Page 1 of 1

Geometric phase kicks x rays down a new path

Posted: Thu Jun 17, 2010 7:34 pm
by DeltaV
http://physics.aps.org/articles/v3/50
A small crystal distortion can dramatically translate the path of an x-ray beam, an effect that could be useful in the development of x-ray optics.

Fascinating !!

Posted: Fri Jun 18, 2010 1:04 pm
by Nik
Uh, that's well within the range of 'active optics' mirror flexing. Of course, shifting X-rays one mm is only a start. Still, it reminds me of the glancing-incidence 'optics' of early X-ray telescopes. The workings resembled a skeletal Fresnel lens or circular Venetian blind, with the focussing done by the near-vertical face of the slats...

Posted: Sat Jun 19, 2010 1:36 am
by rcain
interesting post.

based on understanding of the Electromagnetic_four-potential - http://en.wikipedia.org/wiki/Electromag ... -potential

plenty of scope.

anyone catch this (related) news - http://www2.warwick.ac.uk/newsandevents ... mdoughnuts ?

Posted: Tue Jun 22, 2010 8:37 pm
by 93143
I wonder if something like this could be used to bend the path of X or gamma rays so as to send them laterally through a radiation shield, allowing the shield to be thinner...

Posted: Wed Jun 23, 2010 1:22 am
by D Tibbets
93143 wrote:I wonder if something like this could be used to bend the path of X or gamma rays so as to send them laterally through a radiation shield, allowing the shield to be thinner...
Assuming the stable separation of the electron - exciton (sp?) pair is dependent on the nano ring diameter, and that the smaller the ring, the shorter the light wavelength that is captured, then perhaps some arrangement could be made in which the short wavelength captured light (x-rays or gamma rays) are subsequently released at longer wave length (like fluorescence), or the energy is carried away by some other means (like electrical current). Now you could have a lightweight, thin and very efficient (wishfully) shield against gamma rays, possibly even serving a secondary function of generating useful power.

I don't understand how photovoltaics work. Is this something new, or merely a different, or more accurate way of describing what is happening? That, and possibly pointing a way to better manipulate these properties might be important.
Carrying it to the extream, if you can store gamma rays, and then release them (or there equivalent energy) on demand, it could lead to powerful batteries, or super duper capacitors, lasers, etc.

Dan Tibbets

Posted: Wed Jun 23, 2010 1:32 am
by MSimon
Solar cells work by separating electrons from atoms by light. If the electron lifetime is significantly longer than the drift time it gives the electron time to migrate to the collection electrode. The drift of the electron is caused by the intrinsic field that is created by the PN junction. Of course you have to remove the collected electrons or they will pile up to cancel the field. Extracting a current is all you have to do to accomplish that.

http://en.wikipedia.org/wiki/Solar_cell

Posted: Wed Jun 23, 2010 2:44 am
by 93143
D Tibbets wrote:
93143 wrote:I wonder if something like this could be used to bend the path of X or gamma rays so as to send them laterally through a radiation shield, allowing the shield to be thinner...
Assuming the stable separation of the electron - exciton (sp?) pair is dependent on the nano ring diameter...
...no, I was talking about the original subject of the thread.

I don't expect nano-rings to ever get anywhere near X-ray energies.

Posted: Wed Jun 23, 2010 3:03 am
by D Tibbets
93143 wrote:
D Tibbets wrote:
93143 wrote:I wonder if something like this could be used to bend the path of X or gamma rays so as to send them laterally through a radiation shield, allowing the shield to be thinner...
Assuming the stable separation of the electron - exciton (sp?) pair is dependent on the nano ring diameter...
...no, I was talking about the original subject of the thread.

I don't expect nano-rings to ever get anywhere near X-ray energies.
How about pico- rings. Anybody have any unobtainium which they could use to assemble sub atomic size rings with? 8)

Dan Tibbets

Posted: Wed Jun 23, 2010 9:37 pm
by 93143
Actually, I'm pretty sure nucleons are significantly larger than the wavelengths in question, meaning even neutronium can't give you the necessary feature size. I looked at it once in connection with that 'passive cloaking' nanosurface thing a while back...