High-speed X-ray imaging pixel array detector for synchrotron bunch isolation

Abstract

A wide-dynamic-range imaging X-ray detector designed for recording successive frames at rates up to 10 MHz is described. X-ray imaging with frame rates of up to 6.5 MHz have been experimentally verified. The pixel design allows for up to 8-12 frames to be stored internally at high speed before readout, which occurs at a 1 kHz frame rate. An additional mode of operation allows the integration capacitors to be re-addressed repeatedly before readout which can enhance the signal-to-noise ratio of cyclical processes. This detector, along with modern storage ring sources which provide short (10-100 ps) and intense X-ray pulses at megahertz rates, opens new avenues for the study of rapid structural changes in materials. The detector consists of hybridized modules, each of which is comprised of a 500 mm-thick silicon X-ray sensor solder bump-bonded, pixel by pixel, to an application-specific integrated circuit. The format of each module is 128 Â 128 pixels with a pixel pitch of 150 mm. In the prototype detector described here, the three-side buttable modules are tiled in a 3 Â 2 array with a full format of 256 Â 384 pixels. The characteristics, operation, testing and application of the detector are detailed.

Characterization of CdTe sensors with Schottky contacts coupled to charge-integrating pixel array detectors for X-ray science

“…However, as shown herein, an understanding of these effects is important in 10 We defined an energy threshold per pixel at half the photon peak energy, E. Events above threshold were counted as one photon each, events above 3 times the threshold (1.5E) were counted as two photons, and so on. 11 Electron collection is commonly considered preferable over hole collection due to the larger µτ product for electrons. Figure 20: Distribution of the energy determined by the pixels of each Laue peak.…”

X-ray data processing

“…Originally the electronic detectors were devices such as television-type cameras or multiwire proportional counters (late 1970s to early 1990s), but the major advance was the introduction of image plates and charge-coupled devices (late 1980s to mid 1990s). More recently, these have been superseded by pixel array detectors (‘PAD’s, mid 2000s to present) using either photon counting [ 6 ] or charge integrating [ 7 ] technologies.…”

Sub-microsecond x-ray imaging using hole-collecting Schottky type CdTe with charge-integrating pixel array detectors

“…Previous investigations using a Keck PAD system with silicon sensor [9] determined that the resolution of the time response was limited by the charge collection time of the silicon, some ten nanoseconds, and not the electronic response of the system.…”