Samples with Strong X-Ray Absorption - Revision history

WikiSysop: /* Guidelines for 11-BM Mail-In Samples */

2014-03-30T16:13:52Z

Guidelines for 11-BM Mail-In Samples

← Older revision		Revision as of 16:13, 30 March 2014
Line 17:		Line 17:

	Use the convenient Absorb web utilty to estimate sample absorption:		Use the convenient Absorb web utilty to estimate sample absorption:
	http://11bm.~~xor~~.aps.anl.gov/absorb/absorb.php		http://11bm.xray.aps.anl.gov/absorb/absorb.php

	=== Range of μ*r values ===		=== Range of μ*r values ===

WikiSysop: /* Practical Example */

2014-02-22T01:17:34Z

Practical Example

← Older revision		Revision as of 01:17, 22 February 2014
Line 39:		Line 39:
	* '''Diluted''' capillaries were filled with a homogeneous mixture of SnO<sub>2</sub> powder plus [https://wiki-ext.aps.anl.gov/ug11bm/index.php/Samples_with_Strong_X-Ray_Absorption#Dilution amorphous SiO2 glass powder] to reduce the muR		* '''Diluted''' capillaries were filled with a homogeneous mixture of SnO<sub>2</sub> powder plus [https://wiki-ext.aps.anl.gov/ug11bm/index.php/Samples_with_Strong_X-Ray_Absorption#Dilution amorphous SiO2 glass powder] to reduce the muR

	Main points		'''Main points'''
	* It is import to consider x-ray absorption - compare the solid 1.5 mm SnO2 data (pink scan) with the coated 1.5 mm data (red scan)		* It is import to consider x-ray absorption - compare the solid 1.5 mm SnO2 data (pink scan) with the coated 1.5 mm data (red scan)
	* Even for the same muR value, different preparation methods can give different results		* Even for the same muR value, different preparation methods can give different results
Line 45:		Line 45:
	* Dilution works - but is less successful when the diluent:sample molar ratio goes above 5:1 (muR < ~ 2 in this case for SnO<sub>2</sub> )		* Dilution works - but is less successful when the diluent:sample molar ratio goes above 5:1 (muR < ~ 2 in this case for SnO<sub>2</sub> )

	Rather than use an estimated muR value, the true sample absorption was evaluated for each capillary using a measurement of transmitted beam intensity on a pin diode placed downstream of the sample.		'''Comments'''
			*Rather than use an estimated muR value, the true sample absorption was evaluated for each capillary using a measurement of transmitted beam intensity on a pin diode placed downstream of the sample.
	The key to the success of a coated approach is that larger diameter coated tubes use the full vertical height of the 11-BM x-ray beam (~ 0.6 mm FWHM) , while a smaller diameter capillary (< 0.5 mm) with the same muR value wastes all the photons which do not hit the capillary above and below the sample.		*A large ratio of Intensity to background will normally give higher counts and resolve weak peaks better.
			*The key to the success of a coated approach is that larger diameter coated tubes use the full vertical height of the 11-BM x-ray beam (~ 0.6 mm FWHM) , while a smaller diameter capillary (< 0.5 mm) with the same muR value wastes all the photons which do not hit the capillary above and below the sample.

WikiSysop: /* Practical Example */

2014-02-22T01:15:35Z

Practical Example

← Older revision		Revision as of 01:15, 22 February 2014
Line 48:		Line 48:

	The key to the success of a coated approach is that larger diameter coated tubes use the full vertical height of the 11-BM x-ray beam (~ 0.6 mm FWHM) , while a smaller diameter capillary (< 0.5 mm) with the same muR value wastes all the photons which do not hit the capillary above and below the sample.		The key to the success of a coated approach is that larger diameter coated tubes use the full vertical height of the 11-BM x-ray beam (~ 0.6 mm FWHM) , while a smaller diameter capillary (< 0.5 mm) with the same muR value wastes all the photons which do not hit the capillary above and below the sample.


	''X-ray scattering & absorption of SnO2 powder capillaries; results summary - click for a larger view''		''X-ray scattering & absorption of SnO2 powder capillaries; results summary - click for a larger view''

WikiSysop: /* Practical Example */

2014-02-22T01:15:26Z

Practical Example

← Older revision		Revision as of 01:15, 22 February 2014
Line 49:		Line 49:
	The key to the success of a coated approach is that larger diameter coated tubes use the full vertical height of the 11-BM x-ray beam (~ 0.6 mm FWHM) , while a smaller diameter capillary (< 0.5 mm) with the same muR value wastes all the photons which do not hit the capillary above and below the sample.		The key to the success of a coated approach is that larger diameter coated tubes use the full vertical height of the 11-BM x-ray beam (~ 0.6 mm FWHM) , while a smaller diameter capillary (< 0.5 mm) with the same muR value wastes all the photons which do not hit the capillary above and below the sample.

			''X-ray scattering & absorption of SnO2 powder capillaries; results summary - click for a larger view''

	[[Image:SnO2_SpreadSheet.png\|500px \|link=https://wiki-ext.aps.anl.gov/ug11bm/images/8/89/SnO2_SpreadSheet.png \|alt=Alt text\|Click for a larger view of SnO2_SpreadSheet.png]]		[[Image:SnO2_SpreadSheet.png\|500px \|link=https://wiki-ext.aps.anl.gov/ug11bm/images/8/89/SnO2_SpreadSheet.png \|alt=Alt text\|Click for a larger view of SnO2_SpreadSheet.png]]

	''X-ray scattering & absorption of SnO2 powder capillaries; ~~results summary~~ - click for a larger view''
			''X-ray scattering & absorption of SnO2 powder capillaries; example diffraction patterns - click for a larger view''

	[[Image:SnO2_XRDPlot.png\|500px \|link=https://wiki-ext.aps.anl.gov/ug11bm/images/6/60/SnO2_XRDPlot.png \|alt=Alt text\|Click for a larger view of Image:SnO2_XRDPlot.png]]		[[Image:SnO2_XRDPlot.png\|500px \|link=https://wiki-ext.aps.anl.gov/ug11bm/images/6/60/SnO2_XRDPlot.png \|alt=Alt text\|Click for a larger view of Image:SnO2_XRDPlot.png]]

	~~''X-ray scattering & absorption of SnO2 powder capillaries; example diffraction patterns - click for a larger view''~~

	== Preparation methods to lower absorption ==		== Preparation methods to lower absorption ==

WikiSysop: /* Practical Example */

2014-02-22T01:14:22Z

Practical Example

← Older revision		Revision as of 01:14, 22 February 2014
Line 54:		Line 54:
	''X-ray scattering & absorption of SnO2 powder capillaries; results summary - click for a larger view''		''X-ray scattering & absorption of SnO2 powder capillaries; results summary - click for a larger view''

	~~[[Image:SnO2_XRDPlot.png]]~~
	[[Image:SnO2_XRDPlot.png\|500px \|link=https://wiki-ext.aps.anl.gov/ug11bm/images/6/60/SnO2_XRDPlot.png \|alt=Alt text\|Click for a larger view of Image:SnO2_XRDPlot.png]]		[[Image:SnO2_XRDPlot.png\|500px \|link=https://wiki-ext.aps.anl.gov/ug11bm/images/6/60/SnO2_XRDPlot.png \|alt=Alt text\|Click for a larger view of Image:SnO2_XRDPlot.png]]

WikiSysop: /* Practical Example */

2014-02-22T01:12:53Z

Practical Example

← Older revision		Revision as of 01:12, 22 February 2014
Line 54:		Line 54:
	''X-ray scattering & absorption of SnO2 powder capillaries; results summary - click for a larger view''		''X-ray scattering & absorption of SnO2 powder capillaries; results summary - click for a larger view''

			[[Image:SnO2_XRDPlot.png]]
	[[Image:SnO2_XRDPlot.png\|500px \|link=https://wiki-ext.aps.anl.gov/ug11bm/images/6/60/SnO2_XRDPlot.png \|alt=Alt text\|Click for a larger view of Image:SnO2_XRDPlot.png]]		[[Image:SnO2_XRDPlot.png\|500px \|link=https://wiki-ext.aps.anl.gov/ug11bm/images/6/60/SnO2_XRDPlot.png \|alt=Alt text\|Click for a larger view of Image:SnO2_XRDPlot.png]]

WikiSysop: /* Practical Example */

2014-02-22T01:12:24Z

Practical Example

← Older revision		Revision as of 01:12, 22 February 2014
Line 43:		Line 43:
	* Even for the same muR value, different preparation methods can give different results		* Even for the same muR value, different preparation methods can give different results
	* For highly absorbing compositions, the coated approach often gives the best ratio of Intensity to background		* For highly absorbing compositions, the coated approach often gives the best ratio of Intensity to background
	* Dilution ~~work~~ - but is less successful when ~~the~~ the diluent:sample molar ratio goes above 5:1 (muR < ~ 2 in this case for SnO<sub>2</sub> )		* Dilution works - but is less successful when the diluent:sample molar ratio goes above 5:1 (muR < ~ 2 in this case for SnO<sub>2</sub> )

	Rather than use an estimated muR value, the true sample absorption was evaluated for each capillary using a measurement of transmitted beam intensity on a pin diode placed downstream of the sample.		Rather than use an estimated muR value, the true sample absorption was evaluated for each capillary using a measurement of transmitted beam intensity on a pin diode placed downstream of the sample.

WikiSysop: /* Practical Example */

2014-02-22T01:11:33Z

Practical Example

← Older revision		Revision as of 01:11, 22 February 2014
Line 31:		Line 31:

	As a practical example, 11-BM staff have examined different methods of preparing x-ray absorbing powder samples for transmission capillary diffraction measurements at 30 KeV on the APS beamline 11-BM.		As a practical example, 11-BM staff have examined different methods of preparing x-ray absorbing powder samples for transmission capillary diffraction measurements at 30 KeV on the APS beamline 11-BM.

			The results are discussed here - highlighted in the images and plots below. For each measurement the beamline settings, scan time, and scan parameters were identical. The only variable is method of sample capillary preparation.

	Kapton capillaries containing the same starting SnO<sub>2</sub> powder were prepared by different methods and using different size capillaries.		Kapton capillaries containing the same starting SnO<sub>2</sub> powder were prepared by different methods and using different size capillaries.
Line 36:		Line 38:
	* '''Coated''' capillaries were prepared using grease [https://wiki-ext.aps.anl.gov/ug11bm/index.php/Samples_with_Strong_X-Ray_Absorption#Coated_Capillary described below] to coat the Kapton tube		* '''Coated''' capillaries were prepared using grease [https://wiki-ext.aps.anl.gov/ug11bm/index.php/Samples_with_Strong_X-Ray_Absorption#Coated_Capillary described below] to coat the Kapton tube
	* '''Diluted''' capillaries were filled with a homogeneous mixture of SnO<sub>2</sub> powder plus [https://wiki-ext.aps.anl.gov/ug11bm/index.php/Samples_with_Strong_X-Ray_Absorption#Dilution amorphous SiO2 glass powder] to reduce the muR		* '''Diluted''' capillaries were filled with a homogeneous mixture of SnO<sub>2</sub> powder plus [https://wiki-ext.aps.anl.gov/ug11bm/index.php/Samples_with_Strong_X-Ray_Absorption#Dilution amorphous SiO2 glass powder] to reduce the muR

	The results are highlighted in the images and plots below. For each measurement the beamline settings, scan time, and scan parameters were identical. The only variable is method of sample capillary preparation.

	Main points		Main points

WikiSysop: /* Practical Example */

2014-02-22T01:10:26Z

Practical Example

← Older revision		Revision as of 01:10, 22 February 2014
Line 30:		Line 30:
	=== Practical Example ===		=== Practical Example ===

	As a practical example, 11-BM staff have examined different methods of preparing x-ray absorbing powder samples for transmission capillary diffraction measurements at 30 KeV on the APS beamline 11-BM.		As a practical example, 11-BM staff have examined different methods of preparing x-ray absorbing powder samples for transmission capillary diffraction measurements at 30 KeV on the APS beamline 11-BM.

	Kapton capillaries containing the same starting SnO<sub>2</sub> powder were prepared by different methods and using different size capillaries.		Kapton capillaries containing the same starting SnO<sub>2</sub> powder were prepared by different methods and using different size capillaries.
Line 37:		Line 37:
	* '''Diluted''' capillaries were filled with a homogeneous mixture of SnO<sub>2</sub> powder plus [https://wiki-ext.aps.anl.gov/ug11bm/index.php/Samples_with_Strong_X-Ray_Absorption#Dilution amorphous SiO2 glass powder] to reduce the muR		* '''Diluted''' capillaries were filled with a homogeneous mixture of SnO<sub>2</sub> powder plus [https://wiki-ext.aps.anl.gov/ug11bm/index.php/Samples_with_Strong_X-Ray_Absorption#Dilution amorphous SiO2 glass powder] to reduce the muR

	The results are highlighted in the images and plots below.		The results are highlighted in the images and plots below. For each measurement the beamline settings, scan time, and scan parameters were identical. The only variable is method of sample capillary preparation.

	Main points		Main points
	*		* It is import to consider x-ray absorption - compare the solid 1.5 mm SnO2 data (pink scan) with the coated 1.5 mm data (red scan)
	*		* Even for the same muR value, different preparation methods can give different results
	* For highly absorbing compositions, the coated approach often gives the best ratio of Intensity to background		* For highly absorbing compositions, the coated approach often gives the best ratio of Intensity to background
	* Dilution work - but is less successful when the the diluent:sample molar ratio goes above 5:1 (muR < ~ 2 in this case for SnO<sub>2</sub> )		* Dilution work - but is less successful when the the diluent:sample molar ratio goes above 5:1 (muR < ~ 2 in this case for SnO<sub>2</sub> )

	Rather than use an estimated muR, the true sample absorption was evaluated for each capillary using a measurement of transmitted beam intensity on a pin diode placed downstream of the sample.		Rather than use an estimated muR value, the true sample absorption was evaluated for each capillary using a measurement of transmitted beam intensity on a pin diode placed downstream of the sample.


	The key to the success of a coated approach is that larger diameter coated tubes use the full vertical height of the 11-BM x-ray beam (~ 0.6 mm FWHM) , while a smaller diameter capillary (< 0.5 mm) with the same muR value wastes all the photons which do not hit the capillary above and below the sample.		The key to the success of a coated approach is that larger diameter coated tubes use the full vertical height of the 11-BM x-ray beam (~ 0.6 mm FWHM) , while a smaller diameter capillary (< 0.5 mm) with the same muR value wastes all the photons which do not hit the capillary above and below the sample.
Line 58:		Line 57:
	[[Image:SnO2_XRDPlot.png\|500px \|link=https://wiki-ext.aps.anl.gov/ug11bm/images/6/60/SnO2_XRDPlot.png \|alt=Alt text\|Click for a larger view of Image:SnO2_XRDPlot.png]]		[[Image:SnO2_XRDPlot.png\|500px \|link=https://wiki-ext.aps.anl.gov/ug11bm/images/6/60/SnO2_XRDPlot.png \|alt=Alt text\|Click for a larger view of Image:SnO2_XRDPlot.png]]

	''X-ray scattering & absorption of SnO2 powder capillaries; example diffraction patterns - click for a larger view''		''X-ray scattering & absorption of SnO2 powder capillaries; example diffraction patterns - click for a larger view''




	~~In theory, dilution and reduced capillary sizes should work, but in practice its not always the case.~~

	== Preparation methods to lower absorption ==		== Preparation methods to lower absorption ==

WikiSysop: /* Practical Example */

2014-02-22T01:05:42Z

Practical Example

← Older revision		Revision as of 01:05, 22 February 2014
Line 37:		Line 37:
	* '''Diluted''' capillaries were filled with a homogeneous mixture of SnO<sub>2</sub> powder plus [https://wiki-ext.aps.anl.gov/ug11bm/index.php/Samples_with_Strong_X-Ray_Absorption#Dilution amorphous SiO2 glass powder] to reduce the muR		* '''Diluted''' capillaries were filled with a homogeneous mixture of SnO<sub>2</sub> powder plus [https://wiki-ext.aps.anl.gov/ug11bm/index.php/Samples_with_Strong_X-Ray_Absorption#Dilution amorphous SiO2 glass powder] to reduce the muR

	The ~~main~~ results are highlighted in the images and plots below.		The results are highlighted in the images and plots below.

	~~Key~~ points		Main points
	*		*
	*		*
	* For highly absorbing compositions, the coated approach often gives the best ratio of Intensity to background		* For highly absorbing compositions, the coated approach often gives the best ratio of Intensity to background
	*		* Dilution work - but is less successful when the the diluent:sample molar ratio goes above 5:1 (muR < ~ 2 in this case for SnO<sub>2</sub> )

			Rather than use an estimated muR, the true sample absorption was evaluated for each capillary using a measurement of transmitted beam intensity on a pin diode placed downstream of the sample.


	The key to the success of a coated approach is that larger diameter coated tubes use the full vertical height of the 11-BM x-ray beam (~ 0.6 mm FWHM) , while a smaller diameter capillary (< 0.5 mm) with the same muR value wastes all the photons which do not hit the capillary above and below the sample.		The key to the success of a coated approach is that larger diameter coated tubes use the full vertical height of the 11-BM x-ray beam (~ 0.6 mm FWHM) , while a smaller diameter capillary (< 0.5 mm) with the same muR value wastes all the photons which do not hit the capillary above and below the sample.
Line 61:		Line 64:

	In theory, dilution and reduced capillary sizes should work, but in practice its not always the case.		In theory, dilution and reduced capillary sizes should work, but in practice its not always the case.

	I played with this sometime last year and made nice plots (which have only existed on my computer up to this moment). I attempted a somewhat systematic study on SnO2 powder at 30 KeV, and the main results are shown in the attached image file.

	~~I don't bother here with estimated muR, but rather try to measure it on each sample using the pin diode after the capillary~~

	~~I'd say that the message for you is that coated gives the best ratio of Intensity to background, so small peaks are better resolved; but overall signal / sigma ratio doesn't change as dramatically.~~



	~~Also - for dilution, you start to loose once the molar ratio goes above 5:1 (muR < 2 in this case)~~

	~~Not taken into account here are funky absorption effects on relative peak intensity ratios as a function of 2th, something that one would for sure need to consider for the higher muR numbers.~~

	Hope this helps you to think about an approach for the next samples; maybe I'll be inspired to now post this cleaned up file with the results on the webpage wiki. One day I'd hope to put the results in a short paper which can be used as a reference for the online muR calc tool.

	~~all the best~~
	~~Matthew~~

	== Preparation methods to lower absorption ==		== Preparation methods to lower absorption ==