L. F. Thompson

Characterization and Simulation of the Response of Multi Pixel Photon Counters to Low Light Levels

The calorimeter, range detector and active target elements of the T2K near detectors rely on the Hamamatsu Photonics Multi-Pixel Photon Counters (MPPCs) to detect scintillation light produced by charged particles. Detailed measurements of the MPPC gain, afterpulsing, crosstalk, dark noise, and photon detection efficiency for low light levels are reported. In order to account for the impact of the MPPC behavior on T2K physics observables, a simulation program has been developed based on these measurements. The simulation is used to predict the energy resolution of the detector.

Reanalysis of bubble chamber measurements of muon-neutrino induced single pion production

There exists a longstanding disagreement between bubble chamber measurements of the single pion production channel

Neutrino telescope modelling of Lorentz invariance violation in oscillations of atmospheric neutrinos

\nu_{\mu}p\rightarrow \mu^{-}p\pi^{+}

The use of neural networks in γ-π0 discrimination

from the Argonne and Brookhaven National Laboratories. We digitize and reanalyse data from both experiments to produce cross-section ratios for various interaction channels, for which the flux uncertainties cancel, and find good agreement between the experiments. By multiplying the cross-section ratio by the well-understood charged current quasi-elastic cross-section on free nucleons, we extract single-pion production cross-sections which do not depend on the flux normalization predictions. The

Simulation of muon radiography for monitoring CO2 stored in a geological reservoir

\nu_{\mu}p\rightarrow \mu^{-}p\pi^{+}

Modelling electroluminescence in liquid argon

cross-sections we extract show good agreement between the ANL and BNL datasets.

Future Plans for the ACORNE Collaboration

One possible feature of quantum gravity may be the violation of Lorentz invariance. In this paper, we consider one particular manifestation of the violation of Lorentz invariance, namely modified dispersion relations for massive neutrinos. We show how such modified dispersion relations may affect atmospheric neutrino oscillations. We then consider how neutrino telescopes, such as ANTARES, may be able to place bounds on the magnitude of this type of Lorentz invariance violation.

Geological repositories: scientific priorities and potential high-technology transfer from the space and physics sectors

Abstract A neural network algorithm has been applied to the problem of discriminating between photons and neutral pions using calorimetric information from the ALEPH detector. Results are presented comparing the neural network with the existing ALEPH algorithms. In all cases the performance of the neural network is comparable or superior to that of the conventional algorithms. In particular, at high energies, where these algorithms perform poorly, the neural network is still able to distinguish between the two particle types.

Recent results from the ANTARES deep-sea neutrino telescope

Current methods of monitoring subsurface CO2, such as repeat seismic surveys, are episodic and require highly skilled personnel to acquire the data. Simulations based on simplified models have previously shown that muon radiography could be automated to continuously monitor CO2 injection and migration, in addition to reducing the overall cost of monitoring. In this paper, we present a simulation of the monitoring of CO2 plume evolution in a geological reservoir using muon radiography. The stratigraphy in the vicinity of a nominal test facility is modelled using geological data, and a numerical fluid flow model is used to describe the time evolution of the CO2 plume. A planar detection region with a surface area of 1000 m2 is considered, at a vertical depth of 776 m below the seabed. We find that 1 year of constant CO2 injection leads to changes in the column density of ≲1%, and that the CO2 plume is already resolvable with an exposure time of less than 50 days.

Muon Tomography for Carbon Storage and Monitoring

We present Monte-Carlo simulations of electron transport through liquid argon motivated by our recent observation of electroluminescence light emanating from a thick gaseous electron multiplier (THGEM) in a liquid argon volume. All known elastic and inelastic reaction cross-sections have been accounted for, providing electroluminescence light yield predictions for arbitrary electrostatic fields. This study concludes that the large field gradients needed to produce electroluminescence cannot be accounted for by straightforward electrostatic field calculations based on ideal THGEM holes, suggesting that further experimental investigations are required.