Toroidally bent crystals are used in X Ray spectrometry and in XPS instruments.

 

They are the perfect geometry for point to point focusing.

 

They are used for a single wavelength, as their value of their 2 radii - meridional and sagittal - are fully dependent from the value of the Bragg’s angle.

  

• Meridional – Dispersive direction : Rm = 2 x RRowland

• Sagittal – Focusing direction : Rs = Rm x sin² θ

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On request, AlpyX can study and engineer toroidally bent Johansson crystals.

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