TE-CRG-CI
Measurements at
Helium Temperature
European Course of Cryogenics - CERN
Ch. Balle
Friday, September 3, 2010
Measurements at Helium Temperature
/
2 Sep 2010
Content
• Instrumentation in Cryogenics
• Setups for Measuring Properties of Materials
• Demonstration
Ch. Balle
Friday, September 3, 2010
Measurements at Helium Temperature
/
2 Sep 2010
Instrumentation
Definition
♫ Combination of musical instruments ⚙Branch of engineering dealing with measurements
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Measurement Chain
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Sensor No
Signal Conditioning
Signal Processing
Control
Actuator
Signal Conditioning
Signal Processing
Sensor & Actuator in He Cryogenics
FV
LE
PT
Measuring mainly based on 3 elec. principles:
resistance
capacity
inductance
FT
PT
TE HE
Piping & Instrumentation Diagram
Ch. Balle
Friday, September 3, 2010
Particularities
- electrical wires:
SV
heat load, self heating effect
thermal EMF
- openings of cryostat: tightness, heat load
- mounting:
‘cryoproof’, thermal expansion
F - Flow, L - Level, P - Pressure, T - Temperature,
Measurements at Helium Temperature
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H - Heater, V - Valve
2 Sep 2010
Instrumentation
Temperature Sensor Classification
Range/K
Electrical Thermometer
Semiconductor Diode Thermometer
Silicon Diode
2
... 500
GaAlAs Diode
2
... 500
Thermocouple (TC)
Thermocouple Type T (TCT)
1.2
673
Thermocouple Type J (TCJ)
63
1473
Resistance Temperature Detector (RTD)
Platinum Resist. Tmeter (PRT)
50
... 800
Rhodium Iron Resist. Tmeter (RIRT)
0.6 ... 500
Rhuthenium Oxide Resist. Tmeter (RUX) 0.05... 40
Germanium Resist. Tmeter (GRT)
0.05... 100
Carbon Resist. Tmeter (CRT)
1.4 ... 100
Carbon Glass Resist. Tmeter (CGR)
1.4 ... 325
Cernox Resist. Tmeter (CX)
0.3 ... 325
Cryogenic Linar Temp Sensor (CLTS)
4
... 300
Capacitance Thermometer
1.4 ... 290
Coulomb Blockade Thermometer (CBT)
0.4 ...
1
M e c h a n i c a l T he r m o m e t e r
Vapor Pressure Thermometer
Vapor Pressure (Bulb) Tmeter
Gas Thermometer
Optical Thermometer
0.65 ... 5
... 25
3
Std
Curve
Signal
✔
1.6...0.1 V
0.4...6 V
✔
✔
-6.258...20.872 mV
-8.095...69.553 mV
✔
9...290 Ω
8...100 Ω
100...1 kΩ
1000...1 Ω
10000...100 Ω
1 105...10 Ω
2 104...30 Ω
220...290 Ohm
6...100 nF
Curve Width
✔
-
Accuracy
±1K@4K
± 12 mK @ 4 K
± 1.3 K @ 70 K
± 20 mK @ 4 K
± 20 mK @ 4 K
± 4 mK @ 4 K
± 5 mK @ 4 K
± 5 mK @ 4 K
✔
✔
✔
Fiber Thermometer
Ch. Balle
Friday, September 3, 2010
Measurements at Helium Temperature
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2 Sep 2010
•Instrumentation
Pressure
✘ Sensors for LHe-temperatures
- not commercially developed
- individual Calibration needed
- problem of reproducibility
not interchangeable
✔ Sensor at Troom with connection to cryo environment by capillary tube, but
- makes mechanical cryostat design more complex
- low frequency response of capillary
measurement of static/slowly varying p, only
- thermomolecular pressure effect: pwarm capillary end > pcold capillary end
- Tcapillary ≠ const
Risk of thermoacoustic oscillations (TACONIS effect)
Electrical Pressure Sensor
Piezoresistive Pressure Sensor
Piezoelectric Pressure Sensor
Capacitance Pressure Sensor
Electromagnetic Pressure Sensor
diaphragm separating two pressure chambers
Mechanical Pressure Sensor
Bourdon Pressure Gauge
Ch. Balle
Friday, September 3, 2010
Measurements at Helium Temperature
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2 Sep 2010
•Instrumentation
Level
Mechanical Level Sensor
∆p
Float
Weighing
Hydrostatic
Pressure Difference
Bubbler
(Thermoacoustic Oscillation
TACONIS Effect)
Electrical Level Sensor
R>0
R=0
Superconductor
Ch. Balle
Friday, September 3, 2010
Capacitor
C = •A/d
ε
Resistor
Measurements at Helium Temperature
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2 Sep 2010
•Setups
Heat Capacity Measurement
Ch. Balle
Friday, September 3, 2010
Measurements at Helium Temperature
5 / 9
2 Sep 2010
•Setups
Test of Superconducting Busbar-Splices of the LHC-Magnets
Cu Stabilizer
Superconducting
Cable
Interconnection of Magnets
Cross Section of Busbar
Ch. Balle
Friday, September 3, 2010
Measurements at Helium Temperature
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2 Sep 2010
•Setups
Test of Superconducting Busbar-Splices of the LHC-Magnets
Busbar right-side Magnet
Copper Profile Flat
SnAg Soldering Layer
NbTi Superconductor
Copper Profile U-Shape
Busbar left-side Magnet
Ch. Balle
Friday, September 3, 2010
Measurements at Helium Temperature
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2 Sep 2010
•Setups
Test of Superconducting Busbar-Splices of the LHC-Magnets
SnAg Filler
Ch. Balle
Friday, September 3, 2010
Measurements at Helium Temperature
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2 Sep 2010
•Setups
Test of Superconducting Busbar-Splices of the LHC-Magnets
Test Loop
Primary Coil
Ip ➚
➘
➙
Lp
I
t1
t2
Hall Sensor
Is➘
➚
•
Q
Ls
t3
Hall Sensor
Splice Rsplice
➙
Heater
≋ Liquid He
t4
t5
Ls
=
i(t) = io e τ with τ
Rsplice
t
t
Ch. Balle
Friday, September 3, 2010
Measurements at Helium Temperature
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2 Sep 2010