Principles of Cryostat Design

Abstract

This book enables the reader to learn the fundamental and applied aspects of practical cryostat design by examining previous design choices and resulting cryostat performance. Through a series of extended case studies the book presents an overview of existing cryostat design covering a wide range of cryostat types and applications, including the magnet cryostats that comprise the majority of the Large Hadron Collider at CERN, space-borne cryostats containing sensors operating below 1 K, and large cryogenic liquid storage vessels. It starts with an introductory section on the principles of cryostat design including practical data and equations. This section is followed by a series of case studies on existing cryostats, describing the specific requirements of the cryostat, the challenges involved and the design choices made along with the resulting performance of the cryostat. The cryostat examples used in the studies are chosen to cover a broad range of cryostat applications and the authors of each case are leading experts in the field, most of whom participated in the design of the cryostats being described. The concluding chapter offers an overview of lessons learned and summarises some key hints and tips for practical cryostat design. The book will help the reader to expand their knowledge of many disciplines required for good cryostat design, including the cryogenic properties of materials, heat transfer and thermal insulation, instrumentation, safety, structures and seals. Preface; Acknowledgments; Contents; Contributors; 1 Principles of Cryostat Design; Abstract; 1.1 Cryostat Requirements; 1.2 Cryogenic Properties of Materials; 1.2.1 Thermal Contraction; 1.2.2 Thermal Conductivity; 1.2.3 Heat Capacity; 1.2.4 Material Strength; 1.3 Thermal Insulation and Heat Transfer; 1.3.1 Reducing Conduction Heat Transfer; 1.3.2 Reducing Convection Heat Transfer; 1.3.3 Reducing Radiation Heat Transfer; 1.3.4 Other Insulation Approaches; 1.4 Structural Supports for Cryostats; 1.4.1 Alignment Approaches; 1.4.2 Suspension of Components from a Room Temperature Top Flange 1.4.3 Space Frames1.4.4 Support Posts; 1.4.5 Supports in Space Cryogenics; 1.5 Instrumentation; 1.5.1 Temperature Measurement; 1.5.2 Pressure Measurement; 1.5.3 Flow Measurement; 1.5.4 Level Measurement; 1.5.5 Installation, Wiring, Heat Sinking and Feedthroughs; 1.5.6 Commercial Availability of Instrumentation Systems; 1.5.7 Best Practices for Cryostat Instrumentation; 1.6 Seals and Connections; 1.7 Transfer Lines; 1.8 Safety; 1.9 Thermoacoustic Oscillations; 1.10 Prototyping and Series Testing; References; 2 SSC Collider Dipole Cryostat; Abstract; 2.1 Introduction; 2.2 Vacuum Vessel 2.3 Thermal Radiation Shields2.4 Multilayer Insulation; 2.5 Cryogenic Piping; 2.6 Suspension System; 2.7 Interconnect; 2.8 Test Results; 2.9 Summary; References; 3 Twenty-Three Kilometres of Superfluid Helium Cryostats for the Superconducting Magnets of the Large Hadron Collider (LHC); Abstract; 3.1 The LHC and Its Cryogenic System; 3.2 Feasibility of a Large Distributed Superfluid Helium System; 3.3 Prototype Cryostats and String Tests; 3.4 Industrial Series Production, Installation and Commissioning; 3.5 Concluding Remarks; Acknowledgments; References 4 The Superfluid Helium On-Orbit Transfer (SHOOT) Flight DemonstrationAbstract; 4.1 Introduction; 4.2 Design Considerations; 4.2.1 Structural Requirements; 4.3 Dewar and Cryostat Details; 4.3.1 Dewar Fabrication Details; 4.3.2 Cryostat Details; 4.4 Components; 4.4.1 Development Notes; 4.4.2 Phase Separation; 4.4.3 Liquid Acquisition; 4.4.4 Thermomechanical (Fountain Effect) Pumps; 4.4.4.1 Instrumentation; 4.4.5 Cryogenic Stepper-Motor Valves; 4.4.6 Cryogenic Relief Valves; 4.5 Safety; 4.6 Working with SHOOT on the Ground; 4.7 On-Orbit Operations; 4.8 Summary; References 5 TESLA & ILC CryomodulesAbstract; 5.1 Introduction; 5.2 Definitions; 5.3 Functional Requirements Summary; 5.4 Cryomodule Mechanical Design; 5.4.1 Cryomodule Major Components and Features; 5.4.2 Cryomodule Weight; 5.4.3 Major Interfaces; 5.5 Cryomodule Vacuum Design and Vacuum Vessel; 5.6 Cryomodule Thermal Design and Helium Flow Design; 5.6.1 Major Thermal Design Features; 5.6.2 Design for Large 2 K Heat Transport and Helium Flow; 5.6.3 Pressure Drop Analyses; 5.6.4 Typical TESLA-Style Cryomodule Maximum Allowable Working Pressures; 5.6.5 Instrumentation; 5.6.6 Cryomodule Test Requirements