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Kappa – from a users perspective ?

Kappa – from a users perspective ?. Standard today. Most Labs/synchrotrons use single rotation axis for data collection WHY IS THIS?. The persistence of a single rotation axis. Historical – rotation method –Arndt Wonacott camera etc Cost, ease of implementation, simplicity

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Kappa – from a users perspective ?

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  1. Kappa – from a users perspective ?

  2. Standard today Most Labs/synchrotrons use single rotation axis for data collection WHY IS THIS?

  3. The persistence of a single rotation axis Historical – rotation method –Arndt Wonacott camera etc Cost, ease of implementation, simplicity Implementation of control software Commercially available products –heavily erred to single rotation axis solutions Multi-axes alternatives have been bulky and not easily incorporated into a standard PX setup

  4. The persistence of a single rotation axis Software for utilizing kappa – some say not readily accessible and easily incorporated? - Or is this just a lack of will and man-power… - Jim Pflugrath D*Trek – in use at SBC since 1997 - Bruker/Nonius have very successful system ?? “|Data collection on the Nonius KappaCCD is performed with the Nonius Collect software, an intuitive and user friendly GUI driven program suite, which provides smooth and directed transitions through the phases of indexing, data collection strategy, face indexing and crystal description etc.” Commercially available systems from Nonius and Huber -still somewhat big and precision on the order of 20-30 micron sphere of confusion No concerted effort from user community ??

  5. Nonius kappa

  6. Huber kappa

  7. Use of Kappa Alignment of crystal -allows for intelligent and most efficient route to collection of a complete data set -allows measurement of Friedel mates at same time important for accurate measurement of very small anom. Differences - Completion of data from multiple crystals –a real problem today due to radiation damage from high intensity sources - Collection of diffraction data from around more than one rotation axis significantly improves scaling of data (we want to measure symmetry related measurements in as different a way as possible) -empirical absorption corrections – although less critical at shorter wavelengths has become critical for longer wavelength experiments that are utilizing the very small anomalous signal originating for naturally occurring sulphur atoms in proteins

  8. Mini-Kappa Design compact kappa which will not compromise a standard PX sample /Detector environment High accuracy to match the current state of the art 3rd generation synchrotron sources Rosenbaum/Rock at APS produced a mini-kappa which met to some extent these needs Commercial minikappa from ADSC

  9. Rosenbaum/RockMini-Kappa

  10. ADSC Mini-Kappa

  11. EMBL/ESRF Micro-Kappa Tested very briefly on BM14 mainly to see that design was mechanically sound Performed a real-life S-SAD experiment -360 degrees of data collected at k = 0 -360 degrees of data collected at k = max Apologies – structure solved but

  12. S-SAD results Mean weight and estimated mapCC as a function of resolution d inf - 4.41 - 3.47 - 3.03 - 2.74 - 2.54 - 2.39 - 2.27 - 2.17 - 2.08 - 2.01 <wt> 0.509 0.525 0.534 0.494 0.535 0.522 0.492 0.477 0.489 0.491 <mapCC> 0.742 0.761 0.778 0.733 0.776 0.770 0.735 0.729 0.741 0.740 N 3771 3826 3719 3909 3807 3739 3729 3756 4017 3408 Pseudo-free CC = 54.53 % USE of 90 degrees of k = 0 and k offset sufficient to give interpretable map (caveat Zn was bound!)

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