title: X-ray characterization of a multichannel smart-pixel array detector.
abstract: The Voxtel VX-798 is a prototype X-ray pixel array detector (PAD) featuring a silicon sensor photodiode array of 48 × 48 pixels, each 130 µm × 130 µm × 520 µm thick, coupled to a CMOS readout application specific integrated circuit (ASIC). The first synchrotron X-ray characterization of this detector is presented, and its ability to selectively count individual X-rays within two independent arrival time windows, a programmable energy range, and localized to a single pixel is demonstrated. During our first trial run at Argonne National Laboratory's Advance Photon Source, the detector achieved a 60 ns gating time and 700 eV full width at half-maximum energy resolution in agreement with design parameters. Each pixel of the PAD holds two independent digital counters, and the discriminator for X-ray energy features both an upper and lower threshold to window the energy of interest discarding unwanted background. This smart-pixel technology allows energy and time resolution to be set and optimized in software. It is found that the detector linearity follows an isolated dead-time model, implying that megahertz count rates should be possible in each pixel. Measurement of the line and point spread functions showed negligible spatial blurring. When combined with the timing structure of the synchrotron storage ring, it is demonstrated that the area detector can perform both picosecond time-resolved X-ray diffraction and fluorescence spectroscopy measurements.
authors.affiliation: Northern Illinois University, Department of Electrical Engineering, DeKalb, IL 60115, USA.
authors.forename: Steve
authors.initials: S
authors.lastname: Ross
authors.affiliation: Northern Illinois University, Department of Electrical Engineering, DeKalb, IL 60115, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Haji-Sheikh
authors.affiliation: Voxtel Inc., Beaverton, OR 97006, USA.
authors.forename: Andrew
authors.initials: A
authors.lastname: Huntington
authors.affiliation: Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439, USA.
authors.forename: David
authors.initials: D
authors.lastname: Kline
authors.affiliation: Voxtel Inc., Beaverton, OR 97006, USA.
authors.forename: Adam
authors.initials: A
authors.lastname: Lee
authors.affiliation: Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439, USA.
authors.forename: Yuelin
authors.initials: Y
authors.lastname: Li
authors.affiliation: Voxtel Inc., Beaverton, OR 97006, USA.
authors.forename: Jehyuk
authors.initials: J
authors.lastname: Rhee
authors.affiliation: DePaul University, Department of Physics, Chicago, IL 60614, USA.
authors.forename: Mary
authors.initials: M
authors.lastname: Tarpley
authors.affiliation: Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439, USA.
authors.forename: Donald A
authors.initials: DA
authors.lastname: Walko
authors.affiliation: Northern Illinois University, Department of Electrical Engineering, DeKalb, IL 60115, USA.
authors.forename: Gregg
authors.initials: G
authors.lastname: Westberg
authors.affiliation: Voxtel Inc., Beaverton, OR 97006, USA.
authors.forename: George
authors.initials: G
authors.lastname: Williams
authors.affiliation: Voxtel Inc., Beaverton, OR 97006, USA.
authors.forename: Haifeng
authors.initials: H
authors.lastname: Zou
authors.affiliation: DePaul University, Department of Physics, Chicago, IL 60614, USA.
authors.forename: Eric
authors.initials: E
authors.lastname: Landahl
keywords: CMOS ASIC; X-ray detector; pixel array detector