>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 <[email protected]>: >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 ><[email protected]<mailto:[email protected]>> >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 ><[email protected]<mailto:[email protected]>> 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 ><[email protected]<mailto:[email protected]>> >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 -- Diese Nachricht wurde von meinem Android-Mobiltelefon mit K-9 Mail gesendet.
