Novel Multi-pixel Silicon Photon Detectors and Applications in T2K

Nowadays, numerous fields such as High Energy Physics (HEP), medical imaging devices, portable radiation detectors etc., require a robust, miniature, reliable and readily available photon detector that is stable in a variety of environments, such as the presence of strong magnetic fields. The recently available $\sim$1mm$^{\textrm{2}}$ active area Multi-pixel Photon Counter (MPPC) sensors, produced by Hamamatsu Photonics, have been found to be reliable and an attractive choice for the HEP applications. The following sensor characteristics have been thoroughly tested by T2K collaboration: gain, dark noise, detection efficiency, reliability. These appear to be stable; in addition, the characteristic spread between numerous devices was assessed. Sensors with larger area are being developed for imaging and direct-to-scintillator coupling purposes.Comment: To be published in the proceedings of DPF-2009, Detroit, MI, July 2009, eConf C09072

The T2K Neutrino Flux Prediction

The Tokai-to-Kamioka (T2K) experiment studies neutrino oscillations using an o -axis muon neutrino beam with a peak energy of about 0.6 GeV that originates at the J-PARC accelerator facility. Interactions of the neutrinos are observed at near detectors placed at 280 m from the production target and at the far detector { Super-Kamiokande (SK) { located 295 km away. The ux prediction is an essential part of the successful prediction of neutrino interaction rates at the T2K detectors and is an important input to T2K neutrino oscillation and cross section measurements. A FLUKA and GEANT3 based simulation models the physical processes involved in the neutrino 3 production, from the interaction of primary beam protons in the T2K target, to the decay of hadrons and muons that produce neutrinos. The simulation uses proton beam monitor measurements as inputs. The modeling of hadronic interactions is re-weighted using thin target hadron production data, including recent charged pion and kaon measurements from the NA61/SHINE experiment. For the rst T2K analyses the uncertainties on the ux prediction are evaluated to be below 15% near the ux peak. The uncertainty on the ratio of the ux predictions at the far and near detectors is less than 2 % near the ux pea

First Muon-Neutrino Disappearance Study with an Off-Axis Beam

We report a measurement of muon-neutrino disappearance in the T2K experiment. The 295-km muon-neutrino beam from Tokai to Kamioka is the first implementation of the off-axis technique in a long-baseline neutrino oscillation experiment

Evidence of Electron Neutrino Appearance in a Muon Neutrino Beam

The T2K collaboration reports evidence for electron neutrino appearance at the atmospheric mass splitting, j m2 32j 2:4 103 eV2. An excess of electron neutrino interactions over background is observed from a muon neutrino beam with a peak energy of 0:6 GeV at the Super-Kamiokande (SK) detector 295 km from the beam's origin. Signal and background predictions are constrained by data from near detectors located 280 m from the neutrino production target. We observe 11 electron neutrino candidate events at the SK detector when a background of 3:3 0:4(syst.) events 3 is expected. The background-only hypothesis is rejected with a p-value of 0.0009 (3.1 ), and a t assuming ! e oscillations with sin22 23=1, CP=0 and j m2 32j = 2:4 103 eV2 yields sin22 13=0:088+0:049 0:039(stat.+syst.

Measurement of the Inclusive μ Charged Current Cross Section on Carbon in the Near Detector of the T2K Experiment

T2K has performed the first measurement of νμ inclusive charged current interactions on carbon at neutrino energies of ∼1 GeV where the measurement is reported as a flux-averaged double differential cross section in muon momentum and angle. The flux is predicted by the beam Monte Carlo and 3 external data, including the results from the NA61/SHINE experiment. The data used for this measurement were taken in 2010 and 2011, with a total of 10.8 × 1019 protons-on-target. The analysis is performed on 4485 inclusive charged current interaction candidates selected in the most upstream fine-grained scintillator detector of the near detector. The flux-averaged total cross section is hσCCi = (6.91±0.13(stat)±0.84(syst))×10−39 cm2 nucleon for a mean neutrino energy of 0.85 GeV

Evidence of Electron Neutrino Appearance in a Muon Neutrino Beam

The T2K collaboration reports evidence for electron neutrino appearance at the atmospheric mass splitting, j m2 32j 2:4 103 eV2. An excess of electron neutrino interactions over background is observed from a muon neutrino beam with a peak energy of 0:6 GeV at the Super-Kamiokande (SK) detector 295 km from the beam's origin. Signal and background predictions are constrained by data from near detectors located 280 m from the neutrino production target. We observe 11 electron neutrino candidate events at the SK detector when a background of 3:3 0:4(syst.) events 3 is expected. The background-only hypothesis is rejected with a p-value of 0.0009 (3.1 ), and a t assuming ! e oscillations with sin22 23=1, CP=0 and j m2 32j = 2:4 103 eV2 yields sin22 13=0:088+0:049 0:039(stat.+syst.

The T2K ND280 Off-Axis Pi-Zero Detector

The Pi-Zero detector (PØD) is one of the subdetectors that makes up the off-axis near detector for the Tokai-to-Kamioka (T2K) long baseline neutrino experiment. The primary goal for the PØD is to measure the relevant cross sections for neutrino interactions that generate 0’s, especially the cross section for neutral current 0 interactions, which are one of the dominant sources of background to the μ! e appearance signal in T2K. The PØD is composed of layers of plastic scintillator alternating with water bags and brass sheets or lead sheets and is one of the first detectors to use Multi-Pixel Photon Counters (MPPCs) on a large scal

Characterization and modeling of a Water-based Liquid Scintillator

We have characterised Water-based Liquid Scintillator (WbLS) using low energy protons, UV-VIS absorbance, and fluorescence spectroscopy. We have also developed and validated a simulation model that describes the behaviour of WbLS in our detector configurations for proton beam energies of 210MeV, 475 MeV, and 2 GeV and for two WbLS compositions. Our results have enabled us to estimate the light yield and ionisation quenching of WbLS, as well as to understand the influence of the wavelength shifting of Cherenkov light on our measurements. These results are relevant to the suitability of WbLS materials for next generation intensity frontier experiment