E-rhic-ir-l mailing list

["Christie, William" <christie AT bnl.gov>]

Dear All,
          Below please find the minutes from our eRHIC IR Design meeting that was held on Friday, 2/8/2019. Please note that it was decided that our next meeting will be Friday, February 22nd, starting at 2:30 pm.
          Greetings,
              Bill

        Minutes from the eRHIC IR Design meeting held on 2/8/19
       ---------------------------------------------------------------------------------
* We started with a brief discussion of the agenda for the meeting.
 - Draft Agenda:
    - Update by Steve T. on matching into the electron ring.
    - An update on Holger's magnet studies/simulations
    - Any updates on Dave's list
    - A presentation by Quong on the format and information needed in the draft Change Control form.
    - Update/decision on spin rotator locations
    - AOB

* Before we got started Elke introduced Anna Sofia Nunez, who is a new Post Doc in her group, and will be joining the IR Design effort.
	- Welcome to Anna

* Steve T. reports that he is still working on the electron matching effort. He'll report at the next meeting.

* Holger reports that he doesn't have an update at this time. Still working on it.

* At this point Brett joined us via the phone. Bill read through the E-mail that Brett had sent to the eRHIC IR mailing list.  

   - Brett had sent an E-mail to most/all of the people on the eRHIC IR Design effort. Due to his difficulty speaking, Bill 
read the E-mail to the group. The text is here:

Bob thank you for your concern; I will do my best to get well.

At this point I don't anticipate dialing into the IR meeting which will start in a few 
minutes. Note the trouble I am having is with my voice and not my mind 
so I am writing this email so that it will be very clear what my wishes are for today's meeting.

 And at today's meeting Guillaume will present the work he has so far on the forward IR design 
with interleaved magnets for the forward side (essentially falling back to something similar to the present preCDR).
 It is my considered judgement at this time that this approach gives us 
our most direct path forward to achieve design closure in time to have a new baseline update for June.

 Note while I appreciate that Holger will use, because of lack of time to do anything else, some
 cleaned up version of your forward side-by-side for the April cost review, the forward side-by-side layout is not
 the option I want Guillaume and others to pursue at this time based upon objections I have previously stated.

 So for today's meeting I expect to "adopt," as much as we ever decide anything in these 
bi-weekly meetings, your new side-by-side layout for the rear side only and from this point forward we will concentrate
 on the process I have outlines in other emails for the forward side. I hope that you can work closely with Guillaume very 
closely according to this plan; however, I also don't want Guillaume to be distracted from performing his job (already challenging due
 to RHIC start up) by having to deal with a parallel forward side-by-side design effort. I hope this is now clear in case there had 
been any confusion as to my wishes. – Brett

* Guillaume's Update: 
   - Points out that he has been looking at matching at lower energies as well.
   - Idea is to take 100 GeV as the "baseline" for the matching. Of course all energies need to be accomodated.
   - Use fixed B0 angle, and then match using the magnets.
   - Discussion about the other forward Hadron line magnets (B1, B2, B3) were undetermined lengths. Looking to use existing RHIC
 magnets for these.
   - D5i to take B2B, spare D8 to use for B3
	- Note: Dx field is 3.6 T. D5i and D8 strengths note known in discussion.
   - Would have 33 meters of free space for the forward hadron crab cavity.
   - Rotator magnet between crab cavity and B2B
       - Leaves 11 m for the rotator magnet (on forward side).
  => Guillaume is now more optimistic about the prospects of matching to the hadron ring, as well as accommodating second IR.
   - Plans to use triplets and quads as well, to the extent possible.
   - Brett adds that the ability to make a closed bump is important to avoid problems propagating into the rings.
    - Better to center the beam in the quads.
   - Guillaume will give another update at the next meeting.

* Dave Gassner gives an update on progress with his list of questions:
   - Points out that he had a meeting with a few people this morning, and they have an agreement to meet again next week
to gather more input on questions/answers.
   - Discussion if more instrumentation will be needed to tune collisions
      - Conclusion that likely just the luminosity monitors will be sufficient.
      - Elke suggests the use of some main detector trigger detectors as well.
   - ?? and masks might get handed off to Charlie (Vacuum design).
   - Vadim brings up idea to put a place holder for correctors, sextupoles, etc. magnets.
   - Elke brings up a Synchrotron radiation detector. Do we need this? Asks who wrote this section of the pCDR.
      - Not clear.

* Qiong gives a presentation on the Change Control Process and format. 
    Files eRHICMeeting_DCC_012519.pptx & change-request-crossing-angle.doc attached.
   - Qiong walks us through the presentation and the Change Control process.
   - The baseline for changes is the pCDR from last year.
   - Qiong also walks us through the change control request draft submitted by Christoph for the crossing angle change from 22 to 25 mr.

* Bob walks us through updated slides on the IR design that he's been working on, detailing changes.
    File Bob_190208-IR.pdf attached.
   - Slide #1 lists changes.
   - Bob walks us through other selected slides.
   - Conclusion of the presentation and discussion is that Bob sees his next step as writing up all of the 
details of this current design.

* General discussion about the current (i.e. Bob's updated) IR design and associated magnets. The question is whether
 this design should be presented and costed for the upcoming eRHIC Cost review. Consensus of those present is yes.

* Next meeting in two weeks, on Friday February 22nd.
   - Draft Agenda:
      - Update from Steve on Electron ring matching
      - Update from Guillaume on hadron ring matching
      - Update on Dave's list of questions
      - Update from Bob on status of write up
      - Update from Qiong on the status of the 22 to 25 mr crossing angle Change Control process
      - AOB
		End of meeting

Attachment: eRHICMeeting_DCC_012519.pptx
Description: eRHICMeeting_DCC_012519.pptx

Attachment: change-request-crossing-angle.docx
Description: change-request-crossing-angle.docx

Attachment: Bob_190208-IR.pdf
Description: Bob_190208-IR.pdf