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X-ray sources Sealed tubes - Coolidge type common - Cu, Mo, Fe, Cr, W, Ag intensity limited by cooling req'ments (2-2.5kW) Sealed tubes - Coolidge type.

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Presentation on theme: "X-ray sources Sealed tubes - Coolidge type common - Cu, Mo, Fe, Cr, W, Ag intensity limited by cooling req'ments (2-2.5kW) Sealed tubes - Coolidge type."— Presentation transcript:

1 X-ray sources Sealed tubes - Coolidge type common - Cu, Mo, Fe, Cr, W, Ag intensity limited by cooling req'ments (2-2.5kW) Sealed tubes - Coolidge type common - Cu, Mo, Fe, Cr, W, Ag intensity limited by cooling req'ments (2-2.5kW)

2 X-ray sources Sealed tubes - Coolidge type common - Cu, Mo, Fe, Cr, W, Ag intensity limited by cooling req'ments (2-2.5kW) Intensity also changes w/ take-off angle Sealed tubes - Coolidge type common - Cu, Mo, Fe, Cr, W, Ag intensity limited by cooling req'ments (2-2.5kW) Intensity also changes w/ take-off angle

3 X-ray sources Intensity also changes w/ take-off angle But resolution decreases w/ take-off angle Intensity also changes w/ take-off angle But resolution decreases w/ take-off angle

4 X-ray sources

5 Rotating anode high power - 40 kW demountable various anode types Rotating anode high power - 40 kW demountable various anode types

6 X-ray sources Synchrotron need electron or positron beam orbiting in a ring beam is bent by magnetic field x-ray emission at bend Synchrotron need electron or positron beam orbiting in a ring beam is bent by magnetic field x-ray emission at bend

7 X-ray sources Synchrotron need electron or positron beam orbiting in a ring beam is bent by magnetic field x-ray emission at bend Advantages rad divergence (3-5 4 m) Synchrotron need electron or positron beam orbiting in a ring beam is bent by magnetic field x-ray emission at bend Advantages rad divergence (3-5 4 m)

8 X-ray sources Synchrotron need electron or positron beam orbiting in a ring beam is bent by magnetic field x-ray emission at bend Advantages rad divergence (3-5 4 m) high brilliance wavelength tunable Synchrotron need electron or positron beam orbiting in a ring beam is bent by magnetic field x-ray emission at bend Advantages rad divergence (3-5 4 m) high brilliance wavelength tunable

9 X-ray sources Synchrotron Advantages rad divergence (3-5 4 m) high brilliance wavelength tunable Synchrotron Advantages rad divergence (3-5 4 m) high brilliance wavelength tunable

10 X-ray sources Synchrotron Advantages rad divergence (3-5 4 m) high brilliance wavelength tunable Synchrotron Advantages rad divergence (3-5 4 m) high brilliance wavelength tunable

11 X-ray sources Synchrotron Advantages rad divergence (3-5 4 m) high brilliance wavelength tunable Synchrotron Advantages rad divergence (3-5 4 m) high brilliance wavelength tunable

12 X-ray sources Synchrotron need electron or positron beam orbiting in a ring beam is bent by magnetic field x-ray emission at bend Advantages rad divergence (3-5 4 m) high brilliance wavelength tunable high signal/noise ratio Synchrotron need electron or positron beam orbiting in a ring beam is bent by magnetic field x-ray emission at bend Advantages rad divergence (3-5 4 m) high brilliance wavelength tunable high signal/noise ratio

13 Beam conditioning Collimation

14 Beam conditioning Monochromatization  -filters – matls have at. nos. 1 or 2 less than anode 50-60% beam attenuation placing after specimen/before detector suppresses sample fluorescence allows passage of high intensity & long wavelength white rad. Monochromatization  -filters – matls have at. nos. 1 or 2 less than anode 50-60% beam attenuation placing after specimen/before detector suppresses sample fluorescence allows passage of high intensity & long wavelength white rad.

15 Beam conditioning Monochromatization  -filters – matls have at. nos. 1 or 2 less than anode 50-60% beam attenuation placing after specimen/before detector suppresses sample fluorescence allows passage of high intensity & long wavelength white rad. Monochromatization  -filters – matls have at. nos. 1 or 2 less than anode 50-60% beam attenuation placing after specimen/before detector suppresses sample fluorescence allows passage of high intensity & long wavelength white rad.

16 Beam conditioning Monochromatization Crystal monochromators – LiF, SiO 2, pyrolytic graphite critical – reflectivity ex: for MoK , LiF 9.4% graphite 54 % Monochromatization Crystal monochromators – LiF, SiO 2, pyrolytic graphite critical – reflectivity ex: for MoK , LiF 9.4% graphite 54 %

17 Beam conditioning Monochromatization Crystal monochromators – LiF, SiO 2, pyrolytic graphite critical – reflectivity ex: for MoK , LiF 9.4% graphite 54 % resolution – determines peak/bkgrd ratio & spectral purity best - Si – 10" graphite – 0.52° Monochromatization Crystal monochromators – LiF, SiO 2, pyrolytic graphite critical – reflectivity ex: for MoK , LiF 9.4% graphite 54 % resolution – determines peak/bkgrd ratio & spectral purity best - Si – 10" graphite – 0.52°

18 Beam conditioning Monochromatization Monochromator shape usually flat – problems w/ divergent beams concentrating type – increases I by factor of Monochromatization Monochromator shape usually flat – problems w/ divergent beams concentrating type – increases I by factor of 1.5-2

19 Beam conditioning Monochromatization Monochromator shape focusing monochromators elastically or plastically bend crystal Monochromatization Monochromator shape focusing monochromators elastically or plastically bend crystal

20 Beam conditioning Monochromatization Monochromator shape focusing monochromators elastically or plastically bend crystal Johann geometry radius of curvature = 2R R = radius of instrument focusing circle Monochromatization Monochromator shape focusing monochromators elastically or plastically bend crystal Johann geometry radius of curvature = 2R R = radius of instrument focusing circle

21 Beam conditioning Monochromatization Monochromator shape focusing monochromators elastically or plastically bend crystal Johansson geometry bend radius = 2R ground radius = R Monochromatization Monochromator shape focusing monochromators elastically or plastically bend crystal Johansson geometry bend radius = 2R ground radius = R

22 Beam conditioning Mirrors total reflection below critical angle polished Al or optical glass curved mirrors collimate, can even focus beam (high peak to bkgrd ratio) Mirrors total reflection below critical angle polished Al or optical glass curved mirrors collimate, can even focus beam (high peak to bkgrd ratio)


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