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Gorine Georgi - One of the best experts on this subject based on the ideXlab platform.

  • A New Concept of Sensor for Ultra-high Levels of Radiation based on Radiation Enhanced Oxidation of Copper Thin-films
    Ecole Polytechnique Lausanne, 2020
    Co-Authors: Gorine Georgi
    Abstract:

    The Future Circular Collider (FCC) is the envisioned particle accelerator to be installed in the Geneva area (Switzerland). It could achieve an energy of 100 TeV by colliding proton beams (FCC-hh) travelling through a 100 km tunnel. Unprecedented radiation levels inside the FCC detectors will presumably exceed several tens of MGy with more than 10$^{17}$ particles/cm$^{2}$ . Current solid-state dosimetry technologies based on silicon, are not capable of withstanding such radiation, thus requiring a new type of sensor to be used as dosimeter in the future irradiation facilities and, at a later stage, in the accelerator itself. The aim of this thesis is to develop a Radiation Dependent Resistor (RDR) as novel candidate technology for ultra-high radiation monitoring, and to study the radiation effects that are responsible for the measured increase of resistance of the RDR. Following theoretical and experimental selection processes, copper was chosen as the best candidate material as thin film for the active layer of such radiation sensor. Such approach was never attempted before. The RDR was developed via four experimental phases each including: the micro-fabrication at the CMi Center of MicroNanoTechnology (EPFL), the irradiation tests with protons at the IRRAD Proton Facility (CERN) and neutrons at the TRIGA nuclear reactor (Jožef Stefan Institute), and the characterisation at CERN and EPFL. As result, the RDR was fully prototyped with an optimized process flow, a compact Chip Layout, a radiation hard Printed Circuit Board (PCB), and an online and remote readout system. By analyzing the electrical data and cross-sectional images of the irradiated samples, the conventional theory of high-temperature copper oxidation has proven useful in proposing a new concept of room temperature oxidation which is considerably amplified by radiation (Radiation Enhanced Oxidation). This new interpretation has been implemented in behavioural, analytical and empirical models and validated against experimental data. Through the knowledge gathered in the framework of this thesis, the RDR technology was demonstrated to be compatible with the radiation levels expected in high energy physics experiments such as the HL-LHC and FCC. Additionally, these copper RDR sensors could also be used as dosimeters in particularly radioactive environments such as nuclear and fusion reactors

  • A New Concept of Sensor for Ultra-high Levels of Radiation based on Radiation Enhanced Oxidation of Copper Thin-films
    Lausanne EPFL, 2020
    Co-Authors: Gorine Georgi
    Abstract:

    The Future Circular Collider (FCC) is the envisioned particle accelerator to be installed in the Geneva area (Switzerland). It could achieve an energy of 100 TeV by colliding proton beams (FCC-hh) travelling through a 100 km tunnel. Unprecedented radiation levels inside the FCC detectors will presumably exceed several tens of MGy with more than 10e17 particles/cm2. Current solid-state dosimetry technologies based on silicon, are not capable of withstanding such radiation, thus requiring a new type of sensor to be used as dosimeter in the future irradiation facilities and, at a later stage, in the accelerator itself. The aim of this thesis is to develop a Radiation Dependent Resistor (RDR) as novel candidate technology for ultra-high radiation monitoring, and to study the radiation effects that are responsible for the measured increase of resistance of the RDR. Following theoretical and experimental selection processes, copper was chosen as the best candidate material as thin film for the active layer of such radiation sensor. Such approach was never attempted before. The RDR was developed via four experimental phases each including: the micro-fabrication at the CMi Center of MicroNanoTechnology (EPFL), the irradiation tests with protons at the IRRAD Proton Facility (CERN) and neutrons at the TRIGA nuclear reactor (Jožef Stefan Institute), and the characterisation at CERN and EPFL. As result, the RDR was fully prototyped with an optimized process flow, a compact Chip Layout, a radiation hard Printed Circuit Board (PCB), and an online and remote readout system. By analyzing the electrical data and cross-sectional images of the irradiated samples, the conventional theory of high-temperature copper oxidation has proven useful in proposing a new concept of room temperature oxidation which is considerably amplified by radiation (Radiation Enhanced Oxidation). This new interpretation has been implemented in behavioural, analytical and empirical models and validated against experimental data. Through the knowledge gathered in the framework of this thesis, the RDR technology was demonstrated to be compatible with the radiation levels expected in high energy physics experiments such as the HL-LHC and FCC. Additionally, these copper RDR sensors could also be used as dosimeters in particularly radioactive environments such as nuclear and fusion reactors

Leon Hoffman Luis - One of the best experts on this subject based on the ideXlab platform.

  • Siliciumnitride fotonica voor optogenetica: ontwerp en fabricatie van in vitro en in vivo multi-elektrode-optrode arrays voor optogenetica
    2018
    Co-Authors: Leon Hoffman Luis
    Abstract:

    Optogenetics is a novel method to control cells using light. This lightcontrol is accomplished through a genetic modification of the cells. Invivo neurophysiological research is increasingly using optogenetics, since it offers complementary capabilities to traditional electrophysiology. This has encouraged the development of implantable photonic devices that are able to optically interact with the genetically modified cells. The most basic and widely used device for this purpose is anoptical fiber. Despite its widespread use, this device is not suitable for performing complex experiments involving multiple emission points and electrical recording of neural activity. More complex devices have been engineered to address these limitations. Such devices are either hybrid assemblies of existing microfabricated neural probes with specificallytailored optical fibers or they are neural probes with few integrated optical waveguides. Both types allow combined electrical recording and optical emission. Although such photonic neural probes (optoprobes) perform well, they have a limited number of emission points, use bulky off-Chip light sources such as laser or permit the emission of only one wavelength. It is the purpose of the current research work to develop and characterize a microfabricated optoprobe with many integrated SiNwaveguides and on-Chip light sources of at least two different wavelengths (470 nm and 590 nm).Acknowledgements v Samenvatting vii Abstract ix Contents xi 1 Introduction 1 1.1 Why we build tools to study the brain 1 1.2 Controlling the brain with light 3 1.3 How optogenetics helps brain research 5 1.4 Devices for optogenetics 8 1.4.1 Electrical recording devices 8 1.4.2 Optoelectronic devices 15 1.4.3 Future optogenetic technology 19 1.5 About this thesis 21 2 Test Chip for 450 nm wavelength (blue) silicon nitride waveguides 23 2.1 Introduction 23 2.2 Waveguide cross section design 24 2.3 Grating design and simulations 27 2.3.1 Grating period 27 2.3.2 Grating height and number of periods 30 2.3.3 Bottom and top cladding height 33 2.4 Test Chip design and fabrication 35 2.4.1 Propagation and bend losses 36 2.4.2 Test Chip Layout 39 2.4.3 Chip fabrication and stack 40 2.5 Test Chip measurement setups 41 2.5.1 Optical fiber setup 42 2.5.2 Laser diode setup 43 2.6 Measurements with the optical fiber setup 44 2.6.1 Propagation losses and grating efficiency 44 2.6.2 Bend insertion losses 48 2.7 Measurement with the laser diode setup 51 2.8 Conclusions 57 3 Optobrain: a multi-electrode-optrode array for in vivo and in vitro optogenetics 59 3.1 Introduction 59 3.2 Light source considerations 62 3.3 Waveguide and grating design 63 3.3.1 Waveguide cross-section 63 3.3.2 Grating couplers 66 3.4 Chip devices Layout and dimensions 68 3.4.1 In vivo devices – neural depth probes 68 3.4.2 In vitro device 71 3.5 Chip fabrication 72 3.6 Packaging solution 74 3.6.1 LED packages for in vitro and in vivo applications 74 3.6.2 Laser diode package for in vitro and in vivo applications 76 3.7 Characterization of the packages 78 3.7.1 LED light output characterization 79 3.7.2 Laser diode light output characterization 80 3.7.3 Monte Carlo simulations of light propagation in tissue 82 3.7.4 Laser diode temperature characterization 84 3.8 Characterization of SixNy waveguides technology with metallization 85 3.9 Conclusions 88 4 In vitro and in vivo validation of the optogenetic system for blue light 93 4.1 Introduction 93 4.2 In vitro – patch clamp with SH SY5Y cells 94 4.2.1 Experimental setup and methods 94 4.2.2 Experimental results and discussion 95 4.3 In vitro stimulation of neurons 100 4.3.1 Hippocampal neuron culture and transduction 100 4.3.2 Stimulating and recording setup 100 4.3.3 Biocompatibility to neuron cultures 101 4.3.4 Optical modulation and electrical recording of neurons 102 4.4 Optical stimulation without artifacts 104 4.4.1 Anti light artifact MEOA design 105 4.4.2 Anti light artifact design validation 105 4.5 In vivo optical stimulation 105 4.5.1 Experimental setup and methods 105 4.5.2 Optical stimulation of neurons in vivo 108 4.6 Conclusions 111 5 General conclusions and future perspectives 113 5.1 General conclusions 113 5.2 Future perspectives 116 A Light sensitivity of silicon probes 121 B Considerations in designing waveguide bends for testing 125 C Code for Monte Carlo simulations of light propagation in tissue 127 REFERENCES 129 Publication list 143 Curriculum vitae 145nrpages: 159status: publishe

  • Silicon Nitride Photonics for Optogenetics: Design and Fabrication of In Vitro and In Vivo Multi-Electrode-Optrode Arrays for Optogenetics
    2018
    Co-Authors: Leon Hoffman Luis
    Abstract:

    Optogenetics is a novel method to control cells using light. This lightcontrol is accomplished through a genetic modification of the cells. Invivo neurophysiological research is increasingly using optogenetics, since it offers complementary capabilities to traditional electrophysiology. This has encouraged the development of implantable photonic devices that are able to optically interact with the genetically modified cells. The most basic and widely used device for this purpose is anoptical fiber. Despite its widespread use, this device is not suitable for performing complex experiments involving multiple emission points and electrical recording of neural activity. More complex devices have been engineered to address these limitations. Such devices are either hybrid assemblies of existing microfabricated neural probes with specificallytailored optical fibers or they are neural probes with few integrated optical waveguides. Both types allow combined electrical recording and optical emission. Although such photonic neural probes (optoprobes) perform well, they have a limited number of emission points, use bulky off-Chip light sources such as laser or permit the emission of only one wavelength. It is the purpose of the current research work to develop and characterize a microfabricated optoprobe with many integrated SiNwaveguides and on-Chip light sources of at least two different wavelengths (470 nm and 590 nm).Acknowledgements v Samenvatting vii Abstract ix Contents xi 1 Introduction 1 1.1 Why we build tools to study the brain 1 1.2 Controlling the brain with light 3 1.3 How optogenetics helps brain research 5 1.4 Devices for optogenetics 8 1.4.1 Electrical recording devices 8 1.4.2 Optoelectronic devices 15 1.4.3 Future optogenetic technology 19 1.5 About this thesis 21 2 Test Chip for 450 nm wavelength (blue) silicon nitride waveguides 23 2.1 Introduction 23 2.2 Waveguide cross section design 24 2.3 Grating design and simulations 27 2.3.1 Grating period 27 2.3.2 Grating height and number of periods 30 2.3.3 Bottom and top cladding height 33 2.4 Test Chip design and fabrication 35 2.4.1 Propagation and bend losses 36 2.4.2 Test Chip Layout 39 2.4.3 Chip fabrication and stack 40 2.5 Test Chip measurement setups 41 2.5.1 Optical fiber setup 42 2.5.2 Laser diode setup 43 2.6 Measurements with the optical fiber setup 44 2.6.1 Propagation losses and grating efficiency 44 2.6.2 Bend insertion losses 48 2.7 Measurement with the laser diode setup 51 2.8 Conclusions 57 3 Optobrain: a multi-electrode-optrode array for in vivo and in vitro optogenetics 59 3.1 Introduction 59 3.2 Light source considerations 62 3.3 Waveguide and grating design 63 3.3.1 Waveguide cross-section 63 3.3.2 Grating couplers 66 3.4 Chip devices Layout and dimensions 68 3.4.1 In vivo devices – neural depth probes 68 3.4.2 In vitro device 71 3.5 Chip fabrication 72 3.6 Packaging solution 74 3.6.1 LED packages for in vitro and in vivo applications 74 3.6.2 Laser diode package for in vitro and in vivo applications 76 3.7 Characterization of the packages 78 3.7.1 LED light output characterization 79 3.7.2 Laser diode light output characterization 80 3.7.3 Monte Carlo simulations of light propagation in tissue 82 3.7.4 Laser diode temperature characterization 84 3.8 Characterization of SixNy waveguides technology with metallization 85 3.9 Conclusions 88 4 In vitro and in vivo validation of the optogenetic system for blue light 93 4.1 Introduction 93 4.2 In vitro – patch clamp with SH SY5Y cells 94 4.2.1 Experimental setup and methods 94 4.2.2 Experimental results and discussion 95 4.3 In vitro stimulation of neurons 100 4.3.1 Hippocampal neuron culture and transduction 100 4.3.2 Stimulating and recording setup 100 4.3.3 Biocompatibility to neuron cultures 101 4.3.4 Optical modulation and electrical recording of neurons 102 4.4 Optical stimulation without artifacts 104 4.4.1 Anti light artifact MEOA design 105 4.4.2 Anti light artifact design validation 105 4.5 In vivo optical stimulation 105 4.5.1 Experimental setup and methods 105 4.5.2 Optical stimulation of neurons in vivo 108 4.6 Conclusions 111 5 General conclusions and future perspectives 113 5.1 General conclusions 113 5.2 Future perspectives 116 A Light sensitivity of silicon probes 121 B Considerations in designing waveguide bends for testing 125 C Code for Monte Carlo simulations of light propagation in tissue 127 REFERENCES 129 Publication list 143 Curriculum vitae 145nrpages: 159status: publishe

Jeanmichel Sallese - One of the best experts on this subject based on the ideXlab platform.

  • modeling minority carriers related capacitive effects for transient substrate currents in smart power ics
    IEEE Transactions on Electron Devices, 2015
    Co-Authors: Camillo Stefanucci, Pietro Buccella, Maher Kayal, Jeanmichel Sallese
    Abstract:

    This paper presents an extended model for transient and ac circuit-level simulation of minority carriers propagation through the substrate of smart power integrated circuits (ICs). A p-n junction and a diffusion resistor with capacitive components are proposed to efficiently simulate transient parasitic coupled currents in high-power stages. From a general Chip Layout, an equivalent substrate network including capacitive effects (junction and diffusion capacitances) can be extracted and parasitic bipolar transistor can be simulated for the first time in transient operation by circuit simulators once the minority carriers continuity conditions are satisfied. This paper shows simulation results of the implemented models in good agreement with those obtained from technology computer-aided design. This implies that transient Layout dependent mechanisms between high-voltage aggressor wells and low-voltage victims can be verified in early stages of IC design flow.

D R S Cumming - One of the best experts on this subject based on the ideXlab platform.

  • a large transistor based sensor array Chip for direct extracellular imaging
    Sensors and Actuators B-chemical, 2005
    Co-Authors: M J Milgrew, Mathis O Riehle, D R S Cumming
    Abstract:

    Abstract This paper describes the development and evaluation of a large transistor-based sensor array Chip for direct extracellular imaging. All of the sensors and electronics are designed and fabricated using an unmodified CMOS process. The sensor array Chip consists of a 16 × 16 pixel array of ISFETs along with signal acquisition and readout circuitry. Each ISFET employs a floating gate electrode structure and uses the passivation layer as a pH sensitive membrane. The Chip Layout is optimised so that the surface topography allows cultured cells to be grown directly above the pixel array. On return from the foundry, a double layer of SU-8 photoresist is used to provide a biocompatible and waterproof package for the Chip. An elastomer-based microfluidic chamber is fabricated and integrated for conducting long term cell culture experiments. The performance of the Chip is evaluated using an electrolyte and a well-established confluent cell line. The fabricated circuit provides a linear operating range of 2.5 V that allows each ISFET to operate as a pH sensor in the array. The ISFETs have a threshold voltage of − 1.5 V and a sensitivity of 46 mV/pH.

Tadahiro Kuroda - One of the best experts on this subject based on the ideXlab platform.

  • a cmos impulse radio ultra wideband transceiver for 1mb s data communications and spl plusmn 2 5cm range findings
    Symposium on VLSI Circuits, 2005
    Co-Authors: T Terada, S Yoshizumi, Yukitoshi Sanada, Tadahiro Kuroda
    Abstract:

    A CMOS impulse radio ultra-wideband (IR-UWB) transceiver is developed in 0.18/spl mu/m CMOS. It can be used for a 1Mb/s data transceiver, as well as a range finder within an error of /spl plusmn/2.5cm. Chip Layout area of a transmitter and a receiver is 0.035mm/sup 2/ and 0.38mm/sup 2/, respectively. Power dissipation for 1Mb/s data communications is 0.7mW for the transmitter and 4.0mW for the receiver. Bit error rate is lower than 10/sup -5/ for ranges of shorter than 95cm, and 10/sup -3/ for 1m distance. For use of the range finder, power dissipation of the transmitter is 0.7/spl mu/W for 1000 measurements per second. Electronic field intensity is lower than 35/spl mu/V/m, in compliance with the regulation for the extremely low power radio station. Digital transmitter and clocked correlator are proposed for reduction in both Layout area and power dissipation.