Thermal and Mechanical Characterization
of the TT Detector for the LHCb Experiment
February 22nd, 2007
Physik-Institut Universität Zürich, Angela Büchler
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Outline
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The Trigger Tracker station (TT) in the LHCb experiment
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Construction and alignment of the TT station
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Thermal studies with the test box
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Cooling test of the full station
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Conclusions
February 22nd, 2007
Physik-Institut Universität Zürich, Angela Büchler
2
CERN with the LHCb Experiment
Lake Geneva
Geneva
LHCb
CERN/Meyrin
tunnel of 27 km length
February 22nd, 2007
Physik-Institut Universität Zürich, Angela Büchler
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The LHCb Tracking System
LHCb Outer Tracker Homepage
February 22nd, 2007
Physik-Institut Universität Zürich, Angela Büchler
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The Trigger Tracker station (TT)
LHCb silicon Tracker
➔ 896
LHCb silicon Tracker
February 22nd, 2007
silicon sensors
➔ 512 strips per sensor, pitch 180 μm
➔ 4 detection layers
➔ different colors = different readout sections
Physik-Institut Universität Zürich, Angela Büchler
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The TT support structure
Why is a precise alignment of the rails important?
➔ TT station is a precision tracking device with a spatial resolution of 50 μm
➔ smooth movement of the left and the right C-frames for opening and closing the
detector
➔ prevent torsion of the modules when moving the station
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February 22nd, 2007
Physik-Institut Universität Zürich, Angela Büchler
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The TT support structure
Why is a precise alignment of the rails important?
➔ precise fit of the beam pipe into the beam pipe insulation
➔ exact positioning of the modules in the narrow gaps of the beam pipe insulation
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February 22nd, 2007
Physik-Institut Universität Zürich, Angela Büchler
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Alignment of the rails
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vertical alignment with leveling
instrument using the reference
at the cavern wall and a ruler
mounted to the gliders
horizontal alignment with a
theodolite
horizontal alignment with laser
system mounted to the gliders
Stefan Steiner
February 22nd, 2007
Physik-Institut Universität Zürich, Angela Büchler
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Alignment of the rails
Jean-Christophe Gayde/Stefan Steiner
February 22nd, 2007
Physik-Institut Universität Zürich, Angela Büchler
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Alignment of the rails
February 22nd, 2007
Physik-Institut Universität Zürich, Angela Büchler
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Alignment results x-direction
➔
lower rails within 0.135 mm
➔
upper rails within 0.7 mm
(with theodolite)
February 22nd, 2007
Physik-Institut Universität Zürich, Angela Büchler
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Alignment results leveling
➔
February 22nd, 2007
lower rails within 0.1 mm
➔
upper rails within 1.17 mm
Physik-Institut Universität Zürich, Angela Büchler
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Alignment results
Jeroen van Tilburg
Jeroen van Tilburg
➔
February 22nd, 2007
the beam pipe fits
Physik-Institut Universität Zürich, Angela Büchler
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Alignment results
Jeroen van Tilburg
Jeroen van Tilburg
➔
February 22nd, 2007
the station closes well
Physik-Institut Universität Zürich, Angela Büchler
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Thermal studies in the test box
February 22nd, 2007
Physik-Institut Universität Zürich, Angela Büchler
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Thermal studies in the test box
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cooling system to remove dissipated heat from front end hybrids
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Kapton heaters (brown) simulating the heating load from the hybrids
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46 temperature sensors PT1000 on one cooling plate
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different heating loads: 0 W - 240 W
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different flow rates: 20 ℓ/h – 340 ℓ/h  optimal flow rate?
February 22nd, 2007
Physik-Institut Universität Zürich, Angela Büchler
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Thermal studies in the test box
Stefan Steiner
February 22nd, 2007
Physik-Institut Universität Zürich, Angela Büchler
17
Test box heating load measurements
basic settings:
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cooling fluid C6F14 at -15°C
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average flow rate 250 ℓ/h
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room temperature 23°C – 25°C
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closed cover of the test box
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heating power P = 0 W – 240 W
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thermal equilibrium
test series:
1. with basic settings
2. with dry air
3. with copper strips
4. with copper strips and improved cross section
5. with new cooling booster
Stefan Steiner
February 22nd, 2007
Physik-Institut Universität Zürich, Angela Büchler
18
Test box heating load results
power P = 240 W, flow rate f = 250 ℓ/h:
test series:
1. with basic settings
2. with dry air
3. with copper strips
4. with copper strips and improved cross section
5. with new cooling booster
February 22nd, 2007
Physik-Institut Universität Zürich, Angela Büchler
19
Test box flow rate results
power P = 240 W
ΔT = |Tsensor - Tinlet|
➔ Humidity:
➔ optimal
➔ Re
flow rate f = 250 ℓ/h
= 15812
➔ save
and economic solution
February 22nd, 2007
turbulent
laminar
42 ℓ/h
Recrit = 2656
Physik-Institut Universität Zürich, Angela Büchler
➔ box
temperature: ~ -2°C
➔ lowest
➔ dew
~ 30 %
temperature: ~ -15°C
point: ~ -18°C
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Cooling test TT station
➔
volume cooling with 4 cooling plates
and 4 side plates
➔
chiller with cooling fluid C6F14 of
-15°C
➔
nominal dissipated heat from front
end chips (900 W) simulated by
Kapton heaters
➔
heating load studies: 0 W – 1200 W
➔
➔
42 temperature sensors PT1000
distributed in the volume, in the
supply lines and in the return lines
Stefan Steiner
flow meters in the supply lines
➔ flow rate: 250 ℓ/h (cooling plates),
200 ℓ/h (side plates)
February 22nd, 2007
Physik-Institut Universität Zürich, Angela Büchler
21
Cooling test TT station results
warmest temperature sensors, measuring
the air temperature inside the station from
0 W to 1200 W heating load:
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➔
➔
➔
➔
February 22nd, 2007
at the expected dissipated heat from the
front end chips (900 W) the warmest
temperature in the station is -3°C
30 % above the expected heating load
the maximal temperature in the station is
-1.2°C
maintaining the modules inside the
station at a constant temperature of +5°C
during operation will be possible
no condensation was observed
Physik-Institut Universität Zürich, Angela Büchler
22
TT station warm up results
➔
cooling system and Kapton
heaters switched off
➔
measurement of temperatures
every 30 min
➔
total warm up to room
temperature: ~ 6 h
Function for warm up:
with fitted parameters κ, T0 and Troom
February 22nd, 2007
Physik-Institut Universität Zürich, Angela Büchler
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Conclusions
Alignment:
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lower rails aligned with very high precision: ± 0.1 mm vertically and horizontally
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upper rails: within 1.17 mm vertically and within less than 1 mm horizontally
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the beam pipe fits into the detector and the station closes well
Test box cooling:
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detailed temperature profile of the cooling plate with heating load test series
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new cooling booster successfully implemented: much better heat conduction at
the exposed region of the cooling plate
TT station cooling:
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all temperatures below -3°C at nominal heating load of 900 W
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all temperatures below -1.2°C at 30% above expected heating load
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warm-up of full station took ~ 6 h
February 22nd, 2007
Physik-Institut Universität Zürich, Angela Büchler
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February 22nd, 2007
Physik-Institut Universität Zürich, Angela Büchler
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