E-rhic-ir-l mailing list

[Aschenauer Elke-Caroline <elke AT bnl.gov>]

All,

a couple of points 

- the solution to have split runs between HA and HD to cover the full range of pt will work, but is of course operations wise  an expensive solution

- I mention again it is important to have enough size transverse and longitudinal to have a ZDC which can measure the energy of neutron so we can   

  reconstruct t (pt) for the neutron similarly well as for the protons if we do DVCS on neutrons.

  As there a no free neutron beams / targets this neutrons sit in Deuterium or He-3 beams and therefore we need to also tag the spectator protons, again the

  angle is not a problem the issue is the longitudinal momentum, which my plots which I sent around last week are smeared significantly due to the fermi 

  motion

- the other issue is we focus on the protons, but what is about eA running do all the things work? Do we have the neutron acceptance we need.

-  and last but not least do we have a concept how to integrate the luminosity monitor. This is super important because a high precision luminosity 

   measurement is absolutely critical for EIC, both for ep and eA and especially for polarized running.

elke

On Sep 24, 2017, at 22:12, Palmer, Robert <palmer AT bnl.gov> wrote:

Alexander

I should have explained why I gave you both HA and HD files. In the attached figures, the dash lines are the 1.3 GeV/c pt beam size for HA and the dots are for HD. These are much wider for HA than for HD. You have to do some running with HA for the low pt acceptance, but if you only ran with HA (despite its lower luminosity) you see that the 1.3 GeV acceptance is clipped in B2 and wildly overlaps the neutron detector. Itwould also require a very wide spread for the Roman pots. So there is another reason to split runs between HA and HD to cover the full range of pt.

Bob
<rnnp33k2.eps><dnnp33k2.eps>

 ( `,_' )+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=

  )    `\                                                     -

 /    '. |                                                     +

 |       `,              Elke-Caroline Aschenauer               =

  \,_  `-/                                                       -

  ,&&&&&V         Brookhaven National Lab                         +

 ,&&&&&&&&:       Physics Dept.,            25 Corona Road         =

,&&&&&&&&&&;      Bldg. 510 /2-195          Rocky Point, NY,        -

|  |&&&&&&&;\     20 Pennsylvania Avenue                 11778       +

|  |       :_) _  Upton, NY 11973                                     =

|  |       ;--' | Tel.:  001-631-344-4769   Tel.:  001-631-569-4290    -

'--'   `-.--.   |                           Cell:  001-757-256-5224     +

   \_    |  |---'                                                        =

     `-._\__/     Mail: elke AT bnl.gov        elke.caroline AT me.com          -

            =-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=