Some charge from deeply generated events may also recombine so that the charge is not conserved. Charge that is generated close to the edge of a pixel, or deep in the substrate, can split between pixels. Any charge that reaches (or is generated within) the depletion layer is swiftly drifted to the surface collection site with minimal radial spread. If the charge is generated in a field-free layer, then it moves by diffusion and either recombines or reaches the edge of the depletion layer field. This level of uncertainty must be accounted for in order to ensure the most accurate data. Depending on its generation locale, there is some probability that the photoelectron charge cloud will be split between two or more pixels. Finally, for ultimate operational flexibility within the vacuum chamber, Teledyne Princeton Instruments offers the PI-MTE3 camera, which can be delivered with any of the aforementioned CCD sensors.įor scientific applications that place a high premium on quantitative measurements, it is important that the charge generated by an x-ray photon is collected within one pixel and then transported to the output amplifier without suffering losses from imperfect charge-transfer efficiency (CTE). These models feature a rotatable ConFlat flange, but alternatively it can be supplied with a removable ConFlat flange with a beryllium window. To optimize detector QE, Teledyne Princeton Instruments PIXIS-XB utilizes these sensors in conjunction with a beryllium window, a design that gives researchers the freedom to use the camera without having to attach the detector to the vacuum chamber.įor extremely demanding applications that require x-ray sensitivity spanning the low-to-medium energy range (about 30 eV to 20 keV), Teledyne Princeton Instruments has also designed the SOPHIA-XO and PIXIS-XO cameras that uses a back-illuminated, deep-depletion CCD without AR coating. To achieve a favorable balance between QE, spatial resolution, and blemishes, Teledyne e2v utilizes a 50 μm-thick epitaxial layer. To meet the demand for higher QE in the medium energy x-ray range, CCD manufacturer Teledyne e2v developed front-illuminated, deep-depletion technology several years ago as a way to increase sensitivity. C) Cross section of back-illuminated, deep-depletion CCD. B) Cross section of back-illuminated CCD. Depending on the x-ray energy range, either a back-illuminated CCD without anti-reflection (AR) coating, or a front- or back-illuminated, deep-depletion CCD is used.įigure 2: A) Cross section of front-illuminated, deep-depletion CCD. In direct-detection cameras, the CCD is directly exposed to the incoming x-ray photons, which enables direct absorption (i.e., detection) of the photons. These devices are utilized in many x-ray techniques, including x-ray microscopy, x-ray lithography, x-ray spectroscopy, x-ray crystallography, and x-ray non-destructive testing. Devices have been engineered to detect x-rays in the energy range extending from well below 100 eV all the way up to 100 keV and higher (a full three orders of magnitude), making them invaluable for research in which high sensitivity is combined with two-dimensional detectors. In the scientific market, CCDs have been improved and optimized in a variety of ways to provide high performance across a broad set of applications - from spectroscopy and semiconductor testing to biological imaging and genetic research.ĭesign modifications to scientific-grade CCDs, initially driven by interest in x-ray astronomy applications, have greatly expanded the domain of x-ray imaging and x-ray spectroscopy at synchrotron facilities. CCDs have become increasingly specialized to meet the changing requirements of both commercial and scientific markets.
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