[Brahms-l] Draft decision on light ion species]

A few days ago T.Kirk send out an expected request based on the desire from
CA-D to know
what lightt ion specie would be run this year. I send a brief note that the
draft BUP specifies Fe, but the final proposal would of course come in a few
days.

I enclose the response from Halman, also preliminary, but along the line of
what was shown at the RHIC retreat. Note the do request a short low-energy
run of a light specie at the end of a 10 week run.


flemming

----------------------------------------------------------------
Flemming Videbaek
Physics Department
Brookhaven National Laboratory

e-mail: videbaek@bnl.gov
phone: 631-344-4106

Sent: Wednesday, July 28, 2004 10:17 PM
Subject: Re: IMPORTANT - [Fwd: Draft decision on light ion species]


> Hello Tom.
>
> Speaking for STAR, our Beam Use Proposal
> is nearing the final approval stage within the
> Collaboration. I don't expect significant
> changes, but the comments below should
> be understood in that context.
>
> The STAR proposal is expected to be for an
> intermediate ion in the mass range of
> approximately A=60 (Cu, Fe, Co, Ni...), with the
> exact choice determined by C-AD based on
> what is optimal for the accelerator. STAR will
> propose running this at full energy, with a
> performance based goal of lowering the energy to
> 62.4 GeV for a short run (of order 1 week to 10 days)
> at the end as we did for AuAu if the full energy
> goals have been met. The lower energy run (if progress
> permits) is compelling from STAR's view, given the
> value of comparison data for a lighter species,
> the very low "overhead" demonstrated by C-AD in
> achieving this configuration, and the very high
> cost of coming back to this reduced energy intermediate
> ion configuration for a dedicated run later in the
> program. The integral time proposed for this part
> of the program will be 4+10 weeks.
>
> The remaining 3+11 weeks (31 weeks assumed overall)
> will be proposed for polarized proton running
> with the goal of accumulating > 7 pb**-1 for
> longitudinal proton studies, > 4 pb**-1 for transverse
> spin studies, and 20M min bias pp events for
> heavy ion comparison data.
>
> As a final remark, I would lobby that if there is
> not a clear consensus among the experiments, significant
> differences that may exist are worthy of presentation
> to/consideration by the PAC, unless this body no longer
> is intended to play a role.
>
>
> Regards,
>
> Tim
>
>
>
> Kirk, Tom wrote:
>
> >. July 27, 2004
> >Dear Mark, Tim, Flemming and Bill:
> >The message below reflects the desire of the C-AD
> >accelerator staff to have guidance ahead of time
> >on the intermediate ions to be collided in the
> >heavy ion segment of the FY 2005 data run.  Until I
> >received Thomas' note, I was not aware of the need
> >for this much ion-specific advance preparation.
> >Accordingly, I would like to ask each collaboration
> >to provide me with its best current assessment of
> >the ion species that it expects to request in the
> >BUP this year, along with a statement of the certainty
> >(or uncertainty) that you attach to your choice.
> >If I see sufficient uniformity in these responses,
> >I will make a decision and supply the C-AD with the
> >chosen ion.  If there is a lot of spread, I will
> >seek to engage the spokespersons in a dialog to
> >see if we can reach a consensus ahead of the PAC
> >Meeting.
> >May I have your comments by email on or before Friday,
> >August 13 as requested here?
> > Thanks, Tom
> >
> >
> >
> >
> > ------------------------------------------------------------------------
> >
> > Subject:
> > Draft decision on light ion species
> > From:
> > "Thomas Roser" <roser@bnl.gov>
> > Date:
> > Mon, 26 Jul 2004 17:21:13 -0400
> > To:
> > "Kirk, Tom" <tkirk@bnl.gov>
> >
> >
> > Tom,
> >
> > For the detailed preparation of the set-up of the RHIC injector and
> > RHIC itself, the required ion species of the upcoming RHIC run needs
> > to be known.
> >
> > The ion species will affect everything starting with the ion source,
> > the stripping efficiencies at up to four foil strippers, the
> > rigidities in the three transfer lines and the rigidities and
> > revolution frequencies in all accelerators. All these parameters are
> > developed in detail and optimized for best intensity and emittances
> > before the start-up of the accelerators and, if possible, tested. This
> > is a significant effort by many people and groups (pre-injector, rf,
> > controls,...) and would have to be done separately for the two
> > discussed species (Si and Cu). A draft decision by August 15, 2004,
> > which is still before the start-up of the pre-injector on August 23,
> > 2004, would avoid duplicating this effort.
> >
> > Thank you, Thomas
> >
> > PS: Here is an excerpt with regard to this topic from the RHIC 2004
> > retreat summary:
> >
> > "A concern that was unanimously voiced from the accelerators is that
> > the present timing of the decision process for the RHIC Physics runs
> > does not match the timeline for optimal machine planning . With the
> > schedules for RHIC and BUP’s listed above, a final decision for Run-5
> > would be taken only about 20 days before the start of cool-down,
> > presently planned for October 1st. Plans that are known months in
> > advance would optimize shutdown activity and run preparation by
> > prioritizing activities inherent with a specific operation mode.
> >
> > An example for Run-5 is the selection of a preferred light ion, which
> > impacts injector preparation and RHIC ramp planning. Another example
> > is the priority of low-energy collisions: if it is high, that would
> > raise the priority of work related to RHIC tuning speed and experiment
> > magnet polarity changes. In general, with limited budget and manpower
> > resources, RHIC run preparations must closely match the effective run
> > requirements.
> >
> > Moreover, it has become less important for BUP’s to wait for
> > conclusive experiment data analysis from the most recent run, since
> > more mature and reliable beam performance now provides more data than
> > can be fully analyzed in a few months. Thus there is more to be gained
> > in machine performance and planning by accelerating the BUPs by 2-3
> > months than there is to be lost in the input of physics data analysis
> > to the process.
> >
> > The short term proposal for Run-5 is to have a draft decision on light
> > ion species and energies by August 15, to allow the injector
> > development in early October to be properly planned."
> >
>


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