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[E-rhic-ir-l] Minutes from the eRHIC IR Design meeting held on January 25, 2019.

From: "Christie, William" <christie AT bnl.gov>
To: "e-rhic-ir-l AT lists.bnl.gov" <E-rhic-ir-l AT lists.bnl.gov>
Subject: [E-rhic-ir-l] Minutes from the eRHIC IR Design meeting held on January 25, 2019.
Date: Tue, 29 Jan 2019 22:27:35 +0000

Dear All,
Below please find the minutes from our eRHIC IR Design meeting that was held on Friday, 1/25/2019. Please note that it was decided that our next meeting will be Friday, February 8th, starting at 2:30 pm.
Greetings,
Bill

Minutes from the eRHIC IR Design meeting held on 1/25/19
---------------------------------------------------------------------------------
* We started with a brief discussion of the agenda for the meeting.
- IR Design Discussion, status on decisions to be made (3 vs 4 magnets, Q2pR length, beam angles)
- Steve T. on existence of a matching solution for electrons
- Update from Guillaume
- Update by Doug
- Discussion of the items on Dave Gassner's list of needed information/details
- AOB

* Discussion of IR Design decisions, as detailed in the previous meetings minutes (File: 190125-ir.pdf & .txt, attached):
- It has been decided (Bob, Brett, Holger, ..) that we'll go forward with the "three magnet" design (as opposed to "four magnet" design).
- The idea is to take this as the default design until/unless something arises that prevents this from being possible.
- Bob walks us through the slides that he'd mailed to the IR Design mailing list (attached)
- Started with Slide #14, Conclusions & List of the only significant changes since December 14, 2018:
- Bottom line on slide, conclude that these parameters and choices have settled so that only issues that may arise in matching this design into the electron and Hadron rings, as well as integration into the tunnel, would lead to any significant changes.
- Slide #5, shows table with list of parameters.
- Decision on the length of Q2pR has been made, and is in the table.
- End of discussion/presentation.

* Presentation by Stephen Tepikian (File palmers-ir-2018-12-14.pdf, attached):
- Slide #1, the horizontal scale is distance, with the IP location arbitrarily set to be at 25 m.
- Slide #2, shows the changes in the magnet field strengths to get the necessary beta functions.
- Severe concern expressed by Holger that these field strengths can't be achieved for these magnets.
- Steve asks, if necessary, that Holger give him a maximum field strength
- Answer from Holger is 14 - 15 T/m. This is the upper limit. Anything higher would require major magnet redesign.
- In discussion it is recognized that Steve T. is working with the wrong IR Design parameters. Path forward is for Steve to redo this exercise with Bob's correct parameter set for the IR design. Q0eF magnet is not currently included in Bob's latest design.
- Christoph: Steve is trying to match the geometery. Is the dipole and solenoid angle "fixed"?
- Answer from Vadim, Dipole angles are fixed, due to choice to have perfect spin match at 18 GeV.
- End of discussion

* Guilllame's Update (file Guillaume-1-25-19.pdf, attached):
- Guilame explains that he did a study on the impact of the translation, and rotation, of the IR has on the effort to match the hadrons into the RHIC hadron rings.
- He looked at the translation of the ring at 0.5 m, and 1 m (Doug's default) inward. His conclusion is that, at least in this range, the translation of the IP inward doesn't have a bad/significant impact on the task of matching into the hadron ring.
- He looked at rotation angles of 19 and 17 mr at both of the translated IP points. N.B. that Doug's default rotation angle of the IR is 18 mr (angle of the hadron beam relative to the RHIC beamline). He comes to the same conclusion, that within this range of rotation angles the matching to the hadron ring is not significantly impacted.
- This means that there is some freedom here, at least for the hadron matching, very good.
- Guillamue makes the point that he needs to know the location of the spin rotator on the downstream sie of the IR (actually needs for both sides).
- This lead to some discussion about the length and locations for the spin rotators. The conclusion was that Vadim and Guillaume will discuss this offline.
- Currently Guillaume has matched the hadrons into the ring so that the beam is centered in the D6 and D8 dipoles.
- Question arises about the field strendth fo the RHIC Dx magnets, answer is 4.2 T.

* Quick update by Doug:
- Doug points out that he know has the new Trapazoidal Bypass configuration in his geometry drawings/model.
- In discussion, and based on Guillame's results, we will remain at this point with the translation and rotation parameters that Doug has in his Integration geometry (N.B. these parameters show up in the minutes from the Jan. 11th meeting)

* Dave Gassner's Discussion and request list
- Dave sent an E-mail, pasted in below, with a request for information to assist in refining the eRHIC cost estimate:

Hi Bill,
As we spoke about yesterday, there is a need for IR Instrumentation and Vacuum system parameters & specifications
 so the cost estimates can be updated and is defendable at the upcoming external review.  This include details
 about the following:
 Beam Position Monitors
 Beam Loss Monitors (tuning and machine protection
 Orbit feedback (maintain luminosity)
 Synchrotron Light Monitor (real-time beam size monitoring)
 Crabbing angle measurements - electrons (using synchrotron light) & hadrons (large-button BPM)
 Collimators
 Absorbers
 Masks
 Temperature Monitors - beam pipe & device 
 Neutron Detector (located about 28m from IP in the forward direction)
 Electron Trigger (Located about 30m from IP in the rear direction)
  Thank you,
       Dave
   - Goal is to get a defensible cost estimate.
   - For Beam position monitors, after a bit of discussion, it was suggested that a defendable estimate for
 the number of BPMs would be to assume one BPM for each Quad, in both beam lines.
   - For beam loss monitors the suggestion was that Dave contact Angelika for input.
   - A general proposal for how to proceed with giving Dave assistance in his quest for more information will be
for people to send him any ideas thy may have for his various questions, as well as to send him any suggestions on
who might be someone who can give him some assistance.

* Date and draft Agenda for next meeting:
  - Next meeting in two weeks, which means on February 8th, starting at the usual 2:30 pm.
  - 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
		End of meeting.

Attachment: 190125-ir.pdf
Description: 190125-ir.pdf

#
# -------------------------------------
# zpF3529d Hadron forward 275
#
# beta*_x beta*_y gm emit_x gm emit_y angle_x angle_y mom
# [m] [m] [nm] [nm] [mrad] [mrad] GeV/c
0.9000 0.0430 20.0000 6.1000 25 0 275
#
# name center_z center_x rad1 rad2 length angle B grad ap x
grad alphax betax alphay betay
# [m] [m] {m} [m] [m] [mrad] [T] [T/m]
[T] [m] [m]
B0pF 5.900 -0.0150 0.170 0.170 1.20 -25.0 -1.30 0.000
0.000 -6.553 39.574 -108.929 647.365
Q1ApF 7.730 0.0067 0.045 0.045 1.46 -3.2 0.00 -77.903
-0.035 -12.861 70.148 -75.814 1061.777
Q1BpF 9.565 0.0119 0.065 0.065 1.61 -10.0 0.00 -66.180
-0.043 -33.823 150.758 55.871 1092.779
Q2pF 13.170 0.0100 0.113 0.113 3.80 -9.5 0.00 37.327
0.042 -44.571 539.185 36.872 525.824
B1pF 17.070 0.0180 0.115 0.115 3.00 10.0 -4.57 0.000
0.000 -0.673 632.796 -1.954 469.936
B2apF 30.200 0.2710 0.040 0.040 1.20 17.0 3.30 0.000
0.000 -0.703 650.856 -2.088 523.004
#------------------------------------
#
# -------------------------------------
# zeF3519d Electron forward 18
#
# beta*_x beta*_y gm emit_x gm emit_y angle_x angle_y mom
# [m] [m] [nm] [nm] [mrad] [mrad] GeV/c
0.8300 0.0800 22.0000 3.3000 25 0 18
#
# name center_z center_x rad1 rad2 length angle B grad ap x
grad alphax betax alphay betay
# [m] [m] {m} [m] [m] [mrad] [T] [T/m]
[T] [m] [m]
Q0eF 5.900 0.0000 0.025 0.025 1.20 25.0 0.00 -13.540
-0.003 -13.160 46.051 -16.165 387.278
Q2BeF 9.565 0.0000 0.044 0.057 1.61 25.0 0.00 2.553
0.001 -41.727 292.544 19.130 194.024
Q2CeF 13.070 0.0000 0.068 0.068 3.60 25.0 0.00 3.043
0.002 1.213 499.042 -0.618 126.296
Q3eF 21.470 0.0000 0.030 0.030 1.20 25.0 0.00 -12.012
-0.004 8.026 54.079 22.255 358.648
Q4eF 30.600 0.0000 0.030 0.030 1.20 25.0 0.00 -13.860
-0.004 -2.807 28.137 -10.836 105.963
Q5eF 39.500 0.0000 0.050 0.050 1.20 25.0 0.00 4.023
0.002 -10.842 272.621 0.647 53.669
#------------------------------------
#
# -------------------------------------
# zpR35239d Hadron Rear 275
#
# beta*_x beta*_y gm emit_x gm emit_y angle_x angle_y mom
# [m] [m] [nm] [nm] [mrad] [mrad] GeV/c
0.9000 0.0430 20.0000 6.1000 25 0 275
#
# name center_z center_x rad1 rad2 length angle B grad ap x
grad alphax betax alphay betay
# [m] [m] {m} [m] [m] [mrad] [T] [T/m]
[T] [m] [m]
Q1ApR -6.200 0.0000 0.020 0.026 1.80 0.0 0.00 -84.150
-0.022 -10.408 46.563 -60.940 665.600
Q1BpR -8.300 0.0000 0.028 0.028 1.40 0.0 0.00 -84.150
-0.024 -29.993 123.074 32.917 737.069
Q2pR -12.750 0.0000 0.054 0.054 4.50 0.0 0.00 33.843
0.018 -40.819 594.541 22.648 275.049
#------------------------------------
#
# -------------------------------------
# zeR35239d Electron Rear 18
#
# beta*_x beta*_y gm emit_x gm emit_y angle_x angle_y mom
# [m] [m] [nm] [nm] [mrad] [mrad] GeV/c
0.8300 0.0800 22.0000 3.3000 25 0 18
#
# name center_z center_x rad1 rad2 length angle B grad ap x
grad alphax betax alphay betay
# [m] [m] {m} [m] [m] [mrad] [T] [T/m]
[T] [m] [m]
Q1eR -6.200 0.0000 0.066 0.079 1.80 25.0 0.00 -15.038
-0.012 -18.779 56.141 13.931 378.985
Q2eR -8.300 0.0000 0.083 0.094 1.40 25.0 0.00 14.290
0.013 -29.468 218.668 26.914 163.168
B2eR -12.250 0.0000 0.097 0.139 5.50 25.0 -0.20 0.000
0.000 4.641 205.234 2.663 124.969
Q3eR -31.600 0.3503 0.040 0.040 0.60 34.0 0.00 -6.000
-0.002 0.558 67.334 2.748 45.753
B3eR -34.800 0.3780 0.040 0.040 5.20 31.1 0.25 0.000
0.000 -1.427 75.497 2.826 24.207
#------------------------------------

Attachment: palmers-ir-2018-12-14.pdf
Description: palmers-ir-2018-12-14.pdf

Attachment: Guillaume-1-25-19.pdf
Description: Guillaume-1-25-19.pdf

[E-rhic-ir-l] Minutes from the eRHIC IR Design meeting held on January 25, 2019., Christie, William, 01/29/2019
- Re: [E-rhic-ir-l] Minutes from the eRHIC IR Design meeting held on January 25, 2019., Aschenauer Elke-Caroline, 01/30/2019
  - Re: [E-rhic-ir-l] Minutes from the eRHIC IR Design meeting held on January 25, 2019., Hetzel, Charles, 01/30/2019