Session A8: Neutrino Physics I

Characterizing electron optics in the KATRIN experiment

The Karlsruhe Tritium Neutrino (KATRIN) experiment is a tritium beta decay experiment designed to make a direct, model independent measurement of the electron neutrino mass. The experimental apparatus employs strong magnetic and electric fields in regions of ultra high ($10^{-11}$ mbar) vacuum in order to obtain precise measurements of the electron resulting from tritium decay. A potential background in such a configuration is from electric breakdown due to Penning discharge, where a charged particle confined within a Penning trap (a potential well along a magnetic field line) ionizes residual gas molecules. Using simulation tools developed to locate potential Penning traps within a given magnet and electrode configuration, it is possible to characterize and eliminate or minimize this source of background.   

Calibration Techniques for the Project 8 Neutrino Mass Experiment

The goal of the Project~8 experiment is to measure the mass of the electron neutrino by studying the tritium beta-decay spectrum. To improve upon the current neutrino-mass limits we will use a new type of electron energy spectroscopy: detection the coherent cyclotron radiation emitted by the beta-decay electrons in a magnetic field. The electron energy can be determined from the emitted radiation by finding the relativistic shift of the cyclotron frequency. We are constructing an $^{83m}$Kr source, which emits conversion electrons at 32.1 and 9.4~keV. The source will be useful in characterizing proposed experimental designs, and be an absolute energy calibration for the final design.   

ArgoNeuT Overview and Future Goals

The Argon Neutrino Teststand, ArgoNeuT, is a small scale Liquid Argon Time Projection Chamber (LArTPC). ArgoNeuT is located 350 feet underground and it sits upstream of the MINOS detector on the NuMI beam at the Fermi National Accelerator Laboratory in Batavia, Illinois. It is an R{\&}D project paving the way for construction of larger detectors. ArgoNeuT provides bubble chamber quality images and an excellent background rejection. To date, there are very few measurements of neutral current (NC) $\pi^{0}$ production in the 1-2 GeV range,\footnote{A. A. Aguilar-Arevalo et al., Phys. Lett. B \textbf{664}, 41 (2008)} which is an important region for neutrino oscillation experiments. ArgoNeuT takes measurements in 0.1 to 10 GeV range and will help, among other studies, in analysis of coherent versus resonant pion production. ArgoNeuT will give us a sample of neutrino events in a LArTPC for the first time in the U.S. and the first time ever in a low-energy beam.   

Background decomposition in the MINOS Near detector

The search for electron neutrino appearance in the MINOS Far detector relies strongly on our ability to determine the backgrounds, namely Neutral Current (NC), $\nu_\mu$ Charged Current (CC) and intrinsic beam $\nu_e$ CC events. MINOS makes use of its Near detector measurements to predict the Far detector spectrum thus reducing systematic uncertainties. This procedure must be done separately for each background component due to oscillations and beam line geometry considerations. In this talk we describe a method used by MINOS to accomplish this separation. The method compares data from different beam configurations to unravel the background components in the standard data. It further reduces systematic uncertainties by employing only ratios of simulated quantities.   

Particle identification in MINERvA

Neutrino interactions in MINERvA consist of multiple track-like and shower-like prongs which must be identified and measured so that the events may be classified in exclusive reaction channels. I will describe the way in which we use the prong topology and energy loss profile to separate pions, protons, muons, and electrons and measure their energy and momentum. I will the characterize the performance of our techniques using Monte Carlo simulations and data collected during our 2009 prototype run.   

Development of Optical Positioner for the Double Chooz Experiment

The Double Chooz experiment will measure or put a limit for the neutrino mixing angle theta13. Level of precision of less than 0.6\%, not seen in any earlier reactor neutrino experiments is required for successful measurement. In order to achieve such a low level of systematic error, Double Chooz detectors will be thoroughly calibrated. Position of the calibration devices used must be precisely known both for safety reasons as well as for effectiveness of calibration. Optical positioner will be deployed along with the full volume calibration system and will be used for independent position check of the calibration device using charge information from PMTs. In my talk I will present the current status of the development of optical positioner along with the simulations used to optimize the design.   

Cosmogenic $^{9}Li$ Production in Double Chooz

Measuring a non-zero value for the neutrino mixing angle $\theta_{13}$ sets the scale for future precision measurements in the lepton sector such as CP violation. The search for $\theta_{13}$ at nuclear reactors depends crucially on understanding the backgrounds to the inverse beta decay delayed coincidence signal. Due to its long lifetime and $\beta-n$ decay branches, cosmogenic $^{9}Li$ is expected to be one of the most important sources of background. Recent measurements of $^{9}Li$ production yields are extrapolated to Double Chooz depths and compared to fits based on CHOOZ data.   

Mini-LENS--- Operation of a Prototype Low-Energy Solar Neutrino Spectrometer Underground

The Low-Energy Neutrino Spectroscopy (LENS) Collaboration aims to precisely measure the entire low energy spectrum of solar neutrinos, including the pp, pep, $^{7}$Be decay, and CNO reactions in the sun via real time CC based neutrino capture in $^{115}$In. As a prototype for LENS, we are building 410L mini-LENS, which will demonstrate the detector performance and optimize scaling up to the $\sim $200 ton final LENS detector. The mini-LENS detector design, the planned mini-LENS operational phases, and the continued R{\&}D efforts will be discussed.   

Towards benchmarking the performance of LENS

The Low-Energy Neutrino Spectroscopy (LENS) experiment is designed to precisely measure the fluxes of low-energy solar neutrinos via charged-current reactions to achieve a precision test of solar physics and the MSW-LMA flavor-conversion model through the fundamental equality of the neutrino fluxes and the precisely known solar luminosity in photons. The collaboration is currently developing a (0.7 m)$^{3}$ prototype, miniLENS, that will demonstrate the performance and selectivity of the LENS technology. A 13 liter prototype with the same length scale as miniLENS (but smaller volume) is currently operating at LSU and is being used to benchmark optical properties of the as-built instrument that serve as input parameters into Monte Carlo simulations, and to develop the data acquisition (DAQ) system for miniLENS. Results from studies with the 13-liter prototype and the status of the DAQ development will be presented.   

Study of SNO+ liquid scintillator energy response

SNO+ is a large-volume underground liquid scintillator detector that exploits the infrastructure of the completed Sudbury Neutrino Observatory experiment. The goals of SNO+ include: (1) an extension of current low-energy solar neutrino measurements by detecting neutrinos from the pep and CNO chains, (2) a study of reactor and geo-neutrinos, and (3) a search for neutrino-less double-beta decay, by adding Nd-150 to the scintillator. A deep knowledge of the scintillator energy scale is crucial for the success of SNO+. This talk will describe our efforts to understand the scintillator response to ionizing particles.