720 XTF Search Results (f1-associated-Lesson=Gamma Ray Tools;f2-subject=Instrument);f2-subject%3DInstrument Results for your query: f1-associated-Lesson=Gamma Ray Tools;f2-subject=Instrument Thu, 01 Jan 1970 12:00:00 GMT GRIS instrument schematic. Diagram illustrating the placement of the detectors and shields. Thu, 01 Jan 1970 12:00:00 GMT The Chandra Advanced CCD Imaging Spectrometer (ACIS). The Advanced CCD Imaging Spectrometer is an instrument on the Chandra X-Ray Observatory that consists of an array of charged coupled devices. ACIS is especially useful because it can make X-ray images, and at the same time, measure the energy of each incoming X-ray, so that scientists can make pictures of objects using only X-rays produced by a single chemical element. Thu, 01 Jan 1970 12:00:00 GMT GRIS germanium detectors. GRIS consists of seven of the world's largest, high-purity, n-type germanium (Ge) detectors. The detectors are cooled to liquid nitrogen temperatures (in order to achieve high resolution) and are surrounded by a thick anti-coincidence shield which allows the rejection of background events from true astrophysical events. Thu, 01 Jan 1970 12:00:00 GMT