Johansson Curvature

A Johansson curved optic has its surface cylindrically curved at the radius of the Rowland circle while the lattice, that is curved at 2 times the value of the Rowland circle, is completely tangential to the Rowland circle.

 

So the Johansson optic is achieving the focusing from every point of its surface.

 

The Johansson optic is the best configuration to get a rigorous focusing in the meridional direction of the beam on the detector placed on the Rowland circle.

 

The beam remain diverging in the sagittal direction.

 

There are 2 technologies to produce a Johansson optic, depending on the length of the crystal, and the value of the radius of the Rowland circle :​

•  Single machining  

•  Double machining 

 

These always result in an optic having its lattice cylindrically curved at 2 times the value of the radius of the Rowland circle, and having its surface at the value of the radius of the Rowland circle.

 

AlpyX is applying high precision process, tools and controls to produce its Johansson optics.

 

Miscut orientations are also available.

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

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