Post on 28-Mar-2015
Mechanical/Thermal Measurements
T. Bowcock, J. Carroll
Production Facility
• Have been waiting for release of clean-rooms
• Full release of space next week– Had to move in before handover(!)
Production Facilities
LHCb
R&D
Thermal Measurements
Measuring Temperature
• Use IR camera– Note measurements in vacuo through window
introduce an offset (!)– Extra thermal sensors for recalibration– Linearity
• Is it maintained?
• Seems to be to about 1C over range –20 to +20.
11C (spot)
Ansys Al model(10C)Tochnog
Calibration ModelCalibration Model
0
10
20
30
40
50
60
70
0 5 10 15 20 25
Power
Delta(T)(from nominal)
Calibration ModelCalibration Model
Chipglue
kaptonsensor
ceramic
TPG
Chipglue
kaptonsensor
TPG
CF weave
CF(UD)
Material Radiation Thickness CTE Conductivitylength(cm) (microns) (x10**6) WmK
Sensor silicon 9.3 300 2.8 130
Hybridbaseline composite kapton 32.5 100 4 50
CF(UD) 24.9 95 <1 800
TPG 24.9 300 <1 1700
CF(weave) 24.9 150 <1 10
Hybridbackup composite beryllia 14.4 300 8.3 280
TPG 24 300 <1 1700
Thermal connector
baseline aluminium 13 300 23 202
backup titanium 3.6 300 8.6 157
Paddle CF2 24.9 200 <1 10(10)Paddle base aluminium 8.9 O(3cm) 23 202
Spring steel 1.8 O(3cm) 12 669location base steel 1.8 O(3cm) 12 669
Beryllia Hybrid/TPG Tcool Heat(Chips) Heat Si Max(si) Min(Si) Max(Chips)(backup) -25 10W 0.3W -18.3 -20 -11.7
-25 20W 0.3W -14.2 -16 1.5
-25 24W 0.3W -12.5 -14.4 6.8
-25 36W 0.3W -7.5 -9.6 2.7
Aluminium Nitride/TPG Tcool
-25 10W 0.3W -18 -19.7 -11.2
-25 20W 0.3W -13.5 -15.4 2.6
-25 24W 0.3W -12.5 -13.7 8.5
-25 36W 0.3W -7.5 -8.2 24.5
Carbon Fibre Composite -25 10W 0.3W -15 -17.4 -10.8300 micron TPG(baseline) -25 20W 0.3W -7.3 -9.9 3.3
-25 24W 0.3W -4.2 -7 8.9
-25 36W 0.3W 5 1.8 25.7
Improvements
• Holes in kapton– a la ATLAS
• Non uniform thickness– Frame engineered in CF can reduce operating
temperature by several degrees– Minimize(reduces) the amount of material
Mechanical Hybrid• 2nd prototype CF manufactured
– Photo available if necessary– Bows <50 microns across 10cm– Precision slots manufactured in CF using spark erosion
• But slow and expensive
• 3rd CF prototype– Reduce the bow < 25 microns– Insert the TPG
• Aliminium Nitride Substrates exist (correct size and thickness).– Laser cutting– Bonding to TPG
Electronics
Cooling Bracket & Fixings
Carbon Fiber Paddle
Micrometer Adjusters
Paddle Base
Flat Spring
Location Base
Substrates
Silicon Detectors
x
y y
z
z
x (pitch)
(roll)
(slew)
Pre-alignment Jig
• Two hybrids relative to each other
• Jig being designed…– Relatively simple device
Adjustments- Translations
• X– 6 microns/5 degrees
• Y– 7 microns/5 degrees
• Z– 2 microns/5 degrees (*)
Rotations
• Slew– 0.88 degree for full scale(see Y drive)
• Roll– 0.25 degree for 360 degree adjustments(8
microns drive/5 degree adjustments)
• Pitch– 0.26 degree for 540 degrees adjustment(10
microns approx in y/5 degree)
Thermal Measurements
• Preliminary look at the alignment mechanism– Increase temperature of base by +10 degrees
relative to platform– X,Z movement small but large pitch
• O(100)micron
Conclusions
• Thermal module– Real prototype being built– All components– Calibration model consistent with measurement
• Mechanical Alignement– 2nd prototype mechanism behaves much as expected– Need to understand problem thermal movement
• Module modifications– Cabling (cf. N.A. Smith next week!)