12,040 research outputs found
Coherent Neutrino Scattering in Dark Matter Detectors
Coherent elastic neutrino- and WIMP-nucleus interaction signatures are
expected to be quite similar. This paper discusses how a next generation
ton-scale dark matter detector could discover neutrino-nucleus coherent
scattering, a precisely-predicted Standard Model process. A high intensity
pion- and muon- decay-at-rest neutrino source recently proposed for oscillation
physics at underground laboratories would provide the neutrinos for these
measurements. In this paper, we calculate raw rates for various target
materials commonly used in dark matter detectors and show that discovery of
this interaction is possible with a 2 tonyear GEODM exposure in an
optimistic energy threshold and efficiency scenario. We also study the effects
of the neutrino source on WIMP sensitivity and discuss the modulated neutrino
signal as a sensitivity/consistency check between different dark matter
experiments at DUSEL. Furthermore, we consider the possibility of coherent
neutrino physics with a GEODM module placed within tens of meters of the
neutrino source.Comment: 8 pages, 4 figure
Simultaneous Kummer congruences and -orientations of KO and tmf
Building on results of M. Ando, M.J. Hopkins and C. Rezk, we show the
existence of uncountably many -String orientations of real
K-theory KO and of topological modular forms tmf, generalizing the -
(resp. the Witten) genus. Furthermore, the obstruction to lifting an
-String orientations from KO to tmf is identified with a
classical Iwasawa-theoretic condition. The common key to all these results is a
precise understanding of the classical Kummer congruences, imposed for all
primes simultaneously. This result is of independent arithmetic interest.Comment: final versio
Measuring Active-to-Sterile Neutrino Oscillations with Neutral Current Coherent Neutrino-Nucleus Scattering
Light sterile neutrinos have been introduced as an explanation for a number
of oscillation signals at eV. Neutrino oscillations at
relatively short baselines provide a probe of these possible new states. This
paper describes an accelerator-based experiment using neutral current coherent
neutrino-nucleus scattering to strictly search for active-to-sterile neutrino
oscillations. This experiment could, thus, definitively establish the existence
of sterile neutrinos and provide constraints on their mixing parameters. A
cyclotron-based proton beam can be directed to multiple targets, producing a
low energy pion and muon decay-at-rest neutrino source with variable distance
to a single detector. Two types of detectors are considered: a germanium-based
detector inspired by the CDMS design and a liquid argon detector inspired by
the proposed CLEAR experiment.Comment: 10 pages, 7 figure
The Desktop Muon Detector: A simple, physics-motivated machine- and electronics-shop project for university students
This paper describes an undergraduate-level physics project that incorporates
various aspects of machine- and electronics-shop technical development. The
desktop muon detector is a self-contained apparatus that employs plastic
scintillator as a detection medium and a silicon photomultiplier for light
collection. These detectors can be used in conjunction with the provided
software to make interesting physics measurements. The total cost of each
counter is approximately $100.Comment: 29 pages, 14 figure
The structural properties of the multi-layer graphene/4H-SiC(000-1) system as determined by Surface X-ray Diffraction
We present a structural analysis of the multi-layer graphene-4HSiC(000-1})
system using Surface X-Ray Reflectivity. We show for the first time that
graphene films grown on the C-terminated (000-1}) surface have a
graphene-substrate bond length that is very short (0.162nm). The measured
distance rules out a weak Van der Waals interaction to the substrate and
instead indicates a strong bond between the first graphene layer and the bulk
as predicted by ab-initio calculations. The measurements also indicate that
multi-layer graphene grows in a near turbostratic mode on this surface. This
result may explain the lack of a broken graphene symmetry inferred from
conduction measurements on this system [C. Berger et al., Science 312, 1191
(2006)].Comment: 9 pages with 6 figure
Shuttle extravehicular activity signal processor pulse amplitude modulation decommutator
To provide data with long-term stability and accuracy, the pulse amplitude modulation (PAM) decommutator was synchronized to the PAM-return to zero wavetrain, and each channel was sampled with a common sample and hold circuit and digitized sequentially. The digital value of each channel was then scaled by the digital value of the calibration channels. The corrected digital value of each channel was stored for one complete frame and then transferred to the multiplexer-demultiplexer at a high rate in one block of serial digital data. A test model was built to demonstrate this design approach taken for the PAM decom and performance data was provided. The accuracies obtained with various signal to noise ratios are shown
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