Minutes of the IR FEL Beam Transport Meeting, June 27, 1996

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

ATTENDEES: S. Benson, G. Biallas, D. Douglas, E. Feldl, G. Krafft, C. Murray, M. Wiseman

Decisions/Comments:

M. Wiseman will chair the meeting on July 11 when G. Biallas is on vacation.

D. Douglas reports that some changes to the injector line were necessary. The faces on the large injection chicane dipoles had to change and the Injector line moved by about one and a half inches. This will be incorporated in version 7 of the layout. C. Murray has a copy of the DIMAD correction.

The official energy of the DIMAD will be 42 MeV kinetic and therefore actually 42.5 MeV accounting for the relativistic mass increase in the electrons. The DIMAD deck has to be corrected for this change. Similarly, the upgrade energy will be 74 MeV kinetic and 75 MeV with relativistic correction.

D. Douglas reports that roll tolerances for the dipoles are 1 mradian just like the NP Accelerator.

Report from the vacuum meeting:

Dillon-Townes/Murray - Continuing to define all the transport discontinuities for B. Yunn's impedance/ion trapping analysis.

A valve was placed at the end of the optical chicane

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.

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.

D. Douglas - Check if the existing QJs can be used in the new injection line and publish the injection line. No action

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

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

G. Biallas - 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. M. iseman to appoint an engineer.

L. Harwood - Determine if placing additional dipole(s) or temporarily substituting a stronger dipole at the first dipole of the dump chicane after the cryomodule is the best method of bending pulsed 42 MeV beam into the dump during cryomodule phasing. No action. Prototype Reverse bend Dipole could be supported with existing power supplies. Commissioning using this procedure appears to be viable.

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. Bids for the prototype dipole are due today .

C. Bohn - Have B. Yunn establish the vacuum specification for the remainder of the vacuum system using the criteria of ion trapping. No news

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

C. Bohn - Have B. Yunn examine the impedance effects of a 4 inch wide pipe in the optical chicane area. Cross sections provided,; first glance appears that there is no problem.

E. Feldl - Construct and test a Prototype Sparse Lamination Quad. Damaged board in the Magnet Measurement Stand is repaired. Start of measurements is 3 weeks away.

M. Wiseman - Thermal analysis of the 45 MeV Dump for 30 kW & beam scraper analysis for 45, 79 and 200 MeV. P. Kloeppel starting.

New Action Items :

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



New Action Items for the Vacuum Meeting:

L. Dillon-Townes - Assess the pumping and power supplies required near the dumps in order to maintain the vacuum at the beam line at the 10-8 level.

L. Dillon-Townes - Propose how we do differential pumping.

Here is the brief summary of the vacuum meeting held 6-26-96:

Dillon-Townes/Parkinson/Murray - Defined the vacuum level regions (currently proposed) for the machine and defined bake out regions. Strawperson vacuum specification being generated.

Dillon-Townes/Murray - Continuing to define all the transport discontinuities for B. Yunn's impedance/ion trapping analysis.

B. Yunn's study of the proposed 4" chicane chambers indicate no significant change in impedance from the 6" chambers.

E. Feldl - Chicane OTR will be studied for design. Beam width is needed at this location. Feldl will see Douglas for the specifics of the beam.

Biallas - Reported input from diagnostics meeting:

- Optical cavity drive motor should be fliped 180 degrees to avoid interference.

- One girder is required for the optical cavity to maintain 50 micron accuracy between mirrors.

E. Feldl - Wiggler OTR to be discussed with S. Benson for design parameters.

New Injector DIMAD issued. New layout will be revision "7".

Beam Scrapers - Scrapers may be proposed. Wiseman & Bohn to propose rough element configuration to be given to B. Yunn fopr impedance study.

Electrostatic Precipitators - Current thinking is that the precipitators will be needed. Location and configuration needs to be nailed down. Dillon-Townes will follow-up.

New Action Items from the Diagnostics/Commissioning Meeting:

None

Completed Action Items:

W. Merz - Determine from the actual response of power supplies with respect to jitter, short term drift and long term drift. Analysis written. Complete.

G. Neil - Find out if the mirror mounts can fit and function within proximity of the optical chicane dipoles. Yes, Complete.