>Finally, there is simply no downside in collecting more degrees with proportionally lower dose on the Pilatus. Merging the data recovers the _same_ signal. It has only advantages - so many that I won't write them up here with 1 finger on my tablet.
...Up to the point at which one can no longer index/refine the frames reliably.
And it would be interesting to try to figure out what that point is, or how to push it to even fewer photons.
JPK
With a CCD it's a different story.
Best,
Kay
Am 17. April 2015 15:49:21 MESZ, schrieb Jurgen Bosch <[log in to unmask]>:
>I would disagree.
>My philosophy is: assume this is your only diffracting crystal,
>maximize the outcome by investing some thoughts into it before being
>sorry. Therefore, run strategy and optimize for anomalous pairs being
>collected as close in time as possible.
>If you have the luxury of having multiple crystals you know diffract,
>then it;s a different story.
>
>Regarding the 1degree option, I think that dates back to the dinosaurs
>of crystallography, when only non-decimal numbers were an option to be
>entered in the CLI, yes there was no GUI before :-) Also the
>goniometers are much more accurate these days. More seriously, I think
>this had something to do perhaps with the cost of storage, remember 50
>MB was a lot of space 20 years ago. Your average Pilatus data set today
>comes at 3-5 GB, considering a 6TB drive costs about 250$ today that’s
>nothing. Or reading the files from a DAT4 drive took ages, so you
>really didn’t want to collect fine sliced data.
>
>Jürgen
>......................
>Jürgen Bosch
>Johns Hopkins University
>Bloomberg School of Public Health
>Department of Biochemistry & Molecular Biology Johns Hopkins Malaria
>Research Institute
>615 North Wolfe Street, W8708
>Baltimore, MD 21205
>Office: +1-410-614-4742<tel:%2B1-410-614-4742>
>Lab: +1-410-614-4894<tel:%2B1-410-614-4894>
>Fax: +1-410-955-2926<tel:%2B1-410-955-2926>
>http://lupo.jhsph.edu
>
>On Apr 17, 2015, at 9:25 AM, Kay Diederichs
><[log in to unmask]<mailto:[log in to unmask]>>
>wrote:
>
>Hi Jürgen,
>
>sorry - that's what I get when mailing while boarding ... No, I'd just
>collect 360 degrees, and if the crystal is still ok, another 360, ...
>This way one
>- obtains high completeness and multiplicity
>- can discard frames with "too much" radiation damage
>- does not have to worry about the starting point of data collection.
>To make the most of the second 360°, you should change some parameter:
>wavelength, rotation axis (requires a BL with kappa or Prigo), or at
>least distance (by few percent).
>
>When I read that 1° frames are collected, I just wonder why? Because it
>used to be done like that in the good old times?
>
>HTH,
>
>Kay
>
>On Fri, 17 Apr 2015 11:55:42 +0000, Jurgen Bosch
><[log in to unmask]<mailto:[log in to unmask]>> wrote:
>
>Just to clarify, I think what Kay meant with "strategy" is that you
>don't just shoot at the crystal and collect. You should figure out what
>is the optimum start and end point of your data collection. Best to be
>cautious and not immediately go for highest resolution and not fry your
>crystal. A 4 A complete anomalous data set is better than a partial
>3.2A one.
>J?rgen
>
>
>......................
>J?rgen Bosch
>Johns Hopkins University
>Bloomberg School of Public Health
>Department of Biochemistry & Molecular Biology Johns Hopkins Malaria
>Research Institute
>615 North Wolfe Street<x-apple-data-detectors://4>, W8708 Baltimore, MD
>21205<x-apple-data-detectors://5/0>
>Office: +1-410-614-4742<tel:%2B1-410-614-4742>
>Lab: +1-410-614-4894<tel:%2B1-410-614-4894>
>Fax: +1-410-955-2926<tel:%2B1-410-955-2926>
>http://lupo.jhsph.edu<http://lupo.jhsph.edu/>
>
>On Apr 17, 2015, at 06:37, Kay Diederichs
><[log in to unmask]<mailto:[log in to unmask]>>
>wrote:
>
>Hi,
>I'd say using a Pilatus detector in fine-slicing mode and lowdose/high
>multiplicity will give you better chances to solve the structure. The
>right strategy makes a difference ...
>Best,
>Kay
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