The NOvA long-baseline neutrino experiment uses a pair of large, segmented, liquid-scintillator calorimeters to study neutrino oscillations, using GeV-scale neutrinos from the Fermilab NuMI beam. These detectors are also sensitive to the flux of neutrinos which are emitted during a core-collapse supernova through inverse beta decay interactions on carbon at energies of O(10 MeV). This signature provides a means to study the dominant mode of energy release for a core-collapse supernova occurring in our galaxy. We describe the data-driven software trigger system developed and employed by the NOvA experiment to identify and record neutrino data from nearby galactic supernovae. This technique has been used by NOvA to self-trigger on potential core-collapse supernovae in our galaxy, with an estimated sensitivity reaching out to 10 kpc distance while achieving a detection efficiency of 23% to 49% for supernovae from progenitor stars with masses of 9.6 M-circle dot to 27 M-circle dot, respectively.

We report on a new analysis of neutrino oscillations in MINOS using the complete set of accelerator and atmospheric data. The analysis combines the ν μ disappearance and ν e appearance data using the three-flavor formalism. We measure| Δ m 32 2|=[2.28–2.46]× 1 0− 3 eV 2 (68% CL) and sin 2 θ 23= 0.35–0.65 (90% CL) in the normal hierarchy, and| Δ m 32 2|=[2.32–2.53]× 1 0− 3 eV 2 (68% CL) and sin 2 θ 23= 0.34–0.67 (90% CL) in the inverted hierarchy. The data also constrain δ C P, the θ 23 octant degeneracy and the mass hierarchy; we disfavor 36%(11%) of this three-parameter space at 68%(90%) CL

The complete 5.4 kton MINOS far detector has been taking data since the beginning of August 2003 at a depth of 2070 meters water-equivalent in the Soudan mine, Minnesota. This paper presents the first MINOS observations of nu(mu) and (nu) over bar (mu) charged-current atmospheric neutrino interactions based on an exposure of 418 days. The ratio of upward- to downward-going events in the data is compared to the Monte Carlo expectation in the absence of neutrino oscillations, giving R-up/down(data)/R-up/down(MC)=0.62(-0.14)(+0.19)(stat.)+/- 0.02(sys.). An extended maximum likelihood analysis of the observed L/E distributions excludes the null hypothesis of no neutrino oscillations at the 98% confidence level. Using the curvature of the observed muons in the 1.3 T MINOS magnetic field nu(mu) and (nu) over bar (mu) interactions are separated. The ratio of (nu) over bar (mu) to nu(mu) events in the data is compared to the Monte Carlo expectation assuming neutrinos and antineutrinos oscillate in the same manner, giving R-(nu) over bar mu/nu(data)(mu)/R-(nu) over bar mu/nu(MC)(mu)=0.96(-0.27)(+0.38)(stat.)+/- 0.15(sys.), where the errors are the statistical and systematic uncertainties. Although the statistics are limited, this is the first direct observation of atmospheric neutrino interactions separately for nu(mu) and (nu) over bar (mu).

Upward-going stopping muons initiated by atmospheric nu(mu) and (nu) over bar (mu) interactions in the rock below the Soudan 2 detector have been isolated, together with a companion sample of neutrino-induced single muons, created within the detector, which travel downwards and exit. The downward-going sample is consistent with the atmospheric-neutrino flux prediction, but the upward-going sample exhibits a sizable depletion. Both are consistent with previously reported Soudan 2 neutrino-oscillation results. Inclusion of the two samples in an all-event likelihood analysis, using recent 3D-atmospheric-neutrino-flux calculations, reduces both the allowed oscillation parameter region and the probability of the no-oscillation hypothesis.

The MINERνA experiment at Fermilab will use a fully-active scintillator based fine grained neutrino detector and the high rate NuMI neutrino beam. MINERνA will measure low energy neutrino interaction properties and cross sections to a new level of precision. These measurements will be critical input to present and future accelerator-based neutrino oscillation experiments in this energy range.

We measure the horizontal (|cos(θz)|<0.14 corresponding to a slant depth cut 14 kmwe) neutrino-induced muon flux (Eμ>1.8 GeV) in Soudan 2 to be 4.01 ± 0.50 ± 0.30 × 10−13 cm−2 sr−1 s−1. From the absence of horizontal muons with large energy loss, we set a limit on the flux of muon neutrinos from active galactic nuclei.

We have searched for neutron-antineutron oscillations using the 5.56 fiducial kiloton-year exposure of the Soudan 2 iron tracking calorimeter. We require candidate n-nbar occurrences to have .GE. 4 prongs (tracks and showers) and to have kinematics compatible with nbar-N annihilation within a nucleus. We observe five candidate events, with an estimated background from atmospheric neutrino and cosmic ray induced events of 4.5 \pm 1.2 events. Previous experiments with smaller exposures observed no candidates, with estimated background rates similar to this experiment. We set a lifetime lower limit for oscillation time in iron: T_A(Fe) > 7.2x10^{31} years. The corresponding lower limit for oscillation of free neutrons is \tau_{n-nbar} > 1.3x10^8 seconds.

The MINOS detectors will use extruded plastic scintillator strips, which are readout by wavelength-shifting fibres coupled to multi-pixel photodetectors. This technique provides excellent energy and spatial resolution. The MINOS detectors are described in detail along with results from the light output tests.

Neutrino interactions recorded in a 5.1 fiducial kiloton-year exposure of the Soudan-2 iron tracking calorimeter are analyzed for effects of neutrino oscillations. Using contained single track and single shower events, we update our measurement of the atmospheric nu (mu)/nu (e) ratio-of-ratios and find R = 0.68 +/- 0.11 +/- 0.06. Assuming this anomalously low R-value is the result of nu (mu) flavor disappearance via nu (mu) to nu (tau) oscillation, we select samples of charged current events which offer good resolution, event-by-event, for LIE, reconstruction. Oscillation-weighted Monte Carlo events are fitted to these data events using a chi (2) function summed over bins of log(L/E-nu). The region allowed in the (sin(2) 2 theta, Deltam(2)) plane at 90% CL is obtained using the Feldman-Cousins procedure: 0.46 < sin(2) 2 less than or equal to 1.0 and 2.2 x 10(-4) < m(2) ( 2.2 x 10(-2)eV(2). A small but relatively energetic sample of partially contained nu (mu) events has also been isolated. Their distribution in log(L/E-vis) relative to null oscillation Monte Carlo is compatible with nu (mu) to nu (tau) oscillation scenarios within the parameters region allowed by our contained events.

A shadow of the moon, with a statistical significance of 5 sigma, has been observed in the underground muon flux at a depth of 2090 mwe using the Soudan 2 detector. The angular resolution of the detector is well described by a Gaussian with a sigma of less than 0.3 degrees. The position of the shadow confirms that the alignment of the detector is known to better than 0.15 degrees and has remained stable during ten years of data taking.

A search for nucleon decay into two-body final states containing K-o mesons has been conducted using the 963 metric ton Soudan 2 iron tracking calorimeter. The topologies, ionizations, and kinematics of contained events recorded in a 5.52 kiloton-year total exposure (4.41 kton-year fiducial volume exposure) are examined for compatibility with nucleon decays in an iron medium. For proton decay into the fully visible final states mu(+)K(S)(o) and e(+) K-S(o), zero and one event candidates are observed respectively. The lifetime lower limits (tau/B) thus implied are 1.5 x 10(32) yr and 1.2 x 10(32) yr, respectively. Lifetime lower limits are also reported for proton decay into l(+)K(l)(o), and for neutron decay into nu K-S(o).

We report a measurement of the atmospheric neutrino flavor ratio, R, using a sample of quasi-elastic neutrino interactions occurring in an iron medium. The flavor ratio (tracks/showers) of atmospheric neutrinos in a 3.9 fiducial kiloton-year exposure of Soudan 2 is 0.64±0.11(stat.)±0.06(syst.) of that expected. Important aspects of our main analysis have been checked by carrying out two independent, alternative analyses; one is based upon automated scanning, the other uses a multivariate approach for background subtraction. Similar results are found by all three approaches.

We have studied the energy resolution of a prototype gas tracking calorimeter in a test beam at Fermilab as part of the detector development program for the MINOS long baseline neutrino oscillation experiment. The calorimeter consisted of 25 layers of 1.5 inch thick steel plates interleaved with planes of aluminum proportional tubes. The tube cells are square, with 0.9 cm edges and open tops. Cathode strips were used for read out transverse to the wire cells. The tubes operated with a nonflammable gas mixture of 88% CO{sub 2}, 9.5% isobutane and 2.5% argon which gave an operating range of >500 V (limited by the electronics). We read out the wire signals on the tubes and in some configurations the cathode stripe as well. We studied positrons, pions and muons over a momentum range of 2.5-30 GeV/c and achieved energy resolutions of about 40%/{radical}E for EM and 71%/{radical}E for hadronic showers.

We have searched for the proton decay mode p --> nu K+ using the one-kiloton Soudan 2 high resolution calorimeter. Contained events obtained from a 3.56 kiloton-year fiducial exposure through June 1997 are examined for occurrence of a visible K+ track which decays at rest into mu(+)nu or pi(+)pi(0). We found one candidate event consistent with background, yielding a limit, tau/B(p --> nu K+)> 4.3 x 10(31) years at 90% CL with no background subtraction. (C) 1998 Published by Elsevier Science B.V. All rights reserved.

The atmospheric neutrino flavour ratio measured using a 1.52 kton-year exposure of Soudan 2 is found to be 0.72 ± 0.19−0.07+0.05 relative to the expected value from a Monte Carlo calculation. The possible background of interactions of neutrons and photons produced in muon interactions in the rock surrounding the detector has been investigated and is shown not to produce low values of the ratio.

Deep underground muon events recorded by the Soudan 2 detector, located at a depth of 2100 m of water equivalent, have been used to infer the nuclear composition of cosmic rays in the ``knee`` region of the cosmic ray energy spectrum. The observed muon multiplicity distribution favors a composition model with a substantial proton content in the energy region 8{times}10{sup 5}{endash}1.3{times}10{sup 7} GeV/nucleus. {copyright} {ital 1997} {ital The American Physical Society}

SOUDAN 2 is a 960-ton tracking calorimeter which has been constructed to search for nucleon decay and other phenomena. The full detector consists of 224 calorimeter modules each weighing 4.3 tons. The design and construction of the modules are described. The modules consist of finely segmented iron instrumented with 1 m long drift tubes of 15 mm internal diameter. The tubes enable three spatial coordinates and dE/dx to be recorded for charged particles traversing the tubes.