Dear Olivier,
`AzimuthalIntegrator` instances have two possible origins for the
azimuthal angle, either at 0° or at 180° (the default).
To switch from one to another, you need to call the
`ai.setChiDiscAtZero()` method as described in the documentation at:
https://www.silx.org/doc/pyFAI/latest/api/geometry/index.html#pyFAI.geometry.core.Geometry.setChiDiscAtPi
Note that calling those methods resets the integrator and can have a
penalty in performances. Sometimes it can be worth to have two
integrators, one with each origin (if the memory of the computer
allows).
Cheers,
Jerome
On Tue, 21 Oct 2025 08:50:32 +0000
"TACHE Olivier" (via pyfai Mailing List) <pyfai@???> wrote:
> Dear pyFAI users,
> We would like to integrate our waxs datas for oriented samples, to get a representation integrated intensities vs degrees on a ring.
> This is not what we usually do.
>
> [cid:image001.png@01DC4277.9197FA30]
> My Python code is :
>
> ai = AzimuthalIntegrator()
> ai.load(poni_file)
> npt_azim = 360 # angular resolution
> chi, Ichi = ai.integrate_radial(
> Datas, npt_azim,
> unit="chi_deg",
> radial_unit="q_A^-1",
> azimuth_range=(0, 360),
> method="numpy",
> polarization_factor=None,
> correctSolidAngle=True,
> mask=mask,
> radial_range=(1.0,2.0),
> )
>
> plt.plot(chi, Ichi)
>
> [cid:image006.png@01DC4278.5AB1C220]
>
> The result seems strange (no values after 180°).
>
> Could you help me ?
> Olivier
>
>
>
>
>
> 80 years of science and technologies
>
> [cid:image002.png@01DC4277.9197FA30]<https://www.cea.fr/english>
>
> [cid:image003.png@01DC4277.9197FA30]<https://www.cea.fr/english>
>
>
> [cid:image004.jpg@01DC4277.9197FA30]
>
>
> Olivier TACHÉ
> Nanometric Organisation Laboratory (L.I.O.N.S.)
> UMR 3685 NIMBE CEA - CNRS / Paris-Saclay University
> DRF / IRAMIS / NIMBE
> Building 546 - Room 30 PC 175
> CEA Paris-Saclay - RD306 - 91191 Gif sur Yvette Cedex FRANCE
> +33 (0)6 43 36 05 37 olivier.tache@???<mailto:olivier.tache@cea.fr> [cid:image005.jpg@01DC4277.9197FA30] <https://www.linkedin.com/in/olivier-tache-CEA/>
>
>
>
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