Geoneutrinos Research Articles

SOX: search for short baseline neutrino oscillations with Borexino

The Borexino detector has convincingly shown its outstanding performances in the low energy regime through its accomplishments in the observation and study of the solar and geo neutrinos. It is then an ideal tool to perform a state of the art source-based experiment for testing the longstanding hypothesis of a fourth sterile neutrino with ~ eV2 mass, as suggested by several anomalies accumulated over the past three decades in source, reactor, and accelerator-based experiments. The SOX project aims at successively deploying two intense radioactive sources, made of Cerium (antineutrino) and Chromium (neutrino), respectively, in a dedicated pit located beneath the detector. The existence of such an ~ eV2 sterile neutrino would then show up as an unambiguous spatial and energy distortion in the count rate of neutrinos interacting within the active detector volume. This article reports on the latest developments about the first phase of the SOX experiment, namely CeSOX, and gives a realistic projection of CeSOX sensitivity to light sterile neutrinos in a simple (3+1) model.

Geo-neutrinos from 1353 Days with the Borexino Detector

We present a 1353 days measurement of the geo–neutrino flux in Borexino: the signal was found to be 14.3 ± 4.4 events. This result translates into Sgeo = (38.8 ± 12.0) TNU when a Th/U fixed chondritic mass ratio of 3.9 is assumed. Furthermore Borexino data are compatible with a mantle geo–neutrino signal of (15.4 ± 12.3) TNU.

Neutrino Flavor Sensitivity of Large Liquid Scintillator Detectors

Scintillator detectors are known for their good light yield, energy resolution, timing characteristics and pulse shape discrimination capabilities. These features make the next-generation liquid scintillation detector LENA[1] (Low Energy Neutrino Astronomy) the optimal choice for a wide range of astro-particle topics including supernova-, solar-, and geo neutrinos. In addition to the excellent calorimetric and timing properties, scintillartor detectors (LSDs) are also capable of topology reconstruction sufficient to discriminate with adequate efficiency between electron and muon neutrino induced charge current events and neutral current events in the GeV energy range. This feature makes LENA a competitive tool for the determination of the mass hierarchy (MH) with long baseline neutrino beams such as the proposed CN2PY beam (2288km). This work summarizes the status of the current work on track reconstruction schemes and discusses the sensitivity limit for the neutrino mass hierarchy measurement with LENA.

The SNO+ experiment: status and overview

SNO+ is a multipurpose neutrino experiment nearing its final phase of construction. It builds on the successful Sudbury Neutrino Observatory, located in the worldʼs deepest and cleanest working underground laboratory: SNO-LAB. Its target will be linear alkyl benzene. With elaborate scintillator purification, a carefully designed calibration programme and the use of ultra-clean materials, the detector will have low backgrounds and can operate at low detector energy thresholds. The physics programme of SNO+ encompasses low-energy solar neutrinos, with a particular interest in pep and CNO neutrinos, geo neutrinos, reactor neutrinos and neutrinos originating from a nearby supernova. However, the experiment will focus on the search for neutrinoless double-beta decay by loading the scintillator with 150Nd. In this paper, I will describe the detector and the physics goals.

Geo-neutrinos signal with Borexino

Geo-neutrinos are electron antineutrinos produced in β-decays of long-lived radioactive isotopes naturally present in the Earth (238U, 232Th and 40K). By measuring their fluxes it is possible to have a unique direct probe of our planet’s interior, to reveal the terrestrial distribution of uranium and thorium and to assess the radiogenic contribution to the total heat balance of the Earth. The Borexino experiment is one of the few which can perform a geo-neutrino analysis: we present the evidence of geo-neutrinos’ signal with 252.6 ton·y Borexino data.