High resolution Fourier synthesis hard X-ray imaging based on CdTe strip detectors

Employing Fourier-synthesis optics and one-dimensional position-sensitive detectors, we are developing a novel hard X-ray imager which can work in the ∼10 keV to ∼200 keV range either as a telescope or a microscope. As the detection part of our imager, we have developed a strip detector made of Schottky CdTe diode, with its cathode divided into 64 channels of 150 μm pitch. Electrodes of all channels are gold-stud bonded to a fanout board, and connected to low noise analog ASIC. We read out signals from all channels simultaneously. As the grid optics elements, one-dimensional "modulation collimator" grids of 1 mm thick tungsten have been manufactured, with 10 grid pitches ranging from 0.2 mm to 2 mm with harmonic ratios. Combining the CdTe strip detector and the grids, we have verified hard X-ray imaging performance of this system. Using an ²⁴¹Am source, we have successfully obtained an image in the 10-70 keV range with a spatial resolution of ∼0.5 mm.