 Zone Plates by Janos Kirz and David Attwood

By Janos Kirz and David Attwood. Section 4.4 of the X-Ray Data Booklet, Lawrence Berkeley National Laboratory.

Official text: xdb.lbl.gov/Section4/Sec_4-4.html

The section specifies half-period-zone geometry and distinguishes focal resolution from first-order diffraction efficiency. Its ideal binary amplitude zone plate has first-order efficiency $1/{\pi }^2$.