X-Ray Detector, Cross Grid, Developmental "Bread Board Model"

This is an imaging x-ray detector built by Steve Murray in the early 1970s as part of his PhD research program in 2-dimensional imaging techniques. Under the direction of Riccardo Giacconi, he laboriously hand wound this breadboard model to show that his "cross-grid" design was viable. The copper wire grid is wound in two orthogonal layers and is part of an electronic circuit that is sensitive to incoming electrons. To make it detect x-rays, Murray placed what is called a microchannel plate on top of the grid. Incoming X-rays from a hot source would first hit the front of the microchannel plate and be converted into electrons. The microchannel plate then amplified the resulting electronic charge producing a stream that then hit the dense grid of very fine wires on the detector. The intersections of the wires in the two layers define the x and y coordinates of the charge stream. The resulting signal is used to construct images of the sources of original X-ray pattern. The proof of principle provided by this breadboard detector led to the high resolution X-ray imagers used on orbiting X-ray observatories including HEAO-2 (Einstein), ROSAT, and AXAF (Chandra).It was transferred to NASM from SAO in 2002.