DeutschesFachbuch.de : Matter and Methods at Low Temperatures Von Frank Pobell

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Contents
1 Introduction 1
2 Properties of Cryoliquids 7
2.1 Liquid Air, Liquid Oxygen, Liquid Nitrogen 7
2.2 Liquid Hydrogen 8
2.3 Liquid Helium 13
2.3.1 Some Properties of the Helium Isotopes 13
2.3.2 Latent Heat of Evaporation and Vapour Pressure 17
2.3.3 Specific Heat 20
2.3.4 Transport Properties of Liquid 4 He: Thermal Conductivity and Viscosity ...
2.3.5 Superfluid Film Flow 25
2.3.6 Liquid 3 He and 3 He-4 He Mixtures at Millikelvin Temperatures 27
Problems 32
3 Solid Matter at Low Temperatures 33
3.1 Specific Heat 34
3.1.1 Insulators 34
3.1.2 Metals 38
3.1.3 Superconducting Metals 40
3.1.4 Non-Crystalline Solids 42
3.1.5 Magnetic Specific Heat 44
3.1.6 The Low-Temperature Specific Heat of Copper and Platinum 47
3.1.7 Specific Heat of Some Selected Materials 47
3.1.8 Calorimetry or How to Measure Heat Capacities 50
3.2 Thermal Expansion 58
3.2.1 Thermal Expansion of Solids 58
3.2.2 Dilatometers or How to Measure Thermal Expansions 61
3.3 Thermal Conductivity 62
3.3.1 Lattice Conductivity: Phonons 63
3.3.2 Electronic Thermal Conductivity 67
3.3.3 Thermal Conductivity at Low Temperatures 70
3.3.4 Superconducting Metals 71
3.3.5 Relation Between Thermal and Electrical Conductivity: The Wiedemann-Fran...
3.3.6 Influence of Impurities on Conductivity 74
3.3.7 Thermal Conductivities of Copper, Silver and Aluminum at Low Temperatu...
3.3.8 How to Measure Thermal Conductivities 79
3.4 Magnetic Susceptibilities 81
3.4.1 Magnetic Susceptibilities of Some Selected Materials 81
3.4.2 How to Measure Susceptibilities and Magnetizations 84
Problems 92
4 Thermal Contact and Thermal Isolation 95
4.1 Selection of the Material with the Appropriate Cryogenic Thermal Conduct...
4.2 Heat Switches 97
4.2.1 Gaseous and Mechanical Heat Switches 97
4.2.2 Superconducting Heat Switches 98
4.3 Thermal Boundary Resistance 102
4.3.1 Boundary Resistance Between Metals 102
4.3.2 Boundary Resistance Between Liquid Helium and Solids 105
Problems 113
5 Helium-4 Cryostats and Closed-Cycle Refrigerators 115
5.1 Use of Liquid 4 He in Low-Temperature Equipment 116
5.1.1 Cool-Down Period 116
5.1.2 Running Phase of the Experiment 117
5.2 Helium-4 Cryostats 120
5.2.1 Double-Walled Glass Dewars 121
5.2.2 Metal Dewars 123
5.2.3 Cryostats for T >5 K 124
5.2.4 Cryostats with Variable Temperature for 1.3 K< T< 4.2 K 125
5.2.5 Auxiliary Equipment 130
5.3 Closed-Cycle Refrigerators 133
5.4 Temperature Control 136
5.5 Problems 137
6 Helium-3 Cryostats 139
6.1 Helium-3 Cryostats with External Pumps 140
6.2 Helium-3 Cryostats with Internal Adsorption Pumps 142
Problems 147
7 The 3 He-4 He Dilution Refrigerator 149
7.1 Properties of Liquid 3 He-4 He Mixtures 150
7.1.1 Phase Diagram and Solubility 150
7.1.23 He-4 He Mixtures as Fermi Liquids 153
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Index
AAbsolute zero, 260
Absorptivities of metals, 118
Accommodation coefficient, 119
Acoustic mismatch (impedance), 105-110, 113
Adiabatic demagnetization of paramagnetic salts, 203-213
- cooling power, 204, 206, 208-210, 212
- heat of magnetization, 205
- minimum temperature, 203, 208, 212
- paramagnetic salts, 203, 209, 212
- principle, 204
- refrigerators, 209-212
- space applications, 212
- thermodynamics, 204-206
Adiabatic nuclear demagnetization, 215-258
- cooling power, 216, 217, 228, 239, 243
- double stage nuclear refrigerator, 218, 252-256
- experimental procedure, 218, 221, 222
- heat leaks, 230-238
- heat of magnetization, 221, 222
- history, 217
- hyperfine enhanced ad. nucl. ref., 241-244
- influence of heat load, 228-230
- minimum (final) temperature, 229, 230, 235, 240, 245, 247, 256, 257
- nuclear refrigerators, 218, 244-256
- optimum demagnet, 229
- precooling, 244, 246, 251, 253
- requirements on refrigerants, 239
- temperature regulation, 256
- warming-up time, 229
Adsorption capacity (isotherms) of charcoal, 146
Adsorption cryostats,3 He, 142-145
Adsorption isotherms, 146
Adsorption pump for helium, 142, 183
Ag
- freezing point, 262, 263
- magnetization, 83
- nuclear specific heat, 220
- properties, 224, 225
- residual resistivity ratio, 74
- sintered powder, 171, 172, 370-372
- thermal conductivity, 66, 74, 77
- thermal expansion coefficient, 60
Air, liquid, 2, 7
- Al freezing point, 262
- magnetic impurities in, 75, 77, 78
- magnetization, 83
- nuclear specific heat, 220
- properties, 224, 225, 240
- specific heat, 49
- superconducting transition temperature, 224, 225
- thermal conductivity, 65-67, 77, 99-101
- thermal expansion coefficient, 60, 101
A 12 O 3 (sapphire)
- heat release, 237
- optical transmissivity, 374, 375
- thermal conductivity, 65, 71
Angular radiation pattern of oriented
- nuclei, 348
Anisotropy of 7-rays, thermometry, 268, 277, 345-350
Apiezon, 49, 67, 82
- specific heat, 49
Araldite, thermal conductivity, 60, 69
Atomic potential, 33, 58, 59
AuEr+, 81
- susceptibility, 325
Au, properties, 224, 225
AuIn 2
- nuclear heat capacity, 53
- nuclear magnetic ordering, 53, 240
AuIn 2 , properties, 53, 224, 225, 240, 272, 329, 330
Automatic filling of cryostats, 131-133
BBackground temperature in universe, 2
Be-Cu, elastic properties, 355-357
- mechanical properties, 355, 357
- specific heat, 48
Bellows in pumping lines, 233
BET adsorption technique, 373
Bismuth, 105
Blackbody radiation, 118
Bohr magneton, 207, 215, 397
Boiling points
- cryoliquids, 7, 8- 3 He and 4 He, 8, 14
Boltzmann constant, 261, 395
- determination of, 261
Boltzmann population, 277, 345, 347, 350
Boundary resistance
- between helium and metal sinters, 109, 113
- between helium and solids, 103-113, 169, 176
- between solids, 102
- in dilution refrigerators, 168-174, 183
- magnetic coupling, 110-112
- magnetic field dependence, 112
Brass
- thermal conductivity, 66, 67
- thermal expansion coefficient, 60
Bridge
- capacitance, 357, 358
- inductance (susceptibility), 86, 273
- resistance, 305-308
Brillouin function, 208, 221
CCalorimeters, 50-58
- AC, 54-57
- adiabatic heat pulse, 51-54
- commercial, 57
- differential thermal analysis, 57
- high magnetic field, 56, 57
- rotatable, 374
- thermal relaxation, 54-57
Capacitance bridge, 357, 358
Capacitive level detectors, 133
Capacitive strain gauge (manometer; transducer), 353-358
Carbon resistance thermometers, 293-300
- design, 297, 298
- drift with time, 293
- heat capacity, 297
- heating effects, 294-297
- magnetoresistance, 298-300
- thermal time constants, 298
Carnot cycle, 259
Celsius temperature scale, 260
Charcoal
- adsorption capacity (isotherms), 146
- adsorption cryostats, 142-145
- cold trap, 186, 187
Clausius-Clapeyron equation, 18, 192, 270
Closed-cycle refrigerator, 124, 133-136
- Gifford-McMahon, 133-135, 184
- minimum temperature, 134, 135
- pulse-tube, 133-136, 183, 184
CMN
- adiabatic refrigeration, 205, 209-212
- boundary resistance to 3 He, 110
- entropy, 205
- susceptibility thermometry, 322-324
- thermal conductivity, 67
- thermal time constant, 323
Coaxial cryogenic leads and connector, 97, 361-363
Cold trap, 186, 187
Cold valve, 359-361
Conductance of pumping tube, 142
Conductivity of sintered metals, 174, 370, 372
Connector for cryogenic coaxial leads, 362
Constantan
- electrical resistance, 96
- specific heat, 45, 48, 49
- thermoelectric power, 284, 285
Contact resistance between metals, 102-105
Continuous 4 He evaporation cryostat, see Evaporation cryostats
Continuous heat exchanger, 170-173, 179
Cooling power
-3 He 4 He dilution refrigeration, 153, 157-160, 165, 166, 179, 182-4 He evaporation ...
- nuclear refrigerators, 228-230
- paramagnetic electronic refrigeration, 205, 206
- Pomeranchuk refrigeration, 193, 196-198
- tunnel-junction refrigerators, 377
Cosmic rays, heat leak, 231, 238
Cost of 3 He, 139
Coulomb blockade thermometry, 269, 308-311
Critical magnetic fields, superconductors, 224, 272, 368
Critical temperature (pressure) cryoliquids, 8
-3 He and 4 He, 14 superconductors, 105, 224, 271, 272
Cryogenic
- coaxial leads and connector, 361-363
- motor, 373
- temperature scales, 259-275
- valves, 359-361
- windows, 374, 375
Cryoliquids, properties, 8, 14
Cryoperm, see Normal-conducting shields
Cryopumping, 19, 119
Cryostats
- adsorption, 142-145
consumption of 4 He, 116, 117, 124, 127
cool-down period precooling, 116
- dipstick, 129, 145, 181
- evaporation, 120-129, 140-145
- gas flow, 124
- glass, 121, 1223 He, 139-1454 He, 120-129
- heat sources, 117-120
- metal, 124, 125
- plastic, 124
Crystalline structure of metals, 42
Crystal water in paramagnetic salts, 209
Cu
- electrical conductivity, 72-76
- freezing point, 262
- heat release, 235-237
- internal magnetic field, 220, 226, 229
- Korringa constant, 225
- nuclear antiferromagnetic ordering, 216
- nuclear magnetic resonance, 330, 332
- nuclear magnetic spin entropy, 216, 241, 253
- nuclear magnetization, 221, 329
- nuclear specific heat, 220
- nuclear Zeeman levels, 217
- properties, 224, 225
- residual resistivity ratio, 74
- sintered powder, 370-372
- specific heat, 39, 47-49, 223, 225
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