Antineutrino Spectroscopy with Large Water Čerenkov Detectors

Abstract

We propose modifying large water C erenkov detectors by the addition of 0.2% gadolinium trichloride, which is highly soluble, newly inexpensive, and transparent in solution. Since Gd has an enormous cross section for radiative neutron capture, with summation operatorE(gamma)=8 MeV, this would make neutrons visible for the first time in such detectors, allowing antineutrino tagging by the coincidence detection reaction nu (e)+p-->e(+)+n (similarly for nu (mu)). Taking Super-Kamiokande as a working example, dramatic consequences for reactor neutrino measurements, first observation of the diffuse supernova neutrino background, galactic supernova detection, and other topics are discussed.

Electroweak tests at beta-beams

“…Table 1 illustrates the expected number of events on electrons, protons and oxygen. We assume that theν −p events can be identified by doping the water Cerenkov detector with Gadolinium [23].…”

Probing supernova shock waves and neutrino flavour transitions in next-generation water Cherenkov detectors

“…The estimated signal rate of ∼ 100-400 events/day at 1 kpc should be compared with the background rate from spallation neutrinos (e.g., 1780 events/day at the Kamioka site), reactor neutrinos (e.g., ∼ 500 events/day at the Kamioka site), and from minor contributions (natural radioactivity). We have taken such backgrounds from [18] and rescaled them to a 0.4 Mton mass. Assuming a typical total background rate of ∼ 2500 ± 50 events per day (statistical errors only), the silicon burning signal should then be seen with a statistical significance of 2-8 standard deviations at a reference distance of 1 kpc.…”

“…In this context, the identification of relatively model-independent spectral features is important to disentangle, as far as possible, information related to supernova physics and neutrino emission from those related to neutrino flavor transitions. Recent spectral studies which refer to prospective Mton-class water-Cherenkov detectors include: analyses in the energy domain to probe neutrino mass-mixing parameters [10], to perform multiparameter fits including neutrino emission parameters [11,12], and to identify Earth matter effects [13]; analyses in the time domain to identify the neutronization burst [14,15] or signatures of shock-wave propagation effects [10,16]; analyses in the angular domain to achieve supernova pointing [17]; background reduction projects using gadolinium [18,19]. 1 In this work, we aim at studying some time dependent and independent observables related to (extra)galactic core collapse supernovae, assuming a prospective 0.4 Mton fiducial mass water-Cherenkov detector.…”

Measurement of the neutrino-oxygen neutral-current interaction cross section by observing nuclear deexcitationγrays

“…a direct measurement of the rate of this process with a known neutrino source will be useful for ongoing and proposed projects [11][12][13][14]. This paper reports the first measurement of the neutrino-oxygen NCQE cross section via the detection of de-excitation γ-rays from both primary and secondary interactions.…”