A Von Hamos or sagittaly bent monochromator or optic consists in a flat plate that is cylindrically curved onto a holder presenting a cylindrical surface along the sagittal direction.

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Johann crystals used as Von Hamos configuration produces a focused point at a distance calculated from the radius of curvature.​

 

Von Hamos crystals configuration diffracts producing larger solid angles of detection than flat crystals.

They can also be produced with a conical curvature.

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