Readout Ports Research Articles

PicoTDC: a flexible 64 channel TDC with picosecond resolution

The PicoTDC is a 64 channel TDC (Time to Digital Converter) ASIC, with 3ps or 12ps time binning, developed at CERN for use in a large variety of high channel count scientific instrumentation. Acquired time measurements are processed on-chip with a programmable buffering and triggered data flow architecture before being read out on 1 to 4 byte-wise readout ports with a total readout bandwidth of up to 10 Gbps. Leading edge, falling edge or leading edge together with pulse width can be captured at burst rates as high as 1.2 GHz and sustained rate of 320 MHz per channel. Effective single-shot time resolution has been measured to be 3.7 ps RMS across all 64 channels over its full dynamic range and as good as 1.35 ps RMS when using an on-chip adjustment feature optimized for a specific channel (0.43 ps if averaged over multiple measurements). The PicoTDC is implemented in a 65 nm CMOS process and 20 k chips have been produced and packaged in a 400 pin plastic BGA package.

Focus on photonics, spectroscopy, and spectrometry

Focus on photonics, spectroscopy, and spectrometry

An Impedance Matching Method for LC Passive Wireless Sensors

This paper presents an impedance matching method for increasing the readout distance of an inductor-capacitor (LC) passive wireless sensor. When the impedance of the LC sensor system is equal to that of the measurement system, there is no reflection between the LC sensor system and the measurement system, which maximizes signal-to-noise ratio and readout distance. Complex impedance matching networks at the readout port of the LC sensor system have been analyzed and simulated. The matching capacitor at the readout port is required to change with the sensing capacitor in the LC sensor in order to maintain the same resonant frequency in both readout port and LC sensor. The matching resistor at the readout port has been analyzed and optimized. A varactor-based capacitor was inserted as the matching capacitor, which can be controlled by a DC voltage so that the resonant frequency of the readout port can be scanned within the full range of resonant frequency in the LC sensor. A capacitive humidity sensor constructed from a planar spiral inductor and an interdigital capacitor was used here to demonstrate the proposed impedance matching method. It shows that the readout distance under the impedance matching is 1.5 times as long as that without the impedance matching. The impedance matching analysis gives in-depth insight into the LC sensor system behavior, and the results presented here suggest that the impedance matching method may be utilized the long distance readout of the scaled LC sensor application based on the S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> measurement.

Amplitude-multiplexed readout of single photon detectors based on superconducting nanowires

The realization of large-scale photonic circuit for quantum optics experiments at telecom wavelengths requires an increasing number of integrated detectors. Superconductive nanowire single photon detectors (SNSPDs) can be easily integrated on chip and they can efficiently detect the light propagating inside waveguides. The thermal budget of cryostats poses a limit on the maximum number of elements that can be integrated on the same chip due to the thermal impact of the readout electronics. In this paper, we propose and implement a novel scheme able for an efficient reading of several SNSPDs with only one readout port, enabling the realization of photonic circuits with a large number of modes.

Audio-Band Frequency-Dependent Squeezing for Gravitational-Wave Detectors.

Quantum vacuum fluctuations impose strict limits on precision displacement measurements, those of interferometric gravitational-wave detectors among them. Introducing squeezed states into an interferometer's readout port can improve the sensitivity of the instrument, leading to richer astrophysical observations. However, optomechanical interactions dictate that the vacuum's squeezed quadrature must rotate by 90° around 50Hz. Here we use a 2-m-long, high-finesse optical resonator to produce frequency-dependent rotation around 1.2kHz. This demonstration of audio-band frequency-dependent squeezing uses technology and methods that are scalable to the required rotation frequency and validates previously developed theoretical models, heralding application of the technique in future gravitational-wave detectors.

A Three-Terminal Dual-Pillar STT-MRAM for High-Performance Robust Memory Applications

The design of a three-terminal self-aligned dual-pillar (DP) magnetic tunnel junction (MTJ) utilizing both current-induced spin-transfer torque (STT) and magnetic domain-wall motion effects is proposed for high-speed nonvolatile robust memory applications. The choice of a thin tunneling oxide (~0.9 nm) in a write-in port, spatially and electrically separated from a read-out port incorporating a thicker (~1.8 nm) oxide on an extended thin-film multilayer stack, significantly improves the overall cell stability and parametric process yield of a memory array. A dual-bit-line memory architecture incorporating a single-ended voltage-sensing scheme for fast data readout with just one access transistor per cell is also proposed for the first time. The technology-circuit cooptimization of the proposed single-transistor (1T) DP STT magnetic random access memory (MRAM) cell is carried out using effective mass-based transport simulations in nonequilibrium Green's function formalism and accurate micromagnetic simulations involving the Landau-Lifshitz-Gilbert-Slonczewski equation. The proposed DP STT-MRAM bit cell outperforms a state-of-the-art 1T-1MTJ STT-MRAM cell in terms of higher cell tunneling magnetoresistance, simplified memory array architecture with a single supply for read/write, and significantly lower probability of disturb and access failures under parametric process variations with a marginal increase in critical switching current.

Photon-counting X-ray imaging at kilohertz frame rates

A kilohertz frame rate readout system for Medipix2 chips is being developed at European Synchrotron Radiation Facility (ESRF). This work was initiated with the aim of meeting the growing demand for fast and noise-free X-ray bidimensional detection particularly on synchrotron beamlines. Medipix2 is a photon-counting readout ASIC of 256×256 pixels with 55 μm pitch developed in the framework of the Medipix collaboration managed by CERN. The ESRF readout system is based on a custom interface board named Parallel Readout Image Acquisition for Medipix (PRIAM) a fast PCI interface and a Linux PC. The PRIAM board implementing fast FIFOs and a programmable gate array can read up to five Medipix2 circuits simultaneously in less than 0.3 ms using the 32-bit parallel readout port of Medipix2 and 100 MHz clock frequency. This paper describes the architecture of the PRIAM board, reports on the first test results, and mentions some of the targeted applications.

Multiport-readout frame-transfer 5 megapixel CCD imaging system for TEM applications

A multiport-readout, frame-transfer charge-coupled device (CCD) digital imaging system has been successfully developed and tested for intermediate-high-voltage electron microscopy (IVEM) applications up to 400 keV. The system employs a back-thinned CCD with 2560×1960 pixels and a pixel size of 24 μm×24 μm. In the current implementation, four of the eight on-chip readout ports are used in parallel each operating at a pixel rate of 1- or 2-MHz so that the entire CCD array can be read out in as short as 0.6 s. The frame-transfer readout functions as an electronic shutter which permits the rapid transfer of charges in the active pixels to four masked buffers where the charges are readout and digitized while the active area of the CCD is integrating the next frame. With a thin film-based phosphor screen and a high-performance lens relay, the system has a conversion factor of 2.1 digital units per incident electron at 400 keV, and a modulation transfer function value of 14% at the Nyquist frequency.

Multiport-Readout Frame-Transfer 5 Megapixel CCD Digital System for IVEM Applications

A multiport-readout, frame-transfer charge coupled device (CCD) digital imaging system has been successfully constructed and tested for intermediate-high voltage electron microscopy (IVEM) applications up to 400 keV. The system employs a back-thinned CCD, made by MIT Lincoln laboratories, that comprises 2560 × 1960 pixels and a pixel size of 24 μm × 24 μm. With a frame transfer design, the imager fills nearly the entire usable area of a 100 mm-diameter silicon wafer (FIG. 1). In the current implementation, four of the eight on-chip readout ports are utilized in parallel each operating at a pixel rate of 1 or 2 MHz so that the entire CCD array can be read out in as short as ∼0.6 seconds. The frame-transfer readout functions as an electronic shutter which permits the rapid transfer of charges in the active pixels to four light-shielded buffers (FIG. 1) where the charges are readout and digitized while the active area of the CCD is integrating the next frame. At 2 MHz, charge transfer of 980 CCD rows will be completed in under 0.5 ms, which is much shorter than a typical exposure time of a few seconds. The camera head (FIG.2) and control electronics for CCD sensor were packaged by Photometries (Tuscon, Arizona). Two MaxVideo 200 image processing boards from Datacube (Peabody, MA) are used for high speed online imaging processing. The CCD sensor is electronically cooled to ∼ −40°C during operation.

Streak And Framing Camera Designs Using Surface Acoustic Wave Charge-Transfer Devices

Solid-state imagers with integrated scanning circuits offer many advantages over beam-scanned camera tubes in cost, reliability, size, and range of applications. Solid-state electrical imagers are the realization of available methods for organizing and transferring charges from an image-sensing area to electrical readout ports. Surface acoustic waves (SAWs) traveling on a piezo-electric medium have been shown to support charge transfer in a solid-state device: charges can be injected into electric potential wells that travel at the acoustic speed and may be collected at a different location on the surface. The principles of SAW charge-transfer devices (SAW-CTDs) are reviewed. Design concepts are presented for SAW-CTDs and CCD-CTDs for use as electrical or optical waveform recorders and as imaging devices, e.g., streak and framing cameras, operating in single-shot and continuously cycling modes.