Book contents
- Frontmatter
- Contents
- Preface
- CHAPTER 1 Introduction
- CHAPTER 2 Diffraction Geometry
- CHAPTER 3 The Design of Diffractometers
- CHAPTER 4 Detectors
- CHAPTER 5 Electronic Circuits
- CHAPTER 6 The Production of the Primary Beam (X-rays)
- CHAPTER 7 The Production of the Primary Beam (Neutrons)
- CHAPTER 8 The Background
- CHAPTER 9 Systematic Errors in Measuring Relative Integrated Intensities
- CHAPTER 10 Procedure for Measuring Integrated Intensities
- CHAPTER 11 Derivation and Accuracy of Structure Factors
- CHAPTER 12 Computer Programs and On-line Control
- APPENDIX: Summary of differences between X-ray and neutron diffractometry
- References
- Index
CHAPTER 3 - The Design of Diffractometers
Published online by Cambridge University Press: 21 May 2010
- Frontmatter
- Contents
- Preface
- CHAPTER 1 Introduction
- CHAPTER 2 Diffraction Geometry
- CHAPTER 3 The Design of Diffractometers
- CHAPTER 4 Detectors
- CHAPTER 5 Electronic Circuits
- CHAPTER 6 The Production of the Primary Beam (X-rays)
- CHAPTER 7 The Production of the Primary Beam (Neutrons)
- CHAPTER 8 The Background
- CHAPTER 9 Systematic Errors in Measuring Relative Integrated Intensities
- CHAPTER 10 Procedure for Measuring Integrated Intensities
- CHAPTER 11 Derivation and Accuracy of Structure Factors
- CHAPTER 12 Computer Programs and On-line Control
- APPENDIX: Summary of differences between X-ray and neutron diffractometry
- References
- Index
Summary
Introduction
There is no one ideal X–ray or neutron diffractometer which is equally well suited to the many different investigations which have to be carried out. The principal factors in the performance of a diffractometer are:
Accuracy of intensity measurement
Speed of operation
Number of accessible reflexions
Amount of manual intervention required
Accessibility of specimen
Availability of a computer
Versatility
Reliability
Cost
These varying requirements frequently conflict with one another and the choice of instrument for a given application will depend on the relative importance attached to them. We shall compare later the performance of two specific instruments under the headings listed above.
As we have seen in Chapter 2, diffractometers can be constructed according to two different geometrical arrangements, leading to a division into equatorial and inclination instruments. All diffractometers suitable for the collection of three–dimensional intensity data must have a number of shafts capable of being set independently: in the two arrangements the rotational degrees of freedom are allocated differently between crystal and detector shafts.
The general design of the diffractometer is dictated primarily by the type of geometrical arrangement, and by the method adopted in setting the shafts. The collimator, the goniometer head which supports the crystal, alinement aids such as viewing telescopes and even the detector itself can be thought of as exchangeable attachments which can be selected in accordance with the particular investigation in hand, and are of secondary importance in influencing the design of the instrument.
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- Single Crystal Diffractometry , pp. 65 - 98Publisher: Cambridge University PressPrint publication year: 1966