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bluesky / hklpy

Diffractometer computation library with ophyd pseudopositioner support
https://blueskyproject.io/hklpy
BSD 3-Clause "New" or "Revised" License
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6-circle drawing is mislabeled #324

Open prjemian opened 4 months ago

prjemian commented 4 months ago

The drawing used with the TARDIS example is mislabeled as E6C. Clearly it is not since mu is not part of the detector stack in the E6C geometry. The drawing is correct for the SPEC sixc geometry which is the IUCr 6-circle geometry.

image

The drawing should be psic (the geometry described by Hoydoo Yoo's paper).

Confirm all this before proceeding.

prjemian commented 4 months ago

This is the drawing and description of E6C, from (a private copy of) the libhkl documentation image

prjemian commented 4 months ago

The PETRA3 P09 EH2 libhkl geometry matches the figure above: image

ambarb commented 1 month ago

@prjemian i confirm that the tardis is sixc and we also identified this (hkl-engine-petra3-p09-eh2.c) as the correct picca set of circles.

we ran into some problems when adding a 4th axis so there may still be so circle direction inversion but we are not in a position to resolve that. If we go back to the 4th axis, we will start with this engine (hkl-engine-petra3-p09-eh2.c)

we use the following 3 axes now: omega (theta in sixc), delta, gamma.