E-rhic-ir-l mailing list

[Bill Christie <christie AT bnl.gov>]

Dear All,
    Below please find the minutes from our eRHIC IR Design meeting that 
was held on Friday, 2/16/2018. Please note that our next meeting will be 
on Friday March 2nd.
    Greetings,
        Bill

    Minutes from the eRHIC IR Design meeting held on 2/16/18
-------------------------------------------------------------------------------
* We started with a review, and agreement of/on the Agenda:
    - "Final pCDR" Presentation of Tables
    - Update on Simulations
    - Update from Charles on the Vacuum design
    - Update from Alexei on Impedance calculations
    - AOB

* Discussion of "Final pCDR" Tables:
    - Bill starts with a summary of what the plan had been to arrive at 
these final tables
    - Christoph points out that the Tables Bob sent out have some errors
    - Elke restated the need for these final tables to allow the 
physics simulation effort to proceed
    - This led to a discussion of the need to identify a person to take 
over the responsibility for compiling and taking care of change control 
for these final pCDR beam and magnet parameter tables.
        - Discussion of who this person may be. Various candidates 
briefly discussed, and current conflicting tasks brought up. Settled on 
an agreement that, for the near term (~ 1 month period) this 
responsibility to compile the final tables would be a shared 
responsibility taken by Brett, Guillaume, Steve, and Holger. They'll get 
input from Bob on compiling these tables. The longer term plan (order of 
a month or so) is that this responsibility will be taken by Brett, who 
will be responsible for the IR layout and configuration.
    - Elke and Charles will come up with a document/e-mail detailing 
the information that they need, including magnet design geometry, so 
that the simulation and vacuum efforts can progress. Expectation is that 
this detailed request will be sent out by Monday Feb. 19th.

* Simulation Update by Elke:
    - Alexander is gone for the next week.
    - Waiting for the "Final pCDR" tables, and then ready to get going.
    - Vadim comments that we need to check once this "Final pCDR" 
configuration is available that the IR layout fits geometrically in the 
collider tunnel.
    - Elke reminds us that another item that needs to be checked "at 
one moment (not pCDR)" the effect of the detector solenoidal magnet 
field on the Spin progression of the beam needs to be looked at.

* Vacuum Update by Charles: file eRHIC-2-16-18.pdf
    - Slide #1 shows layout of the detector vacuum pipe up to gate 
valves on either end just prior to first accelerator magnets. Comments 
that there is a "beam shield (Faraday cage)" that surrounds the electron 
beam.
    - Slide #2 shows detail of the design at the two ends of the 
detector vacuum pipe.
    - Slide #3 list some of the detailed parameters for the current 
design. Charles comments that the ipe is circular at the center of the 
detector region, and then transitions to rectangular on the downstream 
electron going end.
    - Slide #4 shows calculations of the synchrotron fan. Input to this 
simulation are the magnet locations and parameters that he has. I 
believe that he stated that the beams were going on the axis of the 
magnets in the present simulations. This effort will be repeated when 
the "Final pCDR" tables are available. He confirms, in response to a 
quston by Christoph that there are no masks in the current configuration 
that is simulated in what is shown.
    - Elke and Charles met with Mike Mapes yesterday. Mike is working 
on costing the vacuum pipes and chambers. the two costing/configuration 
efforts (Mike and Charles (and Elke?)) will be consolidated into one 
estimate.

* Impedance Update by Alexei: I don't have a copy of presentation shown.
    - Slide #1 Alexei explains that to get the impedance code running 
with a finite CPU time requirement he "compacted" the geometry for the 
vacuum pipe/chamber. Shows impedance value vs position along the beam line.
    - Slide #2, shows resonances in the response. States that there is 
clearly optimization still to be done in the design of the vacuum 
pipe/chamber. Further studies required.
    - Alexei has some ideas on how to optimize the design. He will 
iterate with Charles on this.
    - Discussion between Alexei and Brett on some feedback and guidance 
Brett would like to get on such things as heating from the impedance 
calculations. Just one example.

* Discussion on date for next meeting. Agreement that it should be in 
two weeks, which means next meeting will be on Friday March 2nd.
    - Draft Agenda for next meeting:
        - "Final pCDR" Tables
        - Simulation update
        - Vacuum Update
        - Impedance update
        - Introduction to discussions concerning the topic of how to 
deal with ion beams
        - AOB

    Greetings,
        Bill

Attachment: eRHIC 2-16-18 discussion.pdf
Description: Adobe PDF document