Search results for "Measurement"
showing 10 items of 2918 documents
Fast thermometry for trapped ions using dark resonances
2015
We experimentally demonstrate a method to determine the temperature of trapped ions which is suitable for monitoring fast thermalization processes. We show that observing and analyzing the lineshape of dark resonances in the fluorescence spectrum provides a temperature measurement which accurate over a large dynamic range, applied to single ions and small ion crystals. Laser induced fluorescence is detected over a time of only $20\,\mu$s allowing for rapid determination of the ion temperature. In the measurement range of $10^{-1}-10^{+2}\,$mK we reach better than $15\,\%$ accuracy. Tuning the cooling laser to selected resonance features allows for controlling the ion temperatures between $0…
Effects of degenerate sterile neutrinos on the supernova neutrino flux
2004
We consider the possibility that there exist sterile neutrinos which are closely degenerate in mass with the active neutrinos and mixed with them. We investigate the effects of this kind of active-sterile neutrino mixing on the composition of supernova neutrino flux at the Earth. If an adiabatic MSW-transition between active and sterile neutrinos takes place, it could dramatically diminish the electron neutrino flux.
Probing light sterile neutrino signatures at reactor and Spallation Neutron Source neutrino experiments
2017
We investigate the impact of a fourth sterile neutrino at reactor and Spallation Neutron Source neutrino detectors. Specifically, we explore the discovery potential of the TEXONO and COHERENT experiments to subleading sterile neutrino effects through the measurement of the coherent elastic neutrino-nucleus scattering event rate. Our dedicated $\chi^2$-sensitivity analysis employs realistic nuclear structure calculations adequate for high purity sub-keV threshold Germanium detectors.
Experimental searches on sterile neutrinos
2015
While neutrino oscillations among the three active neutrino flavors are by now well established, several anomalies observed at relatively short baselines in oscillation experiments hint towards the existence of one or more additional sterile neutrino flavors. As a consequence, several experiments are in preparation that are dedicated to test the sterile neutrino hypothesis. The present contribution gives an overview of the on-going experimental efforts, highlighting the two projects that are foreseen to start in 2015: SOX deploying a radioactive neutrino source at short distance from the BOREXINO detector at LNGS, and STEREO searching for sterile neutrino oscillations at short distance from…
Atmospheric neutrino observations and flavor changing interactions
1999
Flavor changing (FC) neutrino-matter interactions can account for the zenith-angle dependent deficit of atmospheric neutrinos observed in the SuperKamiokande experiment, without directly invoking neither neutrino mass, nor mixing. We find that FC $\nu_\mu$-matter interactions provide a good fit to the observed zenith angle distributions, comparable in quality to the neutrino oscillation hypothesis. The required FC interactions arise naturally in many attractive extensions of the Standard Model.
Problems in neutrino physics
1990
The three “known” neutrinos νe νµ and ντ, as well as their postulated heavy companions, have been the subject of intense experimental and theoretical research over the last decade. And yet, all the basic questions that we raised when the first, controversial, results on the mass of electron neutrino from triton beta decay were announced and when the new generation of experiments on lepton family changing processes started, remain essentially unanswered, in spite of the impressive effort that went into neutrino research [1]. So we may just repeat some of these questions and then see what we know about them and what remains to be done.
Emittance measurements with optical transition radiation at the S-DALINAC
2020
Abstract A new emittance measurement system has been installed at the superconducting, recirculating electron accelerator S-DALINAC. It is based on the quadrupole-scan technique and beam profile measurements with optical transition radiation. A first demonstration of this setup has been conducted as part of the beam-based alignment of an SRF cavity. The corresponding emittance measurement is described here, and the following data evaluation is discussed.
Coulomb blockade-based nanothermometry in strong magnetic fields
1998
We have performed experiments to test for the susceptibility to strong magnetic fields of electron tunneling in normal metal -based nanostructures for Coulomb blockade primary thermometry. We have confirmed that, to within our accuracy of about ±1%, the single electron charging -induced zero bias differential resistance maximum is unaffected by the field up to 23 T at temperatures of 0.4–4.2 K. We discuss the simple theoretical basis of this immunity. We also report on the practical limitation at low temperatures imposed by superconductivity of aluminium in small magnetic fields.
Reduction of the uncertainty in the measurements of magnetic fields
2014
The paper deals with magnetic field measurement, carried out by using a broadband and isotropic instrument. These measurements are characterized by a very high uncertainty values if compared with the ones usually related to other electrical measurements. For these reasons, if the measurements are performed to assess the exposure of human beings, these large uncertainty values imply a high risk of wrong decision when there is the need to establish if a site complies or does not comply with a specified emission limits. A reduction of the uncertainty values implies a reduction of the risk. With this aim, we propose an approach which, in particular but very typical cases, allows an effective re…
Getting covariantly smeared sources into better shape
2014
The use of covariantly smeared sources in hadronic correlators is a common method of improving the projection onto the ground state. Studying the dependence of the shape of such sources on the gauge field background, we find that localized fluxes of magnetic field can strongly distort the sources. This results in a reduction of the smearing radii that can be reached by iterative smearing prescriptions, in particular as the continuum limit is approached. As a remedy, we propose a novel covariant smearing procedure (“free-form smearing”) enabling the creation of arbitrarily shaped sources, including in particular Gaussians of arbitrary radius, as well as shapes with nodes, such as hydrogenic …