<title>Machine For The Rapid And Accurate Measurement Of Profile</title>

Abstract

A profile measuring machine has been developed for use in the production of X -ray optical mirrors, and its configuration permits the internal measurement of open -ended cylinders.It has been designed to provide for rapid measurement and evaluation of the figure of both ground and polished surfaces.Typically, the shallow curves being measured have lengths of up to 200 mm and sags of a few mm, and positions on the curve are measured with resolutions of 1 pm and 80 nm in the respective directions.The axial position is measured by a Moiré fringe grating system, and the sagittal position by a He -Ne laser interferometer which monitors the separation of the stylus head from a non -load -bearing reference straight edge which is referred directly to the work being measured.A tight metrological loop confers high immunity from the effects of environmental vibration.