Highlights:
On Saturday, April 21, the FEL team and approximately half of the Jefferson
Lab staff educated (and
entertained) about 5,000 visitors from the local area during our 2001
Open House. We had a continuous stream
of visitors from 10:00am to 4:00pm who were shown the FEL, exhibits
in three of the user labs on basic and
applied applications of the FEL, and an exhibit on the planned addition
of the Helios synchrotron to FEL Facility.
On the upgrade front, we now have ac successful model of our small dipoles
that meet the field uniformity
requirements (1/10,000).
Management:
JLab hosted a group of senior managers from Brookhaven National Laboratory
to explore possible
collaborations in the areas of high current injectors and energy recovering
linacs. They are interested in exploring
the limits of these technologies. We agreed to jointly pursue
DOE, NSF, and NIH funding to support initiatives
in this area for application to cooling rings and light sources.
They are also interested in performing electron
transport experiments and code validation on the Upgrade as that becomes
operational. They may be able to
provide some technical assistance in that effort.
A requested summary of our presentation to the Defense Science Board
High Energy Laser Panel on Jan. 25th
was forwarded to the DSB support office this month.
We were visited this month by Dr. Al Skolnick for a tour a and
briefing on the FEL program. Dr. Skolnick was
involved with the management of the Navy laser development program
in the 1970-80's. George Neil and
Michelle Shinn were involved in numerous discussions this month
with Joint Technology Office (JTO) in the
preparation of the final FEL-materials exposure plan for the JTO study
funded for this year.
F. Dylla attended the Spring 2001 Board of Trustees meeting of SURA
and presented an update on the FEL
program. We were pleased to have the Chief of Naval Research,
Admiral Jay Cohen address the SURA Board
on Monday night. The CNR discussed the potential interest of
ONR in SURA's new initiative in coastal science
and gave mention to the existing ONR-SURA relationship for the development
of FELs. We have had three
discussions with the CNR since early February and during all three
occasions he passed on his interest in
strengthening an FEL development program involving Jefferson Lab and
potential partnerships with Navy labs
and industry. George Neil gave presentations on the JLab FEL program
this month at MIT, the Air Force
Institute of Technology in Dayton and at the Stanford FEL Laboratory.
During the visit to AFIT, George had the
opportunity to brief managers in the AFRL in Dayton on our pending
UV development program with the Air
Force.
The FEL program at Jefferson Lab was given high visibility at a Congressional
briefing for the Virginia delegation
on April 26 which was organized by the Virginia Research and Technology
Advisory Commission (VRTAC).
This is the third year that VRTAC has prioritized R&D activities
in Virginia for the benefit of the delegation. The
commission is co-chaired by Adm. Marc Pelaez, a former Chief of Naval
Research and Prof. Anita Jones
(UVA), the former assistant secretary of RDT&E for DOD. Prior
to VRTAC 's briefing on April 26, the current
CNR, Adm. Jay Cohen addressed the commission and again stressed his
agency's interest in continuing FEL
development. On Friday, April 27, we were visited by two current
members of the Defense Science Board
panel on high energy lasers (Dr. Darrell Collier and Dr. Steve Hadley)
for a briefing and tour of the FEL.
Project Cost Performance:
The project (Phase 1) budget for the period June 1, 2000 to September
30, 2001 is $9,029k. The Phase 2
project was approved for $4,500k for a performance period of February
1, 2001 to September 30, 2002. The
project through the month of April has a total of $3,461k of performance
scheduled (assuming the project started
at the originally planned start date of April 1, 2000). The work
performed through the end of April was
$4,003k, which is 44% complete vs 38% scheduled. The actual cost
accrued through April totals $4,711k.
This results in a schedule variance of +$542k and a cost variance of
-$708k.
WBS 3 (Beam Physics):
Initial performance analysis of the IR driver suggested the possibility
of improved chromatic behavior. Minor
changes in sextupole placement led to much better orbit control off
momentum. Modeling of, and fitting on,
chromatic variations of propagated beam envelopes provided a significantly
improved solution for matching
telescopes and produced a procedure for generating large acceptance
matches. A broadband-chromatic model
was developed and applied to optimize the energy-recovery endloop
betatron matching. The resulting solution
provides space for Thomson scattering x-ray generation apparatus.
Field quality issues in the pi-bends and
injection line dipoles were under discussion.
A geometric quasi-perturbative model of the energy recovery arc is being
generated to cross-check DIMAD
acceptance calculations.
WBS 4 (Injector):
Received the ion pumps and part of the flanges order for the gun chamber.
Arranged with the new W&M
student to start implantation work again. A test electrode will be
implanted as warm-up for a Ti electrode which
will run first.
A review of the light box layout, revealed a correction allowing for
a 2" aperture in the light box by going to a 4"
valve. We ordered a 100mm aperture RF shielded gate valve.
Drawings were completed for the cathode
shield. We will build and test the shield mechanism in UHV conditions.
Design changes for the ball cathode were
completed. Ordered bellows for the stalk and shield modifications.
Details for the cathode support tube
modification have been completed.
WBS 5 (SRF):
Helium Vessels received from PHPK were qualified and passed their
QA test this month. We have completed
the electron beam welding for two fundamental power couplers (FPC)
bodies and qualified the procedure. A
kick-off meeting for the thermal shield vendor (ADC) was scheduled
for April 25. Cavity vertical test assembly
(VTA) test began last week for the 7-cell cavity structures. Two tests
have been completed after the standard
buffered chemical polish (BCP) treatment. These cavities show
onset of field emission at 11 MV/m. They will be
re-treated and re-tested until higher gradients are achieved.
WBS 6 (RF):
Zone 3 –
The HVPS is due 8/15/01. The Circulators for this zone have been
received and are being tested. They will be
installed later this summer.
Zone 4 –
Door bracket was modified to close and latch properly. The Cross-Connects
for zones 2 & 4 are now wired
properly. The wiring sheets were turned over to R. Vignato for
documentation. Marked-up drawings were
given to M. Gonzales for ECO's. The Test Data book is being prepared.
Except for #8 circulator out for repair,
this zone is complete and waiting for a cryomodule.
Injector RF –
Factory Acceptance Tests of the 100 kW klystrons are still scheduled
for 6/20/01. The 100 kW Circulators will
be delivered to JLab early next week. The only prospect, PSC,
to upgrade the HVPS's for the 100 kW systems
is still waffling on his offer. I am starting to make up a specification
for the HV power transformer so that we will
be able to do this work. Continued maintenance work on Quarter
power supply. Pursuing specifications for
transformer and inductors for Quarter. The design drawings of
the LCW manifolds for the klystron carts were
signed today..
Gun HVPS –
Glassman has received our spare unit and is working on its upgrade.
The large torus is a long lead item, so it will
several months before they will be finished and tested.
WBS 8 (I&C):
The "Alarms Handler" has been installed in the control room. A piece
of software was added that looks at the
Beam Loss Monitors (BLMs) and prompts the operator if an attempt is
made to open the drive laser shutter
while the machine is in Beam Mode 3, or 4 (unsafe condition). These
updates will help the transition of
operations from the FEL core group to "fresh" operators. (Not "inexperienced"
since they have a great deal of
experience with CEBAF) The server hard drives were also upgraded.
Design activity for a VME based Beam Loss Monitor (BLM) card/system
is ramping up. Informal discussions
are ongoing regarding addition features. The Integrator "front-end"
electronic will remain essentially untouched
but an additional integrator will be added for a "low beam loss" diagnostic.
This second integrator will be
controlled by a DSP, the desire is to have a loss calculated and displayed
in units something like
"nanoamp-seconds". The design of the new four channel VME timing/delay
module continues, the design of the
MPS Input card is proceeding as well.
Initial planning has gone into interfacing the YAG laser in Lab 2 for
the Optics group. The vacuum system layout
Rev. 0 is complete. Drawing are being prepared then they will be reviewed.
The process of gathering parts for
the Ion Pump Power Supplies is nearly complete. Received bids from
Allied and Newark on parts that are still
needed.
Bid requests have been sent out to 5 Contractors for assembly of the
User power supplies for the labs. This will
also help to establish a good source for other up-coming fabrication
jobs. The remaining VME front panels that
were sent out for machining and silkscreen are back. All spare parts
for the VIDMAR in Lab 5
have been ordered. The autotransformers arrived, these are to act as
a back-up in case of a failure of the
50KWatt HPA variacs. These were responsible for a number of hours of
down time during the last run.
EECAD drawings for the Charge Totalizer Current Monitor and the LSS
Alignment Mode Protection Card were
signed off as complete. The Charge Dump Current Monitor Chassis
Fabrication, Assembly and Wiring
Diagrams are out to be checked. The picomotor controller chassis
assembly and fabrication drawings are also
complete.
Cable tray has already been ordered. LCW and vacuum layouts/requirements
are also progressing well.
The Laser Safety System (LSS) master has been updated for operating
multiple hutches in any or all of the user
labs. There is now available status for operation of up to 5 hutches
in the six labs. An "FEL beam-block" shutter
has been developed by the optics group that will allow each hutch to
be manually bypassed for rapid access and
sample changes without dropping the labs LSS. This beam-block
and the user lab shutter provide the two
independent methods of preventing severe biological damage from the
FEL beam to the user. The Lab 2 LSS is
installed and complete. Final certifications for all of the LSS components
require the FEL to be operating so this
will be done just prior to the summer run. (Note: preliminary certs
have been done as a first check and as a
training exercise).
Parts for a prototype BPM using Motorola DSP56F807 and serial CAN bus
including filters and
down-convertors have been ordered. The software development kit is
in for this DSP. The BPMs are a couple
weeks late from Modern Machine but do not yet threaten the schedule.
20 feet of table space has been setup in
the back of the FEL for the electrical assembly of the beam viewers
prior to passing them off for "girder"
installation. During the last go-round this was done in the tunnel-
we're learning. The new design for the OBPM
PCB using the Molectron detectors is complete and assembled, and will
be tested.
First 12 Beam Position Monitors have been delivered. 2 of the viewers
are also here, Master Machine assures us
that they will catch-up. There is no impact on the schedule other than
my desire to get these behind us, girder
assemblies will not start for ~ 3 months. A clean hood will be added
to Area 51 in the FEL to allow for dust free
assembly of the "odds & ends". Some of these are Michelle's Ultra-Viewers!,
and the wiggler viewers. James
continued to spend most of the week finishing up on the LSS system
upgrades. The new box in Lab 2 has been
installed and tested; the LSS Master Chassis has been upgraded to include
all six user labs; plans are in progress
for adding additional protective beam stops to lab 3 for multiple hutches.
The hutch in lab 6 is being equipped
with multiple magnetic switches to ensure all doors on the hutch are
shut prior to beam operation in that lab when
in the hutch mode.
WBS 9 (Transport):
Dipoles
Injector Dipoles (DU/DV)
o DULY Research used their experience with their RADIA magnetic analysis
code, their newly upgraded, high
memory computers and a new element generation algorithm
to investigate the field flatness and integral flatness on
the large injector dipole (GU). They achieved
success, obtaining values for both characteristics of less than 1
part in 10,000 over the good field region.
In addition, the noise in their analysis, the mathematically generated
oscillations were all below these values.
o DULY Research was finally successful in getting their magnetic model
of the small injector Dipole (GV) to
achieve the required tolerances of 1 part in 10,000
for both field flatness and field integral. Their trick for this
“all-ends” magnet was to add a set of trim coils
that raised the saturation of the iron to achieve field uniformity
and to have magnetic shorts on the field clamp to
achieve field integral uniformity.
o They are working on incorporating the findings of the magnetic model
of the GV into a practical hardware
design.
o They have completed drafts of the yoke details of the GU. They continue
work on the details of the coils.
Optical Chicane Dipole (DW)
o We re-checked the drawing set and the back checks were incorporated.
.
o We bought sample strips from five rolls of electrical grade steel
that is destined to be used as the pole tips on
these optical chicane dipoles as well as the 180°
dipoles. We measured their thickness over the very flat center
of the sheets, selected the best roll and bought
enough sheets for all our magnets. (They have to be flat to tenths
of thousandth of an inch).
o Leigh Harwood checked the specification for the major dipole steel
purchase, it was signed off and the
package went out for bid.
o A contract was signed with Innovation Services, a consulting firm
specializing in electrical insulation systems
using epoxy, to review our dipole coil specification
and bring it up to date for the topics of epoxy formulation,
curing, manufacturing and quality control.
Arc Dipoles (GY, GX, GQ)
o Advanced Energy Systems (AES) almost finished designing the 180 degree
dipole (GY). They laid out the
leads, hoses, cover, manifolds and terminal strips
for the path length correctors. At months end they stopped
further detailing pending the final magnetic model
findings.
o A review of the diagnostics requirements led to a new requirement.
Two sets of holes through the yoke plates,
near the coils at around 54 degrees from the face
will be required. These holes will accommodate two periscopes
that look at each other through windows in the outside
surfaces of the vacuum chamber. The two periscopes will
allow a HeNe Laser to establish known optical path
that coincides with the synchrotron light generated at the
apex of the magnet when the beam is centered.
The holes through the yoke plates are similar to the single set
used in the IR Demo. That set produced no
measurable magnetic anomaly.
o The magnetic analysis of the GY with path length correctors ran into
a snag as Dave Douglas found that
increasing the bulk field to correct for the lower
field in the path length corrector slot does not meet the field
tolerance of 1 part in 1000 imposed by dispersed
beam. Tom Schultheiss is calculating how much additional face
steel is needed and how much parallel offset there
is to the beam if it is brought into the magnet perpendicular but
off set and comes out in a similar condition.
David says he can live with a small amount (say 1.5 mm) of off set.
Preliminary results however yield 3 mm. The
final solution may be a compromise between increasing the bulk
field somewhat and allowing a small off set.
o They have begun design and magnetic modeling the Arc Bend Dipole
(GX) after some go-rounds on the exact
geometry.
Quadrupoles
QG (3 inch quad)
o The coils manufacturing specification was checked, coil drawings
signed and the coil package sent out to
vendors for bid.
o The prototype core was sent to the shop for a first pass at determining
the pole end chamfer needed to cancel
out dodecupole
QX (Trim Quad)
o A vendor has agreed to custom make conductor for these quadrupoles
to a defined dimension to a very high
tolerance. This should considerably decrease
the manufacturing problems associated with conductor size that
have plagued us in the past. This is necessary
because tolerance build-up in this multi-turn, conductor geometry
dominated magnet will ruin the field gradient quality.
o We created a working magnetic model and are now debugging its meshing.
Corrector Dipoles (DB & DJ)
o After a low bid was obtained from a new vendor. However, we
discovered that the drawings on the bid were
sent out without a needed specification. A
new package, (that will be easier for vendor’s to understand) is in
vendor’s hands for are-bid.
General
o We continued laying out the girders in 3D IDEAs format and started
laying out the girders and stands, making
the tradeoffs of machined-in features vs. adjustment
mechanisms
o We designed more of the beam chamber in the arcs, firming up the
parameters associated with chamber height.
o We sent out inquires to vacuum vendors to determine if they can make
our style of chamber and received many
responses. The JLab Shop, which did much of
the chamber work last time, may be overloaded at our required
time of fabrication.
o We took our first look at piping the LCW in the upgrade.
o The alignment group at CERN is going to sell us 6 of their heavy
weight rated alignment cartridges for use
under our 180° dipoles so we will not have to
go through the engineering.
WBS 10 (Wiggler):
A preliminary set of magnet measurements were performed on the dispersion
section and verified the first order
field requirements. The magnet must be disassembled to add holes
that the vendor missed on the support stand.
Detailed magnet measurements will start once the magnet is reassembled.
Estimates were received on the magnetic modeling of the wigglers.
The estimates were very high so it was
decided to figure out the strength of the end coils by direct measurements.
We decided to analyze the end coils
of the Wiggler ourselves because the cost to have AES do it was much
greater than simply winding conductor on
the poles and deducing the proper number of turns from measurement
(Analog computer method).
A coil design for the wiggler end correctors has been submitted to the
shop. In the meantime we will be taking
measurements of the DC field in the wiggler vs. the strength of the
end correction using some AT coils left over
from CEBAF. This should allow us to determine the excitation
necessary for these coils. All components for the
wiggler viewers have now been received. The small tubing for
the vacuum chamber has also been received. We
should be able to start machining of the chamber soon.
WBS 11 (Optics):
Meetings were held early in the month to discuss mirror mounting concepts
for the optical cavity assemblies. The
group concurred with our scheme for employing 4 mirrors mounted in
JLab-designed mounts, and so we're now
designing them. An internal document was distributed for comment
that details the design evolution of the optical
cavity. The ultraviewer (alignment) design for 4" tubing is being
detailed. Procurement received three bids to
build two prototype deformable mirrors; we anticipate an award early
this month. A meeting was held to discuss
how best to accommodate ultrashort x-ray production and delivery in
the Upgrade, and still accommodate
optical and electron-beam diagnostics downstream of the wiggler. The
impact for optical diagnostics was that we
will no longer plan on fastening our diagnostic onto the wiggler vacuum
chamber, but will instead design it on a
cross.
The 50% mirror in the User Lab 1 mirror cassette was realigned to make
it's beam coincident with the other two.
Other vacuum parts needed for the User Lab 2 mirror cassette were received.
I & C, in conjunction with the
electrical installation group, wired smoke detectors in the drive laser
enclosure, and in User Lab 2.
Other LSS work also occurred.
The optical cavity assembly conceptual design was reviewed and discussed;
several good points were raised
regarding internally supporting the linear translation, and the stiffness
of the mirror mounts. These comments are
being incorporated in the design. The ultraviewer (alignment) design
for 4" tubing is being detailed. We also
reviewed it and came up with an action item to look at an alternate
baseplate fabrications scheme. We agreed on
a particular mirror orientation (out of two possible). We also
agreed to add an extra cross (with no components)
next to the ultraviewers, to allow for other optical components/diagnostics
to be added at a future date.
Top-level specs on the diagnostic beam dump for the FEL were distributed,
and the requisite make vs buy
comparison is being made. Procurement awarded the contract to
build two prototype deformable mirrors.
Other parts for the manually-actuated safety shutter arrived and were
fitted, the design works well. A few
modifications to hold the limit switches need to be made, and then
we can try it in User Lab 3 The LSOP for
User Lab 2 was submitted for sign off.
The optical cavity assembly design progresses, it now has a stiffer
support frame and accommodates an exterior
motor for translation. The check prints for the new ultraviewer
will be produced today. The manually-actuated
turning mirror (initially for the User Lab 3) was submitted to our
machine shop for fabrication. I & C was
supported in their efforts to test out the LSS. The LSOP for
User Lab 2 has been signed off within the FEL
Dept., and is now with Safety Dept. officialsWe had Robert Chow (LLNL)
here on Tuesday to evaluate our
plans for the Mirror Test Stand (MTS).
Overall, he thought we had a very good plan. He did alert us to
some experimental subtleties, and offered to
share some designs that proved successful in the high average power
laser system (AVLIS) operated at LLNL in
the '80s & '90s. We anticipate receipt of the rest of the
MTS internal hardware next week. We reviewed the
check prints for the new ultraviewer, and identified several changes;
these are being incorporated. We should
proceed to signoff next week. Conceptual designs for the diagnostic
beam dump and the collimator proceeds,
for the latter, S. Benson has done some optical modeling that defines
the types of mirrors we'll need.
Parts for the manually-actuated turning mirror (initially for the User
Lab 3) were received from our machine
shop. Assembling them identified a few minor interferences, these
are being fixed. Supports for the beamline are
being designed and procured. Some work was done on the drive
laser to realign it's output; it will be needed
next week for OBPM tests. The LSOP for User Lab 2 has been signed
off. After we receive some beamline
shields, we'll begin testing the laser, and then begin our first checkouts
of the MTS.
Operations/Commissioning:
A training meeting was held on the optical systems with the MCC operations
coordinator to explain functionality
and characteristics of the cavity and optical transport system.
FEL X-ray Research:
1. Boyce prepared an LOP for the next run. There
are two objectives: a) measure spatial distribution and b)
investigate the anamolous
x-ray peak found in the last run.
2. In order to accomplish the above, some equipment
needs to be modified and I have designed a Pb shield
for the X-ray detector.
I've scrounged two Pb bricks that have never been exposed to radiation
and supplied the
shop with them along with
the design. Casey anticipates the job to be complete by next Wednesday.
3. In parallel with the shop activities, we're working
to modify the detector translator station that will move the
x-ray detector across the
Be window through which the diffracted x-rays emerge.
4. Met with Steve Benson, Michelle Shinn, and Dave
Douglas to discuss the X-ray requirements for the
upgrade. We have decided
to limit the capabilities to x-rays below 50 keV. Further, the quad triplet
can now be
moved closer to the wiggler
and the x-ray chamber will be between that quad triplet and the next quad
triplet. I
am working on a design of
the chamber.
Planning continues for the up-coming runs to support the JTO proposal
and a call for proposals for the summer
run is being prepared. We heard from Peter Schaaf (Univ. of Goettingen)
that the metal nitrides samples that he
made during the recent winter run appear to be very high quality nitrides.