FEL Upgrade Project Weekly Brief
January 16-19, 2001



This week  (Jan.18-19) we hosted the Laser Processing Consortium/FEL User's Workshop.  Over 75 attendees from the LPC, present and potential FEL users attended the workshop.  All seemed to enjoy the reports about FEL results to date and the progress on the upgrade projects.


We prepared for this week's presentations at the LPC Workshop, next week's presentation at the Defense Science Board (Jan. 25).  The project financial reports for December 2000 were reviewed for the preparation of the December monthly report. As of the end of the 2000, the project is 26% complete. We are slightly ahead of schedule (+2%) and slightly behind cost (-1%) relative to the project plan.

WBS 4 (Injector):

Reviewed the internal cesiation and shielding design and decided to keep looking at slightly different  scenarios. Reviewed the new gun chamber concept which moves the solenoid closer to the anode and uses increased pumping through appendage
pumps. We decided to move the concept forward into design.

WBS 5 (SRF):

End Can Technical Review Committee has selected a vendor and award notification is being prepared.

WBS 8 (I&C):

We ccontinued check-out of the new optical beam position monitors in preparation for the start of the user run next week.

WBS 9 (Transport):

Injector Dipoles (DU/DV)
o DULY Research continues to model the small dipole with the aim of achieving quality field over the good field
   region.  They are also starting to layout the new simplified coils.
Optical Chicane Dipole (DW)
o We continued to detailing of this magnet with a small correction to the 3D model to bring it up to the latest
    requirements of David Douglas from the Version 1.1 of the lattice.
Arc Dipoles (GY, GX, GQ)
o We decided that the preliminary way to define the path length corrector dipole for the GY dipole is to have it
    produce a full wavelength of path length correction at 80 MeV, the low end of the operating range of the magnets
    (High is 210 MeV).  This way, we will be able to know where the real ideal path is at low energy and will be able
    to move the dipoles to correct the path length for the high energy cases if the correctors are not strong enough.  As
    designed, the correctors are robust and we may have to add 2 inches to the pole pieces locally in order  to
    accommodate their added field in the iron path when the magnet is run at full field.
o We designed the coil for the path length corrector and transmitted the sketches to AES to incorporate in the designs.
o AES did a number of layout sketches on the 180° dipole in order to start looking at its configuration.
o Robin Wines was able to optimize the position of the edge of the silicone steel (high field replacement for the mu
    metal we used for low field magnets.  She found the flattest field was obtained with an edge 1/3 into the coil bundle.

QX (3.125" Quad) Magnets
Measurement Probe: The tube support was annealed and sent back for final machining.
Trim Quad
A first draft design has been modeled in Tosca-2D.  The required amp-turns put this magnet beyond J-Lab trim card abilities.
Design efforts will continue, assuming a 20A maximum current.  In parallel, T. Hiatt will research the feasibility of building an
asymmetric iron pole quad.
Sextupole with Octupole & H/V Correctors
o We decided to start with an engineering design on the coil needed to produce the required field using the conductor
    used on the GS dipole.
o We then may change current densities in appropriate coils to produce the required amount of:  octupole field,
    vertical corrector field, horizontal corrector field.
o Determine if trim coils with the required amp-turns can be added to the poles to produce the above fields.  If not,
   pursue powering each of the 6 coils with separate power supplies.  Model the effects of non-uniform powering
   errors on sextupole field quality.
Conventional H/V Correctors
o With the aim of utilizing our existing stock of correctors and adding a few more, we decided to formally verify the
   inventory and the fit-up of the existing coils on the new BPMs and then order the needed coils per existing drawings.
Vacuum System
o We continued our discussion of beam chamber dimensions in the arcs and optical chicane.  Since beam impedance
   has become a heightened issue, we will have to check our intended chamber design with the beam physicists.

WBS 10 (Wiggler):

Wiggler Dispersion Dipole (GS) Fabrication is on going.  Coil delivery to PECO is anticipated next week.
Wiggler: Magnetic Measurements:  C. Hutton has started on a rail design for Hall Probe measurements.
Assembly of the thermal switches, buss bars, will be finished early next week.

WBS 11 (Optics):

The prints for the fabricated internal components of the mirror test stand were released for construction, and are out for bid.  We have received one set of bids on the deformable high reflecting mirror design, and are awaiting at least one more before making an award.  The first bid estimate is in line with our expectations.  Design of the optical cavity assemblies progresses.  We have begun the layout of the optical transport system.


We completed hot check-out of the FEL this week in preparation for the start-up of the winter user run next week.  Also during the machine check-out we completed a series a measurements requested by the Radiation Control group to check FEL building shielding calculations.  The results of these measurements will let the plans proceed for eventual operation of the Helios injector with impact on FEL operations and vice versa.

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