摘要:
We are developing and prototyping tantalum X-ray collimators for LOFT (Large Observatory For X-ray Timing), a mission proposal selected by ESA as a candidate mission. LOFT is devoted to X-ray timing and designed to investigate the space-time around collapsed objects. The collimator is micro-fabricated in a two-step process: (i) laser-machining of a hole array in Ta and (ii) chemical etching of the hole with the desired porosity (hole vs. bulk volume). The collimator design was studied by Monte Carlo simulation using SWORD (SoftWare for Optimization of Radiation Detectors). The anticipated collimator performance shows 2 orders of magnitude rejection over 2 degrees. The angular response of the collimator was measured with a commercial X-ray diffractor. The prototype collimates over +/-5 degrees.