Minutes fro the WP meeting #85, June-18-2009

Attendant:

Dean Karlen
Akira Sugiyama
Ralf Diener
Sasha Kaukher
Christoph Rosemann
Patrick Conley
Oliver Schaefer
Thorsten Krautscheid
Martin Killenberg
Klaus Dehmelt

News:
Christoph announced a face-to-face meeting in order to discuss the status of MarlinTPC.
The details will be announced properly in a forthcoming e-mail. It is encouraged to
give feedback regarding possible attendance and possible topics.

PCMAG status:
The magnet was performing smoothly, no problems whatsoever observed during the run
with Micromegas or Bonn-GEMs. The magnet will be shut down in parallel with the DESY
shutdown and will be restarted for the TDC run.

LPTPC status:
The field cage needs some examination during the next beam shutdown. It was observed
that the resistance between the first and the seventh field strip (the z-position of
the anode) dropped from the nominal value 6 MOhm to 5 MOhm during the Micromegas run,
and now to 4 MOhm during the Bonn-GEM run.

News from Bonn pixels/GEM beam/5T magnet tests:
Martin showed some slides and explained the setup of the modules. It turned out the
readout scheme required a synchronization of the 2 quadboards (TimePix), due to the
trigger logic and a shutter because of the MediPix application. Martin reported on a
new plug in mechanism for EUDAQ (see screen shot).
Hardware problems caused a week delay for the beam test. The hardware problem was
basically a TLU problem which did not always block a trigger properly once a busy
signal was sent. Finally the problem was solved and a final schedule for the remaining
beam test was presented.
An LCIO plug in for all possible hardware was introduced: one should use the template
and fill the "hardware"-hits into LCIO format.
Two weeks data taking was ongoing in the 5T magnet. The fields were varied to 5 T, 2T,
and 0T.
A question came up regarding some details for the quad boards. It has four times the
size of a single chip. The gain in the GEMs have not been calculated yet, but lowering
each GEM voltage by 60V  showed still signals. The standard voltage across a GEM is
420V.

News from GEM/TDC readout:

The setup is being prepared for the next beam test.

News from GEM/Altro:
Akira showed slides regarding LP1 analysis and transmission studies for a possible
gating GEM. A systematic study due to varying B-fields is ongoing and a Kalman filter
is being implemented into the analysis chain.
It is still not yet known why the variation between worst/best track associated hit
efficiency is rather large. The drift velocity was consistently measured and one now
tries to find an explanation for the discrepancies of the pad response due to spatially
varying B-field.
Transmission measurement are being performed with the MPiTPC. The efficiency is found
to be about 50% and one effect of the gate is that N_eff varies.

News from Victoria laser system data taking:

Data have not yet been taken with Bonn-GEM setup. For reconstruction with the Micromegas
setup a bug has been removed. Patrick is waiting for pad layout in GEAR. This is part
of MarlinTPC reconstruction. He is also waiting for survey data from the cathode pattern,
but the present data set from Micromegas show small enough deviation so he can reconstruct
tracks.

Update on future beam test schedule:

An updated test beam schedule is available from the link in the Indico page. The
newest entry is the planned assembly of the PCMAG translation stage outside T24,
parallel to the ongoing/future test beam campaigns.