8,447 research outputs found
Noise Characterization and Filtering in the MicroBooNE Liquid Argon TPC
The low-noise operation of readout electronics in a liquid argon time
projection chamber (LArTPC) is critical to properly extract the distribution of
ionization charge deposited on the wire planes of the TPC, especially for the
induction planes. This paper describes the characteristics and mitigation of
the observed noise in the MicroBooNE detector. The MicroBooNE's single-phase
LArTPC comprises two induction planes and one collection sense wire plane with
a total of 8256 wires. Current induced on each TPC wire is amplified and shaped
by custom low-power, low-noise ASICs immersed in the liquid argon. The
digitization of the signal waveform occurs outside the cryostat. Using data
from the first year of MicroBooNE operations, several excess noise sources in
the TPC were identified and mitigated. The residual equivalent noise charge
(ENC) after noise filtering varies with wire length and is found to be below
400 electrons for the longest wires (4.7 m). The response is consistent with
the cold electronics design expectations and is found to be stable with time
and uniform over the functioning channels. This noise level is significantly
lower than previous experiments utilizing warm front-end electronics.Comment: 36 pages, 20 figure
A high aspect ratio Fin-Ion Sensitive Field Effect Transistor: compromises towards better electrochemical bio-sensing
The development of next generation medicines demand more sensitive and
reliable label free sensing able to cope with increasing needs of multiplexing
and shorter times to results. Field effect transistor-based biosensors emerge
as one of the main possible technologies to cover the existing gap. The general
trend for the sensors has been miniaturisation with the expectation of
improving sensitivity and response time, but presenting issues with
reproducibility and noise level. Here we propose a Fin-Field Effect Transistor
(FinFET) with a high heigth to width aspect ratio for electrochemical
biosensing solving the issue of nanosensors in terms of reproducibility and
noise, while keeping the fast response time. We fabricated different devices
and characterised their performance with their response to the pH changes that
fitted to a Nernst-Poisson model. The experimental data were compared with
simulations of devices with different aspect ratio, stablishing an advantage in
total signal and linearity for the FinFETs with higher aspect ratio. In
addition, these FinFETs promise the optimisation of reliability and efficiency
in terms of limits of detection, for which the interplay of the size and
geometry of the sensor with the diffusion of the analytes plays a pivotal role.Comment: Article submitted to Nano Letter
Low-Frequency Noise Phenomena in Switched MOSFETs
In small-area MOSFETs widely used in analog and RF circuit design, low-frequency (LF) noise behavior is increasingly dominated by single-electron effects. In this paper, the authors review the limitations of current compact noise models which do not model such single-electron effects. The authors present measurement results that illustrate typical LF noise behavior in small-area MOSFETs, and a model based on Shockley-Read-Hall statistics to explain the behavior. Finally, the authors treat practical examples that illustrate the relevance of these effects to analog circuit design. To the analog circuit designer, awareness of these single-electron noise phenomena is crucial if optimal circuits are to be designed, especially since the effects can aid in low-noise circuit design if used properly, while they may be detrimental to performance if inadvertently applie
Highly-sensitive superconducting quantum interference proximity transistor
We report the design and implementation of a high-performance superconducting
quantum interference proximity transistor (SQUIPT) based on aluminum-copper
(Al-Cu) technology. With the adoption of a thin and short copper nanowire we
demostrate full phase-driven modulation of the proximity-induced minigap in the
normal metal density of states. Under optimal bias we record unprecedently high
flux-to-voltage (up to 3 mV/) and flux-to-current (exceeding 100
nA/) transfer function values at sub-Kelvin temperatures, where
is the flux quantum. The best magnetic flux resolution (as low as 500
n at 240 mK, being limited by the room temperature
pre-amplification stage) is reached under fixed current bias. These figures of
merit combined with ultra-low power dissipation and micrometer-size dimensions
make this mesoscopic interferometer attractive for low-temperature applications
such as the investigation of the magnetization of small spin populations.Comment: 7 pages, 5 color figure
An efficient approach to noise analysis through multidimensional physics-based models
IEEE TRANS. EL. DEV
Full Counting Statistics of Interacting Electrons
In order to fully characterize the noise associated with electron transport,
with its severe consequences for solid-state quantum information systems, the
theory of full counting statistics has been developed. It accounts for
correlation effects associated with the statistics and effects of entanglement,
but it remains a non-trivial task to account for interaction effects. In this
article we present two examples: we describe electron transport through quantum
dots with strong charging effects beyond perturbation theory in the tunneling,
and we analyze current fluctuations in a diffusive interacting conductor.Comment: To be published in special issue of "Fortschritte der Physik" (ed. by
Wolfgang Schleich
Product assurance technology for custom LSI/VLSI electronics
The technology for obtaining custom integrated circuits from CMOS-bulk silicon foundries using a universal set of layout rules is presented. The technical efforts were guided by the requirement to develop a 3 micron CMOS test chip for the Combined Release and Radiation Effects Satellite (CRRES). This chip contains both analog and digital circuits. The development employed all the elements required to obtain custom circuits from silicon foundries, including circuit design, foundry interfacing, circuit test, and circuit qualification
Feedback cooling of a nanomechanical resonator
Cooled, low-loss nanomechanical resonators offer the prospect of directly
observing the quantum dynamics of mesoscopic systems. However, the present
state of the art requires cooling down to the milliKelvin regime in order to
observe quantum effects. Here we present an active feedback strategy based on
continuous observation of the resonator position for the purpose of obtaining
these low temperatures. In addition, we apply this to an experimentally
realizable configuration, where the position monitoring is carried out by a
single-electron transistor. Our estimates indicate that with current technology
this technique is likely to bring the required low temperatures within reach.Comment: 10 pages, RevTex4, 4 color eps figure
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