sPHENIX cold QCD topical group

[Ralf Seidl <rseidl AT rcf.rhic.bnl.gov>]

Dear Itaru, all,

I had sent Jamie a list of relevant PHENIX ANs at the begin of the run 
when we started discussing the Vernier scans. I cannot share the notes 
here, but many people can obtain them directly. If someone does not have 
access to the PHENIX pages, please contact me as we can now share PHENIX 
notes on a case by case level upon PHENIX Spokesperson approval.

    AN688 ( 200_62GeV)
    AN888 (500GeV)
    AN597 (62GeV)

Generally, I agree with Sasha on the triggers. From my recollection we 
required a fixed number of events rather than a fixed time in the later 
Vernier scans due to the significantly lower rates at large 
displacements. The 5 minute scans are more like the short scans that 
Angelika often does for CAD at the end of fills while we preferred to 
have more data.

Cheers,

Ralf

On 2024-07-10 12:52, Aidala, Christine wrote:
> Dear Itaru and all,
>
> I quickly tried looking for explicit instructions on how to take the
> Vernier scan data from PHENIX days, but I couldn't find them, either.
> In case it is helpful, I did find a 2005 "PHENIX Focus" didactic talk
> by Dave Kawall on how to measure absolute luminosity at RHIC.
>
> Christine
>
> --
> Christine A. Aidala
> Professor, Department of Physics 
> University of Michigan
>
> -----Original Message-----
> From: sphenix-cold-qcd-l-request AT lists.bnl.gov
> <sphenix-cold-qcd-l-request AT lists.bnl.gov> On Behalf Of Alexander
> Bazilevsky
> Sent: Tuesday, July 9, 2024 8:50 PM
> To: sphenix-cold-qcd-l AT lists.bnl.gov
> Subject: Re: [[Sphenix-cold-qcd-l] ] Vernier Scan Instruction
>
> Hi Itaru ans All,
>
> Some correction to my proposal.
> After looking more careful in the vernier scan analyses we did in the
> past, I found that the vertex distribution evolution vs different beam
> displacements was studied with ZDC triggers (as its efficiency is not
> z-dependent, unlike BBC/MBD which is z-dependent), so we'd better
> increase the collected statistics for ZDC-Coincidence. So, my
> corrected proposal for scaledowns:
>
> CLOCK: 10k
> MBD N&S >= 1: 10
> ZDC Coincidence: 0
>
> (actually almost the same as we run it in PHENIX)
>
> and if we can afford collecting also single-side triggers (just in 
> case):
>
> ZDC-North and ZDC-South: 100
> MBD S >= 1 and MBD N >= 1: 500
>
> Regards,
> Sasha.
>
> On 7/9/24 9:51 AM, Alexander Bazilevsky wrote:
> > Thanks, Itaru, for compiling the info!
> >
> > Besides the scaler (GL1P) data, we also need event data: as a maximal
> > set - for all triggers included in GL1P, and as a minimal set - for
> > MBD coincidence trigger and CLOCK (e.g. to study vertex distribution
> > at each beam position to understand the hour glass effect).
> >
> > Since during the vernier scan run our rates vary by a few orders of
> > magnitude, we can not set up reasonable trigger scaledowns which would
> > provide both good life time and good DAQ rate at each step. Therefore
> > we used to release the scaledowns for triggers we collect to saturate
> > the DAQ rate regardless the life time (with the goal to collect as
> > many as possible of triggers we want).
> >
> > So, I suggest the following scale downs:
> >
> > CLOCK: 10k
> > MBD N&S >= 1: 0
> > ZDC Coincidence: 0
> >
> > Not sure how useful could be the one-side trigger data, but if we can
> > afford enabling them, I'd suggest the scaledowns:
> > ZDC-North and ZDC-South: 10
> > MBD S >= 1 and MBD N >= 1: 50
> >
> > In this configuration, the major bandwidth will be occupied by CLOCK
> > and MBD N&S, and only a few % for all other triggers (not necessary,
> > but may be useful).
> >
> > Regards,
> > Sasha.
> >
> >
> >
> > On 7/9/24 5:01 AM, Itaru Nakagawa wrote:
> > > Dear Sasha and Ralf,
> > >
> > >  Here is the draft instruction for the vernier scan. Unfortunately I
> > > cannot find any instruction of the data taking in PHENIX, but here is
> > > what I think is the procedure. Please have a look and send me 
> > > feedback.
> > >
> > > Best regards,
> > >
> > > -itaru
>
> --
> Alexander Bazilevsky
> Brookhaven National Laboratory, Bldg. 510D, 2-232 Upton, NY 11973 Tel:
> 631-344-3712
> Email: shura AT bnl.gov
> -------------------------------------------------