Ultrathin Sensor Research Articles

CLIC vertex detector R&D

In order to achieve its primary objectives of heavy-flavour tagging and tau lepton identification, the CLIC vertex detector must precisely reconstruct displaced vertices. This requires accurate determination of the impact parameter and charge of tracks originating from the secondary vertex. Excellent spatial resolution must therefore be provided down to low polar angles, whilst maintaining low occupancy, low mass and low power dissipation. These requirements challenge current technological limits, and demand a broad programme of R&D. A detector concept is currently under development, comprising a hybrid pixel detector of small-pitch readout ASICs implemented in 65nm CMOS technology (CLICpix) combined with ultra-thin sensors. The readout chips are low-power, and power-pulsing is used to reduce further their power dissipation. This enables a forced gas cooling system in the vertex detector region. In this paper, the CLIC vertex detector requirements are reviewed and the current status of R&D on sensors, readout, powering, cooling and supports is presented.

A stretchable and flexible system for skin-mounted measurement of motion tracking and physiological signals.

In this paper, we present a stretchable wearable system capable of i) measuring multiple physiological parameters and ii) transmitting data via radio frequency to a smart phone. The electrical architecture consists of ultra thin sensors (<; 20 μm thick) and a conformal network of associated active and passive electronics in a mesh-like geometry that can mechanically couple with the curvilinear surfaces of the human body. Spring-like metal interconnects between individual chips on board the device allow the system to accommodate strains approaching ~30% A representative example of a smart patch that measures movement and electromyography (EMG) signals highlights the utility of this new class of medical skin-mounted system in monitoring a broad range of neuromuscular and cardiovascular diseases.

Investigation on Reliability of Embedded Ultrathin Sensor Chip in Organic Substrate Under Drop Impact Loading by Stresses Monitor and FEM Simulation

Investigation on Reliability of Embedded Ultrathin Sensor Chip in Organic Substrate Under Drop Impact Loading by Stresses Monitor and FEM Simulation

Tongue Pressure Modulation for Initial Gel Consistency in a Different Oral Strategy

BackgroundIn the recent hyper-aged societies of developed countries, the market for soft diets for patients with dysphagia has been growing and numerous jelly-type foods have become available. However, interrelationships between the biomechanics of oral strategies and jelly texture remain unclear. The present study investigated the influence of the initial consistency of jelly on tongue motor kinetics in different oral strategies by measuring tongue pressure against the hard palate.MethodsJellies created as a mixture of deacylated gellan gum and psyllium seed gum with different initial consistencies (hard, medium or soft) were prepared as test foods. Tongue pressure production while ingesting 5 ml of jelly using different oral strategies (Squeezing or Mastication) was recorded in eight healthy volunteers using an ultra-thin sensor sheet system. Maximal magnitude, duration and total integrated values (tongue work) of tongue pressure for size reduction and swallowing in each strategy were compared among initial consistencies of jelly, and between Squeezing and Mastication.ResultsIn Squeezing, the tongue performed more work for size reduction with increasing initial consistency of jelly by modulating both the magnitude and duration of tongue pressure over a wide area of hard palate, but tongue work for swallowing increased at the posterior-median and circumferential parts by modulating only the magnitude of tongue pressure. Conversely, in Mastication, the tongue performed more work for size reduction with increasing initial consistency of jelly by modulating both magnitude and duration of tongue pressure mainly at the posterior part of the hard palate, but tongue work as well as other tongue pressure parameters for swallowing showed no differences by type of jelly.ConclusionsThese results reveal fine modulations in tongue-palate contact according to the initial consistency of jelly and oral strategies.

Vertex-detector R&D for CLIC

A detector concept based on hybrid planar pixel-detector technology is under development for the CLIC vertex detector. It comprises fast, low-power and small-pitch readout ASICs implemented in 65 nm CMOS technology (CLICpix) coupled to ultra-thin sensors via low-mass interconnects. The power dissipation of the readout chips is reduced by means of power pulsing, allowing for a cooling system based on forced gas flow. In this paper the CLIC vertex-detector requirements are reviewed and the current status of R&D on sensors, readout and detector integration is presented.

Foot Pressure-Sensor System for Tracking Safety and Health

This paper presents an innovative pressure sensor systemembedded in a sock, which has a number of health care applications. One of these is the low-cost, reliable detection of the bed-departure of Alzheimer’s patients, an increasingly common problem that causes significant stress to caregivers. The system comprises a pressure sensor embedded in a sock and a coin battery-powered microcontroller containing a radiofrequency module. Once the user wanders out of bed and steps onto the floor, the sensor on the sock will immediately detect the pressure caused by his or her body weight and will wirelessly trigger an audible sound in a caregiver’s monitoring unit, which can be a Smartphone, tablet, or dedicated monitor. Furthermore, the pressure sensor and the microcontroller can be combined into one re-attachable unit, which can be stuck conveniently to the ball or heel of the user’s foot or any ordinary sock, slipper or shoe. In addition, the system can function as a highly accurate pedometer that is useful for monitoring the user’s health by tracking changes in his or her gait characteristics. In this study, a prototype sensor sock was developed that included an ultra-thin flexible pressure sensor, microcontroller, Bluetooth low energy module, and control software. The efficacy of the sensor sock in detecting and alerting patients’ wandering has been demonstrated.

72: First investigations of Ultra-Thin 3D silicon detectors as microdosimeters

IMB-CNM (CSIC) has developed a new type of threedimensional diode on ultrathin SOI silicon wafers with 3D columnar structures with P-N junctions fabricated with micromachining techniques for plasma diagnostic applications or neutron detection in demanding environments [1, 2]. The three-dimensional electrodes are columns etched through the silicon instead of being deposited on the surface like in the standard planar diodes. The sensitive volume is a silicon membrane only 10 microns thick (fig.1). The ultra-thin sensors have shown to be insensitive to the gamma radiation background, their membrane structure avoids the backscattering contributions from the supporting silicon wafer and the confinement of the electric field given by the columnar electrodes reduces charge sharing. All these characteristics make the ultra-thin 3D devices the perfect candidates for microdosimetry. Recently, IMB-CNM have carried out the first tests of these devices with beams of 62MeV protons and 95MeV/u C ions. The results of these first experiments show that, although they were not specifically designed for microdosimetric applications, the detectors with ultra-thin 3D structure are able to characterize the therapeutic hadron beams. Results from these proof-of-concept tests will be presented and compared with Monte Carlo simulations using MCNPX and Geant4 codes.

Effect of lingual plates on generating intra-oral pressure during swallowing: an experimental study in healthy subjects

BackgroundAlthough palatal augmentation prostheses (PAPs) can improve dysphagia, their application is compromised in the absence of maxillary abutment teeth. Experimental lingual plates (ELPs) used for raising the tongue may be employed as alternative to PAPs.MethodsInfluence of different ELP designs, plateau (P–type) and drop-shaped (D–type), on the intra–oral pressure during swallowing were tested. Eleven healthy dentate volunteers, with a mean age of 35.5±10.5 years, participated in this study. Tongue pressure on the hard palate was measured using an ultra-thin sensor sheet with five measuring points, whilst performing dry, 5–ml and 15–ml water swallows, with and without the ELPs in situ. Additional pressure sensors were installed in the lingual aspects of the ELPs, and on the vestibular aspect of the lower molars for measuring sublingual and oral vestibule pressures, respectively. Each measurement was recorded thrice. A repeated measures ANOVA was employed to verify differences in duration, maximal magnitude and integrated value for the different experimental situations. Tukey’s post hoc test was performed for comparison testing. Statistical significance was set at p<0.05.ResultsThe sequence of tongue–palate contact on the median line of the hard palate without ELPs was maintained, except for the 15 ml P–type swallow. Tongue pressure started earlier with the D–type but reached its peak nearly at the same time as without ELPs. The peak magnitude and cumulative tongue pressure against the hard palate decreased by wearing ELPs (p<0.05), but was inconsistent between the two types of ELPs and for the different swallowing volumes. Both, maximum and cumulative vestibular pressures were mostly similar or larger with P–type than that with D–type.ConclusionD-type and P-type ELPs seem to have the inverse effect of PAPs on the palatal tongue pressure during swallowing. These first counterintuitive findings do not yet justify rejecting the basic rationale of using ELPs for the treatment of dysphagia; hence a rather biologically designed piezographic lingual plate may be more appropriate.

Oxidation states and the quality of lower interfaces in magnetic tunnel junctions: oxygen effect on crystallization of interfaces

Lower interfaces in magnetic tunnel junctions (MTJs), which are the basic components in many spintronic devices such as magnetoresistive random access memories, have crucial effects on the performance of these devices. To obtain more insight into such interfaces, we have introduced an ultrathin sensor layer of 57Fe at the interface between the lower electrode and the oxide barrier in selected MTJs. This allowed us to perform nuclear resonant scattering measurements, which provide direct information on the magnetic properties and quality of the interfaces. The application of nuclear resonant scattering to study interfaces in MTJs is a unique approach in the sense that it gives information at the atomic level, and specifically from the interface where the sensor layer is deposited. Samples with different tunnel barrier thicknesses and varied oxidation times in the preparation of this barrier have been studied. These show that oxidation can not only increase the magnetic hyperfine fields but also cause an interesting smoothing and crystallizing of the interface. Another interesting finding is the observation of boron diffusion into the lower part of the FeCoB lower electrode towards the Ta seed layer.

An Ultra-Thin Piezoresistive Stress Sensor for Measurement of Tooth Orthodontic Force in Invisible Aligners

A silicon piezoresistive stress sensor is developed to measure the three components of the orthodontic forces of a tooth in invisible aligners. The stress sensor chip consists of multiple piezoresistor rosettes, and is fixed on the tooth surface to measure the orthodontic force induced stresses. An inverse problem algorithm is established to reconstruct the orthodontic forces of the tooth from the measured stresses. A key thinning process is developed using chemical-mechanical polishing to thin the sensor chip from 650 to 100 , such that it can be accommodated to the limited space between the aligner and the tooth, without much influence on the orthodontic force. The ultra-thin thickness enables the sensor chip to be compliance with tooth deformation, and improves the stress measurement sensitivity as much as 40 times, making it capable of measuring small orthodontic force. The sensor design, fabrication, orthodontic stress measurement, and force reconstruction are given in details, and the experimental results demonstrate the feasibility of using miniaturized and ultra-thin sensors to determine the in vitro orthodontic forces.

A Real-Time, Wireless Pressure Monitoring System for Bucking Bulls

To evaluate the animal welfare, many ranchers would like to know the pressure on the animals due to the holsters and ropes. In this paper, a wireless real-time pressure monitoring system was designed based on wireless sensor network. The system consists of several pressure sensor nodes and a sink to coordinate the whole network, collect data from pressure sensor nodes and send the data to PC. An ultra-thin pressure sensor was integrated in the smart moteplatform to form the pressure sensor node. TinyOS, an open-source operating system and nesC language, an extension to C were applied for programming. In the lab test, the result of sensor calibration shows it has a good linearity and the packet delivery rate test verify that the system could operate stably and reliably in a better acceptable link quality. For better presenting to users, an information monitoring interface was used based on MATLAB as a simple demonstration of the whole system.

Charge Signal Processors in a 130 nm CMOS Technology for the Sparse Readout of Small Pitch Monolithic and Hybrid Pixel Sensors

Hybrid pixel detectors are nowadays a robust and mature technology for particle detection as well as for medical and X-ray imaging, but the demands for improved performance for the next generation high energy physics experiments ask for the development of novel devices. Monolithic CMOS pixels have the potential to provide high granularity thin detectors as the sensor and the readout electronics are integrated in the same substrate. However, they suffer from a few limitations closely related to their working principle. 3D vertical integration has the potential of providing a performance breakthrough toward the design of fast, radiation tolerant and ultra thin CMOS radiation sensors. This work will discuss the design of analog circuits for processing the signals from small pitch monolithic and hybrid pixel detectors designed and fabricated in a planar 130 nm CMOS technology and in a 130 nm CMOS technology with vertical integration capabilities. Various solutions complying with different S/N ratio and detector capacitance constraints will be described in this paper by means of circuit simulations and experimental results.

Surface Plasmon Resonance (SPR) Detection of Theophylline via Electropolymerized Molecularly Imprinted Polythiophenes

A facile approach to tailor-made, highly selective, and robust ultrathin sensor film for theophylline detection was demonstrated by an electropolymerized molecularly imprinted polymer (E-MIP) film of a terthiophene derivative. The method involved direct electropolymerization of the H-bond complexing terthiophene monomer. A key enabling step in sensor fabrication is the use of an electrochemically mediated washing step of the template. The formation of the E-MIP film was monitored by in situ electrochemical surface plasmon resonance (EC-SPR) spectroscopy, allowing real-time observation of the simultaneous changes in electrochemical and optical properties of the film. Surface characterization techniques for the electropolymerized films include atomic force microscopy (AFM), ellipsometry, static contact angle, X-ray photoelectron spectroscopy (XPS), and quartz crystal microbalance (QCM). A linear calibration curve (R = 0.994) of the E-MIP/SPR sensor for theophylline detection was obtained with a 10−50 μM−1 r...

Design and optimization of an ultra thin flexible capacitive humidity sensor

In this paper we present the design and fabrication of a humidity sensor on ultra thin (8 μm) flexible polyimide substrate. The ultra thin flexible substrate can be preserved also when a read-out electronic interface is integrated by using Polycrystalline Silicon Thin Film Transistors technology. The sensor device is a capacitor where a thin layer of [bis(benzo cyclobutene)] is used as a dielectric sensitive material between two metal electrodes. The electrode layout has been designed with the aid of numerical simulations in order to optimize the sensor performances. The fabricated sensor has shown sensitivity to relative humidity of 0.38%/RH% and a linearity of 0.996 in the range of 10–90 RH%. Furthermore, measurements regarding the sensor response time, different bending and bias voltage effects have been performed.

Stilbazolium merocyanine systems in Langmuir and Langmuir–Blodgett molecular layers

Stilbazolium merocyanine (1-(12-hydroxydodecyl)-4-[(3-hydroxy-4-oxocyclohexa-2,5-dienylidene)-ethylidene]-1,4-dihydropyridine) was investigated in form of Langmuir and Langmuir–Blodgett films for potential sensor of environment pH and presence of metal ions applications. Two forms of the merocyanine, free-base and protonated were observed in Langmuir films depending on the pH of subphase. The complex comprised of merocyanine and Cu 2+ or Co 2+ metal ions are also able to form stable Langmuir films which compression isotherms are different from non-complex merocyanine. Also films composed of a mixture of merocyanine and fatty acid (eicosanoic acid) were prepared. Attractive and repulsive interactions between molecules in mixture films were observed. All types of the films were successfully transferred onto hydrophobic quartz plates for the purpose of producing solid samples of ultrathin sensors. Multilayers of free-base merocyanine films remain sensitive to the pH of the environment. From the changes in absorbance spectra of the merocyanine film it is possible to evaluate the pH of the microenvironment.

Standing-wave spectrometer

A standing-wave sensor was developed which facilitates the miniaturization of Fourier spectrometers down to the micrometer scale. The spectrometer concept is based on sampling a standing wave by an ultrathin and partially transmissive sensor. The active region of the sensor has a thickness of 30nm–40nm. The standing wave is created in front of a tunable mirror. Varying the position of the mirror results in a phase shift of the standing wave, a modulation of the intensity profile within the ultrathin sensor, and thus, in a modulation of the photocurrent. The spectral information of the incoming light can be determined by the Fourier transform of the sensor signal. The operation principle of the spectrometer is described and the influence of the device design on the spectral resolution of the spectrometer is discussed. Due to the simple linear setup of the sensor and the tunable mirror, the realization of one- and two-dimensional spectrometer arrays is feasible.

Magnetostrictions of CoFe Sensoring Layers in Spin Valves

The effective magnetostriction (/spl lambda//sub s/) of ultrathin CoFe sensor layers has been measured as a function of CoFe and spin-filter nonmagnetic layers over the range from 1.0 to 3.0 nm. The /spl lambda//sub s/ shows an anomalous variation at thicknesses of interest and disagrees with the expectation of the Ne/spl acute/el model, where the surface/interface contribution is supposed to lead to observation that the /spl lambda//sub s/ varies with the well-known reciprocal law of magnetic layer thickness. Within the framework of a coherent strain model proposed herewith, both the deviation of magnetostriction behavior from the reciprocal law and its nonmagnetic layer structure dependence are satisfactorily explained. The interface-induced magnetoelastic coupling, laminated structure dependent strains, and stresses are called for in explaining the magnetostriction of magnetically soft sensor layers.

A new tool to measure pressure under burn garments.

This article introduces a new tool to measure the pressure that is under pressure garments. The Iscan (Tekscan, Inc.) system uses a patented ultra-thin (0.007 inch) sensor with multiple sensing locations that sample continuously at 100 times per second. It is noninvasive, convenient, and quick. The study had two parts. First, we established the validity and reliability of the device. Next, garment/scar interface pressures were measured on new garments with use of the Iscan system. Four garment types were studied, with 10 measurements made in each group: Isotoner gloves (Smith & Nephew Roylan, Inc.); custom-fit pressure gloves; Tubigrip forearm sleeves (Seton Health Care Group); and custom-fit pressure forearm sleeves. Mean garment/scar interface pressures were 18 +/- 2 mm Hg for the Isotoner glove, 34 +/- 5 mm Hg for the custom-fit pressure glove, 20 +/- 7 mm Hg for the Tubigrip sleeve, and 35 +/- 6 mm Hg for the custom-fit sleeve. We concluded that the Iscan system can be used to measure pressure under pressure garments accurately and reliably, and that custom-fit hand and forearm garments provide more pressure than Isotoner gloves or Tubigrip sleeves.

足底圧からみたＰＴＢ歩行装具の免荷効果

The load bearing function of the patellar tendon bearing (PTB) brace was studied using the F-SCAN system of foot pressure analysis.A high frequency response, ultra-thin sensor insole was used to measure plantar pressure at the sole of the foot in normal subjects.The major obfectives of this study were as follows:1) Measurement of the load bearing function of the PTB brace.2) Evaluation of the pressure reducing or increasing effect of the weight bearing board.3) Evaluation of the lower leg component of the PTB brace.The following results were obtained:1) 100% of non-loading was obtained by the PTB brace.2) 82% of non-loading was obtained at the starting point of the weight bearing board. Increasing the board height increases plantar pressure (64% of non-loading at + 5mm, 36% of non-loading at +10mm). Plantar pressures were also reduced by the lower board (91% of non-loading at -5mm, 96% of non-loading at -10mm).3) Lower leg component of the PTB brace had the great load bearing function.

An evaluation of ultrathin ring and band microelectrodes as amperometric sensors in electrochemical flow cells

AbstractGold and platinum ultrathin ring microelectrodes (0.1–0.5 mm thick, 1.5–4 mm diameter) were made by sputtering, from fired metalloorganic paint, and from foil for use as sensors in a thick‐layer wall‐jet flow cell. An end‐on array of three 0.1 μm × 0.5 mm gold band electrodes were mounted parallel to the flow direction in a thin‐layer channel cell. These ultrathin sensors, along with a jet‐centered carbon microdisk, were evaluated in the amperometric flow‐injection mode for temporal stability, calibration sensitivity, detectivity, background signal, and flow rate dependence of the analytical signal using ferrocene samples in acetonitrile containing 10−4–10−2 M TEAP. The detectivity of gold paint ring electrodes made on borosilicate glass was 3–6 nM, an order of magnitude lower than any of the other electrodes tested. Analytical signals from gold paint and foil rings and the carbon microdisk had the best temporal stability. The current for the ultrathin band array in a channel cell was flow rate‐independent, and the exponential dependence of cell current on flow rate was 0.11–0.14 for ultrathin rings in the thick‐layer wall‐jet mode.