IR FEL Monthly Report for April 1997
Navy IR Demo Contract WBS Elements
WBS 1 Project Management
April 1997 was the tenth full month for the IR Demo project funded
by the Navy.
The IR FEL Demo projevt through the month of April 1997 has a
total of $5,659 (less SRF and building) of performance scheduled.
The work performed through the current period os $4,593k or 57%
complete of 70% scheduled. The actual costs accrued through April
totals $5,368k. This results in a schedule variance of -$1,066k
(an increase of $481k) and an increase in the negative cost variance
to $766k. The net change in the cost variance is $382k.
The FEL building construction contractor has not yet satisfied
all the requirements for the completion of BOD2. Installation
work of FEL equipment has continued since BOD1 as equipment and
facilities became available.
An important accomplishment this month was achievement of 400
kV on the photocathode gun with the new HV ceramic assembly.
Experiments with the gun in the Injector Test Stand are therefore
proceeding per the ITS schedule as revised at the end of the ITS
shutdown in February. Ceramic warm window in the cryounit cracked,
causing a setback in cryounit commissioning. Good progress was
made on the critical path items: (1) expediting the placement
of the remaining procurements for transport magnets and (2) keeping
pace with installation activities in the FEL Facility as hardware
became available. We have also managed to keep the Facility off
the critical path despite a 4-week slip in the second floor BOD
date.
At Senator Warner's request, a briefing on the Jefferson Lab FEL
Project was held on 1 April for staff members from the Virginia
congressional delegation and several staff members from the Senate
and House Defense Authorization Committees. D. Barnes, Adm. Baciocco
(MTAC Chair) and F. Dylla gave brief presentations on the present
project, planned upgrades, and the recent MTAC Review of the project.
In response to questions received from the Senate Armed Services
Committee on April 23rd, a letter with supporting material was
prepared and sent summarizing the status of the present IR Demo
project, planned FY97-98 activities and supporting documentation
on the industrial support for the Demo project.
We conducted a 2-day project review for the Navy High Energy Laser
Office on April 14-15. April 14th focused on the status of Instrumentation
and Controls (I&C), RF window testing for the SRF systems,
and the Injector Test Stand. On April 15th the remaining WBS
elements were reviewed by touring FEL hardware that is currently
being tested in the Test Lab and Optics Trailer or installed in
the FEL Building.
A status report on the cost and schedule performance of the project
as of March 31, 1997 was prepared on April 23rd at the request
of the HEL program office for transmission to the Office of Naval
Research.
On April 15-17, Jefferson Lab hosted a workshop sponsored by the
DOD Laser Systems Safety Working groups. J. Cook presented an
overview of the Navy HEL program and G. Neil presented a summary
of the Jefferson Lab FEL program.
A meeting was held with the DOE site office to propose the Accelerator
Readiness Review (ARR) process for the FEL. The essence of the
proposal was to track ARR activities and hold a single formal
ARR early in 1998. DOE's initial response was generally favorable,
but the precise date of the formal ARR is presently undecided.
A draft flow chart was prepared delineating responsibilities among
Accelerator Division groups for commissioning the IR FEL. The
chart and a proposed list of principal investigators for implementation
of the commissioning test plans was reviewed over the next several
weeks by Division management.
G. Neil presented a talk on the Jefferson Lab FEL Program at the
Duke University FEL Laboratory on 3 April 1997. Duke expressed
strong interest in the program because of their experience in
both the IR and UV wavelength bands. The visit gave us an opportunity
to study their electron transport system (which is interesting
because it is compact and has a 10% energy acceptance) and their
optical cavity alignment system (which provides < 100 nrad
of alignment stability). A follow-up visit to Duke by F. Dylla
and H. Grunder occured on April 24th to continue discussions on
collaborative efforts.
The spring meeting of the SURA Board of Trustees was held in Washington
on April 16-17. F. Dylla presented a status report on the FEL
program and met with representatives from the Vanderbilt and Duke
FEL Laboratories on matters of potential and continuing collaboration.
On April 21st, John Holzrichter, the LLNL Associate Director for
Science and Technology, visited Jefferson Lab. Dr. Holzrichter
directs $55M of internally funded R&D at Livermore. The lab's
work on diode-pumped solid state lasers and ablation studies with
short pulse lasers are two projects of joint interest.
On April 22nd, Mike Kelley and his Department Head, Lewis Goodrich,
from DuPont Central Research Laboratories visited Jefferson Lab
for a briefing and tour. In addition to discussing DuPont's contributions
to the FEL program and the LPC, Mr. Goodrich had a specific interest
in the microwave technology used in the CEBAF and FEL accelerators.
WBS 5.0 Instrumentation & Controls
Beam Instrumentation
The stripline Beam Position Monitors (BPMs) arrived and were found
to have a problem with the weld on the feedthru pin to the stripline
material. The pin is moly and the base material is ~1mm thick
by ~ 3 cm stainless steel and insufficient heat was used on the
stainless. The result is that as many as 25% of the welds had
visible cracking. These were repaired by using the Jefferson
Lab electron beam welder to "touchup" all of the welds.
In some cases the pins required a second shot. This repair work
will continue through mid-May as the welder is available. There
are enough BPMs complete to keep ahead of the installation schedule.
The first interferometer from the University of Georgia is nearly
complete. The current plan is to test this device at Vanderbuilt
University FEL. The beam viewers are being installed on the back
leg girders.
Personnel Safety System (PSS)
The installation work continues in the new building. Efforts
are focused on the cable pull between the Main Control Center
(MCC) for the CEBAF machine and the FEL building. This pull is
scheduled for the week of May 12th. The four safety system control
racks will be moved to the FEL building also during the week of
the 12th. The area radiation monitors have arrived and are being
tested then burned in. This is standard acceptance procedure to
ensure proper operation prior to installation. The control units
will mount in the PSS racks prior to moving. Programmable Logic
Controllers (PLCs) have been ordered for the Laser Safety System
(LSS). These will be fabricated as time permits.
Machine Protection System (MPS)
This system is still behind schedule a bit. The MPS equipment
from Argonne has arrived. The Fast Shut Down (FSD) summation
boards are complete while latch cards need assembly and testing.
The system design and documentation continues. The design review
will be held in late June.
Computer Hardware
The equipment for the network and servers is on site and will
be placed in the FEL Building for commissioning in late May.
The network connection to the MCC will also be done the week of
the May 12th. The building contractor has completed the tile
work in the communications room ahead of the other areas to expedite
the server and PSS installation work. The painting in the equipment
gallery is now complete and the first priority rack installation
can proceed. The Analog Monitoring System proposal will be submitted
in May. This system will enable an operator to view any of 96
analog signals from either the (FEL Building) Laser Control Center
or the MCC. The primary use for this system is monitoring phase
and gradient errors while tuning of the SRF cavities. The system
will consist of a series of multiplexers which will patch the
analog signal through to both control rooms. A great deal of
progress has been made on system documentation on the web. By
posting "Only to the Web" we are reducing the cost and
burden on the limited staff of designers. These designers have
a backlog of printed circuit board work.
Software
The ITS continues to serve as a debugging platform for the FEL
software. The multislit system was run in the ITS with the Datacube
Imaging software. This experiment was a success. The system
worked very well with an thru-put of 1 Hz. The documents for
programming the power supply channels and the vacuum controls
are complete.
DC Power
The trim power supplies are mounted and the cable fabrication
has begun. These 32 channel units will be wired to junction boxes
in the tunnel. This will provide an easy way to install, troubleshoot,
and to reconfigure for future upgrades. The box power supplies
will be available to move in June. These are surplus from the
CEBAF energy upgrade.
Vacuum Controls
The Ion Pump Power Supply control cards are being fabricated,
most of the power supplies are complete and awaiting the control
cards. The racks are in place and being outfitted as required.
WBS 6 Cryogenic Distribution
Welding and leak testing of linac transfer line modules is complete.
The transfer lines for the sleeve are ready to install in May.
Fabrication of the field flex can has started. All procurements
are complete. Installation of gas lines in the tunnel is complete
except tie-in to the sleeve gas lines which cannot be done till
the sleeves are installed. Installation of the gas lines at the
CHL are complete except for final tie-in which must wait until
after completion through the sleeves. All procurements for instrumentation
and control are complete. Fabrication is 75% complete. The next
phase is in the building when it is available.
WBS 7 Beam Transport
All remaining dipoles were placed under contact during the month.
Magnet Enterprises International (MEI) of Oakland CA, won the
bid for coils for the Reverse Bends and the 180 Degree Dipoles
as well as the Injection Chicane Dipoles. They should meet the
short delivery schedule because they are lightly loaded and much
of the tooling work on the Optical Chicane Dipole coils is directly
transferable. Process Equipment Co., the manufacturer of most
of the cores of the CEBAF, was awarded the Reverse Bends and the
180 Degree Dipole cores. Injection Chicane Dipole cores were
won by Master Machine, the local manufacturer who fabricated the
original dipole prototype. All cores and parts are being made
in parallel. The first of the Optical Chicane Dipole Coils was
completed by MEI of Oakland Ca. and Everson Electric started fabrication
of the first article core.
The design of the sextupole coils was signed off and sent out
for bid. The sextupole core design was started. In order to
move foreword with the trim quad concept design we decided to
revert to a square style Panofsky quad that would be able to be
measured rather than the rectangular configuration that we have
not been able to measure.
Corrector specifications are three times more restrictive than
the simple design we have for the CEBAF. We are working on two
responses. A cosine theta dipole will give the appropriate field.
However, it is expensive and the fringe field will be extensive.
We are gathering information on how they may be made inexpensively.
A concept of using mu metal as a magnet core in the form of a
very weak window frame dipole is attractive. The coils are relatively
simple and inexpensive and the fringe field is reduced. If we
design the cores right, they can be made for almost the cost of
the material. A prototype is being made.
All 22 newly made weak quads were received and along with the
10 QB quads removed from the CEBAF machine, passed their magnetic
tests.
Stands for the remaining injection elements were signed off and
sent out for bid. Back leg girders were received and assembly
started.
In the vacuum system, optical chicane chambers design neared sign-off
and the reverse bend chambers started design at Northrop Grumman.
The injection X chamber parts were received and preparations
were underway to weld them per a tightly controlled weld specification
The two 100 A power supplies for Injection/Extraction Dipole strings
were ordered.
Engineering design of the beam scraper and insertable dumps started
and detail design finished on the straight ahead dump.
WBS 8 RF Systems
The Chopper cavity was baked along with the other beam line hardware
in ITS this month. The system was reassembled and debugged.
A vacuum interlock was installed for the protection of the cavity.
Final testing and calibration will be done in May.
The 1/4 cryounit mechanical tuners were tested under software
control this month. The heaters will be tested in May. A new
spare 50 kW klystron was received at TJNAF. The failed spare
unit is to be returned to the vendor in May. The new spare unit
will be tested in May. The design review was held at this month
at Hipotronics for the 225 kW variable DC power supply. No major
problems were found. They are still planning to ship the first
unit by June 1. Waveguides were installed and pressure tested
this month for the floor penetrations in the first zone of the
FEL linac. The Cathode Power Supply, High Powered Amplifier,
and 2 sets of Low Level RF racks will be moved to their final
position in the FEL building and cabling started in May.
Design of the gas filled transmission line, the elbow, and the
components internal to the high voltage tank for the photogun
are complete and ready for fabrication. The intermediate (mid-voltage)
torroids have been delivered. The photogun power supply high
voltage tank, was delivered, and is in the accelerator enclosure.
Hipotronics final design review was held April 17. It was a
little light, but they still claim to be able to make the final
ship date at the end of May.
WBS 9.2 Injector Move
At month's end the design of new items for the injector was approximately
80% complete and purchases were approximately 50% complete. The
largest design item remaining is the drive laser transport which
was just beginning at month's end. A site visit with Clean Air
Technology was held to discuss the clean at month's end. A site
visit with Clean Air Technologies was held to discuss the clean
room design. Several interferences were noted and resolved.
The clean room drawing set was recieved by month's end and was
being reviewed. The high voltage tank was delivered and is ready
for installation. Most of the other components are designed and
most components are ordered and due in May.
WBS 9.4 Wiggler
The wiggler construction was completed and the wiggler was measured
and shimmed. Certification scans were completed April 30 at the
14.6 mm gap. Scans were also completed for the 12 mm gap which
will be used for first light. The Certification scans indicated
excellent wiggler performance. The calculated spectrum of the
wiggler is almost indistinguishable from that of an ideal wiggler
with 40.5 periods. The harmonic spectra are almost indistinguishable
from those of an ideal wiggler with 39.5 periods. The wiggler
will be shipped to Jefferson Lab in early May and should be recieved
by May 13. The machine shop has tried several methods to make
the required vacuum tubing for the wiggler vacuum chamber. The
required cross section was achieved but not the required straightness.
Two new approaches were planned at month's end. The design for
the wiggler vacuum chamber and its support are complete. Some
assembly drawings must be checked and signed off but the piece
parts can be ordered now. The machine shop decided to delay full
assembly of the wiggler girder until all parts were available.
The assembly should be complete by May 16.
WBS 9.6 Optics
April saw progress for all the optics within WBS. The optical
transport pipe that was hung in the accelerator enclosure (first
floor), was welded and roughly aligned. We await delivery of
mirror cans and stands to finish installation. We have ordered
the hardware for mounting the upstairs optical transport pipe.
The turning mirrors ("mirror cans"), diagnostic pickoff
and the stands for the optical tables supporting the cavity assemblies
and collimator are still on schedule for delivery in mid-May.
The stepper motor chassis and hardware were built and turned over
to the software engineer for testing. The optical collimator
design is progressing more rapidly, now that we have design support.
The photocathode drive laser optical transport system received
some enhancements to its diagnostics, with cameras permanently
mounted in the cave, and in the Clean Room. The new variable-speed
EO modulator, built using AR coated crystals, rather than index-matching
fluid, was tested and found to not thermally bloom with the nominal
range of input powers used. The RF group continues to investigate
sources of noise that cause the laser's phase to briefly drift
several degrees with respect to the master oscillator. They've
made good progress in reducing the long term peak-to-peak variation
from 3 degrees to about 0.6 degrees. This is within specifications.
Injector, SRF, Facility, and Other
Activities Outside Navy IR Demo Contract
INJECTOR TEST STAND
By month's end, the photocathode gun HV assembly was tested to
400 kV and the gun was operating with electron beam at 350 kV.
The beam was being used to commission the multislit transverse-emittance
diagnostic that will be used to monitor the 10 MeV space-charge-dominated
beam in the injection line. Thus, the newly configured gun seems
to be working well. Moreover, the drive laser also seems to be
working well. The laser was operated several times during the
month in support of diagnostics development, and it operated normally.
The new variable-speed electro-optic modulator (EOM) was tested
and found not to thermally bloom. It is installed and synchronized
with the existing EOM to support upcoming ITS experiments. A
new camera for monitoring the beam profile in the clean room (and
displaying it in both the clean room and control room) was installed.
In addition, the optical-transport system was realigned. We
also tested the EPICS control system developed for the photocathode
gun's high-voltage power supply. This was part of preparing for
remote operation of the system from the Machine Control Center
during the May runs.
High-power radiofrequency (RF) testing of the cryounit began.
Performance of the subject cavity was reverified up to its quench
limit. Its performance was slightly improved from earlier tests,
probably due to a slight difference in ambient static magnetic
field, and the tests indicated cavity performance remains consistent
with its projected 9 MV/m operation. Up to 18 kW, RF was introduced
into the waveguide with no performance degradation of the waveguide.
However, on 24 Apr 97, the ceramic warm window on the cryounit
cracked. This failure was similar in physical appearance to previous
failures that have occurred on test fixtures during qualification.
The cause of this failure was running high power RF (2 kW) through
the window without adequate vacuum in the vacuum waveguide. This
is the same failure mode identified in the previous tests, such
as those done in the ring resonator test assembly. The fundamental
cause was running RF in the ITS cave without functioning RF interlocks
on the cavity waveguide. During this test cycle, the vacuum and
arc interlocks were thought to be functional but were not due
to a wiring error that crossed readings from the two cryounit
waveguides. Steps will be taken to ensure this does not happen
again. Just prior to the failure, the infrared-detector interlock
had been disabled with the belief that it was not functioning
correctly, and this likewise will not happen again. Rework and
verification of interlocks in the ITS cave and FEL Facility will
be a high-priority item prior to any cryomodule RF operations.
Although cryounit commissioning to-date has provided a substantial
amount of useful data, the tests cannot be regarded as complete
because, due to the wiring error, there is no data on the waveguide
vacuum during high-power RF operations, and this data is key.
We therefore developed a plan and schedule to generate new ceramic
warm windows and complete the cryounit commissioning by 1 Jun
97. By month's end, two new warm-window assemblies were completed.
Our prognosis for beating the warm-window problem is favorable.
For example, one accomplishment this month was to process one
of the bad ceradyne ceramics by air-firing it for 30 hours to
oxidize fully its bulk material. Tests of the fired ceramic in
the ring-resonator test assembly indicated greatly reduced dielectric
losses, signifying full recovery of its dielectric performance.
This is an encouraging result.
WBS 3 - CRYOMODULE
Warm Windows
As noted in the ITS section, during 1/4 cryomodule testing the
installed ceramic warm window failed. The failure was the result
of non functional interlocks. The 1/4 cryomodule has been warmed
to room temperature and the window has been removed. Qualification
of the interlocks is underway at this time. The resonant ring
facility has been characterizing ceramic material for dielectric
properties. Suitable ceramics for assembly into warm windows
have been identified. Additional testing of two completed warm
windows assemblies in air up to 50 kW have been completed. These
windows demonstrated good performance during testing. During
preparation for final qualification in the vacuum fixture one
of the warm windows failed. This failure was not associated with
RF operations and is not fully understood at this time. Production
of additional warm windows continues with four assemblies planned
for completion during May. The first of these scheduled for 15
May will be qualified along with the existing ceramic warm window
and installed on the 1/4 cryomodule.
Cryomodule Production
Cavity pair #3 has been turned over for cryounit assembly, this
is the second cavity pair turned over. Tuners have been installed
and assembly continues as planned. The first cryounit is in the
final stage of assembly and continues without problems. The reassembly
of cavity pair #2 has been completed and will be tested in the
VTA the week of 12 May. Cavity pair assembly schedule remains
tight but manageable.
WBS 2 -- BEAM PHYSICS
PARMELA calculations for the machine setup at bunch charges of
60 and 135 pC give well-behaved emittances from gun to wiggler.
The results indicate that going 7.5 degrees off crest in the
injector cryounit improves the bunch-length and momentum-spread
profiles. Sensitivity studies for cavity phase have not yet been
done, but a 5 degree change resulted in only a 10% change in bunch
length, implying that the sensitivity is sufficiently weak.
A series of electron-beam simulations from photocathode to wiggler
was also done to explore the implications of adjusting the charge
per bunch without changing the machine settings. The results
were generally favorable in that, for example, machine settings
were found that reflect a relative insensitivity of electron-beam
properties in going from first-light beam (60 pC per bunch) to
full-power beam (135 pC per bunch). A simulation of zero-current-beam
propagation with these machine settings pointed to some concerns
about beam degradation in this case. The concerns are pragmatic
because ghost pulses will be present, and they will behave as
a zero-current beam. As a consequence, some preliminary tracking
studies through the entire machine were done with this beam, and
these tracking studies suggest that no significant beam loss arises.
Considerable work was done to specify and justify field requirements
for the corrector magnets. Standard CEBAF correctors have a 3%
error in the field uniformity. In the IRFEL, this could conceivably
translate into a factor-of-two error in downstream beam sizes,
whereas 1% field uniformity is probably acceptable. It will take
a considerable amount of time to generate accurate estimates by
way of simulations, and though these simulations will be started
soon, we need to proceed with something sensible.
By month's end, there were four proposed methods for making magnets
to meet the spec : 1) use a "cos-theta" design, 2) use
a television yoke magnet design, 3) add high permeability (mu-metal)
material in the magnet, 4) use a double-coil air-core configuration.
Were option (3) adopted, there are places along the machine without
space to insert mu-metal magnets and not have cross-talk between
them and adjacent devices, an undesirable circumstance. Consequently,
we decided to avoid mu-metal magnets where cross-coupling is a
problem and use air-core correctors with the best measured field
uniformities in those locations. Otherwise we will likely use
either option (3) or (4). If we can do no better than 3% with
the best air cores we can get now, then we may look at a retrofit
after we have a better handle on the problem.
WBS 4 -- IRFEL COMMISSIONING/OPERATION
Considerable progress was made toward putting the Accelerator
Readiness Review (ARR) process on the www. The basic idea is
to have just one ARR sometime early in 1998. Web pages include
prompts for inputs from line managers (usually WBS managers) concerning
whether all required resources, both hardware and people, are
available. The DOE site office approves our basic ARR approach
for the FEL.
We procured a self-calibrating system based on a rotating-coil
probe for use in nulling the dipoles at the switch points leading
to the injector dump and the straight-ahead dump, as well as for
field measurement at the recirculation-dump-chicane dipole needed
for energy calibration of the cavities. Interfacing the hardware
to the control system is the next step. Issues regarding field-uniformity
requirements for the corrector magnets and trim quadrupoles were
coordinated with respect to existing commissioning plans. Considerations
ranged from using "poor" correctors, or even no correctors,
and moving magnet elements if necessary to adjust the beam (at
the expense of having "many knobs" on the transport
lattice), through pressing for high-quality correctors and trim
quads. The general outcome of these discussions is summarized
above under "Beam Physics". Regarding schedule, these
magnets can be clamped on over the existing beam pipe, so installation
can proceed without them.
A draft commissioning process, including potential subsystem owners
and principal investigators, and a draft commissioning schedule
was formulated for the IRFEL as part of prepositioning Accelerator
Division resources for machine turn-on starting 1 Oct 97. Both
are currently under discussion.
Facility
This month showed rapid progress on the facility. At the beginning of the month work was coming to an end on the lower level and framing and roof panels were incomplete on the upper level. By the end of the month the facility was nearly 100% enclosed and many rooms were nearly ready for occupancy. In summary, framing was completed. The roof was completed and sealed early in the month. It has survived several significant downpours and shows no signs of leakage. The roof drain system was finished and works well. The exterior siding was completed except for a small area near the injector and the entrance store front. A very large amount of drywall was hung throughout the month. All labs, the control room, the communication room, and the rf gallery were completed. In most areas the drywall has been taped, spakeled and sealed. Work remains in the injector area and the equipment room. Painting has been completed in the control room and optical control.
The windows were hung in the front, the break room, and the east side. The stairwell and spire remain. The control room has been fully paneled in, the ceiling has been hung, and the lights connected. The control room windows to the gallery were prepped and installed. Building utilities also made major progress. All HVAC units were hung; chilled water is up to but not connected with most units. The HVAC ducting is hung throughout the building. The sprinkler system has been 90% installed. HVAC return ducting was installed in the equipment room. Pumps for the main chiller were placed and plumbed in. Plumbing work proceeded in the bathrooms and achieved 90% completion.
Electrical progress was also great. A very large amount of internal conduit was hung. The main site transformer was hooked up and power was turned on in first the downstairs and then the upstairs. A set of five step down transformers for the RF gallery were hung from the ceiling and their switch boxes hung on the wall. Lights are powered both upstairs and downstairs. We placed the dump pump skid in the lower level and placed some stands in the injector area. The cryogenic lines finished welding and leak testing. They are ready to be welded into the system when the connection is made to the CHL. Preparations for that continued with Jefferson Lab taking over welding of the sleeves from the contractor to ensure that it will meet our alignment specs. LCW pipe welding continued. Safety systems hung most box duct downstairs. Plans were approved for the services piping, cable tray placement, communication routing, and injector crane system. The pressure vessel for the gun HVPS was delivered. RF staff placed some waveguides in the penetrations. The communications rack was delivered to the communication room.
This coming month will see many areas come into full availability
and installation work of Jefferson Lab equipment will proceed
at a more rapid pace. The contractor intends to finish the building
on schedule despite slipping on BOD #2 and it appears at present
that no major impediments to achieving that goal exist. By approving
some minor changes in the electrical design we have achieved
a more effective use of the facility space; by approving slippage
of some non-critical activities such as berming we have allowed
the contractor to make up schedule lost due to manufacturing errors
on exterior paneling; and by coordinating carefully the order
of installation and judicious overtime approval we have managed
to essentially return to our original installation schedule despite
a four+ week slip in BOD #2. We will continue this aggressive
management approach in May to keep the facility off the critical
path for FEL completion in September.
Upcoming Meetings and Reviews
IEEE/APS Particle Accelerator Conference, Vancouver, May 12-15, 1997
BES Combustion Science Workshop, Washington, May 27-29, 1997
SURA Maritime Technical Advisory Committee, June 9-10, 1997
Laser Processing Consortium Meeting, June 25-26, 1997
International FEL Conference, Beijing, August 18-22, 1997
SURA Science and Technology Review, Sept. 29-Oct. 1, 1997