Hi James,
Am 03.02.2009 um 17:38 schrieb James Holton:
Hey Dirk,
You're wrong. ;)
okay, thanks a lot! ;-)
The remarkable part of this is that the integrated spot intensity
(photons) is essentially invariant with how you divide up the unit
cells into mosaic domains. Well, okay, if
Dear James,
what an interesting discussion!
Am 30.01.2009 um 19:42 schrieb James Holton:
...
I think the coherence length is related to how TWO different photons
can interfere with each other, and this is a rare event indeed. It
has nothing to do with x-ray diffraction as we know it. No
was taking it to mean the total
number of photons in a spot (sometimes called the integrated intensity). Then
of course he is correct.
Colin
-Original Message-
From: CCP4 bulletin board on behalf of James Holton
Sent: Fri 30/01/2009 18:42
To: CCP4BB@JISCMAIL.AC.UK
Subject: Re: [ccp4bb] X-ray
After conversing with Bernhard a bit offline I think the relevant
question is:
How far apart can two electrons in the crystal be before their
scattering becomes incoherent ... as in no longer interfering with
each other in the way Bragg described.
The answer to this is about 10 um if the
of Ethan Merritt
Sent: Thu 29/01/2009 19:24
To: CCP4BB@JISCMAIL.AC.UK
Subject: Re: [ccp4bb] X-ray photon correlation length
On Thursday 29 January 2009 10:59:23 Bernhard Rupp wrote:
Ok, following seems to be correct:
a) interaction length = mean free path : relevant for absorption
b
Message-
From: owner-ccp...@jiscmail.ac.uk
[mailto:owner-ccp...@jiscmail.ac.uk] On Behalf Of Bernhard Rupp
Sent: 29 January 2009 18:59
To: 'Nave, C (Colin)'; CCP4BB@JISCMAIL.AC.UK
Subject: RE: [ccp4bb] X-ray photon correlation length
Ok, following seems to be correct
Ethan Merritt wrote:
My impression is that the coherence length from synchrotron sources
is generally larger than the x-ray path through a protein crystal.
But I have not gone through the exercise of plugging in specific
storage ring energies and undulator parameters to confirm this
impression.
From memory, correlation length is the length during which the phase of the
electric field is preserved. It's typically computed by applying time (pulse
width)- frequency (converted to length) uncertainty principle.
V. Nagarajan
JAN Scientific, Inc.
-Original Message-
From: CCP4 bulletin
Bernard
I guess this came from
Aren't detwinning methods appropriate only in the case of true twin
domains which are larger than the X-ray photon correlation length in
order for the assumption to be valid that |F|^2 from each domain can be
summed? This wouldn't give rise to the apparent 'diffuse
reasonable?
BR
From: CCP4 bulletin board [mailto:ccp...@jiscmail.ac.uk] On Behalf Of Nave,
C (Colin)
Sent: Thursday, January 29, 2009 10:14 AM
To: CCP4BB@JISCMAIL.AC.UK
Subject: Re: [ccp4bb] X-ray photon correlation length
Bernard
I guess this came from
Aren't detwinning methods
From: CCP4 bulletin board [mailto:ccp...@jiscmail.ac.uk] On Behalf Of Nave,
C (Colin)
Sent: Thursday, January 29, 2009 10:14 AM
To: CCP4BB@JISCMAIL.AC.UK
Subject: Re: [ccp4bb] X-ray photon correlation length
Bernard
I guess this came from
Aren't detwinning methods appropriate only
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