A parabolic mirror x-ray collimator

A robust and stable x-ray collimator has been developed to produce a parall el beam of x-rays by total external reflection from a parabolic mirror. The width of the gold-coated silica mirror varies along its length, which allo ws it to be bent from a plane surface into a parabolic form by application of unequal bending forces at its ends. A family of parabolas of near consta nt focal length can be formed by changing the screw applied bending force, thus allowing the collimator to cater for a range of wavelengths by the tur ning of a screw. Even with radiation with a wavelength as short as that as Mo K alpha(1) (lambda = 0.07 nm), a gain in flux by a factor of 5.5 was ach ieved. The potential gain increases with wavelength, e.g. for Cu K alpha(1) radiation this amounts to over a factor of ten.