X ray microscopy (was camera obscura)

[Ludwik Kowalski <kowalskil@MAIL.MONTCLAIR.EDU>]

Does somebody understand how a parallel beam of
X-rays is focused by a structure similar to that described
on the web page provided by Bernard? If so then I would
welcome an explanation.

"Multilayer" for light usually refers to layers of materials
whose index of refraction is different. But for X-rays n is
practically one in any material. How can extremely small
differences in n (like 0.001 or less ?) be used to focus?
Perhaps the term "multilayer" means something else
in this context.
Ludwik Kowalski

On Saturday, Aug 16, 2003, at 19:55 US/Pacific, Bernard Cleyet wrote:

> I hadn't heard of pin hole X-Ray cameras either, but Fresnel yes. e.g.:
>
>
> http://www.esrf.fr/UsersAndScience/Publications/Highlights/2002/
> Methods/MET3/
>
>
> Brian Whatcott wrote:
>
> > This note of Ludwik's was quite provocative.
> >
> > Visualizing X-rays at 2 keV was not something
> > I had considered possible.
> >  I very much liked the idea of using a pin hole
> > in a metal box with an xray film plate
> > to visualize (say) a a paper pin high field emitter
> >  impinging on a metal plate  in an evacuated jam-jar ,
> > or perhaps an old thermionic tube, activated
> >  with a few kV.
> >
> > I will admit to difficulty with the unit#98
> > item which Ludwik interjected into his note
> >  - excess heat seems quite unrelated to
> >  visualizing X ray emission, on its face.
> >
> > Brian
> > p.s. I also confirm Bob's observation that
> >  so called web cam pin holes are mini-lenses.
> >
> >
> > At 10:56 AM 8/16/2003 -0700, you wrote:
> >
> >
> > > Many think that the device known as "camera
> > > obscura" has only historical significance. In a
> > > message from a friend I see that he uses this
> > > device to map the distribution of soft X-rays
> > > (about 1.5 keV) over the surface at which they
> > > are emitted. Here is the quote:
> > >
> > > ". . . camera-obscura (objective diameter 0.3mm)
> > > with fixing the X-ray emission onto the X-ray film and
> > > nuclear emulsion . . . "  I will write more about these
> > > strange X-rays in a unit at my web site devoted to
> > > cold fusion. By the ways, unit #98 on that site:
> > >
> > > http://blake.montclair.edu/~kowalskil/cf/
> > >
> > > is about cold fusion experiments performed by
> > > students at Portland State University. Can
> > > somebody give other examples of using a
> > > pinhole camera in research today?
> > > Ludwik Kowalski
> >
> >
> > Brian Whatcott    Altus OK    Eureka!