[Tpe] TPE experiment readiness
burkert
burkert at jlab.org
Thu Apr 1 15:46:28 EDT 2010
Dear Larry,
Sorry if I have been too "candid" in my comments. I agree with you on
the scheduling issue and priority. The review (radiation dose, etc) has
been imposed by management. There exists the notion that TPE was
scheduled last so that no other experiment will be affected by the
anticipated harsh radiation exposure of the CLAS drift chambers (I don't
know where that came from). We will have a review by the end of April to
assess the chances of HDIce to be ready for installation during the
summer down. Immediately before or after that I would like to schedule
the TPE review. It should cover the shielding requirements, the
radiation issue (CLAS + tagger counters), and the luminosity issue, i.e.
can TPE achieve the stated physics goals?. Let me know if you have
further questions.
Volker
Larry Weinstein wrote:
> Dear Volker,
>
> Thank you for your candid response to our exchange. We realize that
> TPE will only run if HDIce cannot. However, we were under the
> impression that the decision had already been made that TPE would run
> first if HDIce was delayed.
>
> No matter which experiment runs in September, the sooner a decision is
> made, the more resources will be available. This is especially true
> for our collaborators at Argonne and Valparaiso who have significant
> administrative restrictions. The TPE run is sufficiently important
> that two of us, Brian and myself, have scheduled our rare and precious
> sabbaticals for Fall 2010, just in case TPE runs.
>
> We completely agree with you that TPE cannot be allowed to damage the
> CLAS detectors. We are now modeling the radiation dose to the tagger
> scintillators. The 3% DC occupancy is a hard limit. We will not
> exceed that. Period. Note that the luminosity for 4 GeV and higher
> electron experiments is limited by the 3% Region 1 DC occupancy
> limit. Our experiment will be similarly limited. If anything, we
> will cause less radiation damage to the drift chambers than standard
> electron runs because the occupancy will not be concentrated in the
> forward wires of Region 1 but will be more evenly distributed. The
> reason that it took almost three years after the test run to
> demonstrate the TPE feasibility is that we are not willing to exceed
> the 3% DC limit.
>
> We were not aware of the need for a technical review panel. If we had
> known this, we would have requested a review panel last year. We
> would greatly appreciate scheduling the review for sometime in May so
> that we can prove our readiness.
>
> With the limited amount of beam time available in the 6 GeV era, it is
> important to maximize the impact of that beam time. I realize that
> the lab has invested a tremendous amount of effort into doing just
> that. This means that lengthy installations should take place during
> long down times, higher priority experiments should run earlier, and
> experiments with external competition should also run earlier. TPE
> was originally scheduled last because a) we had not yet demonstrated
> that the experiment was feasible, b) we did not have any competition
> yet, and c) it was assumed that HDIce would be ready. The first two
> conditions have changed and the third is not certain.
>
> Sincerely,
> Larry Weinstein for the TPE collaboration
>
> -------- Original Message --------
> Subject: Re: [Tpe] Mont's presentation to JSA
> Date: Thu, 25 Mar 2010 18:03:34 -0400
> From: burkert <burkert at jlab.org> <mailto:burkert at jlab.org>
> To: weinstein at odu.edu <mailto:weinstein at odu.edu>
> CC: tpe <tpe at jlab.org> <mailto:tpe at jlab.org>
>
>
>
> Hello,
> you guys shouldn't get too excited about all this.
>
> First of all, TPE was never scheduled to run this fall, and just
> pretending it was doesn't make it true. However, I am indeed considering
> this as one of two options in case HDIce isn't ready, and only then! The
> determination that HDIce will not be ready cannot be made much earlier
> than at the end of May, or early June. If the TPE run is so important
> (which I think it is) then you guys should be able to adjust your
> schedules accordingly.
>
> We at Jlab are currently planning ahead to modify the beamline and
> shielding configuration during the 6 weeks summer down, in case TPE will
> be substituting for HDIce. The 6 weeks is all the time we have
> available. If your travel plans conflict with that, that is too bad.
>
> The other option we consider is running PRIMEX II. These folks seem to
> have fewer problems in being available to prepare the run. In fact,
> they already got their calorimeter fully checked out during the spring
> down time, and they have the advantage that less effort is required to
> get this experiment ready.
>
> There are a number of things that we need to have checked from the TPE
> group. The large luminosity gap from the test run needs to be
> demonstrated to a review committee to have been closed (I have seen the
> rreport where the claim is made. This is a good start, but is not
> sufficient). The radiation dose level at the focal plane that I
> mentioned to Dave as a potential problem, needs to be studied (Pawel
> from RadCon may be able to help). The protection of the drift chamber
> system is another concern. We will have stringent upper limits in
> occupancies during the run.
>
> In general, we should not display an attitude that we don't care what
> experiment comes after us, because TPE is so much more important than
> others.
>
> Again, according to our current schedule TPE can only run if HDIce is
> not ready. If you want to change the priority you need to convince other
> people.
>
> Volker
>
>
>
>
> Brian A Raue wrote:
> > Hi All,
> > From my point, it is crucial that a decision regarding the running of
> > TPE this fall be made as soon as possible. I have been awarded a
> > sabbatical for the fall in the anticipation that we will run. If not, I
> > have to either reschedule the sabbatical or find something else to do soon.
> > Further, I have a grad student now working on the experiment. If we
> > don't run then I need to find him another project. It is unfair to the
> > student for him to spend a significant amount of time preparing for TPE
> > only to have it pulled out from under him.
> >
> > Brian
> >
> > Larry Weinstein wrote:
> >
> >> Dear TPEers,
> >>
> >> There was an interesting paragraph in Mont's March 10 JSA presentation
> >> (slide 21, titled 'FY11 Guidance Scientific Objectives'):
> >>
> >> Hall B:
> >> • Complete data taking on N* with polarized HDIcetarget (especially
> >> neutron
> >> data). Note original plan was to complete this experiment in FY11;
> >> it will likely
> >> be delayed, and we may try to advance PRIMEx-II into this period
> >> instead if
> >> adequate equipment funding is available
> >>
> >>
> >> It is interesting a) that HDIce uncertainties are already known at the
> >> director's level and b) that Primex is still listed as the most likely
> >> experiment to run in its place.
> >>
> >> --
> >> Sincerely,
> >> Larry
> >>
> >> -----------------------------------------------------------
> >> Lawrence Weinstein
> >> University Professor
> >> Physics Department
> >> Old Dominion University
> >> Norfolk, VA 23529
> >> 757 683 5803
> >> 757 683 5809 (fax)
> >> weinstein at odu.edu <mailto:weinstein at odu.edu> <mailto:weinstein at odu.edu>
> >> http://www.physics.odu.edu/~weinstei <http://www.physics.odu.edu/%7Eweinstei>
> >>
> >>
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> >
> >
> >
>
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