E-rhic-ir-l mailing list

["Ptitsyn, Vadim" <vadimp AT bnl.gov>]

Hi, Scott.

 

For the #1 issue (41 GeV polarization): the location of upstream rotator needs to be adjusted ~3-10 mrad (the exact number still needs to be evaluated).

For the #2 issue (spin tune shift): to avoid completely the spin tune shift during the rotator turn on one should have the opposite bending angles between IR and spin rotators (so that the total bending angle between the rotators is 0).

 

 

With best regards,

                                      Vadim Ptitsyn

                                      Electron-Ion Collider Project

                                      Brookhaven National Laboratory

 

 

 

 

From: Berg, J Scott <jsberg AT bnl.gov>
Date: Friday, February 19, 2021 at 9:32 AM
To: Ptitsyn, Vadim <vadimp AT bnl.gov>, e-rhic-ir-l AT lists.bnl.gov <e-rhic-ir-l AT lists.bnl.gov>
Subject: RE: EIC IR Maturity Conversation @ the IR Meeting

Hi Vadim,

 

What are the desired changes in the spin rotator locations (presumably you're talking about geometric angle here)?

 

-Scott

 

From: E-rhic-ir-l <e-rhic-ir-l-bounces AT lists.bnl.gov> On Behalf Of Ptitsyn, Vadim via E-rhic-ir-l
Sent: Friday, February 19, 2021 9:25 AM
To: Witte, Holger <hwitte AT bnl.gov>; e-rhic-ir-l AT lists.bnl.gov; Huang, Haixin <huanghai AT bnl.gov>
Subject: Re: [E-rhic-ir-l] EIC IR Maturity Conversation @ the IR Meeting

 

Dear Holger,

 

These are two issues we still have to resolve on part of hadron spin rotators in the IR:

 

1. With present spin rotator locations the proton longitudinal polarization at 41 GeV can not be achieved. Possible remedies: use spin transparency optics (with a special Snake arrangement to create longitudinal polarization at 41 GeV) or modify (slightly) the rotator’s locations.

 

2. Spin tune shift when turning on spin rotators at the store still needs to be evaluated. But with present rotator locations it is expected to be significant. Possible remedies: run always simultaneously the spin rotators at IR6 and IR8 (even if we do not have an experiment at IR8) or modify (significantly) the rotator’s locations.

 

Hadron polarization team (led by Haixin) is working on these issues.

 

 

With best regards,

                                      Vadim Ptitsyn

                                      Electron-Ion Collider Project

                                      Brookhaven National Laboratory

 

 

 

 

 

From: E-rhic-ir-l <e-rhic-ir-l-bounces AT lists.bnl.gov> on behalf of Witte, Holger via E-rhic-ir-l <e-rhic-ir-l AT lists.bnl.gov>
Date: Friday, February 19, 2021 at 8:55 AM
To: e-rhic-ir-l AT lists.bnl.gov <e-rhic-ir-l AT lists.bnl.gov>
Subject: [E-rhic-ir-l] EIC IR Maturity Conversation @ the IR Meeting

Dear all,

Please remember to send me your two sentences regarding the IR maturity in your area by lunchtime today - thank you!

Best wishes,

Holger


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