An Optimization Approach to Eliminate Crosstalk in Zero-Potential Circuits for Reading Resistive Sensor Arrays

Crosstalk is a well-known problem in resistive sensor arrays (RSAs). The zero-potential method (ZPM) is a commonly used readout circuit that uses multiplexers and demultiplexers to reduce the main sources of crosstalk. However, the internal resistors of these switches cause a secondary crosstalk in the RSA that alters the RSA sensor values read. The solution to the effects of this secondary crosstalk is still a case of study. In previous literature, these resistances have been considered as known and, in most cases, equal for all switch channels. However, in a real situation, they are unknown and may vary between channels. In this work, a least-squares (LSQR) method is presented to obtain the true values of the switches from the read voltage signals. Calibration columns are added to the RSA for this purpose. To prove the performance of the method proposed, several simulations have been carried out with different values of RSA sensors, switch resistances, size of the RSA, and noise level. Results show that the proposed LSQR method allows obtaining simultaneously accurate values for both the RSA sensors and switch internal resistors. In this way, the problem of secondary crosstalk is neutralized. It also shows better performance when compared with existing approaches

Electromagnetic Interference and Compatibility

Recent progress in the fields of Electrical and Electronic Engineering has created new application scenarios and new Electromagnetic Compatibility (EMC) challenges, along with novel tools and methodologies to address them. This volume, which collects the contributions published in the “Electromagnetic Interference and Compatibility” Special Issue of MDPI Electronics, provides a vivid picture of current research trends and new developments in the rapidly evolving, broad area of EMC, including contributions on EMC issues in digital communications, power electronics, and analog integrated circuits and sensors, along with signal and power integrity and electromagnetic interference (EMI) suppression properties of materials

A neural probe with up to 966 electrodes and up to 384 configurable channels in 0.13 μm SOI CMOS

In vivo recording of neural action-potential and local-field-potential signals requires the use of high-resolution penetrating probes. Several international initiatives to better understand the brain are driving technology efforts towards maximizing the number of recording sites while minimizing the neural probe dimensions. We designed and fabricated (0.13-μm SOI Al CMOS) a 384-channel configurable neural probe for large-scale in vivo recording of neural signals. Up to 966 selectable active electrodes were integrated along an implantable shank (70 μm wide, 10 mm long, 20 μm thick), achieving a crosstalk of −64.4 dB. The probe base (5 × 9 mm2) implements dual-band recording and a 1

The ALICE TPC, a large 3-dimensional tracking device with fast readout for ultra-high multiplicity events

The design, construction, and commissioning of the ALICE Time-Projection Chamber (TPC) is described. It is the main device for pattern recognition, tracking, and identification of charged particles in the ALICE experiment at the CERN LHC. The TPC is cylindrical in shape with a volume close to 90 m^3 and is operated in a 0.5 T solenoidal magnetic field parallel to its axis. In this paper we describe in detail the design considerations for this detector for operation in the extreme multiplicity environment of central Pb--Pb collisions at LHC energy. The implementation of the resulting requirements into hardware (field cage, read-out chambers, electronics), infrastructure (gas and cooling system, laser-calibration system), and software led to many technical innovations which are described along with a presentation of all the major components of the detector, as currently realized. We also report on the performance achieved after completion of the first round of stand-alone calibration runs and demonstrate results close to those specified in the TPC Technical Design Report.Comment: 55 pages, 82 figure

Integrated Electronics for Wireless Imaging Microsystems with CMUT Arrays

Integration of transducer arrays with interface electronics in the form of single-chip CMUT-on-CMOS has emerged into the field of medical ultrasound imaging and is transforming this field. It has already been used in several commercial products such as handheld full-body imagers and it is being implemented by commercial and academic groups for Intravascular Ultrasound and Intracardiac Echocardiography. However, large attenuation of ultrasonic waves transmitted through the skull has prevented ultrasound imaging of the brain. This research is a prime step toward implantable wireless microsystems that use ultrasound to image the brain by bypassing the skull. These microsystems offer autonomous scanning (beam steering and focusing) of the brain and transferring data out of the brain for further processing and image reconstruction. The objective of the presented research is to develop building blocks of an integrated electronics architecture for CMUT based wireless ultrasound imaging systems while providing a fundamental study on interfacing CMUT arrays with their associated integrated electronics in terms of electrical power transfer and acoustic reflection which would potentially lead to more efficient and high-performance systems. A fully wireless architecture for ultrasound imaging is demonstrated for the first time. An on-chip programmable transmit (TX) beamformer enables phased array focusing and steering of ultrasound waves in the transmit mode while its on-chip bandpass noise shaping digitizer followed by an ultra-wideband (UWB) uplink transmitter minimizes the effect of path loss on the transmitted image data out of the brain. A single-chip application-specific integrated circuit (ASIC) is de- signed to realize the wireless architecture and interface with array elements, each of which includes a transceiver (TRX) front-end with a high-voltage (HV) pulser, a high-voltage T/R switch, and a low-noise amplifier (LNA). Novel design techniques are implemented in the system to enhance the performance of its building blocks. Apart from imaging capability, the implantable wireless microsystems can include a pressure sensing readout to measure intracranial pressure. To do so, a power-efficient readout for pressure sensing is presented. It uses pseudo-pseudo differential readout topology to cut down the static power consumption of the sensor for further power savings in wireless microsystems. In addition, the effect of matching and electrical termination on CMUT array elements is explored leading to new interface structures to improve bandwidth and sensitivity of CMUT arrays in different operation regions. Comprehensive analysis, modeling, and simulation methodologies are presented for further investigation.Ph.D

Scalable Control and Measurement of Gate-Defined Quantum Dot Systems

There is currently a worldwide effort towards the realisation of large-scale quantum computers that exploit quantum phenomena for information processing. While these computing systems could potentially redefine the technological landscape, harnessing quantum effects is challenging due to their inherently fragile nature and the experimentally demanding environments in which they arise. In order for quantum computation to be viable it is first necessary to demonstrate the operation of two-level quantum systems (qubits) which have long coherence times, can be quickly read out, and can be controlled with high fidelity. Focusing on these key requirements, this thesis presents four experiments towards scalable solid state quantum computing using gate-defined quantum dot devices based on gallium arsenide (GaAs) heterostructures. The first experiment investigates a phonon emission process that limits the charge coherence in GaAs and potentially complicates the microwave control of multi-qubit devices. We show that this microwave analogy to Raman spectroscopy can provide a means of detecting the unique phonon spectral density created by a nanoscale device. Experimental results are compared to a theoretical model based on a non-Markovian master equation and approaches to suppressing electron-phonon coupling are discussed. The second experiment demonstrates a technique involving in-situ gate electrodes coupled to lumped-element resonators to provide high-bandwidth dispersive read-out of the state of a double quantum dot. We characterise the charge sensitivity of this method in the few-electron regime and benchmark its performance against quantum point contact charge sensors. The third experiment implements a low-loss, chip-level frequency multiplexing scheme for the readout of scaled-up spin qubit arrays. Dispersive gate-sensing is realised in combination with charge detection based on two radio frequency quantum point contacts to perform multiplexed readout of a double quantum dot in the few-electron regime. Demonstration of a 10-channel multiplexing device is achieved and limitations in scaling spin qubit readout to large numbers using multiplexed channels discussed. The final experiment ties previously presented results together by realising a micro-architecture for controlling and reading out qubits during the execution of a quantum algorithm. The basic principles of this architecture are demonstrated via the manipulation of a semiconductor qubit using control pulses that are cryogenically routed using a high-electron mobility transistor switching matrix controlled by a field programmable gate array. Finally, several technical results are also presented including the development of printed circuit board solutions to allow the high-frequency measurement of nanoscale devices at cryogenic temperatures and the design of on-chip interconnects used to suppress electromagnetic crosstalk in high-density spin qubit device architectures

Low Noise Readout Circuits for Particle and Radiation Sensors

The present thesis follows a three years' work in design, realization and operation of electronic circuits for the readout of particle and radiation sensors, carried out in close collaboration with the Istituto Nazionale di Fisica Nucleare (INFN), sezione di Milano Bicocca. The work was mainly focused to applications in particle physics experiments which are currently in the construction phase, or to existing experiments which planned major hardware upgrades in the next years, involving the design of new front-end circuits. The circuits developed are in principle applicable also outside the field of pure science research, for applications in nuclear instrumentation, medical imaging, security and industrial scanners, and others.Comment: PhD thesis, Universit\`a degli Studi di Firenze, 201

Production accompanying testing of the ATLAS Pixel module

The ATLAS Pixel detector, innermost sub-detector of the ATLAS experiment at LHC, CERN, can be sensibly tested in its entirety the first time after its installation in 2006. Because of the poor accessibility (probably once per year) of the Pixel detector and tight scheduling the replacement of damaged modules after integration as well as during operation will become a highly exposed business. Therefore and to ensure that no affected parts will be used in following production steps, it is necessary that each production step is accompanied by testing the components before assembly and make sure the operativeness afterwards. Probably 300 of about total 2000 semiconductor hybrid pixel detector modules will be build at the Universität Dortmund. Thus a production test setup has been build up and examined before starting serial production. These tests contain the characterization and inspection of the module components and the module itself under different environmental conditions and diverse operating parameters. Once a module is assembled the operativeness is tested with a radioactive source and the long-time stability is assured by a burn-in. A fully electrical characterization is the basis for module selection and sorting for the ATLAS Pixel detector. Additionally the charge collection behavior of irradiated and non irradiated modules has been investigated in the H8 beamline with 180 GeV pions