Documentation: The Multiple-Detector System for the powder diffractometer B2 (HASYLAB / DESY)

The documentation of the Multiple-Detector System is an essential part of this project. It guarantees a good understanding of the scientific aspects of this project and of the functionality of the whole system. In addition it supports the user in planning and executing its experiment. According to the complexity the documentation is subdivided into the following books:

  • PhD Thesis
  • Technical handbook
  • Technical drawings
  • Script: analyser crystals and monochromators

    To simplify the handling of these books they are available as electronical documents (pdf-files) on a CD-ROM which can be ordered. This way of publication offers considerable advantages: quick access to scientific and technical information, background information, interactive programs and links to local contact persons. The user can choose his individual way to read the books. Graphics can be enlarged and updated information are accessible via the web. I`m sorry about that the documentation is written in German but there are regulations.

    "Welcome to the project"

    The start page will give you an overview and guides you to that item you are interested in.

    Start page of the project: Multiple-Detector-System

    You can select the books: PhD Thesis (Dissertation), Technical handbook Technisches Handbuch, Technical drawings Technische Zeichnungen, Script: analyser crystals and monochromators Skript: Analysatorkristalle - Monochromatoren

    PhD Thesis

    The title of the thesis is "Multiple-detector-system for the high resolution powder X-ray diffractometer B2 at HASYLAB (DESY) - development, design and operation of an highly efficient measuring system for structure analysis of powder data using synchrotron radiation"

    PhD Thesis

    Abstract:

    High-resolution powder diffraction experiments at synchrotron radiation sources are expensive and time consuming until now. With the new multiple-detector-system (MDS) at the beamline B2 at HASYLAB (DESY) we have achieved a major breakthrough in increasing the efficiency of the measurements and the expansion of the experimentel options. The MDS - four diffractometers in parallel beam geometry for high-resolution powder diffraction experiments in one compact unit - has a maximum gain factor of approximately 4 according to the net measuring time of conventional diffractometers. Additionally the simultaneously detection of different angular ranges enables an judgement of the data quality already at the running measurement. Using the small divergence of the incident beam the Bragg reflection angles are measured with highest angular resolution and independent of the sample position. The hardware of the MDS is modular designed. Functional units as the simultaneously steping motor drives for the analyser and scintillation counters, individual crystal position units and adjustable lead shields ensure the precise operation of the MDS. The control of the MDS is an integral part of the beamline B2 operating software. All processes are controled by one computer. The uniform software layout enables the user a short training period. The synchronous drives of the four analyser units make time consuming adjustments unnecessary, a significant point of the MDS efficiency. The positioning accuracy of the analyser units is 0.00034 . The modulare system of the analyser units consists in their exchangeable crystal analysers, flat Si(111) crystal analysers and Ge(111) channel-cut crystal analysers. This allows the MDS to work in a wavelength range from 0.6 Å (20.7 keV) to 2.5 Å (4.96 keV). Further advantages of the MDS are: high signal gain factor of the detectors, integration in existing sample environments e.g. the cryostat, the heater and the vacuum chamber, flat specimen and capillary samples can be used. Cross talk between the entrance and the exit of the analysers at short wavelengths is eliminated by adjustable lead shields. Special analyser shielding houses automatically adapted to the beam path enhance the typical peak / background ratio to 300 to 1. An important application are experiments with different wavelengths to use the anomalous scattering of X-rays for phase determination and to differentiate different groups of atoms.

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    Technical handbook

    The technical handbook stands for the common appendix of the thesis focusing the technical and engineering aspects of the project.

    Technical handbook

    The contents of the technical handbook:

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    Technical drawings

    The multiple-detector-system is completely designed with AutoCAD®. Based on the threedimensional model manufacturing drawings are made.

    Technical drawings

    The manufacturing drawings are arranged in groups of functional units. Illustrative overviews show the position of the part and are link to the drawings. Additional to the pdf-file format the drawings are stored on the CD-ROM in the dxf- and dwg-file format. This opens the way to use the free and comfortable VoloViewer which is stored on the CD-ROM too.

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    Script: analyser crystals and monochromators

    Script: analyser crystals and monochromators

    This script came into being during the development of the multiple-detector-system. It is an overview and summary about different aspects which are essentially for the design of the multiple-detector-system. Apart from elementary basics which are imperative for the understanding of x-ray functional units advanced topics are shortly introduced to encourage the reader for a more deeper insight. Useful background information e.g. the dynamic theory support the understanding of the thesis.

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    © 2001   Last update 30.04.2001   All photographs taken by W.-H. Kaps   We acknowledge financial support by the BMBF (05SM8VTA39).