On 10-10-15 10:37 AM, James Holton wrote:
> ...
>
> In fact, anyone with a Pilatus detector (and a lot of extra beam
> time) can verify the self-interference of photons in macromolecular
> crystal diffraction. Since the source-to-detector distance of a
> typical MX beamline is about 30 m, it takes 100 nanoseconds for a
> "photon" generated in the storage ring to fly down the beam pipe, do
> whatever it is going to do in the crystal, and then (perhaps)
> increment a pixel on the detector. So, as long as you keep the time
> between photons much greater than 100 nanoseconds you can be fairly
> confident that there is never more than one photon anywhere in the
> beamline at a given instant.
>
> ...
Does the length of the beamline really matter? As long as the photons
are spaced apart more than the coherence length (several 1000 A to
several 10um on a synchrotron beamline according to Bernard's post) they
should be considered independent events. So the photon rate can probably
be 5 to 6 orders of magnitude higher while still doing "single photon
diffraction" experiments.
Bart
--
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Bart Hazes (Associate Professor)
Dept. of Medical Microbiology& Immunology
University of Alberta
1-15 Medical Sciences Building
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Canada, T6G 2H7
phone: 1-780-492-0042
fax: 1-780-492-7521
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