Free standing zone plates can be used to focus and monochromatize atom beam
s. A method for manufacturing free-standing silicon zone plates is describe
d. Zone plates with 100 nm and 50 nm outermost zone width have now been fab
ricated with this method. The zone plates are designed for focusing a heliu
m atom beam at thermal energy. The focal length of the first diffraction or
der for a de Broglie wavelength of lambda(dB) = 0.09 nm is 300 mm. Initial
measurements of the focusing properties of the zone plates have been made.