Medipix2: A 64-k pixel readout chip with 55-/spl mu/m square elements working in single photon counting mode
04 Nov 2001-Vol. 49, Iss: 5, pp 2279-2283
TL;DR: The Medipix2 as discussed by the authors is a pixel-detector readout chip consisting of 256 /spl times/ 256 identical elements, each working in single photon counting mode for positive or negative input charge signals.
Abstract: The Medipix2 chip is a pixel-detector readout chip consisting of 256 /spl times/ 256 identical elements, each working in single photon counting mode for positive or negative input charge signals. Each pixel cell contains around 500 transistors and occupies a total surface area of 55 /spl mu/m /spl times/ 55 /spl mu/m. A 20-/spl mu/m wide octagonal opening connects the detector and the preamplifier input via bump bonding. The preamplifier feedback provides compensation for detector leakage current on a pixel by pixel basis. Two identical pulse height discriminators are used to create a pulse if the preamplifier output falls within a defined energy window. These digital pulses are then counted with a 13-b pseudorandom counter. The counter logic, based in a shift register, also behaves as the input-output register for the pixel. Each cell also has an 8-b configuration register which allows masking, test-enabling and 3-b individual threshold adjust for each discriminator. The chip can be configured in serial mode and readout either serially or in parallel. The chip is designed and manufactured in a 6-metal 0.25-/spl mu/m CMOS technology. First measurements show an electronic pixel noise of 140 e~ root mean square (rms) and an unadjusted threshold variation around 360 e~ rms.
Citations
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CERN1
21 Oct 2007-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: In this paper, the authors proposed a novel approach for the readout of a TPC at the future linear collider is to use a CMOS pixel detector combined with some kind of gas gain grid.
Abstract: A novel approach for the readout of a TPC at the future linear collider is to use a CMOS pixel detector combined with some kind of gas gain grid. A first test using the photon counting chip Medipix2 with GEM or Micromegas demonstrated the feasibility of such an approach. Although this experiment demonstrated that single primary electrons could be detected the chip did not provide information on the arrival time of the electron in the sensitive gas volume nor did it give any indication of the quantity of charge detected. The Timepix chip uses an external clock with a frequency of up to 100 MHz as a time reference. Each pixel contains a preamplifier, a discriminator with hysteresis and 4-bit DAC for threshold adjustment, synchronization logic and a 14-bit counter with overflow control. Moreover, each pixel can be independently configured in one of four different modes: masked mode: pixel is off, counting mode: 1-count for each signal over threshold, TOT mode: the counter is incremented continuously as long as the signal is above threshold, and arrival time mode: the counter is incremented continuously from the time the first hit arrives until the end of the shutter. The chip resembles very much the Medipix2 chip physically and can be readout using slightly modified versions of the various existing systems. This paper presents the main features of the new design, electrical measurements and some first images.
1,004 citations
TL;DR: This paper investigates to which extent energy-sensitive photon counting devices, operated in the pulse-mode, are capable of revealing quantitative information about the elemental composition of the absorber, and addresses the question of measuring and imaging the local density of a gadolinium-based contrast agent in the framework of a generalized dual-energy pre-processing.
Abstract: After passage through matter, the energy spectrum of a polychromatic beam of x-rays contains valuable information about the elemental composition of the absorber. Conventional x-ray systems or x-ray computed tomography (CT) systems, equipped with scintillator detectors operated in the integrating mode, are largely insensitive to this type of spectral information, since the detector output is proportional to the energy fluence integrated over the whole spectrum. The main purpose of this paper is to investigate to which extent energy-sensitive photon counting devices, operated in the pulse-mode, are capable of revealing quantitative information about the elemental composition of the absorber. We focus on the detection of element-specific, K-edge discontinuities of the photo-electric cross-section. To be specific, we address the question of measuring and imaging the local density of a gadolinium-based contrast agent, in the framework of a generalized dual-energy pre-processing. Our results are very promising and seem to open up new possibilities for the imaging of the distribution of elements with a high atomic number Z in the human body using x-ray attenuation measurements. To demonstrate the usefulness of the detection and the appropriate processing of the spectral information, we present simulated images of an artherosclerotic coronary vessel filled with gadolinium-based contrast agent. While conventional systems, equipped with integrating detectors, often fail to differentiate between contrast filled lumen and artherosclerotic plaque, the use of an energy-selective detection system based on the counting of individual photons reveals a strong contrast between plaque and contrast agent.
578 citations
CERN1
TL;DR: In this article, a pixel detector readout chip was developed with a new front-end architecture aimed at eliminating the spectral distortion produced by charge diffusion in highly segmented semiconductor detectors.
Abstract: A prototype pixel detector readout chip has been developed with a new front-end architecture aimed at eliminating the spectral distortion produced by charge diffusion in highly segmented semiconductor detectors. In the new architecture neighbouring pixels communicate with one another. At the corner of each pixel summing circuits add the total charge deposited in each sub-group of 4 pixels. Arbitration logic assigns a hit to the summing circuit with the highest charge. In the case where incoming X-ray photons produce fluorescence-a particular issue in high-Z materials-the charge deposited by those fluorescent photons will be included in the charge sum provided that the deposition takes place within the volume of the pixels neighbouring the initial impact point. The chip is configurable such that either the dimensions of each detector pixel match those of one readout pixel or detector pixels are 4 times greater in area than the readout pixels. In the latter case event-by-event summing is still possible between the larger pixels. As well as this innovative analog front-end circuit, each pixel contains comparators, logic circuits and two 15-bit counters. When the larger detector pixels are used these counters can be configured to permit multiple thresholds in a pixel providing spectroscopic information. The prototype chip has been designed and manufactured in an 8-metal 0.13 mum CMOS technology. First measurements show an electronic pixel noise of ~ 72 e-rms (Single Pixel Mode) and ~ 140 e-rms (Charge Summing Mode).
349 citations
Cites background from "Medipix2: A 64-k pixel readout chip..."
...The performance of the Medipix2 imaging system is limited by the sharing of charge between neighbouring pixels....
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...The Medipix2 [5] pixel dimensions are 55 m 55 m....
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...This work was undertaken in the framework of the Medipix2 Collaboration (http://www. cern.ch/MEDIPIX)....
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...The authors would like to thank the support and encouragement of the Medipix2 and Medipix3 collaborations....
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Journal Article•
TL;DR: The initial in vivo images of the mouse heart and spine show that U-SPECT-I can be used for novel applications in the study of dynamic biologic systems with a clear projection to clinical applications and opens up new possibilities for the suborgan-level study of radiotracers in mouse models.
Abstract: A major advance in biomedical science and diagnosis was accomplished with the development of in vivo techniques to image radiolabeled molecules, but limited spatial resolution has slowed down applications to small experimental animals. Here, we present a SPECT system (U-SPECT-I) dedicated to radionuclide imaging of murine organs at a submillimeter resolution. Methods: The high performance of U-SPECT-I is based on a static triangular detector setup, with a cylindric imaging cavity in the center and 75 gold micropinhole apertures in the cavity wall. The pinholes are focused on a small volume of interest such as the mouse heart or spine to maximize the detection yield of -photons. Three-dimensional molecular distributions are iteratively estimated using the detector data and a statistical reconstruction algorithm that takes into account system blurring and data noise to increase resolution and reduce image noise. Results: With 0.6-mm-diameter pinholes, the maximum fraction of detected photons emitted by a point source (peak sensitivity) is 0.22% for a 15%-wide energy window and remains higher than 0.12% in the central 12 mm of the central plane. In a resolution phantom, radioactively filled capillaries as small as 0.5 mm and separated by 0.5 mm can be distinguished clearly in reconstructions. Projection data needed for the reconstruction of cross sections of molecular distributions in mouse organs can readily be obtained without the need for any mechanical movements. Images of a mouse spine show 99m Tc-hydroxymethylene diphosphonate uptake down to the level of tiny parts of vertebral processes. These are separated clearly from the vertebral and intervertebral foramina. Using another tracer, one can monitor myocardial perfusion in the left and right ventricular walls, even in structures as small as the papillary muscles. Conclusion: U-SPECT-I allows discrimination between molecular concentrations in adjacent volumes of as small as about 0.1 L, which is significantly smaller than can be imaged by any existing SPECT or PET system. Our initial in vivo images of the mouse heart and spine show that U-SPECT-I can be used for novel applications in the study of dynamic biologic systems with a clear projection to clinical applications. The combination of high resolution and detection efficiency of U-SPECT-I opens up new possibilities for the suborgan-level study of radiotracers in mouse models.
328 citations
01 Aug 2009-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: The PILATUS hybrid pixel detector as discussed by the authors combines silicon sensors with CMOS processing chips by a 2D micro bump-bonding interconnection technology developed at the Paul Scherrer Institute.
Abstract: The hybrid pixel technology combines silicon sensors with CMOS-processing chips by a 2D micro bump-bonding interconnection technology developed at Paul Scherrer Institute [C. Broennimann, E.F. Eikenberry, B. Henrich, R. Horisberger, G. Huelsen, E. Pohl, B. Schmitt, C. Schulze-Briese, M. Suzuki, T. Tomizaki, H. Toyokawa, A. Wagner. J. Synchrotron Rad. 13 (2005) 120 [1] ; T. Rohe, C. Broennimann, F. Glaus, J. Gobrecht, S. Heising, M. Horisberger, R. Horisberger, H.C. Kaestl, J. Lehmann, S. Streuli, Nucl. Instr. and Meth. Phys. Res. A 565 (2006) 303 [2] ]. PILATUS hybrid pixel detectors like other instruments [X. Llopart, M. Campell, R. Dinapoli, D. San Segundo, E. Pernigotti. IEEE Trans. Nucl. Sci. 49 (2002) 2279 [3] ; N. Boudet, J.-F. Berar, L. Blanquart, P. Breugon, B. Caillot, J.-C. Clemens, I. Koudobine, P. Delpierre, C. Mouget, R. Potheau, I. Valin, Nucl. Instr. and Meth. Phys. Res. A 510 (2003) 41 [4] ] are operating in the so-called “single photon counting mode”: Every X-ray quantum is directly converted into an electrical signal and counted by the detector system. Several prototype detectors in various geometries were produced, tested and established at different synchrotron beamlines worldwide. We explain the technology and present some recent highlights from various fields of applications.
293 citations
References
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01 Apr 2015
TL;DR: The Art of Electronics as mentioned in this paper is widely accepted as the best single authoritative book on electronic circuit design and includes 90 oscilloscope screenshots illustrating the behavior of working circuits, dozens of graphs giving highly useful measured data of the sort that is often buried or omitted in datasheets but which you need when designing circuits, and 80 tables (listing some 1650 active components), enabling intelligent choice of circuit components by listing essential characteristics (both specified and measured) of available parts.
Abstract: At long last, here is the thoroughly revised and updated third edition of the hugely successful The Art of Electronics. It is widely accepted as the best single authoritative book on electronic circuit design. In addition to new or enhanced coverage of many topics, the third edition includes 90 oscilloscope screenshots illustrating the behavior of working circuits, dozens of graphs giving highly useful measured data of the sort that is often buried or omitted in datasheets but which you need when designing circuits, and 80 tables (listing some 1650 active components), enabling intelligent choice of circuit components by listing essential characteristics (both specified and measured) of available parts. The new Art of Electronics retains the feeling of informality and easy access that helped make the earlier editions so successful and popular. It is an indispensable reference and the gold standard for anyone, student or researcher, professional or amateur, who works with electronic circuits.
1,528 citations
Book•
01 Jan 1980
TL;DR: The Art of Electronics as mentioned in this paper is widely accepted as the best single authoritative book on electronic circuit design and includes 90 oscilloscope screenshots illustrating the behavior of working circuits, dozens of graphs giving highly useful measured data of the sort that is often buried or omitted in datasheets but which you need when designing circuits, and 80 tables (listing some 1650 active components), enabling intelligent choice of circuit components by listing essential characteristics (both specified and measured) of available parts.
Abstract: At long last, here is the thoroughly revised and updated third edition of the hugely successful The Art of Electronics. It is widely accepted as the best single authoritative book on electronic circuit design. In addition to new or enhanced coverage of many topics, the third edition includes 90 oscilloscope screenshots illustrating the behavior of working circuits, dozens of graphs giving highly useful measured data of the sort that is often buried or omitted in datasheets but which you need when designing circuits, and 80 tables (listing some 1650 active components), enabling intelligent choice of circuit components by listing essential characteristics (both specified and measured) of available parts. The new Art of Electronics retains the feeling of informality and easy access that helped make the earlier editions so successful and popular. It is an indispensable reference and the gold standard for anyone, student or researcher, professional or amateur, who works with electronic circuits.
712 citations
01 Aug 1991-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: In this paper, scaling laws for the analog front end and related problems for detectors in the range from microstrips to pixel detectors are discussed for fast and low power building blocks (charge sensitive preamplifier, shaper, discriminator and analog storage).
Abstract: Scaling laws for the analog front end and related problems are discussed for detectors in the range from microstrips to pixel detectors. Design strategies for fast- and low-power building blocks (charge-sensitive preamplifier, shaper, discriminator and analog storage) are looked into. Merging of functions for minimal transistor counts, local analog storage versus digital-only output (trade-offs and limitations) and precision of and matching between readout elements are also discussed.
222 citations
"Medipix2: A 64-k pixel readout chip..." refers methods in this paper
...Krummenacher [ 5 ] based on a differential CMOS amplifier as shown in Figure 3. A differential input amplifier was chosen for better rejection of substrate and power supply noises....
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CERN1
TL;DR: In this article, a single photon counting pixel detector readout chip (PCC) was derived from previous work in the CERN RD19 collaboration for particle physics tracking devices, recently developed for high energy physics experiments.
Abstract: A single Photon Counting pixel detector readout Chip (PCC) has been derived from previous work in the CERN RD19 collaboration for particle physics tracking devices, recently developed for high energy physics experiments. The readout chip is a 64 x 64 matrix of identical 170 {micro}m x 170 {micro}m cells. It is to be bump-bonded to an equally segmented 1 cm{sup 2} matrix of semiconductor sensors, e.g. Si or GaAs. Each readout cell comprises a preamplifier, a discriminator and a 15-bit counter. The input noise is 170 e{sup {minus}} rms. At the lowest nominal threshold of 1,400 e{sup {minus}} (5.1 keV in Si) the cells exhibit a threshold distribution with a spread before adjustment of 350 e{sup {minus}} rms. Each cell has a 5-bit register which allows masking, test-enable and 3-bit individual threshold adjust. After adjustment the threshold spread is reduced to 80 e{sup {minus}} rms. Absolute calibration of the electrically measured equivalent charge can be done once the readout chip is bump-bonded to a detector.
222 citations
CERN1
TL;DR: An asynchronous version of a binary pixel readabout circuit has been implemented in an array with 16 columns at 500 mu m pitch and 63 rows at 75 mm m pitch in this paper.
Abstract: An asynchronous version of a binary pixel readabout circuit has been implemented in an array with 16 columns at 500 mu m pitch and 63 rows at 75 mu m pitch. This readabout chip has been bonded with solder bumps to a silicon detector with matching pixel elements. Event information in a pixel can be strobed into a local memory by a trigger signal and subsequently read out. Without a strobe the information is continuously cleared. The complete hybrid detector has been successfully tested with ionizing particles from a radioactive source. Three such devices have been put in the CERN heavy-ion experiment WA94 in the Omega spectrometer, where they recorded particle tracks from high-multiplicity /sup 32/S interactions. Preliminary data indicate a noise of approximately 60 e/sup -/ and a threshold spread of approximately 500 e/sup -/. The timing characteristics are adequate for a fixed-target experiment. >
92 citations
"Medipix2: A 64-k pixel readout chip..." refers methods in this paper
...The electronic noise is measured using the s-curve method [ 9 ] because of the poor precision in the measurement of the pream-...
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