The neutron-induced fission cross section of 237 Np was experimentally determined at the high-resolution and high-intensity facility n TOF , at CERN, in the energy range 100 keV to 9 MeV, using the 235 U( n,f ) and 238 U( n,f ) cross section standards below and above 2 MeV, respectively. A fast ionization chamber was used in order to detect the fission fragments from the reactions and the targets were characterized as far as their mass and homogeneity are concerned by means of α spectroscopy and Rutherford backscattering spectroscopy respectively. Theoretical calculations within the Hauser-Feshbach formalism have been performed, employing the EMPIRE code, and the model parameters were tuned in order to successfully reproduce the experimental fission cross-sectional data and simultaneously all the competing reaction channels.

The ICARUS T600 detector, with its 470 tons of active mass, is the largest liquid Argon TPC ever built. Operated for three years in the LNGS underground laboratory, it has collected thousands of CNGS neutrino beam interactions and cosmic ray events with energy spanning from tens of MeV to tens of GeV, with a trigger system based on scintillation light, charge signal on TPC wires and time information (for beam related events only). The performance of trigger system in terms of efficiency, background and live-time as a function of the event energy for the CNGS data taking is presented.

The neutron-induced fission cross section of 234U has been measured at the CERN n_TOF facility relative to the standard fission cross section of 235U from 20 keV to 1.4 MeV and of 238U from 1.4 to 200 MeV. A fast ionization chamber (FIC) was used as a fission fragment detector with a detection efficiency of no less than 97%. The high instantaneous flux and the low background characterizing the n_TOF facility resulted in wide-energy-range data (0.02 to 200 MeV), with high energy resolution, high statistics, and systematic uncertainties bellow 3%. Previous investigations around the energy of the fission threshold revealed structures attributed to s-vibrational levels, which have been confirmed by the present measurements. Theoretical calculations have been performed, employing the TALYS code with model parameters tuned to fairly reproduce the experimental data

The ICARUS T600 detector, the largest liquid Argon Time Projection Chamber (LAr-TPC) realized after many years of R&D activities, was installed and successfully operated for 3 years at the INFN Gran Sasso underground Laboratory. One of the most important issues was the need of an extremely low residual electronegative impurity content in the liquid Argon, in order to transport the free electrons created by ionizing particles with very small attenuation along the drift path. The solutions adopted for the Argon recirculation and purification systems have permitted to reach impressive results in terms of Argon purity and a free electron lifetime exceeding 15 ms, corresponding to about 20 parts per trillion of O-2-equivalent contamination, a milestone for any future project involving LAr-TPCs and the development of higher detector mass scales.

The Italian Istituto Nazionale di Fisica Nucleare (INFN) and the ICARUS program have originally developed the technology of the LAr-TPC. Exposed in the underground Hall B of the Gran Sasso National Laboratory in Assergi, at 730 km to the neutrino beam from CERN, this large-scale neutrino experiment has been performed with remarkable detection efficiency and it has now successfully completed a three years physics continuous program. It has been a complete success, featuring a smooth operation, high live time, and high reliability. A total of about 3000 CNGS neutrino events have been collected and are being actively analyzed. In the next two years ICARUS will be considerably improved at CERN with an extensive R&D program. The external dewars of the present T600 detector (760 tons of ultra high purity LAr) will be extensively overhauled and complemented with a similar 1⁄4 scale T150 detector. The R&D improvements are performed in a close collaboration with the LBNE experiment to which the six above INFN Institutions are now participating members. As a main new novelty, a SC magnetic field of about 1 Tesla will be introduced inside the LAr volumes, in analogy to the performance of the traditional bubble chambers. During 2016 it is proposed to move the whole experiment to FNAL where short base line neutrino beams are available, nicely complementing the already approved MicroBooNe LAr-TPC experiment which will start operation in 2014. The presence of ICARUS at FNAL is an important addition to MicroBooNE since, in the absence of “anomalies”, the signals of several detectors at different distances from the beam should be a precise copy of each other for all experimental signatures. Because of its reduced mass, the anti-neutrino signal in MicroBooNE is too weak for a sensitive comparison. A definitive clarification of the LSND anomaly therefore requires also the exploration of the anti-neutrino signal provided by a much larger T600 mass. The presence of a magnetic field is required in order to separate the anti-neutrino signal in the simultaneous presence of the neutrino, induced background with the help of a dual magnetized baseline arrangement and the T150 at a much shorter distance. We propose to locate the T600 detector along the Booster Neutrino Beam line (BNB) at an approximate distance of about 700 m; the T150 detector will be located at about 150 ± 50 m from the target. The T600 will also receive in addition a large number (>10 /year) of νe events from the off-axis kaon-neutrino NUMI beam peaked around about 1 GeV in order to adequately prepare for the LBNE long baseline experiment. The ICARUS improved program will be operated as an additional element of the wide short baseline neutrino FNAL physics program. Intended primarily in the framework of the preparatory work for the LBNE collaboration, the ICARUS team is also interested in extending the participation to other short baseline neutrino activities collaborating with the already existing FNAL groups.

The preponderance of matter over antimatter in the early Universe, the dynamics of the supernova bursts that produced the heavy elements necessary for life and whether protons eventually decay --- these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our Universe, its current state and its eventual fate. The Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed plan for a world-class experiment dedicated to addressing these questions. LBNE is conceived around three central components: (1) a new, high-intensity neutrino source generated from a megawatt-class proton accelerator at Fermi National Accelerator Laboratory, (2) a near neutrino detector just downstream of the source, and (3) a massive liquid argon time-projection chamber deployed as a far detector deep underground at the Sanford Underground Research Facility. This facility, located at the site of the former Homestake Mine in Lead, South Dakota, is approximately 1,300 km from the neutrino source at Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino charge-parity symmetry violation and mass ordering effects. This ambitious yet cost-effective design incorporates scalability and flexibility and can accommodate a variety of upgrades and contributions. With its exceptional combination of experimental configuration, technical capabilities, and potential for transformative discoveries, LBNE promises to be a vital facility for the field of particle physics worldwide, providing physicists from around the globe with opportunities to collaborate in a twenty to thirty year program of exciting science. In this document we provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess.

The INFN and the ICARUS collaboration originally developed the technology of the LAr-TPC. Located the underground LNGS Hall-B, the ICARUS T600 detector has been performed over three years with remarkable detection efficiency featuring a smooth operation, high live time, and high reliability. About 3000 CNGS neutrino events have been collected and are being actively analyzed. ICARUS will now be moved to CERN for an extensive R&D program. The T600 detector will be overhauled and complemented with a similar T150 detector. These improvements are performed in collaboration with the LBNE experiment, of which several INFN Institutions are now members. As a novelty, a SC magnetic field of about 1 T will be introduced. During 2016 it is proposed to move the experiment to FNAL where short base line neutrino beams are available, complementing the approved MicroBooNe experiment which will start operation in 2014. The ICARUS detectors at FNAL will be an important addition since, in absence of anomalies, the signals of several detectors at different distances from the target should be a copy of each other for all experimental signatures. Due to the reduced mass, in MicroBooNE the anti-neutrino signal is too weak for a sensitive comparison. Hence, a definitive clarification of the LSND anomaly requires the exploration of the anti-neutrino signal provided by the much larger T600. The magnetic field will allow separating the anti-neutrino signal from the neutrino-induced background. It is proposed to expose the T600 at the Booster NuBeam at ~700 m from target; the T150 will be located at ~150 m. The T600 will also receive >10^4 nu_e events/year from the off-axis NUMI beam peaked around 1 GeV and exploitable to prepare for the LBNE experiment. The ICARUS teams are also interested in extending the participation to other short baseline neutrino activities collaborating with existing FNAL groups.

We report an updated result from the ICARUS experiment on the search for ν μ →ν e anomalies with the CNGS beam, produced at CERN with an average energy of 20 GeV and traveling 730 km to the Gran Sasso Laboratory. The present analysis is based on a total sample of 1995 events of CNGS neutrino interactions, which corresponds to an almost doubled sample with respect to the previously published result. Four clear ν e events have been visually identified over the full sample, compared with an expectation of 6.4±0.9 events from conventional sources. The result is compatible with the absence of additional anomalous contributions. At 90 % and 99 % confidence levels, the limits to possible oscillated events are 3.7 and 8.3 respectively. The corresponding limit to oscillation probability becomes consequently 3.4×10−3 and 7.6×10−3, respectively. The present result confirms, with an improved sensitivity, the early result already published by the ICARUS Collaboration.

We report an early result from the ICARUS experiment on the search for a ν μ →ν e signal due to the LSND anomaly. The search was performed with the ICARUS T600 detector located at the Gran Sasso Laboratory, receiving CNGS neutrinos from CERN at an average energy of about 20 GeV, after a flight path of ∼730 km. The LSND anomaly would manifest as an excess of ν e events, characterized by a fast energy oscillation averaging approximately to \(\sin^{2}(1.27\Delta m^{2}_{\mathrm{new}}L/E_{\nu})\approx 1/2\) with probability \(P_{\nu_{\mu}\rightarrow \nu_{e}} = 1/2 \sin^{2}(2\theta_{\mathrm{new}})\). The present analysis is based on 1091 neutrino events, which are about 50 % of the ICARUS data collected in 2010–2011. Two clear ν e events have been found, compared with the expectation of 3.7±0.6 events from conventional sources. Within the range of our observations, this result is compatible with the absence of a LSND anomaly. At 90 % and 99 % confidence levels the limits of 3.4 and 7.3 events corresponding to oscillation probabilities \(\langle P_{\nu_{\mu}\rightarrow \nu_{e}}\rangle \le 5.4 \times 10^{-3}\) and \(\langle P_{\nu_{\mu}\rightarrow \nu_{e}}\rangle \le 1.1 \times 10^{-2} \) are set respectively. The result strongly limits the window of open options for the LSND anomaly to a narrow region around (Δm 2,sin2(2θ))new=(0.5 eV2,0.005), where there is an overall agreement (90 % CL) between the present ICARUS limit, the published limits of KARMEN and the published positive signals of LSND and MiniBooNE Collaborations.

Liquid Argon Time Projection Chamber (LAr TPC) detectors offer charged particle imaging capability with remarkable spatial resolution. Precise event reconstruction procedures are critical in order to fully exploit the potential of this technology. In this paper we present a new, general approach to 3D reconstruction for the LAr TPC with a practical application to the track reconstruction. The efficiency of the method is evaluated on a sample of simulated tracks. We present also the application of the method to the analysis of stopping particle tracks collected during the ICARUS T600 detector operation with the CNGS neutrino beam.

The Am-243 neutron capture cross section has been measured at the n_TOF facility(1) in the 0.7 eV-2 keV energy range. The n_TOF Total Absorption Calorimeter(2) (TAC) composed by 40 BaF2 crystals has been used in the measurement for detecting the electromagnetic cascades produced in the 243Am(n,gamma) reactions. All current evaluations in the resolved resonance region are based essentially in fission measurements and in only one transmission measurement.(3) The analysis of the measurement has been finished recently, and it is ready for its distribution to the EXFOR nuclear database. In addition, the data obtained with the TAC provide valuable information on the level density in the compound nucleus Am-244 and on its electromagnetic de-excitation scheme. In particular, the 243Am data, will be combined with data from previous measurements of Am-241, (240)pu, Np-237 and U-233,U-234,U-236 and with future measurements of U-235,U-238 for a systematic investigation of the photon strength functions in actinides.

Neutron-induced fission cross section measurements of 233U, 243Am and 241Am relative to 235U have been carried out at the neutron time-of-flight facility n_TOF at CERN. A fast ionization chamber has been employed. All samples were located in the same detector; therefore the studied elements and the reference 235U target are subject to the same neutron beam.

We have measured the neutron capture cross sections of the stable magnesium isotopes Mg-24,Mg-25,Mg-26 in the energy range of interest to the s process using the neutron time-of-flight facility n_TOF at CERN. Capture events from a natural metal sample and from samples enriched in Mg-25 and Mg-26 were recorded using the total energy method based on (C6H6)-H-2 detectors. Neutron resonance parameters were extracted by a simultaneous resonance shape analysis of the present capture data and existing transmission data on a natural isotopic sample. Maxwellian-averaged capture cross sections for the three isotopes were calculated up to thermal energies of 100 keV and their impact on s-process analyses was investigated. At 30 keV the new values of the stellar cross section for Mg-24, Mg-25, and Mg-26 are 3.8 +/- 0.2 mb, 4.1 +/- 0.6 mb, and 0.14 +/- 0.01 mb, respectively.

A new experiment with an intense 2 GeV neutrino beam at CERN SPS is proposed in order to definitely clarify the possible existence of additional neutrino states, as pointed out by neutrino calibration source experiments, reactor and accelerator experiments and measure the corresponding oscillation parameters. The experiment is based on two identical LAr-TPCs complemented by magnetized spectrometers detecting electron and muon neutrino events at Far and Near positions, 1600 m and 300 m from the proton target, respectively. The ICARUS T600 detector, the largest LAr-TPC ever built with a size of about 600 ton of imaging mass, now running in the LNGS underground laboratory, will be moved at the CERN Far position. An additional 1/4 of the T600 detector (T150) will be constructed and located in the Near position. Two large area spectrometers will be placed downstream of the two LAr-TPC detectors to perform charge identification and muon momentum measurements from sub-GeV to several GeV energy range, greatly complementing the physics capabilities. This experiment will offer remarkable discovery potentialities, collecting a very large number of unbiased events both in the neutrino and antineutrino channels, largely adequate to definitely settle the origin of the observed neutrino-related anomalies.

The OPERA Collaboration (2011) [1] has reported evidence of superluminal vi, propagation between CERN and the LNGS. Cohen and Glashow (2011) [2] argued that such neutrinos should lose energy by producing photons and e(+)e(-) pairs, through Z(0) mediated processes analogous to Cherenkov radiation. In terms of the parameter delta equivalent to (v(v)(2) - v(c)(2))/v(c)(2), the OPERA result corresponds to delta approximate to 5 . 10(-5). For this value (note that (v(v) - v(c))/v(c) approximate to delta/2 approximate to 2.5 . 10(-5)) of delta, a very significant deformation of the neutrino energy spectrum and an abundant production of photons and e(+)e(-) pairs should be observed at LNGS. We present an analysis based on the 2010 and part of the 2011 data sets from the ICARUS experiment, located at Gran Sasso National Laboratory and using the same neutrino beam from CERN. We find that the rates and deposited energy distributions of neutrino events in ICARUS agree with the expectations for an unperturbed spectrum of the CERN neutrino beam, as also reported by OPERA. Our results therefore refute a superluminal interpretation of the OPERA result according to the Cohen and Glashow (2011) prediction [2] for a weak current analog to Cherenkov radiation. In a dedicated search, no superluminal Cherenkov-like e(+)e(-) pair or gamma emission event has been directly observed inside the fiducial volume of the "bubble chamber-like" ICARUS TPC-LAr detector, setting the much stricter limit of delta < 2.5 . 10(-8) at the 90% confidence level, comparable with the one due to the observations from the SN1987a (M.J. Longo, 1987 [4]). The observations of high energy neutrino events by Super-Kamiokande and Ice Cube are also pointing to a much stricter limit on delta. (c) 2012 Elsevier B.V. All rights reserved.

Neutron-induced fission cross section measurements of U-233, Am-243 and Am-241 relative to U-235 have been carried out at the neutron time-of-flight facility n_TOF at CERN. A fast ionization chamber has been employed. All samples were located in the same detector; therefore the studied elements and the reference U-235 target are subject to the same neutron beam.

The yield of the neutron capture reaction ${}^{232}$Th($n,\ensuremath{\gamma}$) has been measured at the neutron time-of-flight facility n_TOF at CERN in the energy range from 1 eV to 1 MeV. The reduction of the acquired data to the capture yield for resolved resonances from 1 eV to 4 keV is described and compared to a recent evaluated data set. The resonance parameters were used to assign an orbital momentum to each resonance. A missing level estimator was used to extract the $s$-wave level spacing of ${D}_{0}=17.2\ifmmode\pm\else\textpm\fi{}0.9$ eV.

This proposal describes an experimental search for sterile neutrinos beyond the Standard Model with a new CERN-SPS neutrino beam. The experiment is based on two identical LAr-TPC's followed by magnetized spectrometers, observing the electron and muon neutrino events at 1600 and 300 m from the proton target. This project will exploit the ICARUS T600, moved from LNGS to the CERN "Far" position. An additional 1/4 of the T600 detector will be constructed and located in the "Near" position. Two spectrometers will be placed downstream of the two LAr-TPC detectors to greatly complement the physics capabilities. Spectrometers will exploit a classical dipole magnetic field with iron slabs, and a new concept air-magnet, to perform charge identification and muon momentum measurements in a wide energy range over a large transverse area. In the two positions, the radial and energy spectra of the nu_e beam are practically identical. Comparing the two detectors, in absence of oscillations, all cross sections and experimental biases cancel out, and the two experimentally observed event distributions must be identical. Any difference of the event distributions at the locations of the two detectors might be attributed to the possible existence of {\nu}-oscillations, presumably due to additional neutrinos with a mixing angle sin^2(2theta_new) and a larger mass difference Delta_m^2_new. The superior quality of the LAr imaging TPC, in particular its unique electron-pi_zero discrimination allows full rejection of backgrounds and offers a lossless nu_e detection capability. The determination of the muon charge with the spectrometers allows the full separation of nu_mu from anti-nu_mu and therefore controlling systematics from muon mis-identification largely at high momenta.

During May 2012, the CERN-CNGS neutrino beam has been operated for two weeks for a total of ~1.8 × 1017 p.o.t., with the proton beam made of bunches, few ns wide and separated by 100 ns. This beam structure allows a very accurate time of flight measurement of neutrinos from CERN to LNGS on an event-by-event basis. Both the ICARUS-T600 PMT-DAQ and the CERN-LNGS timing synchronization have been substantially improved for this campaign, taking advantage of additional independent GPS receivers, both at CERN and LNGS as well as of the deployment of the “White Rabbit” protocol both at CERN and LNGS. The ICARUS-T600 detector has collected 25 beam-associated events; the corresponding time of flight has been accurately evaluated, using all different time synchronization paths. The measured neutrino time of flight is compatible with the arrival of all events with speed equivalent to the one of light: the difference between the expected value based on the speed of light and the measured value is δt = tof c −tof ν  = 0.10 ± 0.67stat. ± 2.39syst. ns. This result is in agreement with the value previously reported by the ICARUS Collaboration, δt = 0.3 ± 4.9stat. ± 9.0syst. ns, but with improved statistical and systematic accuracy.