajectory
and thereby introduce numerical errors. We continue to make systematic
progress.
WBS 4 -- IRFEL COMMISSIONING/OPERATION
The detailed injector setup procedure and test plan is now written.
The procedure covers start-up of the photocathode gun, rough
setup of the injector, and setup of the 10 MeV injector dump.
It parallels that of the nuclear physics injector setup, involving
a threading procedure and use of transient phasing and dispersed
viewers to crest cavities and set gradients. The FEL injector
however, is more complicated in that it runs the second cryounit
cavity 27.5 degrees off crest and uses a lower injection energy
into the cryounit. Another difficulty is that the cavity gradients
and phase loops will not be characterized initially. Consequently
a fine setup procedure must make use of the existing diagnostics
to set the buncher and two cryounit cavities' phase and gradients
to the required precision. PARMELA simulations of the injector
were run to determine an expedient procedure for setting the injector
parameters.
In the FEL Facility, the high-voltage system was completed and
tested, including installation of the elbow leading from the
stack to the gun. On 25 Sep 97 the gun reached 420 kV in just
3 hours of processing. Subsequently, on 29 Sep 97, we generated
"first electron beam" in the FEL Facility, i.e., 350
kV photoelectrons.
Upcoming Meetings and Reviews
Scientific Opportunities for Fourth Generation Light Sources,
October 27-29, 1997 (Argonne National Lab)