The reactor antineutrino anomaly might be explained by the oscillation of reactor antineutrinos toward a sterile neutrino of eV mass. In order to explore this hypothesis, the STEREO experiment ...measures the antineutrino energy spectrum in six different detector cells covering baselines between 9 and 11 m from the compact core of the ILL research reactor. In this Letter, results from 66 days of reactor turned on and 138 days of reactor turned off are reported. A novel method to extract the antineutrino rates has been developed based on the distribution of the pulse shape discrimination parameter. The test of a new oscillation toward a sterile neutrino is performed by comparing ratios of cells, independent of absolute normalization and of the prediction of the reactor spectrum. The results are found to be compatible with the null oscillation hypothesis and the best fit of the reactor antineutrino anomaly is excluded at 97.5% C.L.
A new concept for the simultaneous detection of primary and secondary scintillation in time projection chambers is proposed. Its core element is a type of very-thick GEM structure supplied with ...transparent electrodes and machined from a polyethylene naphthalate plate, a natural wavelength shifter. Such a device has good prospects for scalability and, by virtue of its genuine optical properties, it can improve on the light collection efficiency, energy threshold and resolution of conventional micropattern gas detectors. This, together with the intrinsic radiopurity of its constituting elements, offers advantages for noble gas and liquid based time projection chambers, used for dark matter searches and neutrino experiments. Production, optical and electrical characterization, and first measurements performed with the new device are reported.
Abstract
One of the main challenges in Environmental sciences is the identification and chemical evolution of polluting traces (e.g, cadmium or antimony) in soil, which requires long acquistion times ...for accurate measurements at synchrotron facilities. In this context, the potential of a new generation multi-element germanium detectors to identify traces at 0.1-1 ppm in a reasonable time has been studied using Allpix Squared framework 1. This code has been customized to include the three dimensional electric and weighting field maps generated by COMSOL Multiphysics software, and several features to model the sample environment at SOLEIL synchrotron and the signal response of a germanium detector equipped with a Digital Pulse Processor (DPP). The full simulation chain has been validated by experimental data from SAMBA beamline of SOLEIL synchrotron. This work presents a first estimation of the detection limit to cadmium traces in a soil sample for a future multi-element germanium detector, using this simulation chain.
The CCube reconstruction algorithm for the SoLid experiment Abreu, Y.; Amhis, Y.; Arnold, L. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
September 2024, Letnik:
1066
Journal Article
Recenzirano
Odprti dostop
The SoLid experiment is a very-short-baseline experiment aimed at searching for nuclear-reactor-produced active-to-sterile antineutrino oscillations. The detection principle is based on the pairing ...of two types of solid scintillators: polyvinyl toluene and 6LiF:ZnS(Ag), which is a new technology used in this field of Physics. In addition to good neutron-gamma discrimination, this setup allows the detector to be highly segmented (the basic detection unit is a 5 cm side cube). High segmentation provides numerous advantages, including the precise location of inverse beta decay (IBD) products, the derivation of the antineutrino energy estimator based on the isolated positron energy, and a powerful background reduction tool based on the topological signature of the signal. Finally, the system is read out by a network of wavelength-shifting (WLS) fibres coupled to a photodetectors. This paper describes the design of the reconstruction algorithm that allows maximum use of the granularity of the detector. The goal of the algorithm is to convert the output of the optical-fibre readout to the list of the detection units from which it originated. This paper provides a performance comparison for three methods and concludes with a choice of the baseline approach for the experiment.
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