SEARCH · Searcharxiv
Search indexed arXiv papers on artificial intelligence, large language models, computer vision and robotics. Read source abstracts and follow links to arXiv.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
We have investigated the possibility of measuring the electron neutrino mass with sub-eV sensitivity by studying the electron capture decay of 163-Ho with cryogenic microcalorimeters. In this paper we will introduce an experiment's concept, discuss the technical requirements, and identify a roadmap to reach a sensitivity of 0.1 eV and beyond.
Fine pixel CCD (FPCCD) is one of the candidate sensor technologies for the vertex detector used for experiments at the International Linear Collider (ILC). A vertex detector system for the International Large Detector (ILD) using FPCCD sensors has been designed. We report on the R&D status of FPCCD sensors, as well as the vertex detector design for ILD.
This report describes the physics potential and experiments at a future multi-TeV e+e- collider based on the Compact Linear Collider (CLIC) technology. The physics scenarios considered include precision measurements of known quantities as well as the discovery potential of physics beyond the Standard Model. The report describes the detector performance required at CLIC, taking into account the interaction point environment and especially beaminduced backgrounds. Two detector concepts, designed around highly granular calorimeters and based on concepts studied for the International Linear Collider (ILC), are described and used to study the physics reach and potential of such a collider. Detector subsystems and the principal engineering challenges are illustrated. The overall performance of these CLIC detector concepts is demonstrated by studies of the performance of individual subdetector systems as well as complete simulation studies of six benchmark physics processes. These full detector simulation and reconstruction studies include beaminduced backgrounds and physics background processes. After optimisation of the detector concepts and adopting the reconstruction algorithms the results show very efficient background rejection and clearly demonstrate the physics potential at CLIC in terms of precision mass and cross section measurements. Finally, an overview of future plans of the CLIC detector and physics study is given and a list of key detector R&D topics needed for detectors at CLIC is presented.
The Digital Hadron Calorimeter (DHCAL) is a large prototype of an imaging calorimeter using Resistive Plate Chambers (RPCs) as active media. The readout is segmented into 1\times1 cm2 pads, each with a single bit resolution, hence the denomination of digital. The total channel count is close to 500,000. The DHCAL construction and assembly was completed in fall 2010, followed by a series of test beam campaigns in the FTBF test beam at Fermilab. In this paper we report on the analysis of events collected with the broadband muon beam. These events are utilized to geometrically align the layers horizontally and vertically, to establish the response as function of position on a single readout pad, and to measure the performance characteristics of the RPCs, i.e. the efficiency and average pad multiplicity. The latter were measured in both 'clean' regions of the detector, i.e. away from structures such as the rims of the chambers, and as function of position on the entire vertical plane. In addition, the paper reviews the preliminary measurements of the noise rate in the detector.
Here a synchronous phase-demodulation method for high spatial frequency (HSF), concentric-rings Placido fringe pattern is proposed. The earliest use of this concentric-rings pattern was to gauge non-spherical irregularities of the human cornea by Portuguese ophthalmologist Antonio Placido in 1880. Most modern corneal topographers use Placido patterns to test human cornea irregularities; a field of application of this paper. Another field of application of HSF conic-carrier fringe patterns is to test wavefronts using what may be called the Placido-Hartmann screen test. These screens would be formed by periodic concentric ring apertures. A Placido-Hartmann test would be sensitive to the radial slope of the wavefront under measurement. Finally as in the Hartmann-Shack test, one may use a radial lenslet array of toroidal-shaped lenses to test the radial slope of a wavefront at the focal plane. The main advantage of estimating the radial slope of a wavefront using a HSF Placido pattern is that a single radial slope image is sufficient to integrate the full wavefront shape.
This proposal describes an experimental search for sterile neutrinos beyond the Standard Model with a new CERN-SPS neutrino beam. The experiment is based on two identical LAr-TPC's followed by magnetized spectrometers, observing the electron and muon neutrino events at 1600 and 300 m from the proton target. This project will exploit the ICARUS T600, moved from LNGS to the CERN "Far" position. An additional 1/4 of the T600 detector will be constructed and located in the "Near" position. Two spectrometers will be placed downstream of the two LAr-TPC detectors to greatly complement the physics capabilities. Spectrometers will exploit a classical dipole magnetic field with iron slabs, and a new concept air-magnet, to perform charge identification and muon momentum measurements in a wide energy range over a large transverse area. In the two positions, the radial and energy spectra of the nu_e beam are practically identical. Comparing the two detectors, in absence of oscillations, all cross sections and experimental biases cancel out, and the two experimentally observed event distributions must be identical. Any difference of the event distributions at the locations of the two detectors might be attributed to the possible existence of ν-oscillations, presumably due to additional neutrinos with a mixing angle sin^2(2theta_new) and a larger mass difference Delta_m^2_new. The superior quality of the LAr imaging TPC, in particular its unique electron-pi_zero discrimination allows full rejection of backgrounds and offers a lossless nu_e detection capability. The determination of the muon charge with the spectrometers allows the full separation of nu_mu from anti-nu_mu and therefore controlling systematics from muon mis-identification largely at high momenta.
We discuss two projects exploring the integration of thin CMOS pixel sensors in order to prototype ladders matching the geometry needed for the ILD vertex detector. The PLUME project has designed and fabricated full-size and fully functional double- sided layers which currently reach 0.6 % X0 and aim for 0.3 % X0 in mid-2012. Another approach, SERNWIETE, consists in wrapping the sensors in a polyimide-based micro-cable to obtain a supportless single-sided ladder with a material budget around 0.15 % X0. First promising samples have been produced and the full-size prototype is expected in spring 2012.
For the first time we have fabricated a high granularity micropattern solid-state detector (MSSD) with the unipolar time-differential property for ultrafast pulse response. Optical, x-ray, and gamma-ray photoconductivity measurements prove the unipolar time-differential response with a speed improvement factor of ~400 for amorphous selenium MSSD. The significance of the results presented here is the ability to reach the intrinsic physical limit for detector pulse speed by transitioning from the transit-time-limited response, which depends on the bulk carrier transport mechanism, to range-limited response set by the spatial dispersion of the photo-induced carrier cloud. Furthermore, the combination of the time-differential and the avalanche-multiplication properties of the proposed micropattern solid-state detector can yield another great leap forward in the field of radiation detectors with applications ranging from high-energy, nuclear, and astro- physics, to industrial and medical diagnostics, and crystallography.
Thin and large area NaI(Tl) scintillator to search for WIMPs dark matter was developed. The performance of thin and wide area NaI(Tl) showed good enough to search for dark matter. The energy threshold was as low as 2keV and the energy resolution was about 24% in FWHM at 60keV.
Conceptual Design Report developed for the Water Cherenkov Detector (WCD) option for the far detector of the Long Baseline Neutrino Experiment.
The Daya Bay Reactor Neutrino Experiment is designed to measure the neutrino mixing angle theta13 to world-leading precision. The experiment deploys identical antineutrino detectors at distances of 400-1900m from six reactors in Daya Bay, China. Each detector incorporates two general-purpose monitoring cameras to ensure their safe construction, transportation and operation. The cameras must meet usage goals while satisfying stringent constraints on radioactivity, materials compatibility, interference and reliability. This article describes the system design, integration, operation and performance.
An unbinned maximum likelihood analysis of CDMS low-energy data reveals a strong preference (5.7 sigma C.L.) for a model containing an exponential excess of events in the nuclear recoil band, when compared to the null hypothesis. We comment on the possible origin of such an excess, establishing a comparison with anomalies in other dark matter experiments. A recent annual modulation search in CDMS data is shown to be insufficiently sensitive to test a dark matter origin for this excess.
Longitudinal resolution and lateral sensitivity are decisive characteristics that determine the suitability of a nanopore sensor for sequencing a strand of DNA as well as other important polymers. Previous modeling of DNA induced ionic current blockades in single atom thick graphene nanopores has shown these nanopores to have sufficient longitudinal resolution to distinguish individual nucleobases along the length of a DNA molecule. Here we experimentally focus on the sensitivity to small changes in DNA diameter that can be discerned with graphene nanopores. We show that remarkably large sensitivities (0.5 nA/A)are obtained when the nanopore is tailored to have a diameter close to that of the polymer of interest. Our results have been obtained with double-stranded DNA (dsDNA). Smaller graphene nanopores that can be tuned to the diameter of single-stranded DNA (ssDNA) for sequencing have only recently been demonstrated. Our results indicate that nanopore sensors based on such pores will provide excellent resolution and base discrimination, and will be robust competitors to protein nanopores that have recently demonstrated sequencing capability.
One way to proof or exclude the existence of axion like particles is a microwave light shining through the wall experiment. In this publication we will emphasize on the engineering aspects of such a setup, currently under development at CERN. One critical point, to achieve meaningful results, is the electromagnetic shielding between axion-emitter and -receiver cavity, which needs to be in the order of 300 dB to improve over existing experimental bounds. The RF leakage or electromagnetic crosstalk between both cavities must be well controlled and quantified during the complete duration of the experiment. A very narrow band (in the 10^-6 Hz range) homodyne detection method is used to reveal the axion signal from background thermal noise. The current status of the experiment is presented.
High channel density and space restrictions required that the front end electronics integrated into the active elements of calorimeter. For that purpose novel readout chain base on Application-Specific Integrated Circuit (ASIC) designed for the Electromagnetic Calorimeter for the future International Linear Calorimeter experiment. In this paper, the performance study of ASIC with injected charge is presented.
The modular hadron calorimeter with micro-pixel avalanche photodiodes readout for the NA61/SHINE experiment at the CERN SPS is presented. The calorimeter consists of 44 independent modules with lead-scintillator sandwich structure. The light from the scintillator tiles is captured by and transported with WLS-fibers embedded in scintillator grooves. The construction provides a longitudinal segmentation of the module in 10 sections with independent MAPD readout. MAPDs with pixel density of $~10^{4}$/mm$^2$ ensure good linearity of calorimeter response in a wide dynamical range. The performance of the calorimeter prototype in a beam test is reported.
Accessing and characterizing a flow impose a number of constraints on the employed measurement techniques; in particular optical methods require transparent fluids and windows in the vessel. Whereas one can adapt apparatus, fluid and methods in the lab to these constraints, this is hardly possible for industrial mixers. We present in this article a novel measurement technique which is suitable for opaque or granular flows: an instrumented particle, which continuously transmits the force/acceleration acting on it as it is advected in a flow. Its density is adjustable for a wide range of fluids and because of its small size and its wireless data transmission, the system can be used both in industrial and scientific mixers allowing a better understanding of the flow within. We demonstrate the capabilities and precision of the particle by comparing its transmitted acceleration to alternative measurements, in particular in the case of a turbulent von Kármán flow. Our technique shows to be an efficient and fast tool to characterize flows.
In this paper we show how appropriate superpositions of Bessel beams can be successfully used to obtain arbitrary longitudinal intensity patterns of nondiffracting ultrasonic wavefields with very high transverse localization. More precisely, the method here described allows generating longitudinal acoustic pressure fields, whose longitudinal intensity patterns can assume, in principle, any desired shape within a freely chosen interval 0 < z < L of the propagation axis, and that can be endowed in particular with a s t a t i c envelope (within which only the carrier wave propagates). Indeed, it is here demonstrated by computer evaluations that these very special beams of non-attenuated ultrasonic field can be generated in water-like media by means of annular transducers. Such fields "at rest" have been called by us << Acoustic Frozen Waves >> (FW). The paper presents various cases of FWs in water, and investigates their aperture characteristics, such as minimum required size and ring dimensioning, as well as the influence they have on the proper generation of the desired FW patterns. The FWs are particular Localized Solutions to the wave equation that can be used in many applications, like new kinds of devices, such as, e.g., acoustic tweezers or scalpels, and especially various ultrasound medical apparatus; e.g. for attempting the destruction of tumor cells without affecting the preceding and subsequent (and surrounding) tissues. Keywords: Ultrasound; Frozen Waves; Bessel beam superpositions; Non-diffractive waves; Localized Waves; Annular transducers.