E-rhic-ir-l mailing list

[Bill Christie <christie AT bnl.gov>]

Dear All,
    Below please find the minutes from the eRHIC IR Design mtg that was 
held on 9/22/17.
    Greetings,
        Bill

    eRHIC Design mtg. Date September 22, 2017.
   -------------------------------------------------------------
* We started with a brief discussion regarding the idea to consider a 3 
mr rotation of the IR configuration relative to the collider system. The 
conclusion was that it had been decided not to pursue this change/idea 
at this time.

* We discussed a bit the actions that Bob had taken after our last 
meeting, suggesting that perhaps we were not optimizing the design for 
the EIC physics program. Consensus that this was not needed nor helpful.

* We went through a presentation that had been put together by Holger.
    - Resulted from meetings that Bob, Holger, and Alexander had had 
over the previous few weeks.
    - Holger showed a slight design modification to the Septum magnet 
design that increased the the phi acceptance from ~ 180 to ~270 degrees.
    - The redesign changes/reduces the magnetic field quality 
considerably.
    - Bob and Alexander did/had expressed their opinions that they were 
Ok with this decrease in field quality.
    - Bill points out that Elke would be the right person to make this 
judgement.
    - In answer to a question that had come up in the previous meeting, 
concerning whether the mechanical tolerances required for the Septum 
magnet posed a challenge, Holger indicated that for both the original 
and modified Septum design their is no concern/issue with achieving the 
needed tolerances.
    - Stated that the original "straight" septum design could be 
upgraded to give the ~270 degree acceptance at any future time.
    - Restatement, that the baseline design will be the 
original/straight Septum magnet design.
        - further stated that the baseline is for it to be a normal 
(i.e. not superconducting) magnet design.

* Lattice Matching Update:
    - Still working on the geometry/coordinate system setup.
    - Guillaume brought up a discussion dealing with the Beta* in the 
IR design, ~ 2 cm. Question whether anyone had thought about the Beta 
wave issue.
        - This lead to a fairly length discussion with a lot of back 
and forth about how one could/should approach this linear optics isssue.
            - Summary at the end of this discussion was that the linear 
optics calculations would get started, and that there was agreement on 
the procedure.

    Agenda for the next (10/6) meeting:
    - Update from Guillaume on the linear Optics
    - Updates from Alexander and Holger on the xfer of the geometry for 
the simulations setup.
            END OF MEETING.