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[lcdds 114] Re: Minutes of the forth meeting for the IR task force, 8/3
[lcdds 114] Re: Minutes of the forth meeting for the IR task force, 8/3
Ronald Dean Settles <settles@xxxxxxxxxxxx>
Thu, 4 Aug 2005 09:13:58 +0200 (CEST)
Hello Toshiaki and everybody!
Toshiaki, the choices in your minutes
below look o.k. to me, I only want to comment on the Z-peak running for
calibration. (Everybody, I think, has seen my mail on the Z-peak running
for calibration that Mark Thomson and I worked out; it is attached for
The question is, what luminosity can we
expect for Z-peak running for detector calibration? As said in the
attached mail, my recollection is 10^32 from the Tesla studies, if the
machine doesn't do any special gymnastics. I don't have that old curve
(for the Z-peak luminosity) with me at the moment, and I am not exactly
sure what the value is (or was).
However to get the 10^33 (which is needed for
the GigaZ experiment), I recall that the machine did have to do special
beam-gymnastics. Thus I don't know how realistic it is to use this number
for Z-peak calibration or asking for 1/fb calibration data for the Ecal.
Since such running might be done at the beginning during the
commissioning of the machine and detector(s), it is probably too
optimistic. If it is, the Ecal has to work out a strategy, like
calibration of modules in test beams during manufacture or use of cosmics
to be used along with the Z-peak data. I think our Calice friends have
thought about this calibration issue, but I don't know what they concluded
On Thu, 4 Aug 2005, T.Tauchi wrote:
> Dear Colleagues;
> Can you find a minute of the forth meeting for the IR task force ?
> We welcome your comment and suggestion.
> The next meeting is 10th August, 1:30pm-3pm, 3gokan 425 and TV conference
> with 31100.
> Our homepage is http://acfahep.kek.jp/subg/ir/bds/mdi/IR.task.force.htm .
> Best wishes,
> Toshiaki Tauchi
> Minutes of the forth meeting for the IR task force
> • Date and time: 3rd August, 14:00-15:00
> • Place: 3-gokan, 425, KEK
> • TV conference (ID=31100)
> Participants: T.Tauchi, Y.Sugimoto (KEK), Abe, H.Yamamoto (Tohoku univ.),
> Matsunaga (Tsukuba univ.)
> We discussed on the present status of the task force studies and the
> WWS/urgent questions.
> 1. Baseline design of the beam pipe design
> We discussed on what is the baseline design of IR-region, i.e. beam pipe
> and forward calorimeters. Since the accelerator will be operated in the wide
> space of five parameter sets (nominal. lowQ, lowP, largeY and high
> luminosity), the baseline design should be optimized for the most
> challenging set, i.e. the high luminosity one. There must be a long shutdown
> before the 1 TeV operation, the design can be optimized at Ecm=500GeV.
> The baseline design geometry can be found here, which is extracted from
> Sugimoto's talk at the previous meeting.
> 2. Pair monitor geometry and installation in Jupiter
> H.Yamamoto pointed out that the pair monitor (3D pixel detector) requires a
> space of 5cm length and 10cm outer radius in front of the CH2 mask. The
> monitor can be modeled by a silicon disc with 2mm thickness and hole(s) of
> beam pipe(s) . As shown in the baseline design, there is a 5cm long space
> between J and K. So, there is no problem at present. We asked Miyamto for
> installation of the pair monitor in Jupiter.
> 3. Immediate plans
> (1) Beam pipe parameters at B=4 and 5 tesla, and also for the new 1TeV high
> luminosity parameter sets which A.Seryi has recently suggested , by
> (2) Updates of IR geometries based on the baseline parameters as well as
> DID, anti-solenoid fields. by A.Miyamoto
> (3) Pair background simulation in VTX, IT and TPC by Jupiter, by A. Sugiyama
> 4. The urgent questions by WWS
> We discussed on our replies on Q6(L*),Q7(VTX_R),Q8(2&20mr) and
> Q10(mini-veto), which are directly related to the detector concept. Our
> preferred L* and crossing angle should be longer than 4.5m and less than 2m
> rad, respectively. The vertex innermost radius(VTX_R) has been defined for
> free from the core of pairs as shown in the baseline design, which depends
> on the solenoid field of B=3T and the machine parameter set. These choices
> must be verified by the Jupiter full simulation of GLD detector in respect
> to the background tolerances.
> Also, we discussed on the Z-pole running for the detector calibration. The
> conditions such as luminosity, period and frequency will be determined by
> the CAL-calibration for large number of channels to be calibrated, while the
> TPC and VTX may require the Z-pole running in the same way as the LEP2
> experiments. Sugimoto roughly estimated the conditions for the digital CAL-
> calibration as follows; The total channel number would be 106 for 100 m2
> scintillator in the electromagnetic calorimeter with 1 cm2 readout by the
> silicon photo-multipliers. Each readout area must be calibrated by MIP
> particles, i.e. muons from the Z-pole whose cross section is about 1.5nb.
> Integrated luminosity is estimated to 1fb-1 for 10 days with L=1033/cm2/s,
> where 3x106 muons will be produced. Each CAL-area will be hit by 3 muons. If
> the CAL need more muons, the luminosity must be significantly greater than
> 1033/cm2/s . Also, muons in jets may be used as well as cosmic rays.
> Apparently, the CAL needs more clever calibration method for reducing the
> luminosity at Z-pole. Matsunaga agreed that the CAL group will discuss on
> this issue in details.
> The questions and replies will be updated in following home page.
> The questions with replies and comments
From settles@xxxxxxxxxxxx Thu Aug 4 08:29:22 2005
Date: Fri, 22 Jul 2005 08:56:47 +0200 (CEST)
From: Ronald Dean Settles <settles@xxxxxxxxxxxx>
Cc: "lcdds@xxxxxxxxxxxxxx" <lcdds@xxxxxxxxxxxxxx>
Subject: [gld-eb 86] Re: WWS urgent questions
Hello Toshiaki, Mike and everybody,
I agree with your answers, Mike, and thanks for putting them
together (I hadn't found time to do so during the last few days).
I have one addtional piece of information. Mark Thomson and I
went throught the exercise at Daegu of answering the question of
how often we will need calibration runs at the Z pole. The answer needs a
guess at how often problems with the detector will occur that require
calibration data. To not just make a blind guess, we took the data from
Lep2 running, where this procedure (Z pole running for calibration) was
used several times when detector problems cropped up. The last year of
Lep2 running (2000), where things were really being pushed by the machine,
the track record was:
Z Running needed at Lep2:
=>per detector<= 3/pb at the beginning of the year, and
" one run of 0.5/pb during the year
So, we propose then to use the following working hypothesis:
Z Running for ILC:
=>per detector<= 10/pb at the beginning of a year, and
" one run of 1/pb during a year
since the detector(s) will be more complicated.
If I remember correctly, the projected Z-pole luminosity for
Tesla for "calibration" (i.e. no special beam gymnastics to push up the
luminosity like would be needed for the "GigaZ") would be 10^32/cm^2sec
so that calibration at the beginning of the year would take
=>per detector<= 30hours of beam and during the year =>per detector<=
3hours of beam.
To repeat, this is just a guess, but at least it is based on
At the very beginning of the ILC operation, much more Z
running would be needed for calibration of the detector(s). This will
mainly be determined by the calorimeter; Calice has studied this but I
don't remember what their number is, maybe somebody else does...
On Thu, 21 Jul 2005, Mike Ronan wrote:
> Hi Tauchi-san,
> Here are some comments on MDI questions that were asked concerning the
> TPC. (I'm sure Ron will have additional comments.)
> Q3 (150nsec bunch spacing impact to detectors, CAL? )
> Q4 (upper limit of background hit rates in your detectors)
> Q5 (backgrounds from the parameter sets are acceptable?)
> Q11(backgrounds for 2mrad and 20mrad crossing angles)
> Q12 (DID impact to the TPC performance)
> Q13 (anti-solenoid impact to the pair monitor performance and background to
> the VTX)
> Q17 (detector assembly procedure)
> The TPC timing resolution is about 1.5 nsec. so that tracks from a
> bunch 150 nsec. apart would not be confused. The integrated random
> background over the TPC readout time of 50 microsec. would be the same
> for the two bunch spacing options.
> The TPC pattern recognition can tolerate more than 20X nominal random
> backgrounds, for example from synchrotron radiation. Backgrounds from
> compton scattering and neutrons can result in track segments, the choice
> of gas and high magnetic should mitigate these backgrounds. Muon
> backgrounds should not be a problem. Electrons and positrons from pairs
> and hadrons from two-photon interactions will be confused with genuine
> tracks; however, TPC particle identification will help in identifying
> some of these backgrounds. Background simulation studies need to be updated.
> We would need to run background simulations for the different
> parameter sets.
> Also requires background simulation studies.
> At this time we expect that the magnetic field will be mapped well
> enough to correct for any E x B distortions at the level of 10 microns.
> Yes, Z pole calibration would be needed to fully understand the E x B
> corrections. The Z pole runs would be needed at the time of precision
> measurements. Otherwise, calibration events like e+e- -> W+W- should
> Need to leave time for magnetic field mapping in the assembly procedure.