No Arabic abstract
Optimization of an area detector involves compromises between various parameters like frame rate, read noise, dynamic range and pixel size. We have implemented and tested a novel front-end binning design in a photon-integrating hybrid pixel array detector using the MM-PAD-2.0 pixel architecture. In this architecture, the pixels can be optionally binned in a 2$times$2 pixel configuration using a network of switches to selectively direct the output of 4 sensor pixels to a single amplifier input. Doing this allows a trade-off between frame rate and spatial resolution. Tests show that the binned pixels perform well, but with some degradation on performance as compared to an un-binned pixel. The increased parasitic input capacitance does reduce the signal collected per x-ray as well as increases the noise of the pixel. The increase in noise is, however, less than the factor of 2 increase one would observe for binning in post-processing. Spatial scans across the binned pixels show that no measured signal intensity is lost at the inner binning unit boundaries. In the high flux regime, at a 2$times$2 pixel wide beam spot (FWHM) size, binned mode responds linearly up to a photon flux of ~10$^{7}$ x-rays/s, and performs comparably with un-binned mode up to a photon flux of ~10$^{8}$ x-rays/s. While this study demonstrates a proof of concept for front-end binning in integrating detectors, we also identify changes to this early-stage prototype which can further improve the performance of binning pixel structures.
The Adaptive Gain Integrating Pixel Detector (AGIPD) is an x-ray imager, custom designed for the European x-ray Free-Electron Laser (XFEL). It is a fast, low noise integrating detector, with an adaptive gain amplifier per pixel. This has an equivalent noise of less than 1 keV when detecting single photons and, when switched into another gain state, a dynamic range of more than 10$^4$ photons of 12 keV. In burst mode the system is able to store 352 images while running at up to 6.5 MHz, which is compatible with the 4.5 MHz frame rate at the European XFEL. The AGIPD system was installed and commissioned in August 2017, and successfully used for the first experiments at the Single Particles, Clusters and Biomolecules (SPB) experimental station at the European XFEL since September 2017. This paper describes the principal components and performance parameters of the system.
The CMS experiment will include a pixel detector for pattern recognition and vertexing. It will consist of three barrel layers and two endcaps on each side, providing three space-points up to a pseudoraditity of 2.1. Taking into account the expected limitations of its performance in the LHC environment an 8-9 layer pixel detector for an upgraded LHC is discussed.
We describe a hybrid pixel array detector (EMPAD - electron microscope pixel array detector) adapted for use in electron microscope applications, especially as a universal detector for scanning transmission electron microscopy. The 128 x 128 pixel detector consists of a 500 um thick silicon diode array bump-bonded pixel-by-pixel to an application-specific integrated circuit (ASIC). The in-pixel circuitry provides a 1,000,000:1 dynamic range within a single frame, allowing the direct electron beam to be imaged while still maintaining single electron sensitivity. A 1.1 kHz framing rate enables rapid data collection and minimizes sample drift distortions while scanning. By capturing the entire unsaturated diffraction pattern in scanning mode, one can simultaneously capture bright field, dark field, and phase contrast information, as well as being able to analyze the full scattering distribution, allowing true center of mass imaging. The scattering is recorded on an absolute scale, so that information such as local sample thickness can be directly determined. This paper describes the detector architecture, data acquisition (DAQ) system, and preliminary results from experiments with 80 to 200 keV electron beams.
This paper presents the design of a new monolithic Silicon-On-Insulator pixel sensor in $200~nm$ SOI CMOS technology. The main application of the proposed pixel detector is the spectroscopy, but it can also be used for the minimum ionizing particle (MIP) tracking in particle physics experiments. For this reason few differe
Purpose: CMOS pixel sensors have become extremely attractive for future high performance tracking devices. Initial R&D work has been conducted for the vertex detector for the proposed Circular Electron Positron Collider that will allow precision Higgs measurements. It is critical to achieve low power consumption to minimize the material budget. This requires careful optimization of the sensor diode geometry to reach high charge-over-capacitance that allows reduction in analog power consumption. Methods: The electrode area and footprint are two critical elements in sensor diode geometry and have deciding impacts on the sensor charge collection performance. Prototype CMOS pixel sensor JadePix-1 has been developed with pixel sectors implementing different electrode area and footprint and their charge collection performance has been characterized with radioactive resources. Results: Charge-to-voltage conversion gains are calibrated with low energy X-ray. Noise, charge collection efficiency, charge-over-capacitance and signal-to-noise ratio are obtained for pixel sectors of different electrode area and footprint. Conclusion: Small electrode area and large footprint are preferred to achieve high charge-over-capacitance that promises low analog power consumption. Ongoing studies on sensor performance before and after irradiation, combined with this work, will conclude on the diode geometry optimization.