FEL Upgrade March 2002 Monthly Report

Completion of the gun chamber and leak check of the ceramic stack highlighted significant steps forward for the upgraded injector gun this month. The optic systems made major headway with the release of drawings for the alignment assembly and procurement an ultrafast diagnostic laser.

In the transport area we potted a complete coil pair for the optical chicane dipoles and all 3" quadrupoles for the IR system are now in hand and meet spec. The first of the Upgrade hardware was installed in the FEL vault this month: support stands for the return leg magnets. The wiggler assembly is ready for transfer to the FEL vault in April. Significant progress was made toward completion of the last major RF system component: the high power amplifier (HPA) for the upgrade injector klystrons.

We hosted a very important set of visitors to the FEL Facility on March 15th; the Chief of Naval Research, Admiral Jay Cohen; Congressman Duncan Hunter, who heads the R&D subcommittee from the House Armed Services Committee and two local members of the House Armed Services Committee, Congresswoman Jo Ann Davis and Congressman Randy Forbes. We had the opportunity to give the delegation a briefing on the FEL program and a show and tell on the JTO-funded laser material studies and the CWM-NASA project on carbon nanotube production. By all accounts the visit was well received and we were honored to have the opportunity.

We are pleased to announce that both ONR and DOE have signed the new Memorandum of Agreement (MOA) for the FY02/03 activities on the 10 kW upgrade and the related FEL technology development grants from the Joint Technology Office.

We are also pleased to acknowledge the efforts of our colleague Michael Kelley, who was notified this month of a winning grant from the Defense University Instrumentation Program (DURIP). The $467k grant will cover the development of pulse compression and stretching equipment for the FEL user labs.

We are pleased to congratulate one of our FEL industrial partners, AES, Inc. of Princeton NJ, who was awarded two JTO grants this month for support of the joint AES/Jefferson Lab project on development of high current injectors for FELs.

On Wednesday March 7 we made a requested visit with the RDT&E subcommittee staff of the Senate Armed Services Committee, which was a follow-up to visits from this committee to the Jefferson Lab for a briefing on the FEL program in December and January. On Friday March 15th we hosted visitors from the House Armed Services Committee as noted in the Highlights section above.

On Friday March 8, we were visited by the Dr. Reinhart Poprawe, Managing Director of the Fraunhofer Institute of Laser Technology (ILT) in Aachen, Germany. The ILT has a unique international reputation in laser materials processing. Their program is 50 % supported by industry. We discussed several areas of potential collaboration.

F. Dylla and the JLab Director, Christoph Leemann, attended the quarterly meeting of Virginia’s Research and Technology Advisory Committee (VRTAC) on March 18-19th, which hosted a briefing for the Virginia Congressional delegation on R&D priorities for the Commonwealth. VRTAC continues to support Jefferson Lab’s nuclear physics and FEL programs.

We completed draft CRADAs and work statements for two industrial collaborations and forwarded the documents to DOE for review. One CRADA is in support of the AES 100 mA injector development project; the second CRADA supports the request by AMAC, International for testing of high power rf windows.

The project monthly reports for February 2002 were distributed to the DOE, ONR and AFRL program offices.

Discussions were held this month with the ONR contract monitor on a draft agenda for the upcoming May 1-3, 2002, FEL project semiannual review. We distributed the agenda for comments by the review committee. Preparations began for the review with discussions on the potential presentation material, and likely tour sites for inspection of hardware.

Meetings were held this week on potential revisions to the lab's Environmental Assessment in order to accommodate proposed building modifications for addition of the Helios synchrotron and the planned 100 kW FEL Upgrade to the FEL Facility.

George Neil presented a colloquium at RPI on results from the recently completed FEL user run.

Project Cost Performance:
The Phase 1 FEL Upgrade project budget for the period June 1, 2000 to September 30, 2001 is $9,029k. The first phase of the project was fully obligated as of the end of September. The total Phase 1 project cost to date-actual costs plus commitments is $9,029k as planned for Phase 1 completion.

The Phase 2 FEL Upgrade project was approved for $4,500k for a performance period of February 1, 2001 to September 30, 2002. Actual funds transferred from ONR to DOE for this effort in FY02 were $4,442k. Work for Phase 2 proceeded to plan during this reporting period. Actual charges of $94k were accrued for March for total accrued costs of $2700k to date for Phase 2. A significant amount of earned value ($785k) was claimed for the project this month as we met a large peg point for the Injector RF Systems (HPA) in addition to expected progress in several other WBS elements. Work scheduled for March was $655k for a total of $1673k for Phase 2 to date; work performed for March was $785k for a total of $2019k for Phase 2 to date, which results in 38% scheduled vs. 45% performed for the Phase 2 project. At present the cost variance for Phase 2 is -$681k and the schedule variance is $346k. We expect to meet the planned cost at completion of Phase 2 effort. The program is presently on track to begin commissioning efforts in September 2002.

The UV FEL project was approved for $2,836k for a performance period from September 2001 to September 30, 2002. Actual charges of $183k were accrued through March for a total accrued costs of $648k since project start. Work scheduled for March was $256k for a total of $860k for the UV project to date, work performed for March was $298k for a total of $878k for the UV project to date, which results in 30% scheduled vs. 31% performed for the UV project. At present the cost variance for the UV project is $229k and the schedule variance is $18k. The program is on track to meet the statement of work requirements on schedule and within the available budget.

WBS 3 (Beam Physics):
Analysis of GX, GQ and GY field quality underwent a femto-review; see WBS 9 - Biallas for results and actions.

A simple geometric description of the UV trajectory through the GX was derived.

Documentation of endloop dipole considerations was started.

During discussions this month of the vacuum chamber design we learned that the year-old beam stay clears could be modified with no significant impact at this point to extend performance to maintain capability for the 100 kW level. This situation was addressed with our usual methods of give-and-take between the chief lattice design and the hardware designers and brought to rapid and satisfactory conclusion. Having agreed on a means of dealing with issues of tracking and matching amongst endloop dipoles, we began discussions with WBS 9(George B. & co.) and AES to have it happen. We also started writing it up to document the rather arcane UV geometry and allow people to review our conclusions.

WBS 4 (Injector):
The gun chamber has been completed. The ceramic stack was leak checked and found to be tight.

The cathode support tube was mounted into W&M's implantation system for the final surface treatment

While implanting the cathode support tube some arcing occurred. We have decided to redesign the mount for the support tube in the implanter, polish out the damage and start again. The shop completed the gun mounting ring which mounts the gun chamber to the stand. Polishing was started on the ball cathode. A mount for implanting the ball cathode was submitted to the shop. Completed preliminary designs on the shielded bellows between the gun and the lightbox and the shielded bellows/BPM combination between the lightbox and the buncher.

Gun HVPS Tank - A design review for the combined running and conditioning resistors was held this month. Agreement was finally reached on how to join the 2 major pieces. The existing probes and fittings will be used to operate the internal motor and check the resistance. The running portion of the resistor was received. The HV tank is being manufactured by Industrial Alloy Fabrication of Richmond. It is due 10 May. Parts have been ordered and are being received for the connections into the tank. The large ceramic cylinder is on order.

An important DC Field Emission test of a previously hydrogen cleaned GaAs wafer was completed at 60 MV/m. Three emitters were found at 54, 47 and 30 MV/m of applied electric field. The maximum observed current was around 2 nA. The current was observed to be very erratic while varying the applied voltage to obtain the field enhancement factor, which was found to be between 30 and 60. The data are being analyzed to estimate the effect of cesium on the emission current. An EDX spectrum was taken and indium was found on one of the emitters which is non intrinsic and resulted most likely from the handling procedure. The rest of the wafer shows only Gallium and Arsenic as expected. Calculations show that for similar emitters on an activated wafer, the field emission current in the 6 MV/m configuration is on the order of pico-Amps, but at 10 MV/m the current is on the order of micro-Amps

PARMELA simulations of upgrade gun performance show an improvement in the longitudinal and transverse emittances after fine tuning of the buncher gradient and solenoid field. The results up to the end of the 1/4 Cryounit are: z-emittance ~18 deg-keV, x-emittance ~5.7 mm-mrad, and y-emittance ~4.5 mm-mrad. Work is in progress towards transporting the beam to the end of the Linac.

WBS 5 (SRF):
Received the thermal shield and receipt inspection has started. QA was completed on the vacuum vessel components; they were returned to the vendor for minor modifications. Final inspections have not yet occurred. A dry assembly of the hardware for the first Upgrade cryomodule has started. (This first assembly goes to CEBAF; the FEL Upgrade project gets the second Upgrade cryomodule scheduled for assembly and completion next fiscal year).

Five cavity assemblies with end group welds have been assembled for the first Upgrade cryomodule.

The cabinet and parts for the on-site electropolish system have been received.

WBS 6 (RF):
Quarter Klystrons - The drawings for the klystron carts were completed and signed this month. Two additional klystron carts will be made by our machine shop. The first 12' of main LCW piping in the RF Gallery is being replaced to increase flow and to add the larger taps (2.5 inch ball valves) for the upgrade. This effort will take several weeks to complete when the welders are available after the CEBAF shutdown ( about April 22).

Quarter HVPS - The wiring and documentation for the Upgrade HVPS continues. Checkout should be able to start 1 April.

Zone 3 - Complete. Waiting for final test with the new Upgrade cryomodule next fiscal year.

Zone 4 - Complete. Waiting for LCW to make final system test on equipment in position 8.

WBS 8 (Instrumentation):
A big thank you to the operations group for the additional help during the CEBAF shutdown. The operators are assisting in the BPM detector testing, assembly and testing of beam viewer cameras, and fabrication of a number of VME boards required for the upgrade.

A VME digital interface card has been designed and prototypes are in the procurement phase.

Magnet locations have been nailed down and cable installation plan is in order and will begin soon.

A test stand for beamviewers and cameras has been assembled this will test the operation of the solenoid and air valves as well as the sensors that indicate viewer position. We will also be looking at the indicators on the foil that will allow better determination of beam location and size on the viewer. Inputs into EPICS will also be tested.

The final push is on to complete all tasks associated with beam viewer system. This effort will complete mechanical assembly, camera rework, control chassis fab and pre assembly of camera support structure. Upon completion, the remaining viewer assemblies will be delivered to the magnetgirder assembly area in the Test Lab. Additionally the CCD elements which suffered radiation damage are being replaced.

The beamviewer locations have been assigned to channels / chassis and has been turned over to software for signal names and screen upgrades. The dust covers for the beamviewers have been designed and ordered, the drawing for the beam viewer test box has been turned over to E-cad.

All of the 3" Beam Position Monitors (BPM) are being retested prior to delivery to the Test Lab, of the 44 detectors (176 feedthrus) 2 feedthrus were found to be intermittent. These will have to be reworked prior to installation. The test was to prevent any problem detectors from being installed.

Progress continues on the Beam Loss Monitoring System upgrade, the number and locations of monitors has been defined. Designs were completed on the Breakout Module and turned over to EECAD for documentation. There is a need for a "diagnostic" mode for the BLMs but it was decided that installing an additional 6 to 8 "floaters", which are not interlocked to the Fast Shut-Down (FSD) system, provides the best solution. By having independent control over the tube voltage one can get 6 decades of "gain", this cannot be accomplished on the interlocked tubes without compromising the system integrity.

The DC power trim channels have been assigned and are being inputted in the web site for generation of cable labels. The additional trim rack should be installed in the gallery in the next few weeks. A meeting was also held regarding the "super trim" power supply, these are 75Volt/20Amp bipolar supplies. Fourteen (14) of these are required for the IR/UV machine, we will order two (2) spares. The only remaining procurement is for seven (7) 100 amp power supplies.

Efforts to organize and track the I&C group’s hardware and documentation based on a hand-held bar-code scanner are coming to fruition. The system has now been functionally integrated into a database. It works as follows:

1. Scan any bar-coded item with the hand-held scanned (or any number of items)
2. Key-in any additional notes to describe the item(s)
3. Park the hand-held scanner in it's cradle and press UPLOAD to the pc
4. Open the resultant text file in any text editor to confirm (and/or edit)
5. Logon to http://laser.jlab.org/data and click "Add new items" from the menu on the left.
6. Cut and paste the text file from the hand-held scanned into the form field listed as Paste Barcodes
7. Press Submit (The form will regenerate with the information you pasted)
8. Review the Current Location, Associated System, Hardware Category & Machine Nomenclature pull-downs
    (All this can be edited later as well and so it is optional at this point)
9. Press the Submit New Items Information button to finish the procedure.
The location for the ion chamber on the wiggler has been identified and D. Dotson has begun work on the communication upgrade to EPICS. (RS-232 to 485). The fourth LeCroy HV pod for the additional Beam Loss Monitors (BLM) has been procured. The Altera programming development for IOC Interfacing and BLM logic is proceeding. EECAD continues to work on documentation for open projects (MPS Input Module, Digital Timing Module, etc.) The main effort has been to get the prototype of the VME Interface stuffed, programmed and working and to continue developing the schematic for the BLM MPS card

WBS 9 (Transport):
Optical Chicane Dipoles (GW)
•   At Magnet Enterprises International in Oakland CA, they potted the second coil successfully, making a complete pair for the first
    article magnet. They got a third coil ready for potting and wound a fourth. They are making up an additional winding mandrel to
    increase production rate.
•   Return legs were ground to their final size and the top and bottom slabs finished heat treatment. Final finish machining of a
    core awaits slab grinding followed by tap and hole machining and final assembly.
•   Field clamps are in process. Covers and manifolds are on hand.
Injector Dipoles (DU/DV)
•   Master Machine picked up steel yoke material and torch cut it into the pieces for manufacturing.
•   We signed off the revision A drawings and have distributed them to both Master Machine (Cores) and Wang NMR (Coils) for
•   WANG NMR successfully wound the wound GV Coil and made the GU winding tool. They subsequently are winding all the coils.
Arc Dipoles (GY, GX, GQ)
•   David Douglas completed his analysis of the use of the Bend and Reverse Bend Dipoles (GX & GQ) as well as the 180° Dipole
    (GY) at all levels of excitation using the magnetic model analysis from AES. The conclusion is that the magnets meet specification
    at 210 MeV/c but have to be modified to be used successfully throughout the full range of excitation anticipated (a lower limit of
    80 MeV/c). Modifications are:

- Close the gap on the GY by .016 inches to provide more headroom for the shunt at low energy.

- Add separate, ganged 2500 G-cm correction coils to the GQ dipole coils astride the existing correction coil for use in matching the dipoles to the GX magnets at low energy.

- Shave the length of the GQ by 5 mm and the GX by 3 mm to bring the field integrals down to match the core field at low energy. We will expand the length to the high-energy requirement using shims.

- The UV operation of the GX may need both plus and minus ability as well as a shortened magnet. Through that arc we will maintain the 3 mm decrease in length and place a trim power supply on those portions of the coils that are switched out during UV operation.

•   AES has been given the Task order to assess the GQ-GX dipoles at lower energy with shorter pole tips. They are also designing a
    shim system as part of Revision A for the pole tips to reconfigure the magnets for high energy use.
•   Wang NMR of CA continues making the GY coil winding mandrel and they are designing the potting mold for the GY coils.
•   Bosma Machine heat treaded the GY core pieces and return legs and started final machining.
•   We received the best and final offers for the GQ-GX magnets. The contracts were let to Process Equipment C. of the Dayton Area
    and Wang NMR of Livermore CA.
3 inch quad (QX)
• All QX quadrupoles needed for the IR portion of the FEL Upgrade are now on hand.
• Production measurements were taken on 53 QX Quadrupoles with no evident rejections.
• Eighteen QX Quadrupoles were qualified for installation in the machine by sign off by David Douglas.
• Production measurements continued on the remaining QX Quadrupoles with no evident rejection.
Trim Quad (QT)
•   Milhous Control of Virginia is making the side coils with the material we recently supplied them and reports that a first article will
    be available soon. Tom Hiatt is scheduled to inspect the magnet.
Sextupole (SF)
•   DULY Research has generated a successful magnetic design that does not operate in saturation. We have set up a task order
    with them to make the drawings, copying the successful construction methods of the dispersion section coils and the quadrupole
Octupole (OT)
• Work on this magnet is on furlough until the sextupole is designed.
Beam Line and Vacuum
•   AES continues drawing up the chambers throughout the arcs. In checking the chamber configuration, we found that the chamber
    passes the 10 kW beam easily but restricts the beam in two places for 100 kW in the second arc. We will change the design to a
    wider configuration in those positions. The configuration for this 15% acceptance in the second arc is in the hands of AES and
    the task order is modified to account for the extra work.
•   Design of the Arc Dipole Stands continued.
•   Butch Dillon-Townes finished updating the schedule and passed it on the scheduling folks for incorporation into the master
•   LCW system design continues. This month we concentrated on fabrication practice and design for commissioning. Since the
    CEBAF System is already pure, we have to minimize disruption of its quality as we open our system to it.
•   The drawings of the region at the end of the cryomodules was completed and is under review for signing.
•   Design continued on the details for the telescope region after the cryomodules.

WBS 10 (Wiggler)
The wiggler/ dispersion section assembly for the FEL Upgrade is ready for transfer to the FEL vault after completion of our characterization measurements. The transfer is scheduled for late April.

WBS 11 (Optics):
The drawings for the mirror metrology system (OCMMS) were signed and released for procurement.

We received the amplifiers and piezo actuators that will make the OCMMS test stand very nearly complete. We received some input on alternate ways to implement the feedback system for the fast steering, and after discussion, will work along the lines of an analog implementation (with digital readbacks).

A spreadsheet detailing the vacuum wiring for the various optical assemblies (optical cavity, collimator and turning mirror cassettes) was generated and given to I&C so they can have electrical schematics produced and order components such as vacuum feedthroughs. The UHV stepper motors (to be used in the optical cavity and collimator) began testing this month. The I & C group were able to create settings for their stepper motor controller that produced smooth operation. We determined (to an accuracy of +/- 60 nm) that there is no backlash when reversing direction.

The drawing for the leadscrew for the optical cavity assemblies completed check and will go out for procurement soon.

The drawing packages to date, plus icons for the other components, are being integrated in a complete system print. These drawings were collected into a presentation that was sent to our technical monitor (J. Albertine) and to C. Brau of the review committee, as a way to update them on the progress in optics. Accompanying this report was an update on the deformable mirror test results to date.  As a result of a scheduled teleconference, we determined there was no need for an on-site visit before the May review.

Thanks to S. Benson's modeling efforts, we have a good idea of the optical layout for the collimator, and can generate specifications for the design. He was also able to complete calculations to define the outcoupler figure, so we can go out for bid on those components. Modeling efforts by J. Gubeli on the 50kW optical beam dump are proceeding. The preliminary drawings for one possible design of the 50 kW laser beam dump are nearly complete.

We began collecting more data on the deformable mirror assembly in the mirror test stand (MTS), with the goal of studying the ROC as a function of water flow rate. We also spent some time determining the sensitivity of the ROC measurement, using the laser interferometer, to software and hardware parameters.

A requisition for an ultrafast laser system was signed this month. The procurement of the ultrafast laser was switched from sole source to commercial bid. This laser will be used for FEL output and electron beam physics studies. After evaluating the submitted proposals, an award was made to Spectra-Physics. This will be JLab's first sub 100 fs light source.

Progress was also made in compressing the pulsewidth of the "waste" drive laser IR output, using nonlinear effects in a single-mode fiber. So far, we have determined that the damage threshold is greater than 70 MW/cm^2, in excess of the manufacturer's claim of 50 MW/cm^2. As a reminder, this hardware will be used for diagnosing electron beam dynamics and their effect on the FEL. In parallel with this effort is one to design an insertable mirror to route the THz light to a point where it can interact with a synchronized ultrafast laser. Calculations show the relative insensitivity of the wavefront of the THz light to misalignment of this mirror.

UV FEL Progress:
For the UV FEL optics, we are in the process of reviewing of the last 10 years literature on laser induced damage thresholds in the UV and DUV is underway. On the UV cavity, modeling continues on the cryocooled mirrors. The optical penetrations between the vault and upstairs were checked and added to our system print, so we can determine how to integrate the UV optical transport with the IR transport.

Other Activities:
We provided the Injector Source group with advice on how to improve the modelocking of their drive laser for the G0 project. They also used our optical inspection microscopy to look at one of their ball cathode assemblies. This month the Optics Group gave a tour to Mr. W. Decker, of Brashear LP. Brashear built the beam director for the THEL project, and is interested in our program

UV FEL Microengineering Tool Development (Aerospace Corporation)
In March the JLab microengineering project team proceeded with the continued concept design of the experimental station. We have nearly completed the concept design phase where tradeoffs of capabilities versus complexity were analyzed from the perspective of the following machine subsystems. 1) Optics, processing wavelengths and optical beam delivery. 2) Motion control. 3) Pattern transfer (CAD/CAM). 4) Process control. 5) System vision, 6) Metrics, documentation and safety, 7) New process development. 8) User support and tool maintenance. All this has been done in preparation of a Systems Requirement Review to be assembled in the June time frame.

A small task had been initiated in February to explore a new laser material processing approach, where ion implantation technology and a frequency up-converted IR FEL (e.g. 532 nm) can be combined for mutual benefit. The merged processing approach enables the fabrication of patterned micro/nanometer scale structures, in semiconductors, over large areas (>400 mm dia). The initial results from this small task look promising. A silicon wafer was oxygen ion implanted through a mask using traditional techniques. A green laser was then used to excavate the silicon around the SiO2 patterns. We successfully made 200nm thick freestanding pattern SiO2 films that stretch over 100 microns. The process needs to be refined and this will be co-sponsored by an Aerospace Internal IR&D funds. The project looks very feasible and utilizes a laser in a very novel way. In this process the laser is used to remove material and as such will require high average powers if large areas (100mm – 200mm) are to be covered.