The manufacture of a very high precision x-ray collimator array for rapid tomographic energy dispersive diffraction imaging (TEDDI)

Abstract

A very high resoln. x-ray collimator array has been constructed for use with tomog. energy dispersive diffraction imaging (TEDDI). The collimator consists of a 16 × 16 array of 50 μm diam. holes in a series of 0.1 mm tungsten plates aligned to a tolerance of ±2 μm. The min. angular divergence of the transmitted x-ray beams through each transmission pathway in the collimator array has been designed to be 0.02°, which is equiv. to an energy dispersed resoln. of 250 eV with an aspect ratio of 6000:1. The collimator array has been matched to the development of an energy sensitive x-ray detector array for TEDDI studies of materials. The very high tolerance of the aperture size and placement was achieved by utilizing high intensity femtosecond pulse duration laser machining from a diode pumped solid state laser (DPSS). Using a novel arrangement the laser acted as the principal alignment and cutting tool. The collimator transmission function has been tested using a uniform synchrotron radiation flood field. The transmission and spatial uniformity were found to be consistent with the design parameters for TEDDI applications and also as a diffracted beam collimator for monochromatic powder diffraction studies. [on SciFinder(R)]