This paper presents the design of a front-end circuit for monolithic active pixel sensors. The circuit operates with a sensor featuring a small, low-capacitance (< 2 fF) collection electrode and is ...integrated in the DPTS chip, a proof-of-principle prototype of 1.5 mm × 1.5 mm including a matrix of 32 × 32 pixels with a pitch of 15 μm. The chip is implemented in the 65 nm imaging technology from the Tower Partners Semiconductor Co. foundry and was developed in the framework of the EP-R&D program at CERN to explore this technology for particle detection. The front-end circuit has an area of 42 μm 2 and can operate with a power consumption as low as 12 nW. Measurements on the prototype relevant to the front-end will be shown to support its design.
An ever-increasing demand for high-performance silicon sensors requires complex sensor designs that are challenging to simulate and model. The combination of electrostatic finite element simulations ...with a transient Monte Carlo approach provides simultaneous access to precise sensor modelling and high statistics. The high simulation statistics enable the inclusion of Landau fluctuations and production of secondary particles, which offers a realistic simulation scenario. The transient simulation approach is an important tool to achieve an accurate time-resolved description of the sensor, which is crucial in the face of novel detector prototypes with increasingly precise timing capabilities. The simulated time resolution as a function of operating parameters as well as the full transient pulse can be monitored and assessed, which offers a new perspective for the optimisation and characterisation of silicon sensors.
In this paper, a combination of electrostatic finite-element simulations using 3D TCAD and transient Monte Carlo simulations with the Allpix2 framework are presented for a monolithic CMOS pixel sensor with a small collection electrode, that is characterised by a highly inhomogeneous, complex electric field. The results are compared to transient 3D TCAD simulations that offer a precise simulation of the transient behaviour but long computation times. Additionally, the simulations are benchmarked against test-beam data and good agreement is found for the performance parameters over a wide range of different operation conditions.
Hybrid pixel detectors require a reliable and cost-effective interconnect technology adapted to the pitch and die sizes of the respective applications. During the ASIC and sensor R&D phase, and in ...general for small-scale applications, such interconnect technologies need to be suitable for the assembly of single-dies, typically available from Multi-Project-Wafer submissions. Within the CERN EP R&D programme and the AIDAinnova collaboration, innovative hybridisation concepts targeting vertex-detector applications at future colliders are under development. This contribution presents recent results of a newly developed in-house single-die interconnection process based on Anisotropic Conductive Film (ACF). The ACF interconnect technology replaces the solder bumps with conductive particles embedded in an adhesive film. The electro-mechanical connection between the sensor and the read-out chip is achieved via thermo-compression of the ACF using a flip-chip device bonder. A specific pad topology is required to enable the connection via conductive particles and create cavities into which excess epoxy can flow. This pixel-pad topology is achieved with an in-house Electroless Nickel Immersion Gold (ENIG) plating process that is also under development within the project. The ENIG and ACF processes are qualified with the Timepix3 ASIC and sensors, with 55 um pixel pitch and 14 um pad diameter. The ACF technology can also be used for ASIC-PCB/FPC integration, replacing wire bonding or large-pitch solder bumping techniques. This contribution introduces the ENIG plating and ACF processes and presents recent results on Timepix3 hybrid assemblies.
A biosensor that uses ion-channel switches Cornell, B. A; Braach-Maksvytis, V. L. B; King, L. G ...
Nature (London),
06/1997, Letnik:
387, Številka:
6633
Journal Article
Recenzirano
Biosensors are molecular sensors that combine a biological recognition mechanism with a physical transduction technique. They provide a new class of inexpensive, portable instrument that permit ...sophisticated analytical measurements to be undertaken rapidly at decentralized locations. However, the adoption of biosensors for practical applications other than the measurement of blood glucose is currently limited by the expense, insensitivity and inflexibility of the available transduction methods. Here we describe the development of a biosensing technique in which the conductance of a population of molecular ion channels is switched by the recognition event. The approach mimics biological sensory functions and can be used with most types of receptor, including antibodies and nucleotides. The technique is very flexible and even in its simplest form it is sensitive to picomolar concentrations of proteins. The sensor is essentially an impedance element whose dimensions can readily be reduced to become an integral component of a microelectronic circuit. It may be used in a wide range of applications and in complex media, including blood. These uses might include cell typing, the detection of large proteins, viruses, antibodies, DNA, electrolytes, drugs, pesticides and other low-molecular-weight compounds.
Using novel synthetic lipids, a tethered bilayer membrane (tBLM) was formed onto a gold electrode such that a well-defined ionic reservoir exists between the gold surface and the bilayer membrane. ...Self-assembled monolayers of reservoir-forming lipids were first adsorbed onto the gold surface using gold−sulfur interactions, followed by the formation of the tBLM using the self-assembly properties of phosphatidylcholine-based lipids in aqueous solution. The properties of the tBLM were investigated by impedance spectroscopy. The capacitance of the tBLM indicated the formation of bilayer membranes of comparable thickness to solvent-free black (or bilayer) lipid membranes (BLM). The ionic sealing ability was comparable to those of classical BLMs. The function of the ionic reservoir was investigated using the potassium-specific ionophore valinomycin. Increasing the size of the reservoir by increasing the length of the hydrophilic region of the reservoir lipid or laterally spacing the reservoir lipid results in an improved ionic reservoir. Imposition of a dc bias voltage during the measurement of the impedance spectrum affected the conductivity of the tBLM. The conductivity and specificity of the valinomycin were comparable to those seen in a classical BLM.
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