Book contents
- Frontmatter
- Contents
- List of contributors
- Preface
- SECTION A DETECTION AND QUANTIFICATION OF X-RAYS
- 1 Recent developments in X-ray detectors and their relevance in biological X-ray microanalysis
- 2 Quantitative software for biological applications of X-ray microanalysis
- 3 X-ray mapping techniques in biology
- 4 Quantitative X-ray microanalysis of thin sections in biology: appraisal and interpretation of results
- SECTION B ASSOCIATED TECHNIQUES
- SECTION C SPECIMEN PREPARATION
- SECTION D APPLICATIONS OF X-RAY MICROANALYSIS IN BIOLOGY
- Index
1 - Recent developments in X-ray detectors and their relevance in biological X-ray microanalysis
from SECTION A - DETECTION AND QUANTIFICATION OF X-RAYS
Published online by Cambridge University Press: 04 August 2010
- Frontmatter
- Contents
- List of contributors
- Preface
- SECTION A DETECTION AND QUANTIFICATION OF X-RAYS
- 1 Recent developments in X-ray detectors and their relevance in biological X-ray microanalysis
- 2 Quantitative software for biological applications of X-ray microanalysis
- 3 X-ray mapping techniques in biology
- 4 Quantitative X-ray microanalysis of thin sections in biology: appraisal and interpretation of results
- SECTION B ASSOCIATED TECHNIQUES
- SECTION C SPECIMEN PREPARATION
- SECTION D APPLICATIONS OF X-RAY MICROANALYSIS IN BIOLOGY
- Index
Summary
Introduction
In 1949, Castaing and Guinier combined for the first time the technique of electron optics and X-ray analysis for the production of the first electron probe analyser (Castaing & Guinier, 1949). Developments continued during the years from a static beam instrument into a scanning device. However, all the analysis was initially limited to thick specimens and it was only at a later date that the first prototype microanalyser was specifically developed for thin specimens (Duncumb, 1962). The detection and counting of X-rays was done by using conventional wavelength dispersive crystal spectrometers. A major breakthrough in X-ray analysis came in 1968 with the development of the solid state energy dispersive X-ray detector (Fitzgerald, Keil & Heinrich, 1968). This type of detector provided higher collection efficiency than the wavelength dispersive spectrometer as well as more reproducible results because mechanical movements were no longer necessary.
Nowadays X-ray microanalysis is a well used technique for analysis of biological material in combination with the transmission and scanning electron microscopes. In this chapter new developments on the energy dispersive detectors will be discussed. Special attention will be given to the advantage of using a high purity germanium crystal instead of Si(Li) crystal in the EDS detector.
X-ray generation
When a focused electron beam hits a specimen several processes occur at the surface and in the specimen. In Fig. 1.1 a schematic presentation of the different interactions is presented.
- Type
- Chapter
- Information
- X-ray Microanalysis in BiologyExperimental Techniques and Applications, pp. 3 - 18Publisher: Cambridge University PressPrint publication year: 1993