what data need to be measured?
DESCRIPTION
What data need to be measured?. Scattering from: specimen in its container empty specimen container standard or calibration specimen. What data need to be measured?. Scattering from: specimen in its container empty specimen container standard or calibration specimen dark count (noise) - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: What data need to be measured?](https://reader035.vdocuments.site/reader035/viewer/2022062814/568167ad550346895ddcfbe4/html5/thumbnails/1.jpg)
What data need to be measured?
Scattering from:
specimen in its container
empty specimen container
standard or calibration specimen
![Page 2: What data need to be measured?](https://reader035.vdocuments.site/reader035/viewer/2022062814/568167ad550346895ddcfbe4/html5/thumbnails/2.jpg)
What data need to be measured?
Scattering from:
specimen in its container
empty specimen container
standard or calibration specimen
dark count (noise)
detector dead time
background
![Page 3: What data need to be measured?](https://reader035.vdocuments.site/reader035/viewer/2022062814/568167ad550346895ddcfbe4/html5/thumbnails/3.jpg)
What data need to be measured?Scattering from:
specimen in its container
empty specimen container
standard or calibration specimen
dark count (noise)
detector efficiency
background
transmissions of each specimen
incident beam intensity
![Page 4: What data need to be measured?](https://reader035.vdocuments.site/reader035/viewer/2022062814/568167ad550346895ddcfbe4/html5/thumbnails/4.jpg)
What data need to be measured?
Scattering from:
specimen in its container
empty specimen container
standard or calibration specimen
to get absolute intensity measurements, standard must have known scattering intensity
![Page 5: What data need to be measured?](https://reader035.vdocuments.site/reader035/viewer/2022062814/568167ad550346895ddcfbe4/html5/thumbnails/5.jpg)
What data need to be measured?
Scattering from:
specimen in its container
empty specimen container
standard or calibration specimen
dark count (noise)
includes errant x-rays - measure w/ strongly absorbing material in place of specimen
may vary with time
![Page 6: What data need to be measured?](https://reader035.vdocuments.site/reader035/viewer/2022062814/568167ad550346895ddcfbe4/html5/thumbnails/6.jpg)
What data need to be measured?
Scattering from:
specimen in its container
empty specimen container
standard or calibration specimen
dark count (noise)
detector efficiency
scale each datum to that of a detector w/ constant efficiency
![Page 7: What data need to be measured?](https://reader035.vdocuments.site/reader035/viewer/2022062814/568167ad550346895ddcfbe4/html5/thumbnails/7.jpg)
What data need to be measured?
Scattering from:
specimen in its container
empty specimen container
standard or calibration specimen
dark count (noise)
detector efficiency
scale each datum to that of a detector w/ constant efficiency
![Page 8: What data need to be measured?](https://reader035.vdocuments.site/reader035/viewer/2022062814/568167ad550346895ddcfbe4/html5/thumbnails/8.jpg)
What data need to be measured?
Scattering from:
specimen in its container
empty specimen container
standard or calibration specimen
dark count (noise)
detector efficiency
background
e.g., pure solvent, or pure matrix material
![Page 9: What data need to be measured?](https://reader035.vdocuments.site/reader035/viewer/2022062814/568167ad550346895ddcfbe4/html5/thumbnails/9.jpg)
What data need to be measured?
Scattering from:
specimen in its container
empty specimen container
standard or calibration specimen
dark count (noise)
detector efficiency
background
transmissions of each specimen
cut beam intensity, measure direct beam I w/ & w/ospecimen
![Page 10: What data need to be measured?](https://reader035.vdocuments.site/reader035/viewer/2022062814/568167ad550346895ddcfbe4/html5/thumbnails/10.jpg)
What data need to be measured?
General procedure:
1. Scale all data to incident beam monitor (synchrotron beam decays w/ time)
![Page 11: What data need to be measured?](https://reader035.vdocuments.site/reader035/viewer/2022062814/568167ad550346895ddcfbe4/html5/thumbnails/11.jpg)
What data need to be measured?
General procedure:
1. Scale all data to incident beam monitor (synchrotron beam decays w/ time)
2. Correct for detector efficiency
![Page 12: What data need to be measured?](https://reader035.vdocuments.site/reader035/viewer/2022062814/568167ad550346895ddcfbe4/html5/thumbnails/12.jpg)
What data need to be measured?
General procedure:
1. Scale all data to incident beam monitor (synchrotron beam decays w/ time)
2. Correct all data for detector efficiency
3. Correct all data for empty cell and dark count
Now have:
Ispecimen = (Ispecimen - Idark) - (Tcell full/Tcell empty)(Icell empty -Idark)
Ibkgrd = (Ibkgrd - Idark) - (Tbkgrd/Tcell empty)(Icell empty -Idark)
Istd = (Istd - Idark) - (Tstd/Tcell empty)(Icell empty -Idark)corr
corr
corr
![Page 13: What data need to be measured?](https://reader035.vdocuments.site/reader035/viewer/2022062814/568167ad550346895ddcfbe4/html5/thumbnails/13.jpg)
What data need to be measured?
General procedure:
Ispecimen = (Ispecimen - Idark) - (Tcell full/Tcell empty)(Icell empty -Idark)
Ibkgrd = (Ibkgrd - Idark) - (Tbkgrd/Tcell empty)(Icell empty -Idark)
Istd = (Istd - Idark) - (Tstd/Tcell empty)(Icell empty -Idark)
4. Get absolute I s
Iabs = (Ispecimen f(q)/ Istd) (tstd Tstd/tspecimen Tspecimen)
Ibkgrd = (Ibkgrd f(q)/ Istd) (tstd Tstd/tbkgrd Tbkgrd)
corr
corr
corr
corr corr
corr
final
final
![Page 14: What data need to be measured?](https://reader035.vdocuments.site/reader035/viewer/2022062814/568167ad550346895ddcfbe4/html5/thumbnails/14.jpg)
What data need to be measured?
General procedure:
Ispecimen = (Ispecimen - Idark) - (Tcell full/Tcell empty)(Icell empty -Idark)
Ibkgrd = (Ibkgrd - Idark) - (Tbkgrd/Tcell empty)(Icell empty -Idark)
Istd = (Istd - Idark) - (Tstd/Tcell empty)(Icell empty -Idark)
4. Get absolute I s
Iabs = (Ispecimen f(q)/ Istd) (tstd Tstd/tspecimen Tspecimen)
Ibkgrd = (Ibkgrd f(q)/ Istd) (tstd Tstd/tbkgrd Tbkgrd)
5. Subtract bkgrd
corr
corr
corr
corr corr
corr
final
final
![Page 15: What data need to be measured?](https://reader035.vdocuments.site/reader035/viewer/2022062814/568167ad550346895ddcfbe4/html5/thumbnails/15.jpg)
What data need to be measured?
Background treatment - complexneed to consider what bkgrd should be - w/ solns or dispersions, bkgrd usually includes
scatteringfrom solvent or dispersion medium & sample cell
![Page 16: What data need to be measured?](https://reader035.vdocuments.site/reader035/viewer/2022062814/568167ad550346895ddcfbe4/html5/thumbnails/16.jpg)
What data need to be measured?
Background treatment - complexneed to consider what bkgrd should be - w/ solns or dispersions, bkgrd usually includes
scatteringfrom solvent or dispersion medium & sample cell
Standard specimenreproduciblestableknown scattering datascattering must be highisotropic scattering
![Page 17: What data need to be measured?](https://reader035.vdocuments.site/reader035/viewer/2022062814/568167ad550346895ddcfbe4/html5/thumbnails/17.jpg)
Instrument resolution
See
Need to consider
wavelength spreadcollimation effectsdetector resolution
![Page 18: What data need to be measured?](https://reader035.vdocuments.site/reader035/viewer/2022062814/568167ad550346895ddcfbe4/html5/thumbnails/18.jpg)
Instrument resolution
Wavelength spread
Lab x-rays + monochromator
Monochromator crystal set to scatter characteristic line - wavelength spread is result of combined effects of
natural line widthmosaic spread of monochromator crystal collimation before & after crystal
![Page 19: What data need to be measured?](https://reader035.vdocuments.site/reader035/viewer/2022062814/568167ad550346895ddcfbe4/html5/thumbnails/19.jpg)
Instrument resolution
Wavelength spread
Lab x-rays + monochromator
Monochromator crystal set to scatter characteristic line - wavelength spread is result of combined effects of
natural line widthmosaic spread of monochromator crystal collimation before & after crystal
Synchrotron spectrum conts - wavelength spread determined only by mosaic spread of monochromator &
collimation
![Page 20: What data need to be measured?](https://reader035.vdocuments.site/reader035/viewer/2022062814/568167ad550346895ddcfbe4/html5/thumbnails/20.jpg)
Instrument resolution
Wavelength spread
Lab x-rays + monochromator
Monochromator crystal set to scatter characteristic line - wavelength spread is result of combined effects of
natural line widthmosaic spread of monochromator crystal collimation before & after crystal
Synchrotron spectrum conts - wavelength spread determined only by mosaic spread of monochromator &
collimation
Both conventional & synchrotron X-ray sources - wavelength spread ~/<> typically <10-3 & neglected in most
cases
![Page 21: What data need to be measured?](https://reader035.vdocuments.site/reader035/viewer/2022062814/568167ad550346895ddcfbe4/html5/thumbnails/21.jpg)
Instrument resolution
Collimation
![Page 22: What data need to be measured?](https://reader035.vdocuments.site/reader035/viewer/2022062814/568167ad550346895ddcfbe4/html5/thumbnails/22.jpg)
Instrument resolution
Detector
3 contributions to spatial resolution
division of detector into pixels
method of detection
method of position determination
latter 2 dominant
![Page 23: What data need to be measured?](https://reader035.vdocuments.site/reader035/viewer/2022062814/568167ad550346895ddcfbe4/html5/thumbnails/23.jpg)
Instrument resolution
Combined resolution fcn
arameter related to FWHM of function
ex:
![Page 24: What data need to be measured?](https://reader035.vdocuments.site/reader035/viewer/2022062814/568167ad550346895ddcfbe4/html5/thumbnails/24.jpg)
Instrument resolution
Combined resolution fcn
arameter related to FWHM of function
ex: