Often this reflect crystal size - a small crystal in a big beam (or one
with a long path in air) on a home source would see the small
diffraction signal drop below the noise level quite quickly - often at
the low resolution intensity dip that sits very approximately around 6
Angstrom. On a synchrotron source with a tight low-divergence beam that
matches more closely the crystal dimensions that same crystal will
appear to do rather better.
Also one is more likely to expose the crystal longer (in terms of total
photon numbers) at a synchrotron, which itself begets better signal/noise.
Alternatively: everyone tries harder before synchrotron trips....
Phil Jeffrey
Princeton
On 9/28/10 1:27 PM, Francis E Reyes wrote:
Hi all
I'm interested in the scenario where crystals were screened at home and
gave lousy (say < 8-10A) but when illuminated with synchrotron radiation
gave reasonable diffraction ( > 3A) ? Why the discrepancy?
Thanks
F
