Single Crystal Diffractometry ( Cambridge Monographs on Physics )

Publication series ：Cambridge Monographs on Physics

Author： U. W. Arndt; B. T. M. Willis

Publisher： Cambridge University Press‎

Publication year： 2009

E-ISBN: 9780511863332

P-ISBN(Paperback): 9780521112291

Subject： O721 crystal X - ray, electron and neutron diffraction theory

Keyword：物理学

Language： ENG

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Single Crystal Diffractometry

Description

The first stage in the determination of a crystal structure is the measurement of the intensities of the Bragg reflexions. This book is concerned with counter-methods of measuring these intensities. The use of counter methods has spread rapidly in recent years with the development of quantum detectors and of automatically controlled diffractometers. The authors of this book were among the first workers to design and operate automatic X-ray and neutron diffractometers; they have visited laboratories throughout the world where such instruments have been installed. Originally published in 1966, this book covers all aspects of single crystal diffractometry. A discussion of the geometrical principles of diffraction by single crystals is followed by a description of diffractometers and of their component parts, including radiation detectors and detector circuits.

Chapter

CHAPTER 1 Introduction

1.1 X-ray techniques for measuring Bragg reflexions

1.2 Neutron techniques for measuring Bragg reflexions: comparison with X-ray techniques

1.3 Automatic diffractometers

1.4 Accuracy of counter methods

1.5 Speed of counter methods

1.6 Cost of counter methods

CHAPTER 2 Diffraction Geometry

2.1 General considerations

2.2 Cylindrical polar co-ordinates in reciprocal space

2.3 Inclination method

2.4 Normal-beam equatorial method

2.5 Comparison of inclination and equatorial methods

2.6 The simultaneous measurement of reflexions

CHAPTER 3 The Design of Diffractometers

3.1 Introduction

3.2 Digital shaft setting

3.3 Analogue shaft setting

3.4 Radiation shielding

3.5 Collimator alinement

3.6 Crystal mounting

3.7 The provision of special environments

3.8 The Hilger-Ferranti four-circle diffractometer

3.9 The Royal Institution linear diffractometer

3.10. A comparison of the four-circle and linear diffractometers

3.11 Some other designs

CHAPTER 4 Detectors

4.1 Introduction

4.2 X-ray gas ionization counters

4.3 Scintillation counters for X-rays

4.4 Semi-conductor detectors for X-rays

4.5 Principles of neutron detection

4.6 Gas-filled detectors for neutrons

4.7 Semi-conductor neutron detectors

4.8 Scintillation counters for neutrons

4.9 Counting losses

4.10 Co-ordinate detectors

CHAPTER 5 Electronic Circuits

5.1 Introduction

5.2 Valve and transistor circuits

5.3 The counting chain

5.4 Noise and interference

5.5 Testing of counting chain

CHAPTER 6 The Production of the Primary Beam (X-rays)

6.1 Introduction

6.2 X-ray sources

6.3 Collimators

6.4 The elimination of unwanted radiation

6.5 Crystal monochromators

6.6 Total external reflexion

6.7 Primary beam monitoring

CHAPTER 7 The Production of the Primary Beam (Neutrons)

7.1 Neutron collimators

7.2 Neutron spectrum emerging from collimator

7.3 Crystal monochromators

7.4 Mechanical monochromators

7.5 Neutron diffractometry using ' white' primary beam

CHAPTER 8 The Background

8.1 Introduction

8.2 Thermal diffuse scattering

8.3 White radiation background

8.4 Incoherent scattering of X-rays

8.5 Incoherent scattering of neutrons

8.6 Parasitic scattering

8.7 Background and rocking range

CHAPTER 9 Systematic Errors in Measuring Relative Integrated Intensities

9.1 Absorption

9.2 Extinction

9.3 Simultaneous reflexions

CHAPTER 10 Procedure for Measuring Integrated Intensities

10.1 Choice of crystal size and shape

10.2 Alinement of crystal

10.3 Correct assignment of signs of crystallographic axes

10.4 Measurement of lattice parameters

10.5 Choice of scan

10.6 Strategy for exploring reciprocal space

10.7 Counting statistics and period of counting

CHAPTER 11 Derivation and Accuracy of Structure Factors

11.1 Lorentz factor

11.2 Polarization factor

11.3 Observed structure factors: absolute measurements

11.4 Calculated structure factors

11.5 Comparison of observed and calculated structure factors

CHAPTER 12 Computer Programs and On-line Control

12.1 Diffractometer input and output

12.2 Types of computer programs

12.3 Direct connexion to a computer

APPENDIX Summary of differences between X-ray and neutron diffractometry

References

Index

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