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S. Escoffier

Publications and source records attributed to S. Escoffier.

202 records · Page 12Linked to original sources

Neutrino detection of transient sources with optical follow-up observations

The ANTARES telescope has the opportunity to detect transient neutrino sources, such as gamma-ray bursts (GRBs), core-collapse supernovae (SNe), flares of active galactic nuclei (AGNs)... To enhance the sensitivity to these sources, we are developing a new detection method based on the observation of neutrino bursts followed by an optical detection. The ANTARES Collaboration is implementing a fast on-line event reconstruction with a good angular resolution. These characteristics allow to trigger an optical telescope network in order to identify the nature of the neutrinos (and high energy cosmic-rays) sources. This follow-up can be done with a network of small automatic telescopes and required a small observation time. An optical follow-up of special events, such as neutrino doublets in coincidence in time and space or single neutrino having a very high energy, would not only give access to the nature of the sources but also improve the sensitivity for neutrino detection from SNe or GRBs.

astro-ph↗

The ANTARES detector: background sources and effects on detector performance

The ANTARES Collaboration is deploying a large neutrino detector at a depth of 2475 m in the Mediterranean Sea, 40 km off shore from La Seyne-sur-Mer in South France. The construction of this 12-line detector with 75 phototubes per line will be completed early 2008. Data taking has begun since April 2005 with an instrumentation line also equipped with optical modules. The first 5 detector lines are operational since January 2007. The telescope is aimed to observe high energy cosmic neutrinos through the detection of the Cerenkov light produced by up-going induced muons. Background sources are due to atmospheric neutrinos as well as misreconstructed atmospheric muons. Additional backgrounds inherent to the sea water environment come from 40K decay and marine organisms' luminescence. While the contribution of the former is expected to be constant at a level of about 45 kHz, the bioluminescence has shown large time variations, with periods of very high activity, up to several hundred kHz. Description of these background sources will be reported, and effects on detector performance will be described. Methods recently developed to improve the detection efficiency in high background periods will be described, together with some of the results obtained.

astro-ph↗

Accurate measurement of the electron beam polarization in JLab Hall A using Compton polarimetry

A major advance in accurate electron beam polarization measurement has been achieved at Jlab Hall A with a Compton polarimeter based on a Fabry-Perot cavity photon beam amplifier. At an electron energy of 4.6 GeV and a beam current of 40 uA, a total relative uncertainty of 1.5% is typically achieved within 40 min of data taking. Under the same conditions monitoring of the polarization is accurate at a level of 1%. These unprecedented results make Compton polarimetry an essential tool for modern parity-violation experiments, which require very accurate electron beam polarization measurements.

physics.ins-det↗

First electron beam polarization measurements with a Compton polarimeter at Jefferson Laboratory

A Compton polarimeter has been installed in Hall A at Jefferson Laboratory. This letter reports on the first electron beam polarization measurements performed during the HAPPEX experiment at an electron energy of 3.3 GeV and an average current of 40 $μ$A. The heart of this device is a Fabry-Perot cavity which increased the luminosity for Compton scattering in the interaction region so much that a 1.4% statistical accuracy could be obtained within one hour, with a 3.3% total error.

hep-ex↗