Summary of 8th WP meeting 30/08/2006
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Wednesday 30 August
West Coast East Coast W.Europe Japan
07.00 10.00 16.00 23.00
Present:
Markus Ball
Ties Behnke
Paul Colas
Madhu Dixit
Ivor Fleck
Keisuke Fujii
Michael Hauschild
Katsumasa Ikematsu
Leif Jonsson
Alexander Kaukher
Dean Karlen
Martin Killenberg
Takeshi Matsuda
Dan Peterson
Peter Schade
Oliver Schaefer
Ron Settles
Akira Sugiyama
Jan Timmermans
Peter Wienemann
AGENDA
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See the agendafoils
http://www.mppmu.mpg.de/~settles/tpc/lp/wpmtg/wp8thmeeting30august2006r.ppt
or
http://www.mppmu.mpg.de/~settles/tpc/lp/wpmtg/wp8thmeeting30august2006r.pdf
-1.News
a.Formation of the LCTPC/LP Collaboration
b.WWS-R&D-panel tracking review at Beijing
c.PIRE (Dan)
-2.WP meeting
a.Gem gating (RS)
b.Gem endplate for the LP (Akira)
c.Fieldcage (Ties)
d.LP endplate/electronics discussion (Leif, Dan)
-3.Future meetings
-Paris endcap meeting 12-15 September
-Eudetmeeting at MPI 18-20 October
-Valencia European WS 6-10 November
-Beijing Asian WS February 3-7 February
-4.AOB
1. News
---------------------------------
1a. Status of the LCTPC/LP collaboration (foils#3-9)
The Collaboration-Board (CB) of group representatives is complete now.
The names in the CB and TB have been circulated earlier this week to
all the groups and are shown again on foils 6, 7 and 8.
A proposal by the SP for the next steps will be sent to the CB and TB
within the next few days.
1b. WWS-R&D-panel tracking review at Beijing (foil#10).
As already announced the WWS-R&D Panel is planning to start regular
reviews of the different R&D projects for the LC detector at the regional
LC meetings. The idea is to start by reviewing tracking (TPC and Silicon)
at Beijing, then other subsystems at subsequent workshops. We would have
to update the report every 1.33 years if this procedure is adopted. The
modus operandi is still being worked out.
1c. PIRE (Dan) (foil#11).
?Partnerships for International Research and Educatin is a program
enabling funding for an NSF "key-collaborator" lab (Cornell)
participating in an international research undertaking. Dan will be
submitting the preliminary proposal for LCTPC work using the names the
workpackage conveners. If his proposal passes the first round, letters
from the WP conveners and/or the LCTPC collaboration will be required.
Dan will inform us about the details.
Madhu added that he is working on a similar program in Canada.
2. WP Meeting
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2a.Gem gating (foil#12)
The discussion on gating with Gem started last meeting; it is something
we should test first with small prototypes before it can be implemented
on a LP endplate. Exchanges of ideas on how to do this a.s.a.p. have
started (Fabio Sauli, Akira Sugiyama, Madhu Dixit, Martin Killenberg, RS);
anyone interested is invited to join. Madhu commented that the schemes
should be simulated first before any hardware tests are done; Martin and
Ties said that the simulation tools exist. The problem is to find someone
who has the time to do the job (it would be a nice diploma-thesis topic).
2b. Gem endplate (foil#13)
Akira as convener for the Gem-endplate workpackage sent around an email
asking for each group interested in participating in this WP to send him
an email expressing its intentions. RS pointed out that the same is
true for the other workpackages, and that this information will be
necessary for setting up the LCTPC collaboration planning.
The groups are requested to react.
2c. LP fieldcage (foils#14,15)
Ties showed the FC drawing, which was already discussed at the Eudet
tracking meeting in Amsterdam in January. The OD is 80cm, to leave enough
room for Si detectors outside the FC and inside the PCMAG. The FC length
is 60cm; RS and Peter Schade looked at the field map which shows a
magnetic-field inhomogeneity of about 1%, and this is about what will be
expected for the LCTPC due to the anti-DID. Michael Hauschild questioned
whether the B-inhomogeneity is larger, so the B-map has been added to the
agendafile, see foil#15. There it is seen that the Br change is ~0.8%
relative to Bz at r=6cm for a 60cm drift region centered at the Bmax,
while the Bz change is ~3.3% relative to Bz, i.e. it depends on which
component is being talked about. The B-homogeniety for the LCTPC is
quoted in terms of \int Br/Bz dz which could be as large as 20 mm with
the antiDID (it was 2mm for Aleph) which leads to (with 2m drift) Br
\approx 0.01Bz. The radial component is the "dangerous" one for the
momentum measurement, thus a 60cm driftlength gives the amont of
correction we have to learn how to do at the LP. Mahdu suggested that the
it might be better if drift region should be longer (say 80cm). RS
thought that one of the important tasks will be to show that we know how
to make the field corrections, and that they should be neither too large
nor too small, so this discussion will need another iteration. Michael
suggested we could use the Harp (TPC90) magnet if the field gradient
turns out to be too large.
2d.More on the LP electronics (Leif)(foils#16,17) and LP endplate
(Dan)(foils#18,19)
The discussion of the last meeting (16 August) was continued.
-TPC inner overpressure:
The stiffness of the endplate is needed to contain the inner overpressure
while not allowing to much bowing of a sector. An overpressure of 7mbar
(1bar = ca. 1 atmosphere) was used in the Aleph TPC, so what do we need
for the LP and LCTPC? The was a question whether zero overpressure
would work. Since the TPC will have a few million pads with
through-connection to the electronics channels, it will be difficult if
not impossible to make the TPC completely tight (Aleph leaked at about 2
liters per day, which was not a lot, being only 5x10-5 of the total
volume). Also tightness of the multi-layer boards can be a big issue. In
addition we want to flow the gas, which will require an overpressure. So
there are several reasons for needing an inner overpressure and we have to
decide how much. With 7mbar the force on the endplate would be around
35kg.
-Pads->connector->electronics.
An example of mapping pads-to-connector with a multilayer board is seen
in foil#17. As mentioned above (2c) the gas-tightness of the multilayer
board is an issue. As said at the 16.08.2006 meeting other possibilities
are pad-connector using thin flexible wires (RS) or a "bed of nails"
(Dan); either of these would allow cooling air to be blown between the
padplane and the electronics plane. Dan showed an exersize worked out
(foils#18,19) with 5.5mm^2/channel, and Leif thought smaller might be
possible.
4. Future meetings (foil#11)
---------------------------------
-The next phonemeeting will be in two weeks, on the 13th of September
-Paul/Akira are organizing the 'endcap meeting' in Paris 12-14 September;
details have been sent to everybody.
-The annual Eudet meeting will be in Munich 18-20 October,
-the European LC workshop in Valencia 6-10 November, and
-the Asan LC workshop in Beijing 4-7 February 2007.
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