Minutes of the IR FEL Beam Transport Meeting, July 18, 1996

Meetings are held in Room 84, Trailer City on Thursday at 1:30 P.M.

ATTENDEES: S. Benson, G. Biallas, C. Bohn, L. Dillon-Townes, K. Jordan, G. Krafft, R. Legg, C. Murray, G. Neil, M. Wiseman

Decisions/Comments:

A schedule of the Beam Transport design activity was included in the Minutes. It will be touched on at each meeting Principles are urged to have schedule information about their assigned items at the meeting.

We again discussed the locations of the beam scrappers. The preferred locations are: 1) the beam pipe after the first dipole in the optical chicane and one half wavelength away in the straight section following the optical chicane. C. Murray is to put place holders in those positions that include ion pumps to take the increased vacuum loading.

D. Douglas reports that the beam spot from a reversed polarity injection chicane dipole would be an unacceptable 5 cm. wide. He recommends reverting to the old scheme of putting an additional injection chicane dipole into the dump line to get the beam line away from the cryomodule.

Electrostatic precipitator after the cryomodule was placed in a corrector dipole's position and the air core dipole was superimposed over a BPM.

G. Biallas appealed for formed bellows over welded bellows. They are much less expensive and trap fewer particulates. The small gaps between convolutions can be minimized by using formed bellows that have been "crushed down". Gardner Bellows in California and Cal-Flex in France make such bellows.

The Magnet design review was put off to the start of September when L. Harwood will have a good idea of the design of the dipoles for low field. The vacuum review was put off to two weeks later than the magnet review.

Action Items:

L. Dillon-Townes/C. Murray/B. Yunn - Maintain latest layout/ define the vacuum tube at all discontinuities, refine impedance analyses and write the Tech. Note. Definition of discontinuities half finished and the list is about complete. C. Murray is to get the graphical descriptions of the beam pipes to B. Yunn on a piecemeal basis. The DIMAD for the injector was generated by D. Douglas and passed to B. Dillon-Townes for distribution.

G. Biallas - Get the BT contracts signed. Contracts needed to be changed to new DIMAD configuration. No action.

A. Guerra - Start definition of a girder for the wiggler, diagnostics and quad telescopes that maintains position of the elements within 50 µm (0.002 in.) during change-out of the wiggler. No news.

R. Legg - Determine what is the best method of bending pulsed beam into the dump during cryomodule phasing. The belief of most of the group is that the ability to bend to the dump is needed full time rather than just commissioning. K. Jordan argues that the MO will be considerably more stable in this machine and therefore phasing will only be needed once. No resolution yet.

G. Biallas/L. Harwood - Provide a good value for field enhancement factor for the style of magnets we are anticipating. Verify the K value of 0.45 that D. Douglas uses in his optics calculations. The Prototype dipole is awarded to New England Technicoil for the coils and Master Machine for the core. It should be delivered in three weeks. L. Harwood will use it as a test bed to try out the ideas on reducing the effects of low field operation rather than make a prototype injector dipole.

G. Biallas - Examine the categories on the Web and propose alterations. No action.

J. Karn - Test a Prototype Sparse Lamination Quad. Magnet measurement stand now operational. Quad may be tested next week.

M. Wiseman - Thermal analysis of the 45 MeV Dump for 30 kW & beam scraper analysis for 45, 79 and 200 MeV. P. Kloeppel has finished 50 MeV and 200 MeV EGS runs. Thermal design has started.

R. Legg - Check D. Douglas' numbers on the new DIMAD. Started

New Action Items :

C. Bohn - Determine the position of the beam scrapers by September 18.

New Action Items for the Vacuum Meeting:

None

Summary of Minutes from July 17, 1996 Vacuum Meeting

New Action Items from the Diagnostics/Commissioning Meeting:

None

Completed Action Items:

C. Bohn - Establish a clean statement of the energy range of the machine. Authorization for nominal upgrade 75 MeV dipoles (Actual design point 79 MeV) was given by M7. F. Dylla to present recommended plans for upgrade to the M7 on Monday. Complete.

D. Douglas - Check if the existing QJs can be used in the new injection line and publish the injection line. Complete. D. Douglas reports that the QJs are fine for the injector.

C. Bohn - Have B. Yunn establish the vacuum specification for the remainder of the vacuum system using the criteria of ion trapping. Complete. The vacuum specs of 10 -9 Torr for the pipe near the cryomodule and for 10 -8 for everywhere else are fine.

C. Bohn - Have B. Yunn examine the impedance effects of a 4 inch wide pipe in the optical chicane area. Complete. Report from B. Yunn that the 4 inch pipe in the optical chicane is OK.

T. Siggins/K. Jordan - Review proposed Shielded Viewers for vacuum construction properties. T. Siggins reviewing the drawings. Complete.