mechanical/thermal measurements t. bowcock, j. carroll

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!)