Cryocoolers: Theory And Applications

Preface......Page 6
Contents......Page 8
About the Editor......Page 9
1.1 Introduction......Page 11
1.2 Classification of Cryocoolers......Page 13
1.3.1 Stirling Cryocoolers......Page 15
1.3.2 Gifford-McMahon (G-M) Cryocoolers......Page 18
1.3.3 Pulse Tube Cryocooler (PTC)......Page 20
1.3.3.1 Classification of PTCs Based on Geometry......Page 22
1.3.3.2 Classification of PTCs Based on Phase Shifting Mechanism......Page 23
1.4 Regenerators......Page 25
1.5 Compressor for Regenerative Cryocoolers......Page 27
1.6 Joule–Thomson (J-T) Cryocoolers......Page 28
1.7.1 Stirling Cryocooler Analysis......Page 31
1.7.3 Pulse Tube Cryocooler Analysis......Page 32
1.7.4 Joule–Thomson Cryocooler Analysis......Page 34
1.7.4.2 Mixture Optimization......Page 35
1.7.4.3 Correlation for Local Heat Transfer Coefficients......Page 36
1.8 Worldwide Scenario......Page 37
1.8.1 Cryopumps......Page 38
1.8.2 MRI Systems......Page 40
1.8.3 NMR......Page 42
1.8.4 IR Sensors/Detectors......Page 44
1.8.6 Cryocooler-Based Liquefiers......Page 45
1.8.7 Miniaturized J-T Cryocooler......Page 47
1.9 Invisible and Reliable Cryogenics......Page 48
References......Page 49
2.1 Overview of Cryosurgery and Cryosurgical Probes......Page 57
2.2 MGJT Cryoprobes and Cycles......Page 60
2.3 MGJT Cryoprobe with Precooling......Page 63
2.4 Commercial Options for Cryoablation Systems......Page 67
2.5 Construction Features......Page 68
2.6 Precautions......Page 70
2.7 Future Direction......Page 71
References......Page 72
3 Mixed Refrigerant Joule–Thomson Cryocooler for CoolingHigh-Temperature Superconductor Cables......Page 74
3.1 Introduction......Page 75
3.2 MRJT Refrigerator for Cooling Below 77 K......Page 80
3.3 NF (Nonflammable) MRJT Refrigerator for Cooling Below 77 K......Page 81
3.4 Configuration of the Designed NF MRJT Refrigerator for Cooling HTS Cable......Page 83
3.5 Design Analysis Results of the Practical NF MRJT Cryogenic Refrigerator for HTS Cable......Page 84
3.6 Reliability of Cascade System......Page 86
3.7 Concluding Remarks......Page 88
References......Page 89
4.1 Introduction......Page 91
4.2 Cryogen-Free Cryostats......Page 93
4.3 Powerful Cryogen-Free Dilution Refrigerators Used in Neutron Scattering Experiments......Page 95
4.4 Cryogen-Free Advanced Superconducting Magnets for Neutron Scattering Experiments......Page 96
4.5 Specialised Cryogen-Free Sample Environment Systems......Page 98
4.6 Cryogen-Free Technology in Neutron Scattering Instruments......Page 101
4.7 Conclusions......Page 102
References......Page 104
5.1 Introduction......Page 107
5.2.1 Basis of ADR Operation......Page 110
5.2.2 Multistaging to Increase the Temperature Range and Performance......Page 112
5.2.3 Heat Rejection from an ADR......Page 114
5.2.4 Phasing of Heat Loads......Page 116
5.3.1 Thermal Links......Page 120
5.3.2 Optimization of Magnetic Current Leads......Page 122
5.3.3 Thermal and Mechanical Considerations for Multistage ADRs......Page 124
References......Page 126
6.1 Introduction......Page 129
6.3 Early High Power SC Generators: Examples......Page 131
6.4 Basics of SC Generator Design......Page 133
6.5 Early Generator Cryogenics......Page 135
6.6 Cryocooler Rotor Cooling Technologies for SC Generators and Motors......Page 140
6.7.1 Overview of Available, Commercial Coolers for HTS Machinery......Page 141
6.7.3 Cryocooler Integration: Schematics and Options......Page 143
6.7.4 Conduction Cooling of Racetrack Coils......Page 144
6.7.5 Conduction Cooling of Rotor Assembly......Page 145
6.7.6 Thermosiphon Cooling......Page 147
6.7.7 Remote Cooling Applications......Page 152
6.8.1 Example: Wind Energy Application—Overview......Page 156
6.9 Summary......Page 159
References......Page 160
7.1 Cryocoolers Used in Research Cryostats......Page 163
7.2 History of Dry Cryostats......Page 164
7.3 Elements of Cryostat Design......Page 165
7.3.1 Cryocooler, the Engine That Drives the Cryostat......Page 166
7.3.2 Vacuum Shroud Design......Page 167
7.3.4 Sample Holder Design......Page 169
7.3.5.2 What Window Materials Are Acceptable......Page 170
7.3.5.5 Maximizing the Optical Signal to the Sample (F-Number (F#))......Page 171
7.3.5.6 Wiring and Instrumentation......Page 172
7.4.1 Thermal Budget......Page 173
7.4.2 Cryostat Construction: Material Selection......Page 174
7.4.3.1 Thermal Conductivity......Page 175
7.4.4 Vacuum Considerations......Page 176
7.5.1 Ultra-Low Vibration Cryostats......Page 177
7.5.1.1 Gas Gap Vibration Isolation (ULV and XLV)......Page 179
7.5.1.3 Drift Control......Page 180
7.6 Popular Applications for Low Temperature Research......Page 182
7.6.1 Optical Spectroscopy......Page 183
7.6.2 Electrical Transport......Page 184
7.6.4 Cryostat for Electro-Optical Experiments......Page 185
7.6.6 Cryostats for UHV and XHV......Page 186
7.6.8 Cryostat for Nano-Optics......Page 187
7.6.9 XLV Cryostats for Atomic Microscopy (STM, AFM, SEM)......Page 188
7.6.9.1 Dry Cryo-STM......Page 190
8.1 Introduction......Page 191
8.2 Working of the DPWG......Page 192
8.2.2 Coaxial and In-Line Pulse Tubes......Page 194
8.4 Use of the Device......Page 196
References......Page 197
9.1.1 The Importance of Cryocoolers for the Medical Industry: Saving Helium......Page 198
9.1.2 Saving Helium at the Factory......Page 199
9.1.4 Saving Helium When Decommissioning a System......Page 200
9.2 Conventional MRI Scanner Schematics and Cryogenics......Page 201
9.3 Cryocooler Integration......Page 202
9.4 Cryocooler Integration Examples......Page 203
9.5 Cryocooler for Cryostat and Magnet Cooldown......Page 206
9.7 Cryocoolers for Standalone Metabolic Imaging Devices......Page 207
9.8 Conclusions......Page 209
References......Page 211
10 Cryocoolers for Helium Liquefaction......Page 212
10.1 Introduction......Page 213
10.2.1 Heat Exchange Between Gas and Cryo-Refrigerator......Page 214
10.2.2 Liquefaction System and Method......Page 216
10.2.2.1 Heat Exchange Process During Initial Cooldown......Page 217
10.2.2.2 Heat Exchange Process During Liquefaction......Page 219
10.2.2.3 Advanced Technology Liquefier (ATL)......Page 222
10.2.2.4 Advanced Technology Liquefier (ATL) with Pressurized Insert......Page 224
10.3.1 Gas Purification by Cryo-condensation......Page 228
10.3.2 Purifier Design......Page 231
10.4 Theoretical Calculations of the ATL Liquefaction Process......Page 233
10.4.1 Mass Balance......Page 234
10.4.2 Heat Exchange Balance......Page 235
10.5 Summary......Page 240
References......Page 242