Cryogenic ion trapping for next generation quantum technologies

Quantum technology has made great strides in the last two decades with trapped ions demonstrating all the necessary building blocks for a quantum computer. While these proof of principle experiments have been demonstrated, it still remains a challenging task to scale these experiments down to smaller systems. In this thesis I describe the development of technology towards scalable cryogenic ion trapping and quantum hybrid systems. I first discuss the fundamentals of ion trapping along with the demonstration of ion trapping on a novel surface electrode ion trap with a ring shaped architecture. I then present the development of a cryogenic vacuum system for ion trapping at ~4 K, which utilizes a closed cycle Gifford McMahon cryocooler with a helium gas buffered ultra-low vibration interface to mechanically decouple a ultra-high vacuum system. Ancillary technologies are also presented, including a novel in-vacuum superconducting rf resonator, low power dissipation ceramic based atomic source oven and an adaptable in-vacuum permanent magnet system for long-wavelength based quantum logic. The design and fabrication of microfabricated surface ion traps toward quantum hybrid technologies are then presented. A superconducting ion trap with an integrated high quality factor microwave cavity and vertical ion shuttling capabilities is described. The experimental demonstration of the cavity is also presented with quality factors of Q6~6000 and Q~15000 for superconducting niobium nitride and gold based cavities respectively, which are the highest demonstrated for microwave cavities integrated within ion trapping electrode architectures. An ion trap with a multipole electrode geometry is then presented, which is capable of trapping a large number of ions simultaneously. The homogeneity of five individual linear trapping regions are optimized and the design for the principle axis rotation of each linear region is presented. An overview of microfabrication techniques used for fabricating surface electrode ion traps is then presented. This includes the detailed microfabrication procedure for ion traps designed within this thesis. A scheme for the integration of ion trapping and superconducting qubit systems as a step towards the realization of a quantum hybrid system is then presented. This scheme addresses two key diffculties in realizing such a system; a combined microfabricated ion trap and superconducting qubit architecture, and the experimental infrastructure to facilitate both technologies. Solutions that can be immediately implemented using current technology are presented. Finally, as a step towards scalability and hybrid quantum systems, the interaction between a single ion and a microwaves field produced from an on chip microwave cavity is explored. The interaction is described for the high-Q microwave cavity designed in this thesis and a 171Yb+ion. A description of the observable transmission from the cavity is described and it is shown that the presence of a single ion can indeed be observed in the emission spectrum of high-Q microwave cavity even in the weak coupling regime

Microdischarge-Based Pressure Controlling Devices and their Applications to Chemical Sensing in Harsh Environments.

Microdischarges offer an alternative and often advantageous sensing and actuation method that has not been significantly exploited in microtransducers. This thesis explores the capabilities of microdischarges to address problems such as cavity pressure control, cavity pressure detection, and purity control of fill gases, which are relevant to microsystems. Microdischarge-based transducers have been developed for these purposes. One interesting aspect of microdischarge-based transducers is the wide latitude of operating temperatures, as they are advantageous for room and high temperature operation. On-chip sputter-ion pumps control the pressure and gas purity in cavities. They consist of thin-film titanium electrodes patterned on glass substrates. Microdischarges sputter the cathodes, resulting in the selective chemisorption of titanium-reactive gases. Using DC discharges, these devices have reduced the pressure by 168 Torr in an air-filled, hermetically sealed, 6.33 cm3 package. Starting at 200 Torr, the pressure reduction rate of air is 7.2 Torr/h; oxygen 11.5 Torr/h, and nitrogen 3.4 Torr/h. Relative humidity is reduced at 6%/h. The pumps do not remove helium, purifying gas environments by selectively removing contaminating nitrogen and oxygen. A theoretical model outlining the dependency of gas removal rates on microdischarge parameters is presented. Microdischarge-based pressure sensors operate by correlating the measured change in spatial current distribution of pulsed DC microdischarges with pressure. One sensor version uses three-dimensional arrays of horizontal bulk metal electrodes embedded in quartz substrates with electrode diameters of 1-2 mm and 50-100 µm inter-electrode spacing. These devices have been operated over 10-2,000 Torr, at temperatures as high as 1,000˚C. The maximum measured sensitivity is 5,420 ppm/Torr, while the minimum temperature coefficient of sensitivity is -550 ppm/K. Sensors of a second version use planar electrodes, with 0.13 mm2 active areas. To explore the utility of pressure controlling devices, these transducers are combined with an optical emission sensor to create a high temperature gas phase chemical detection microsystem. The microdischarge-based pressure sensor determines the sample and backfilling gas pressure while the microscale-sputter-ion pump purifies the gas environment. The contaminating nitrogen concentration has been reduced by 56.5x relative to helium and the spectral detection limit has been improved by 8x for carbon at 200°C.Ph.D.Electrical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/62245/1/scottwri_1.pd

Micro-poutres résonantes à base de films minces de nitrure d’aluminium piézoélectriques, application aux capteurs de gaz gravimétriques

Resonant MEMS and NEMS are excellent candidate for the realization of low cost and high resolution gas sensing systems that have several applications in security, defense, and environment and health care domains. However, the question of the transduction technique used to couple micro or nano scale signals to the macro scale is still a key issue. Piezoelectric transduction can be advantageously exploited but has been rarely studied at the nano-scale. The objective of this PhD is thus to progress toward the realization of high-resolution gas sensor using piezoelectric micro/nano cantilevers resonators and cover the whole prototyping chain from device fabrication to proof of principle experiment. Our first contribution in this research relates the analytical modeling of the sensing performance and the system and design optimization. In particular we demonstrate that decreasing the piezoelectric active film thickness below 100 nm is particularly beneficial. The second contribution relates the fabrication, characterization and demonstration of the high sensing performances of 80 μm long cantilevers embedding a 50 nm thick piezoelectric AlN film for transduction. These devices exhibit state of the art performances in terms of resonance frequency deviation down to the 〖10〗^(-8) range. They allow thus the detection of Di-Methyl-Methyl-Phosphonate vapors, a sarin gas simulant, with concentration as low as 10 ppb. Although the level of integration of our sensing system is not sufficient for real life application, these results prove the high potential of these piezoelectric cantilever resonators for future industrial development.Les MEMS et NEMS résonants sont d'excellents candidats pour la réalisation de systèmes de détection de gaz haute résolution et faible couts ayant des applications dans les domaines de la sécurité, la défense, l'environnement et la santé. Cependant, la question du choix des techniques de transduction est toujours largement débattue. La transduction piézoélectrique pourrait être avantageusement exploitée mais elle est encore peu connue à l'échelle nanométrique. L'objectif de cette thèse est donc de progresser vers la réalisation de capteur de gaz à haute résolution à l'aide résonateurs à base de micro / nano poutres piézoélectriques en couvrant la chaîne de prototypage complète depuis les techniques de dépôt des matériaux jusqu'à l'expérience de preuve de principe de mesure de gaz. Pour cela, notre première contribution concerne la modélisation analytique des performances et l'optimisation, design et système, d'un capteur de gaz à base de poutres résonantes piézoélectriques. En particulier, nous démontrons que la diminution de l'épaisseur du film piézoélectrique actif sous la barre des 100 nm permet d'atteindre les meilleures performances. La deuxième contribution concerne la fabrication, la caractérisation et la démonstration des performances capteur de poutres résonantes de 80 μm de long exploitant un film piézoélectrique en AlN de 50 nm d'épais. Ainsi nous avons démontré expérimentalement la stabilité fréquentielle exceptionnelle de ces dispositifs atteignant des déviations standard de l'ordre de 〖10〗^(-8), au niveau de l’état de l'art. Ainsi, ils permettent la détection de vapeurs Di -Methyl -méthyl- phosphonates, un simulateur de gaz sarin, avec des concentrations aussi faibles que 10 ppb. Bien que le niveau d'intégration de notre système de détection ne soit pas suffisant, ces résultats prouvent le fort potentiel de ces résonateurs cantilever piézoélectriques pour un développement industriel futur

Ultra-thin silicon technology for tactile sensors

In order to meet the requirements of high performance flexible electronics in fast growing portable consumer electronics, robotics and new fields such as Internet of Things (IoT), new techniques such as electronics based on nanostructures, molecular electronics and quantum electronics have emerged recently. The importance given to the silicon chips with thickness below 50 μm is particularly interesting as this will advance the 3D IC technology as well as open new directions for high-performance flexible electronics. This doctoral thesis focusses on the development of silicon–based ultra-thin chip (UTC) for the next generation flexible electronics. UTCs, on one hand can provide processing speed at par with state-of-the-art CMOS technology, and on the other provide the mechanical flexibility to allow smooth integration on flexible substrates. These development form the motivation behind the work presented in this thesis. As the thickness of any silicon piece decreases, the flexural rigidity decreases. The flexural rigidity is defined as the force couple required to bend a non-rigid structure to a unit curvature, and therefore the flexibility increases. The new approach presented in this thesis for achieving thin silicon exploits existing and well-established silicon infrastructure, process, and design modules. The thin chips of thicknesses ranging between 15 μm – 30 μm, were obtained from processed bulk wafer using anisotropic chemical etching. The thesis also presents thin wafer transfer using two-step transfer printing approach, packaging by lamination or encapsulation between two flexible layerand methods to get the electrical connections out of the chip. The devices realised on the wafer as part of front-end processing, consisted capacitors and transistors, have been tested to analyse the effect of bending on the electrical characteristics. The capacitance of metal-oxide-semiconductor (MOS) capacitors increases by ~5% during bending and similar shift is observed in flatband and threshold voltages. Similarly, the carrier mobility in the channel region of metal-oxide-semiconductor field effect transistor (MOSFET) increases by 9% in tensile bending and decreases by ~5% in compressive bending. The analytical model developed to capture the effect of banding on device performance showed close matching with the experimental results. In order to employ these devices as tactile sensors, two types of piezoelectric materials are investigated, and used in extended gate configuration with the MOSFET. Firstly, a nanocomposite of Poly(vinylidene fluoride-co-trifluoroethylene), P(VDF-TrFE) and barium titanate (BT) was developed. The composite, due to opposite piezo and pyroelectric coefficients of constituents, was able to suppress the sensitivity towards temperature when force and temperature varied together, The sensitivity to force in extended gate configuration was measured to be 630 mV/N, and sensitivity to temperature was 6.57 mV/oC, when it was varied during force application. The process optimisation for sputtering piezoelectric Aluminium Nitride (AlN) was also carried out with many parametric variation. AlN does not require poling to exhibit piezoelectricity and therefore offers an attractive alternative for the piezoelectric layer used in devices such as POSFET (where piezoelectric material is directly deposited over the gate area of MOSFET). The optimised process gave highly orientated columnar structure AlN with piezoelectric coefficient of 5.9 pC/N and when connected in extended gate configuration, a sensitivity (normalised change in drain current per unit force) of 2.65 N-1 was obtained

Microelectromechanical Systems and Devices

The advances of microelectromechanical systems (MEMS) and devices have been instrumental in the demonstration of new devices and applications, and even in the creation of new fields of research and development: bioMEMS, actuators, microfluidic devices, RF and optical MEMS. Experience indicates a need for MEMS book covering these materials as well as the most important process steps in bulk micro-machining and modeling. We are very pleased to present this book that contains 18 chapters, written by the experts in the field of MEMS. These chapters are groups into four broad sections of BioMEMS Devices, MEMS characterization and micromachining, RF and Optical MEMS, and MEMS based Actuators. The book starts with the emerging field of bioMEMS, including MEMS coil for retinal prostheses, DNA extraction by micro/bio-fluidics devices and acoustic biosensors. MEMS characterization, micromachining, macromodels, RF and Optical MEMS switches are discussed in next sections. The book concludes with the emphasis on MEMS based actuators

Particle Physics Reference Library

This third open access volume of the handbook series deals with accelerator physics, design, technology and operations, as well as with beam optics, dynamics and diagnostics. A joint CERN-Springer initiative, the “Particle Physics Reference Library” provides revised and updated contributions based on previously published material in the well-known Landolt-Boernstein series on particle physics, accelerators and detectors (volumes 21A,B1,B2,C), which took stock of the field approximately one decade ago. Central to this new initiative is publication under full open acces

Proceedings of the 10th IEA International Workshop on Beryllium Technology, September 19 - 21, 2012, Karlsruhe, Germany (KIT Scientific Reports ; 7650)

The 10th IEA Beryllium Workshop (BeWS-10) was organized by the Karlsruhe Institute of Technology (KIT) with participants from Europe, U.S.A., Russia, Japan, and Kazakhstan. The main topics of the 30 papers in the proceedings are: the overview of the Be-related activities in Europe, U.S.A., RF, and Japan, results on the Be irradiation program HIDOBE-01, beryllide intermetallic compounds, technology and safety issues, and modeling of the Be radiation resistance

Bibliography of Lewis Research Center technical publications announced in 1986

This compilation of abstracts describes and indexes the technical reporting that resulted from the scientific and engineering work performed and managed by the Lewis Research Center in 1986. All the publications were announced in the 1986 issues of Scientific and Technical Aerospace Reports (STAR) and/or International Aerospace Abstracts (IAA). Included are research reports, journal articles, conference presentations, patents and patent applications, and theses

Label-free and Multi-parametric Monitoring of Cell-based Assays with Substrate-embedded Sensors

Various approaches have been pursued on the basis of electrochemical or piezoelectric transducers, particularly of the quartz crystal microbalance (QCM), to monitor non-invasively and in real-time cellular states and reactions with substrate-embedded sensors. On the one hand, these comprised the technical development of piezoelectric sensors with multiple read-out spots and the integration of additional non-invasive (electro- and optochemical) sensor technologies on the QCM surface. On the other hand, a variety of studies and cell-based assays (CBAs) have been performed in order to test the sensor performances and to gain a deeper understanding of the sensors’ readout parameters with respect to their information content about the biophysical properties and the metabolic behavior of cells. Fig. 7–1 presents an overview of the different projects on the basis of QCM sensor disks presented in this thesis. In the first project (Fig. 7–1 A) a novel electrode layout was designed on the basis of commercial 5 MHz AT-cut quartz disks to implement two independent readout spots on the QCM surface. This also comprised the construction of new measurement chambers for the electrical actuation and sensing of quartz oscillations. These two-electrode QCM sensors (2ElQ) are also referred to as multichannel QCM (MQCM). The developed MQCM sensor spots on one quartz disk exhibited a strong interference, even though they were operated sequentially, which is in contrast to the results of previous theoretical calculations. The resonances could be successfully decoupled by coating half of the quartz surface and one sensor spot, respectively, with a thin and rigid film of photoresist. This quartz loading with mass caused a shift in the resonance spectra of the coated resonator to lower frequencies and efficient decoupling. The operation of the decoupled MQCM sensors demonstrated both, a sensitive and equal change in the oscillation characteristics of the two resonators upon loading of the quartz with medium. The Q-factor was not significantly different for the two resonators, qualifying the MQCM for its application in CBAs. Building on the preceding development of the double-electrode quartz disks, a novel electrode layout has been realized at the sensor surface, which enables the complementary electrochemical (impedance spectroscopical) characterization of the substrate-liquid interface in addition to its mechanical characterization by the piezoelectric transducers (Fig. 7–1 B). This layout was achieved by removing a small area of the insulating photoresist on the coated electrode in the photolithographic process. By this, a coplanar electrode arrangement of a small working electrode and a bigger counter electrode was created. This sensor combination on the basis of the MQCM is an improvement of the so-called 2nd generation QCM to what we call the 3rd generation QCM, and which is also referred to as QCM-ECIS. Various electrode layouts, varying in size and number of the working electrode(s), were fundamentally characterized microscopically and by profilometry regarding the geometrical properties and by means of impedance spectroscopy with respect to the sensing performances in QCM- and ECIS-mode. An optimal electrode layout was identified and defined as standard for subsequent applications in CBAs. In both QCM- and ECIS studies of cell-covered sensor surfaces significant changes in the characteristic sensing parameters with respect to the cell-free electrodes are measurable. In addition to the measurement of absolute signal changes, the transducer technologies of QCM and ECIS also enable to monitor the kinetic changes of the readout parameters with high temporal resolution. This allows to use the dual sensors for monitoring and analyzing the states of adherent cell cultures in any kind of assay, label-free, non-invasively, and in real-time. Mechanical (QCM-mode) and the dielectric (ECIS-mode) characteristics of cell adhesion were simultaneously measured for two different cell lines (MDCK II and NRK), with high reproducibility for each. The total and kinetic parameter changes in both sensing modes distinguished clearly and were specific for the cell lines under test. The signals from both QCM-mode and ECIS-mode recordings also reported on significant impacts of the presence/ absence of bivalent cations (Ca2+, Mg2+) on the attachment and spreading kinetics and behavior of MDCK II cells. Aside from cell adhesion studies, the cytomechanical and cell morphological reactions towards various stimuli were monitored and analyzed by QCM-ECIS in a multitude of cellular assays: systematic softening and stiffening of cells (using agents for disassembling the actin cytoskeleton and cross-linking protein structures, respectively), intracellular stimulation (using a second messenger analogue), as well as electrical manipulation (electroporation (ELPO) and wounding) of cell layers (applying invasive voltage pulses). The applicability of electrical actuation and the subsequent non-invasive, time-resolved, and dual sensing with the electrodes of the QCM-ECIS substrates has been successfully demonstrated. The monitoring of CBAs with the dual QCM-ECIS sensor chips developed in this thesis provides not only a multiplication of the information gain due to the complementarity of QCM and ECIS readout parameters. The simultaneous, time-resolved measurements also enable the kinetic correlation of the sensor signals in novel 2 D and 3 D diagrams, which offers the hitherto unprecedented opportunity for a more detailed view and analysis of the coherence or consecutiveness of mechanical and morphological/ dielectric changes of a cell layer under study. A third research project focused on the combination of optical-chemical sensors (OCS) with the piezoelectric (QCM) sensor technology. For this purpose, the quartz crystal surface was coated with a polymer film with embedded phosphorescent indicator dye for the target analyte. The luminescence properties were measured by means of fluorescence (phosphorescence) lifetime imaging (FLIM). By using a temperature-sensitive paint (TSP), an increase in temperature on the sensor surface upon high-amplitude oscillations was monitored and imaged this way in one project (Fig. 7–1 C). Based on this experimentally determined local heating on the QCM surface and the thereby generated temperature gradient in the liquid above the resonator, a thermophoretic convection in the fluid has been simulated. Theoretical considerations showed that the convection profile in the measurement vessel counteracts and even largely prevents the sedimentation of cells onto the sensor surface. It is suggested that the effect of thermophoresis is crucial especially in studies of biomolecular interactions on QCM surfaces at elevated shear amplitudes and driving voltages, respectively, which however has not been considered in literature to date. The phosphorescence quenching capability of oxygen was utilized in a second imaging project to monitor and image the local concentration and distribution of oxygen on the growth substrate of cells by means of a so-called pressure(/oxygen)-sensitive paint (PSP) (Fig. 7–1 D). A home-made experimental setup was constructed for sensor calibration and the imaging of subcellular oxygen, consisting of a FLIM setup coupled to an upright microscope and a temperature- and oxygen-controlled calibration and measurement chamber suitable for cellular applications. The cytocompatible sensor films have been characterized under various test conditions (in air, under medium, at different temperatures) regarding their sensitivity and response characteristics to different oxygen partial pressures. The oxygen consumption of cells adherently grown on the sensor film was successfully monitored and imaged by this setup. The time-resolved measurements demonstrated a significantly faster consumption of oxygen of a cell layer stimulated with a respiration chain decoupler compared to an unstimulated control cell layer. Taken together, various technical improvements of piezoelectric sensors (QCM) have been realized (MQCM, QCM-ECIS, ELPO-QCM-ECIS, QCM-OCS), which provide a significant information gain in cell-based applications. The sensors developed enable the high-content screening (HCS) of adherent cell lines in a wide range of assay formats and provide complementary physico-chemical information for obtaining a more complete picture of the state of cells and their reactions in contact to diverse stimuli. All sensor techniques share the characteristics of time-resolved, label-free, and non-invasive monitoring. This allows to disclose and analyze even the kinetics, delayed effects, recoveries, and fluctuations of physicochemical alterations of a studied cell layer, in addition to the absolute parameter changes, which is a valuable improvement compared to classical endpoint assays. The approach of combined, independent sensor systems also provides the novel possibility to bring parameters obtained by the different readout technologies from one cell layer in a temporal correlation, by which new insights into physiological relationships are possible

Nuclear Propulsion Technical Interchange Meeting, volume 2

The purpose of the meeting was to review the work performed in fiscal year 1992 in the areas of nuclear thermal and nuclear electric propulsion technology development. These proceedings are an accumulation of the presentations provided at the meeting along with annotations provided by authors. The proceedings cover system concepts, technology development, and system modeling for nuclear thermal propulsion (NTP) and nuclear electric propulsion (NEP). The test facilities required for the development of the nuclear propulsion systems are also discussed