Low-Temperature X-Ray Diffraction

I: Introduction and Applications.- 1. Introduction.- 1.1. Historical Background.- 1.2. Cooling Apparatus.- 1.2.1. Provision for Cooling the Sample.- 1.2.1.1. Gas Stream.- 1.2.1.2. Conduction.- 1.2.1.3. Immersion.- 1.2.2. Control and Measurement of the Sample Temperature.- 1.2.3. Frost Prevention.- 1.3. Problem Areas in Designing LTXRD Apparatus.- 1.3.1. Absorption of X-Radiation.- 1.3.2. Size of Instrument.- 1.3.3. Frost Formation.- 1.3.4. Temperature Stability.- 1.3.5. Temperature Calibration.- 1.3.6. Misalignment.- 1.3.7. Sample.- 2. Applications.- 2.1. Solidified Liquids and Gases.- 2.2. Crystal-Structure Analysis.- 2.3. Electron-Density Distribution.- 2.4. Radiation Damage.- 2.5. Protein Crystallography.- 2.6. Defect Structures.- 2.7. Solid-Solid Phase Transition.- 2.7.1. Plastic Crystals.- 2.7.2. Metastable States.- 2.7.3. Phase Transitions.- 2.7.4. High-Pressure, Low-Temperature Studies.- 2.8. Thermal Expansion Coefficients and Precision Lattice Constants.- 2.9. Low-Temperature Powder Patterns.- 2.10. Other X-Ray Diffraction Applications.- 2.11. Application of Low-Temperature Methods to Other Types of Physical Measurements.- II: Low-Temperature X-Ray Diffraction Apparatus.- 3. Gas-Stream Cooling Apparatus.- 3.1. General Principles.- 3.1.1. Gas Generator.- 3.1.2. Transfer Lines and Nozzle.- 3.1.3. Temperature Control.- 3.1.4. Temperature Measurement.- 3.1.5. Frost Prevention.- 3.1.6. Rate of Cryogen Consumption.- 3.1.7. Gas-Stream Systems.- 3.1.8. Protection of X-Ray Apparatus.- 3.2. The Cold-Stream Nozzle.- 3.2.1. Size of the Opening.- 3.2.2. Outer Stream.- 3.2.3. Construction.- 3.2.4. Calibration of Temperature Gradient.- 3.3. Construction of a Simple Gas-Stream Apparatus.- 3.3.1. The Nozzle.- 3.3.2. The Heat Exchanger.- 3.3.3. Dry Gas.- 3.3.4. Temperature Control System.- 3.4 More Sophisticated Low-Temperature Gas-Stream Systems.- 3.4.1. Gas Stream from External Source.- 3.4.1.1. Mechanical Refrigeration.- 3.4.1.2. Heat Exchanger Immersed in Cold Bath.- 3.4.2. Gas Stream from Boiling Liquid Nitrogen.- 3.4.2.1. The Reservoir as Gas Generator.- 3.4.2.2. Reservoir Fills Small Gas Generator.- 3.4.2.3. Reservoir Fills Large Gas Generator.- 3.4.3. Gas Stream from Boiling Liquid Hydrogen or Liquid Helium.- 3.4.3.1. Weissenberg Goniometer.- 3.4.3.2. Single-Crystal Diffractometer.- 3.4.3.3. Rotation Camera.- 3.4.3.4. Powder Camera.- 3.4.4. Chambers Cooled by Gas Streams.- 3.5. Special Considerations for Specific X-Ray Diffraction Instruments.- 3.5.1. Weissenberg Goniometer.- 3.5.1.1. Back-Stream Method.- 3.5.1.2. Layer-Line Screens.- 3.5.1.3. Nozzle Support.- 3.5.1.4. Film Cassette.- 3.5.1.5. Rat-Plate Adapter.- 3.5.1.6. Upper-Level Photographs.- 3.5.2. Precession and Oscillation-Rotation Cameras.- 3.5.3. Single-Crystal Diffractometer.- 3.5.4. Powder Cameras and Diffractometer.- 3.6. Summary of Gas-Stream Methods.- 4. Conduction-Cooling Apparatus.- 4.1. General Principles.- 4.1.1. Introduction.- 4.1.2. Advantages of Conduction-Cooling Techniques.- 4.1.3. Disadvantages of Conduction-Cooling Techniques.- 4.1.3.1. Limitations on Data Collection.- 4.1.3.2. Absorption of X-Ray Beam.- 4.1.3.3. Thermal Gradients.- 4.1.3.4. Sample Preparation in Situ.- 4.2. Cryostat Design Requirements.- 4.2.1. Frost.- 4.2.2. Beryllium Windows.- 4.2.3. Temperature Gradients.- 4.2.4. Continuous-Flow Cryostat.- 4.3. Special Considerations for Individual X-Ray Instruments.- 4.4. Conduction Cooling via Liquefied Gases.- 4.4.1. Single-Crystal Cryostats for Use with Liquid Helium.- 4.4.2. Single-Crystal Cryostats for Use with Liquid Nitrogen.- 4.4.3. Powder-Sample Cryostats for Use with Liquid Helium or Liquid Nitrogen.- 4.4.3.1. Camera Apparatus.- 4.4.3.2. Liquid-Helium Cryostats for Powder Diffractometers.- 4.4.3.3. Liquid-Nitrogen Cryostats for Powder Diffractometers.- 4.4.3.4. Diffractometer Adapters.- 4.5. Conduction Cooling via Mechanical Refrigeration.- 4.6. Conduction Cooling via Thermoelectric Cooling.- 4.7. Conduction Cooling via Joule-Thomson Expansion.- 5. Immersion-Cooling Apparatus.- 5.1. General Principles.- 5.2. Immersion of Sample in Cold Liquid.- 5.2.1. Spraying.- 5.2.2. Dripping.- 5.2.3. Dipping.- 5.3. Immersion of Camera in Cold Liquid.- 5.4. Use of Cold Room.- III: Low-Temperature X-Ray Diffraction Techniques.- 6. Sample Preparation.- 6.1. Sample Preparation: Samples Solid at Room Temperature.- 6.1.1. Well-Behaved Solids.- 6.1.2. Unstable Samples.- 6.1.3. Protein Samples.- 6.1.4. Phase Transitions.- 6.2. Sample Preparation: Samples Liquid at Room Temperature.- 6.2.1. Crystallization Prior to Mounting.- 6.2.2. Crystallization Simultaneously with Mounting.- 6.2.3. Crystallization after Mounting.- 6.2.3.1. Filling and Sealing of Capillary Tubes.- 6.3. Sample Preparation: Samples Gaseous at Room Temperature.- 6.4. Preparation of Reactive or Radioactive Samples.- 6.5. Techniques for Preparing Randomly Aligned Powder Samples.- 7. Crystal-Growing-Techniques.- 7.1. Samples Solid at Room Temperature.- 7.2. Samples Liquid or Gaseous at Room Temperature.- 7.2.1. Crystal Growth at Low Temperatures Prior to Mounting the Crystal.- 7.2.2. Crystal Growth from the Melt; Sample in Capillary Tube.- 7.2.2.1. Growth Not on the X-Ray Instrument.- 7.2.2.2. Growth by Controlling the Temperature of a Gas Stream.- 7.2.2.3. External Heating.- 7.2.2.4. Special Problems.- 7.2.3. Crystal Growth from the Melt; Sample Not in Capillary Tube.- 7.3. Crystal Growth below the Temperature of Phase Transition.- 7.3.1. Slow Cooling.- 7.3.2. Annealing.- 7.3.3. Growth from Solution.- 7.4. Test for Centrosymmetric Crystal.- 8. Data Collection and Reduction.- 8.1. Temperature of Data Collection.- 8.1.1. Choice of Temperature.- 8.1.2. Temperature Calibration.- 8.2. Apparatus to Be Used for Data Collection.- 8.2.1. Protection of the X-Ray Instrument.- 8.2.2. Film at Low Temperature.- 8.2.3. Alignment and Calibration of Apparatus.- 8.3. Data Collection.- 8.3.1. Strategy of Data Collection.- 8.3.2. Check for Single Crystal.- 8.3.3. Alignment of Crystal.- 8.3.4. Radiation Damage.- 8.4. Data Reduction.- 8.4.1. Absorption Corrections.- 8.4.1.1. Powder Sample.- 8.4.1.2. Absorption by Windows and Sample Holder.- 8.4.1.3. Sample in Capillary Tube and Completely Bathed in the Beam.- 8.4.1.4. Sample in Capillary Tube and Larger than the Beam.- 8.4.1.5. Effect of Capillary Tube on Background Measurement.- 8.4.2. Refinement of Disordered Models.- 9. Future Trends in Low-Temperature X-Ray Diffraction.- IV: Appendices, Bibliography, and Index.- Appendix 1. Temperature Measurement.- Appendix 2. Cryogenic Liquids and Solids.- Appendix 3. Mechanical Refrigeration.- Appendix 4. Joule-Thomson Expansion Cooling.- Appendix 5. Thermoelectric Devices.- Appendix 6. Dewars.- Appendix 7. Transfer Lines.- Appendix 8. Insulation.- Appendix 9. Frost Prevention.- Appendix 10. Miscellaneous Gas-Flow Accessories.- Appendix 11. Low-Temperature Adhesives and Greases.- Appendix 12. List of Manufacturers of Low-Temperature Equipment and Accessories.- Appendix 13. Recommended Procedure for Describing Low-Temperature Apparatus in Publications.- B.1. Introduction.- B.2. Alphabetical Listing.- B.3. Apparatus Code-Number Listing.- B.4. Techniques and Applications Code-Number Listing.