Transcript 8 th International Workshop on DEPFET Detectors and applications

8th International Workshop on
DEPFET Detectors and applications
Thermo-mechanical
activities at Valencia
V. Castillo, C. Lacasta, A. Oyanguren, P. Ruiz
(IFIC - Valencia)
21/9/2011
Outline
 Mock-up status at VLC
 Studies of air flow cooling:
- Effect of CO2 cooling + air flow at several
temperatures on the ladders
 Conclusions
 Plans at VLC
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Mock-up
Thermally
isolated box
with dry atmosphere
CO2 open
system
Nitrogen
liquid Dewar
(cooled air)
Mock-up
IR camera
chiller
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Mock-up
Mock-up status:
- Mechanical dummy temporarily fixed in the CrCo sample:
(plastic nut + screw ended with a wire embedded in the hole)
- Thermal grease for the thermal contact
- One resistor sample in the outer layer
- Set voltages:
Sensor: 12 V  P ~ 1W
Switchers: 3V  P ~ 0.25 W
DCDs/DHPs: 20V  P ~2.5 W
It works!
(appart from the left switchers)
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Mock-up
Calibration tool for the IR camera: ( depends on the material)
Al box filled with coolant: cooled down with chiller, heated with heaters. Study material 
(broken) mechanical dummy
DCD/
DHP
switcher
 ~ 0.65
DCD/
DHP
sensor
Marker
Al
Tape 1
Tipp
-ex
Kapton
Cu
Tape 2
grease
 ~ 0.35
T= 90ºC
 ~ 0.18
T= -10ºC
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Air flow studies
(vair (inlet) ~ 2m/s)
- Effect of blowing air at room temperature:
DCD/
DHP
DCD/
DHP
(corrected emmisivity)
DCD/
DHP
DCD/
DHP
Camera position
-The air flow (at room T) decreases
and homogenizes the temperature
along the detector.
 Decreases T ~ 15 C
 Max T along the ladder 18C 8C
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Air flow studies
(vair (inlet) ~ 2m/s)
- Cooling down the end flanges with CO2
T (ºC)
- Blowing air/N2 at different temperatures (cooled down with N2 liquid atmosphere)
25 ºC
Camera position
(corrected emmisivity)
Looking at the central region of the sensor:
- Detector on: T ~ 45ºC
- Effect of CO2 + air flow : T ~ 20ºC (or below)
Looking at the edges:
- Bumps ?? (crab legs)
- With CO2 + air flow T along the ladder ~ 20ºC (!?)
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Air flow studies
- Problems of IR transparence due to the
thickness of the detector:
Detector on, CO2 in the end flanges, no air flow
- Tipp-ex marks behind in the Cu inner ladder
End flanges
sensor
Present setup
switchers
Sensor and switchers: expected about same  and behaviour
(corrected emmisivity)
- sensor
- switchers
T(ºC)
left switchers off
Tipp-ex marks behind
End flanges
Camera position
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Previous setup
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Air flow studies
- Detector on, CO2 in the endflanges, cooled air flow
T(ºC)
- sensor
- switchers
T~10ºC
Effect of IR transparence
due to the thickness of the sensor (?)
(corrected emmisivity)
Camera position
 Effect of a polycarbonate sheet (IR opaque)
behind the mechanical dummy (i.e. between
the inner and outer ladders:
A few degrees (~3) difference, not observed
for the switchers region, due to the reflexion
in the inner ladder, seen by the IR camera
through the thick sensor.
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C. Mariñas
simulation
Air flow studies
- More realistic conditions for the
detector, set voltages so:
Sensor:  P ~ 0.5W
Switchers:  P ~ 0.5W
DCDs/DHPs:  P ~ 8W
T (ºC)
- Inner cupper ladder covered with a
polycarbonate dummy, opaque to IR
Sensor
Camera position
(corrected emmisivity)
Detector on
Background (room T)
End flanges cooled with CO2
Air flow at room T
Air/N2 flow cooled [-8,-15]C
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Air flow studies
- Sensor region (P~0.5W):
T (ºC)
Sensor
Detector on
Background (room T)
End flanges cooled with CO2
Air flow at room T
Air/N2 flow cooled [-8,-15]C
Camera position
- Temperature for the sensor when switching on the detector: ~ 60 C
- Cooling the endflanges (CO2): T sensor< 25 C (~ room T  to check colder environment)
- Blowing air at room T  T sensor < 20 C and homogenus
- Blowing cooled air (-8,-15) C  T sensor < 15 C and homogeneus
- Tmax along the sensor ~ 10 C (contact + remaining transparence)
- For a proper T estimation from the enflanges one should have all detectors on
(but should be ok following the Karlsruhe test
(see next page))
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Air flow studies
From Karlsruhe (S. Heindl, Feb 2011) :
PT1000s
Silicon pieces with resistors (20W each)
120W + CO2 Cooling:
 Endflange at < -10 C (most probes)
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Air flow studies
- Switchers region (P~0.5W):
T (ºC)
Switchers
(corrected emmisivity)
Detector on
Background (room T)
End flanges cooled with CO2
Air flow at room T
Air/N2 flow cooled [-8,-15]C
Camera position
- Only right switcher was operating
- Temperature for the switchers when the detector is switched on ~ 40 C
- Cooling the endflanges (CO2): T sensor ~ 20-30 C (room T  to check colder environm.)
- Blowing air at room T  T sensor < 25 C and homogenus
- Blowing cooled air (-8,-15) C  T sensor < 25 C and homogeneus
- Small Tmax along the detector < 10 C
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Conclusions
- Valencia mockup set up and understood.
- At present, all tests show:
 Cooled air flow decreases the ladder temperature below ~20C
 Tmax along the ladder less or around 10C
- Valencia activity on thermo-mechanical issues will smoothly decrease in the
next year, but at present this setup may be used for any envisaged thermal test
In particular:
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Mock-up
- Test air flow cooling with the CO2 return
Until now, air or N2 gaseous cooled by the atmosphere inside the liquid N2 Dewar (-80C)
New CO2 exchanged system to cool down the air flow:
1.5m pipe coil at the CO2 return to cool down the air:
Air flow temperature in the outlet ~ -5 - 0 C
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Plans
- Test air flow effect in the inner
ladders (mainly for the switchers)
through carbon fibers
Carbon fibers
- Set up the new endflanges of
aluminium and/or stainless steel
(ladders better screwed, better
fixed and better thermal contact)
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Al samples
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Plans
- Test possible vibrations in the detectors due to the air flow
Capacitive Non-Contact Displacement detectors:
ATLAS setup
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Backup
 Dummy ladders:
Polycarbonate
Al
Cu
Heaters
Resistor samples
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Backup
 Effect of air velocity
Air flow
Inne ladder
Outer ladder
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Cooling block
- It is enough to have a very low speed flow air
to achieve a proper heat dissipation in the
ladder (1WT~ 6-7ºC),
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(Expected behaviour from Carlos simulations)
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T (ºC)
30
28
26
24
22
20
0
0,5
1
1,5
2
2,5
3
3,5
Air v (m/s)
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Backup
 Inner ladder:
T (C)
heaters (3W)
Air flow T~0C*
Air flow T~-20C *
CO2, No air flow
Camera position
* entering in the box; T in the CB?
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