Stacking of micro-aperture arrays: A new strategy to construct Söller collimator for x rays

A stacking strategy to construct a light-weight collimator is proposed in this paper by which micro-aperture arrays can be assembled as a novel Söller collimator. Compared to Söller collimators made from conventional methods, our strategy enabled a substantial mass reduction up to 67% for a field of view of 2°. 21 micro-aperture arrays were fabricated by fiber laser drilling, and the Söller collimator was thereafter afforded by stacking and aligning the arrays. The processing consistency of the arrays and the alignment of the assembled collimator were examined by optical microscopy and x-ray computer tomography. Collimation tests were conducted to evaluate the feasibility of the stacking strategy. Based on this new strategy, higher aspect ratios can be fulfilled, which also allows for a significant mass reduction compared to the conventional Söller collimator.