Integrated Circuit Design for Radiation Sensing and Hardening.

Beyond the 1950s, integrated circuits have been widely used in a number of electronic devices surrounding people’s lives. In addition to computing electronics, scientific and medical equipment have also been undergone a metamorphosis, especially in radiation related fields where compact and precision radiation detection systems for nuclear power plants, positron emission tomography (PET), and radiation hardened by design (RHBD) circuits for space applications fabricated in advanced manufacturing technologies are exposed to the non-negligible probability of soft errors by radiation impact events. The integrated circuit design for radiation measurement equipment not only leads to numerous advantages on size and power consumption, but also raises many challenges regarding the speed and noise to replace conventional design modalities. This thesis presents solutions to front-end receiver designs for radiation sensors as well as an error detection and correction method to microprocessor designs under the condition of soft error occurrence. For the first preamplifier design, a novel technique that enhances the bandwidth and suppresses the input current noise by using two inductors is discussed. With the dual-inductor TIA signal processing configuration, one can reduce the fabrication cost, the area overhead, and the power consumption in a fast readout package. The second front-end receiver is a novel detector capacitance compensation technique by using the Miller effect. The fabricated CSA exhibits minimal variation in the pulse shape as the detector capacitance is increased. Lastly, a modified D flip-flop is discussed that is called Razor-Lite using charge-sharing at internal nodes to provide a compact EDAC design for modern well-balanced processors and RHBD against soft errors by SEE.PhDElectrical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/111548/1/iykwon_1.pd

Optical wireless data transfer for rotor detection and diagnostics

A special application of optical wireless data transfer, namely on-line monitoring and diagnostic of rotors in turbines and engines, has been considered in this thesis. In this application, to maintain line of sight, i.e. data transfer, between a sensor placed on a rotating component inside the turbine and a monitoring point placed in a fixed position outside the turbine, a periodic fast fading channel is generated, which gives the transceivers more flexibility regarding their mounting location. The communication in such a channel is affected by the intermittency and variation of the signal power, which produces a unique channel condition that influences the performance of the optical transceiver. To investigate the channel condition and the error rate of the periodic fast fading channel with signal fluctuation, a model is developed to simulate the optical channel by considering the variation of signal power as a result of the change in the relative position of the photodiode with respect to the Lambertian radiation pattern of the LED, in a simplified linear geometry. The error rate is estimated using the Saddlepoint approximation on a specific threshold strategy. The results show that the channel can afford the sensor data transmission and the performance can be improved by modifying several parameters, such as geometrical distance, transmitter power and load resistor. Compared to a normal channel, a higher load resistor on the photodiode front end has the advantage of decreasing the noise level and increasing the data capacity in the fast fading channel. The analysis of the automatic gain control amplifier indicates that a higher load resistor needs a lower loop gain and from the model of the Transimpedance amplifier (TIA), the bandwidth extension from the amplifier is more significant for a higher resistor. In addition to the theoretical model, an experimental setup is built to emulate the channel in practice. The degree of similarity between the experimental setup and the theoretical model of the channel is estimated from the comparison of the generated communication windows. Since it has been found that differences exist in the duration of the communication window and the variation of the signal power, scaling factors to ensure their compatibility have been derived. Transceiver hardware which implemented the modelled functionality has been developed and a protocol to establish the communication with the required error rate has been proposed. Using the hardware implementation, a detection method for both rising and falling edges of the signal pulses and a threshold strategy have been demonstrated. The device power consumption is also estimated. What is more, the electromagnetic environment of a squirrel cage motor is simulated using the finite element method to investigate the interference and the possibility of providing power to the IR communication devices using power scavenging. In the conclusion, the key findings of the thesis are summarised. A solution is proposed for sensor data transfer using an optical channel for rotor monitoring applications, which involves the design of the IR transceiver, the implementation of the developed protocol and the power consumption estimation

Characterization And Optimization Of Avalanche Photodiodes Fabricated By Standard Cmos Process For High-Speed High-Speed Photoreceivers

A dissertation presented on the characterization and optimization of avalanche photodiodes fabricated by standard CMOS process (CMOS-APD) for high-speed photoreceivers, beginning with the theory and principle related to photodetector and avalanche photodiodes, followed by characterization,optimization, and wavelength dependence of CMOS-APD, and finally link up with the transimpedance amplifier. nMOS-type and pMOS-type silicon avalanche photodiodes were fabricated by standard 0.18 μm CMOS process, and the currentvoltage characteristic and the frequency response of the CMOS-APDs with and without the guard ring structure were measured. CMOS-APDs have features of high avalanche gain below 10 V, wide bandwidth over 5 GHz, and easy integration with electronic circuits. In CMOS-APDs, guard ring structure is introduced for high-speed operation with the role of elimination the slow photo generated carriers in a deep layer and a substrate. The bandwidth of the CMOS-APD is enhanced with the guard ring structure at a sacrifice of the responsivity. Based on comparison of nMOS-type and pMOS-type APDs, the nMOS-type APD is more suitable for high-speed operation. The bandwidth is enhanced with decreasing the spacing of interdigital electrodes due to decreased carrier transit time and with decreasing the detection area and the PAD size for RF probing due to decreased device capacitance. Thus, an nMOS-type APD with the electrode spacing of 0.84 μm, the detection area of 10 x 10 μm², the PAD size for RF probing of 30 x 30 μm² along with the guard ring structure was fabricated. As a results, the maximum bandwidth of 8.4 GHz at the avalanche gain of about 10 and the gain-bandwidth product of 280 GHz were achieved. Furthermore, the wavelength dependence of the responsivity and the bandwidth of the CMOS-APDs with and without the guard ring structure also revealed. At a wavelength of 520 nm or less, there is no difference in the responsivity and the frequency response because all the illuminated light is absorbed in the p+-layer and the Nwell due to strong light absorption of Si. On the other hand, a part of the incident light is absorbed in the Psubstrate and the photo-generated carriers in the P-substrate are eliminated by the guard ring structure for the wavelength longer than 520 nm, and then bandwidth was remarkably enhanced at the sacrifice of the responsivity. In addition, to achieve high-speed photoreceivers, two types of TIA which are common-source and regulated-cascode TIAs were simulated by utilizing the output of the CMOSAPDs.The figure of merits of gain-bandwidth product was used to find the ideal results of the transimpedance gain and bandwidth performance due to trade-offs between both of them. The common-source TIA produced the transimpedance gain of 22.17 dBΩ, the bandwidth of 21.21 GHz and the gain-bandwidth product of 470.23 THz × dBΩ. Besides that, the simulated results of the regulated-cascade TIA configuration demonstrate 79.45 dBΩ transimpedance gain, 10.64 GHz bandwidth, and 845.35 THz × dBΩ gain-bandwidth product. Both of these TIA results meet the target of this research and further encouraging this successful CMOS-APDs to realize high-speed photoreceivers

Design and development of non-contact bio-potential electrodes for pervasive health monitoring applications

For the advent of pervasive bio-potential monitoring, it will be necessary to utilize a combination of cheap, quick to apply, low-noise electrodes and compact electronics with wireless technologies. Once available, all electrical activity resulting from the processes of the human body could be actively and constantly monitored without the need for cumbersome application and maintenance. This could significantly improve the early diagnosis of a range of different conditions in high-risk individuals, opening the possibility for new treatments and interventions as conditions develop. This paper presents the design and implementation of compact, non-contact capacitive bio-potential electrodes utilising a low impedance current-to-voltage configuration and a bootstrapped voltage follower, demonstrating results applicable to research applications for capacitive electrocardiography and capacitive electromyography. The presented electrodes use few components, have a small surface area and are capable of acquiring a range of bio-potential signals

Design of analog front-ends for the RD53 demonstrator chip

The RD53 collaboration is developing a large scale pixel front-end chip, which will be a tool to evaluate the performance of 65 nm CMOS technology in view of its application to the readout of the innermost detector layers of ATLAS and CMS at the HL-LHC. Experimental results of the characterization of small prototypes will be discussed in the frame of the design work that is currently leading to the development of the large scale demonstrator chip RD53A to be submitted in early 2017. The paper is focused on the analog processors developed in the framework of the RD53 collaboration, including three time over threshold front-ends, designed by INFN Torino and Pavia, University of Bergamo and LBNL and a zero dead time front-end based on flash ADC designed by a joint collaboration between the Fermilab and INFN. The paper will also discuss the radiation tolerance features of the front-end channels, which were exposed to up to 800 Mrad of total ionizing dose to reproduce the system operation in the actual experiment

Dynamical control of one- and two-dimensional optical fibre scanning

This thesis investigates the dynamical control of one- and two-dimensional optical fibre scanning. One dimensional scanning is performed with a mechanically biaxial polarisation-preserving fibre mounted on a piezoelectric transducer with one of its principal mechanical axes aligned parallel to the excitation direction. The addition of an apertured reflector in front of the imaging lens allows a position sensing mechanism based on intermittent optical feedback to be integrated into the scanner. Over-scanning the lens generates timing pulses interlaced with back-scattered signals from the target. The timing information can be used for closed loop control of the phase and amplitude of vibration. Suitable control algorithms are developed and their convergence and stability is studied. This thesis also investigates the construction of fibres with enhanced mechanically asymmetry and their dynamical properties during two-dimensional imaging based on Lissajous scan patterns. Dip-coating is proposed as a method of forming two-cored waveguide cantilevers from two separate, parallel fibres that are encapsulated in a plastic coating. The frequency ratio between the two orthogonal bending mode resonances can be controlled with number of coatings. An exact image reconstruction algorithm based on Lissajous scanning is proposed. Latency, transient response and steady-state phase errors are all shown to cause dramatic deterioration of the reconstructed image. Solutions are provided by ensuring the correct starting time for data acquisition and introducing a drive phase correction to one of the axes. Two methods of resolution enhancement are demonstrated. The first is based on combining data sets obtained during separate scans carried out with deliberately applied phase offsets. The second operates by combining data sets from separate imaging operations carried out using the two different fibre cores. Finally, this thesis demonstrates potential applications in optogenetics by combining the two operations of imaging and writing, using different light sources that may also have different wavelengths.Open Acces

A four-beam optical polarimeter for robust particle shape detection

Particle shape detection and measurement are important features in the more general field of particle analysis and characterisation. Knowledge of the particle shape is useful in a wide variety of industrial applications. Although it is often practically feasible to use imaging technologies for particle shape analysis, this is not often a sufficiently efficient method for widespread on-line or in situ applications. In many applications it would be sufficient to have an indicator of particle shape, in the same way that a turbidity sensor is an indicator of the amount of particles present. Scattered polarized light from individual particles will be shown as a useful tool for particle shape detection. In principle, the presence of non-spherical particles can be diagnosed by analysing the change in polarisation state following scattering and in particular exploiting a configuration in which spherical particles produce no such changes. The concerns of this thesis are the design and implementation of optical polarimeters for the detection of non-spheres in an aqueous suspension, with particular emphasis on a robust implementation. [Continues.

Optically Powered Highly Energy-efficient Sensor Networks

In optically powered networks, both, communication signals and power for remotely located sensor nodes, are transmitted over an optical fiber. Key features of optically powered networks are node operation without local power supplies or batteries as well as operation with negligible susceptibility to electro-magnetic interference and to lightning. In this book, different kinds of optically powered devices and networks are investigated, and selected applications are demonstrated

Electrochemical noise limits of femtoampere-sensing, CMOS-integrated transimpedance amplifiers

Low-noise operational amplifiers are an important tool in the life sciences. Biosensor measurements typically rely on low-noise transimpedance amplifiers to record biological signals. Two different techniques were used to leverage the advantages of low-noise circuitry for bioelectronics. A CMOS-integrated system for measuring redox-active substrates using electrochemical read-out at very low noise levels is presented. The system incorporates 112 amplifier channels capable of current sensing with noise levels below 1 fArms in a 3.5-Hz bandwidth. The amplifier is externally connected to a gold microelectrode with a radius of 15 µm. The amplifier enables measurement of redox-couples such as potassium ferrocyanide/ferricyanide with concentrations down to 10 nM at current levels of only 300 fA. The electrochemical noise that sets the limits of detection is also measured and analyzed based on redox mass transfer equation and electrochemical impedance spectroscopy. Secondly, CMOS-integrated low noise junction field-effect transistors (JFETs) were developed in a standard 0.18-µm CMOS process. These JFETs reduce input referred flicker noise power by more than a factor of 10 when compared with equally sized n-channel MOS devices by eliminating oxide interfaces in contact with the channel. We show that this improvement in device performance translates into a factor-of-10 reduction in the input-referred noise of integrated CMOS operational amplifiers when JFET devices are used at the input

Development of an autonomous lab-on-a-chip system with ion separation and conductivity detection for river water quality monitoring

This thesis discusses the development of a lab on a chip (LOC) ion separation for river water quality monitoring using a capacitively coupled conductivity detector (C⁴D) with a novel baseline suppression technique.Our first interest was to be able to integrate such a detector in a LOC. Different designs (On-capillary design and on-chip design) have been evaluated for their feasibility and their performances. The most suitable design integrated the electrode close to the channel for an enhanced coupling while having the measurement electronics as close as possible to reduce noise. The final chip design used copper tracks from a printed circuit board (PCB) as electrodes, covered by a thin Polydimethylsiloxane (PDMS) layer to act as electrical insulation. The layer containing the channel was made using casting and bonded to the PCB using oxygen plasma. Flow experiments have been conduced to test this design as a detection cell for capacitively coupled contactless conductivity detection (C⁴D).The baseline signal from the system was reduced using a novel baseline suppression technique. Decrease in the background signal increased the dynamic range of the concentration to be measured before saturation occurs. The sensitivity of the detection system was also improved when using the baseline suppression technique. Use of high excitation voltages has proven to increase the sensitivity leading to an estimated limit of detection of 0.0715 μM for NaCl (0.0041 mg/L).The project also required the production of an autonomous system capable of operating for an extensive period of time without human intervention. Designing such a system involved the investigation of faults which can occur in autonomous system for the in-situ monitoring of water quality. Identification of possible faults (Bubble, pump failure, etc.) and detection methods have been investigated. In-depth details are given on the software and hardware architecture constituting this autonomous system and its controlling software