OT: Zaujimavost - novy detektor zaznamenal prve castice
Daniel Valuch
daniel.valuch@wanadoo.fr
Pátek Červenec 22 15:16:59 CEST 2005
Niektore casti detektorov zrazok castic su uz hotove a zacinaju sa
postupne skusat a zahorovat.
Tu je par obrazkov zo stavby detektoru ATLAS z podzemia
http://cdsweb.cern.ch/search.py?recid=855456 (tie rury s oranzovymi
pasikmi su supravodive cievky).
A cely clanok:
The ATLAS barrel tile calorimeter has recorded its first events
underground using a cosmic ray trigger, as part of the detector
commissioning programme.
A cosmic ray muon recorded by the ATLAS barrel tile calorimeter at
18:30, on 21 June 2005. The calorimeter has three layers and a pointing
geometry. The light trapezoids represent the energy deposited in the
tiles of the calorimeter depicted as a thick disk.
ATLAS has recorded its first events underground. On the evening of 21
June, the ATLAS detector, now being installed in the underground
experimental hall UX15, reached an important psychological milestone:
the barrel hadronic tile calorimeter recorded the first cosmic ray
events in the underground cavern. An estimated million cosmic muons
enter the ATLAS cavern every 3 minutes, and the ATLAS team decided to
make good use of some of them for the commissioning of the detector.
The purpose-built trigger system selected cosmic rays - mainly muons -
passing ‘back-to-back' through the top and bottom of the calorimeter.
Although only 8 of the 128 calorimeter slices (‘superdrawers') were
included in the trigger, beautiful muon tracks were seen traversing the
detector.
A complete ‘slice' of the ATLAS detector ran in a test beam during 2004,
but this is the first time that events have been recorded underground.
For two weeks, experts of different disciplines from CERN and the
experiment (cooling, high-voltage, front-end electronics, data
acquisition, offline), led by Richard Teuscher, worked underground in
USA15, the counting room next to the main ATLAS cavern. The goal of the
exercise was the commissioning of hardware and software systems,
monitoring long-term stability and checking module uniformity and
performance. The test used final components for the whole signal chain
up to the counting room and valuable experience was gained for the whole
tile calorimeter system.
The project leader for the tile calorimeter, Robert Stanek, said: "The
first picture of cosmic rays from the ATLAS pit is like a snapshot - it
captures many years of hard work by a team from dozens of countries
around the world."
This is just the first stage of a long ATLAS commissioning programme.
After the completion of the installation of the barrel toroid magnet
system, the barrel calorimeter will move to its final position in autumn
2005 (from the temporary ‘parking' position it occupies now) and the
final services will be connected. This autumn, a fraction of the muon
spectrometer already installed in the pit will join the programme. The
electromagnetic calorimeter will then be integrated after being cooled
down in spring 2006.
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