FEL Upgrade Project Weekly Brief
August 7-11, 2000


During a brief operational test of our 6 micron optics, we obtained a new power record for this wavelength of 950 watts.  This power was obtained with 3.5 mA of driver current.


Following the completion of the summer run last Friday, much of this week was spent preparing and reviewing our presentations for next week's presentations at the International FEL Conference (Raleigh) and the following week's Linac Conference. The following papers will be given at the FEL Conference and the associated FEL User's Workshop at Raleigh:

  1. Performance of the Photocathode Gun for the TJNAF FEL (Siggins)
  2. Beam Breakup in the JLab FEL Upgrade (Merminga)
  3. Collective Effects in the JLab FEL Upgrade (Merminga)
  4. JLab IR Demo FEL Photocathode Quantum Efficiency Scanner (Gubeli)
  5. Sensitivity of the CSR Self-Interaction to the Local Longitudinal Charge Concentration of a Bunch (Li)
  6. Nonlinear Harmonic Generation in Multi-Stage Optical Klystrons (Fruend/Neil)
  7. Dispersively Enhanced Bunching in High Gain Free-Electron Lasers (Neil/Fruend)
  8. An Experimental Study of an FEL Oscillator with a Linear Taper  (Benson)
  9. Micromachining of Polyimide Driven by a High Average Power IR FEL  (Kelley)
 10. Performance and Capabilities of the Jefferson Lab FEL User Facility (Shinn)
 11. Transient Mirror Heating Theory and Experiment in the JLab IR Demo FEL (Benson)
 12. Short Pulse X-rays at JLab (Boyce)
 13.  Metal Processing with the JLab FEL (Shinn)

At the Linac Conference held during Aug. 21-25 at Monterey, Dave Douglas will be presenting an invited talk on the accelerator physics associated with the IR Demo in addition to a poster presentation summarizing the present status of the Upgrade design.

The first progress review for the Upgrade project will be held on October 23.  John Albertine will chair the review on behalf of ONR.  The review team who attended the project kick-off meeting in June has been invited.

WBS 3  (Beam Physics)

The paper that Dave Douglas has prepared for the Linac Conference on the IR Demo summarizes our present understanding of the beam physics in the current FEL driver accelerator.  The companion paper summarizes the specifications and the design progress to date on the driver Accelerator for the upgrade.  Both papers will be posted on the JLab web site in the next week.

WBS 4 (Injector)

We received a suitable high power resistor and have modified it for use in the high voltage breakdown test stand which we are using to qualify new electrode materials and surface treatments. These qualification tests should re-commence next month on our baseline stainless steel electrodes and the prototype nitrogen implanted electrodes supplied by CWM.

We heated the test chamber and Cesiator while running a nitrogen purge through it with vacuum at the 10-2 Torr range, maintained by a turbopump.  The hydrocarbons came down by about two orders of magnitude.  This allowed us to find the leak in the electrical feedthrough of the thin film monitor.  It is being fixed and the remainder of the system is down to 2.2x10-8 Torr and


Procurement packages noted last week are proceeding.

WBS 6 (RF)

Assembly of waveguides and circulators for zone 4 is in progress.  Final positioning of the HPA rack and the Cathode Power Supply is scheduled for next week.

Assembly of the HPA rack for zone 4 is in progress in building 89.  The waveguides for this zone are being fabricated.

Progress reports from CPI on the 100 kW Klystron and AFT on the 100 kW Circulators were received.  They are both on schedule.  AFT has submitted a mechanical drawing of the circulator for review.  The Design Review of the 100 kW Klystron is scheduled for 8/29 at Jefferson Lab.

The specification for the High Voltage Power Supply for the 100 kW Klystrons is being modified and will be ready for issue next week.

The transmission line for the photo-cathode gun will be removed next week and carefully examined as a source of the HVPS arcs we have been experiencing.  The HV Stacks will also be examined and cleaned.

WBS 8  (I & C)

Installation is progressing for the User Lab Patch video and analog patch system, all of the mini-racks are installed under the cable tray and the cable terminations are proceeding.

System Development for a "streaming video" feed from the Machine Video System to remote Viewers is proceeding, this will replace the "web cam" operated from the laser.jlab.org server. the old method was to digitize the black and white image
through the MaxVideo VME digitizer and pass the image (then jpg'd) to FELSRV then on to "laser". The path is now direct from a PC digitizer on a stand-alone PC (named cruncher) to "laser". This will greatly enhance the remote trouble shooting capabilities of the FEL.

Cable pulls and installation for User Networking (User LAN) is also proceeding.  This allows users to connect to an internal LAN in the FEL to remotely control the PCs they bring in for each individual experiment, additionally they are able to access email and the web.  A User LAN print server has also been setup for the B/W & color laser printers.

Discussions are continuing with the HPEE group on the best solutions to the upgrades new DC power requirements.

WBS 9 (Transport)

We continued layout of the GX Prototype, starting laying the final detail, which will act as a basis for the detail drawings.  We still need to solve field clamp mounting and the electrical cover.  We continued to process variations of the 3D magnetic model of the GX dipole (22 hours per run) and concentrated on interpreting the data by generating plots of core field and uniform gradient of
the field integral through good field region.
The report of the Technical Evaluation Team is nearly complete for the engineering services contract.  Overall layouts concentrated on integrating the BPMs with the existing inventory of corrector dipoles.  The assembly drawing defining the regions of the machine was signed off.

WBS 10 (Wiggler)

Optical Klystron (WBS 10.2)
Coils have been installed on the four cores of the Northrop Grumman Wiggler and hose fabrication has started.  We started detail design of the cooling water manifold.
Dispersion Section
Details of all parts are being signed.  Because of interest in duplicating our dispersion section by other labs we will send the dispersion section to outside fabrication.  This will yield a better price at higher quantities as well as eliminate tie up of our shop personnel.

WBS 11 (Optics)

The preliminary design report on the thermal modelling of the R5 cavity mirrors completed by AES, Inc., was forwarded to
J. Albertine for his review.


The only operations for the week was noted in the Highlights section.

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