X-ray focusing - Revision history

KevinYager: /* See Also */

2015-09-24T20:50:58Z

‎See Also

KevinYager: /* See Also */

2015-08-28T21:50:38Z

‎See Also

KevinYager: /* See Also */

2015-06-23T16:22:32Z

‎See Also

KevinYager at 21:45, 16 June 2014

2014-06-16T21:45:15Z

KevinYager: /* See Also */

2014-06-16T14:29:51Z

‎See Also

KevinYager: Created page with "X-rays interact weakly with matter and are thus difficult to focus. The x-ray refractive index of most materials is extremely close to 1.0, which means that refraction..."

2014-06-16T13:54:25Z

Created page with "X-rays interact weakly with matter and are thus difficult to focus. The x-ray refractive index of most materials is extremely close to 1.0, which means that refraction..."

New page

[[X-rays]] interact weakly with matter and are thus difficult to focus. The x-ray [[refractive]] index of most materials is extremely close to 1.0, which means that refraction is extremely weak and the conventional kinds of optics used in visible-light optics (glass lenses, metal mirrors, polarizers, etc.) are not applicable. Nevertheless, a variety of tricks can be used to direct and focus x-rays.

For instance, since x-rays undergo [[Refractive_index#Total_external_reflection|total external reflection]] at very shallow angles (grazing-incidence), one can use extremely flat materials to slightly reflect x-rays. For instance, silicon wafers coated with metal stripes are typically used to achieved the required flatness, while having a sufficiently large electron density so that the [[critical angle]] is reasonably large. Because these mirrors are being used at grazing-angles, the [[beam projection]] is quite large: x-ray mirrors must typically be 100 mm to 2 m in length along the beam. An x-ray mirror can be very slightly bent, in which case the curvature effectively acts as a focusing optic. (Note that the radius of curvature is typically 6-30 km!)

==Focusing Optics==
* '''Mirrors:''' Grazing-incidence mirrors that are slightly curved in order to focus the x-ray beam.
** '''Kirkpatrick-Baez Mirrors:''' Two mirrors oriented at right angles.
** '''Wolter Mirrors:''' Can be used to form images of extended (non-point-source) objects. Cylindrically symmetric mirrors.
* '''Capillary optics:''' Bundles of light-guiding pipes/capillaries can be used to focus.
* '''Compound Refractive Lenses (CRL):''' Sequences of curved interfaces, to accumulate refractive effects and achieve focusing. (c.f. [http://en.wikipedia.org/wiki/Compound_refractive_lens CRL])
* '''Fresnel Zone Plates (FZP):''' Use diffraction effects (from rings of progressively different spacing/size) to focus beam.
* '''Laue lens:''' Uses [http://en.wikipedia.org/wiki/Bragg%27s_law Bragg diffraction] in order to focus beam (usually using a tilted crystal). Multilayer Laue lenses (MLL) can be used as effectively 1-D half-linear-zone-plates.
* '''Kinoform lenses:''' Combine refractive and diffractive designs. (c.f. [http://jclub.chess.cornell.edu/images/smilgies%20talk.pdf Detlef Smilgies presentation])

==See Also==
[http://www.xradia.com/technology/basic-technology/focusing.php Xradia tutorial]
[http://en.wikipedia.org/wiki/Compound_refractive_lens Wikipedia: Compound refractive lens]

@@ Line 17: / Line 17: @@
 * [http://en.wikipedia.org/wiki/Compound_refractive_lens Wikipedia: Compound refractive lens]
 * Figure 2 in: Gene E. Ice, John D. Budai, Judy W. L. Pang [http://www.sciencemag.org/content/334/6060/1234 The Race to X-ray Microbeam and Nanobeam Science] ''Science'' '''2011''', 334 (6060), 1234-1239. [http://dx.doi.org/10.1126/science.1202366  doi: 10.1126/science.1202366]
-*Yoshinobu Nozue, Yuya Shinohara and Yoshiyuki Amemiya [http://www.nature.com/pj/journal/v39/n12/abs/pj2007168a.html Application of Microbeam Small- and Wide-angle X-ray Scattering to Polymeric Material Characterization] ''Polymer Journal'' '''2007''', 39, 1221–1237 [http://dx.doi.org/10.1295/polymj.PJ2007077 doi:10.1295/polymj.PJ2007077]
+* Yoshinobu Nozue, Yuya Shinohara and Yoshiyuki Amemiya [http://www.nature.com/pj/journal/v39/n12/abs/pj2007168a.html Application of Microbeam Small- and Wide-angle X-ray Scattering to Polymeric Material Characterization] ''Polymer Journal'' '''2007''', 39, 1221–1237 [http://dx.doi.org/10.1295/polymj.PJ2007077 doi:10.1295/polymj.PJ2007077]

← Older revision		Revision as of 21:50, 28 August 2015
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	* [http://en.wikipedia.org/wiki/Compound_refractive_lens Wikipedia: Compound refractive lens]		* [http://en.wikipedia.org/wiki/Compound_refractive_lens Wikipedia: Compound refractive lens]
	* Figure 2 in: Gene E. Ice, John D. Budai, Judy W. L. Pang [http://www.sciencemag.org/content/334/6060/1234 The Race to X-ray Microbeam and Nanobeam Science] ''Science'' '''2011''', 334 (6060), 1234-1239. [http://dx.doi.org/10.1126/science.1202366 doi: 10.1126/science.1202366]		* Figure 2 in: Gene E. Ice, John D. Budai, Judy W. L. Pang [http://www.sciencemag.org/content/334/6060/1234 The Race to X-ray Microbeam and Nanobeam Science] ''Science'' '''2011''', 334 (6060), 1234-1239. [http://dx.doi.org/10.1126/science.1202366 doi: 10.1126/science.1202366]
		+	*Yoshinobu Nozue, Yuya Shinohara and Yoshiyuki Amemiya [http://www.nature.com/pj/journal/v39/n12/abs/pj2007168a.html Application of Microbeam Small- and Wide-angle X-ray Scattering to Polymeric Material Characterization] ''Polymer Journal'' '''2007''', 39, 1221–1237 [http://dx.doi.org/10.1295/polymj.PJ2007077 doi:10.1295/polymj.PJ2007077]

← Older revision		Revision as of 16:22, 23 June 2015
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	* [http://www.xradia.com/technology/basic-technology/focusing.php Xradia tutorial]		* [http://www.xradia.com/technology/basic-technology/focusing.php Xradia tutorial]
	* [http://en.wikipedia.org/wiki/Compound_refractive_lens Wikipedia: Compound refractive lens]		* [http://en.wikipedia.org/wiki/Compound_refractive_lens Wikipedia: Compound refractive lens]
		+	* Figure 2 in: Gene E. Ice, John D. Budai, Judy W. L. Pang [http://www.sciencemag.org/content/334/6060/1234 The Race to X-ray Microbeam and Nanobeam Science] ''Science'' '''2011''', 334 (6060), 1234-1239. [http://dx.doi.org/10.1126/science.1202366 doi: 10.1126/science.1202366]

← Older revision		Revision as of 21:45, 16 June 2014
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−	[[X-rays]] interact weakly with matter and are thus difficult to focus. The x-ray [[refractive]] ~~index~~ of most materials is extremely close to 1.0, which means that refraction is extremely weak and the conventional kinds of optics used in visible-light optics (glass lenses, metal mirrors, polarizers, etc.) are not applicable. Nevertheless, a variety of tricks can be used to direct and focus x-rays.	+	[[X-rays]] interact weakly with matter and are thus difficult to focus. The x-ray [[refractive index]] of most materials is extremely close to 1.0, which means that refraction is extremely weak and the conventional kinds of optics used in visible-light optics (glass lenses, metal mirrors, polarizers, etc.) are not applicable. Nevertheless, a variety of tricks can be used to direct and focus x-rays.

	For instance, since x-rays undergo [[Refractive_index#Total_external_reflection\|total external reflection]] at very shallow angles (grazing-incidence), one can use extremely flat materials to slightly reflect x-rays. For instance, silicon wafers coated with metal stripes are typically used to achieved the required flatness, while having a sufficiently large electron density so that the [[critical angle]] is reasonably large. Because these mirrors are being used at grazing-angles, the [[beam projection]] is quite large: x-ray mirrors must typically be 100 mm to 2 m in length along the beam. An x-ray mirror can be very slightly bent, in which case the curvature effectively acts as a focusing optic. (Note that the radius of curvature is typically 6-30 km!)		For instance, since x-rays undergo [[Refractive_index#Total_external_reflection\|total external reflection]] at very shallow angles (grazing-incidence), one can use extremely flat materials to slightly reflect x-rays. For instance, silicon wafers coated with metal stripes are typically used to achieved the required flatness, while having a sufficiently large electron density so that the [[critical angle]] is reasonably large. Because these mirrors are being used at grazing-angles, the [[beam projection]] is quite large: x-ray mirrors must typically be 100 mm to 2 m in length along the beam. An x-ray mirror can be very slightly bent, in which case the curvature effectively acts as a focusing optic. (Note that the radius of curvature is typically 6-30 km!)

@@ Line 14: / Line 14: @@
 ==See Also==
-[http://www.xradia.com/technology/basic-technology/focusing.php Xradia tutorial]
+* [http://www.xradia.com/technology/basic-technology/focusing.php Xradia tutorial]
-[http://en.wikipedia.org/wiki/Compound_refractive_lens Wikipedia: Compound refractive lens]
+* [http://en.wikipedia.org/wiki/Compound_refractive_lens Wikipedia: Compound refractive lens]