195859032
Photomultiplier tube testing for the MiniBooNE experiment
The recent discoveries in the neutrino sector in the Standard Model have opened a new frontier in high energy physics. Understanding neutrinos and how they interact is crucial to continuing to verify the Standard Model and look for beyond Standard Model physics. The MiniBooNE experiment is a /spl nu//sub /spl mu///spl rarr//spl nu//sub e/ oscillation search designed to confirm or rule out the neutrino oscillation signal seen by the LSND experiment at the Los Alamos National Laboratory. The MiniBooNE detector, a sphere filled with mineral oil and lined with 8" Hamamatsu photomultiplier tubes (PMTs), uses Cerenkov imaging to identify /spl nu//sub /spl mu// and /spl nu//sub e/ interactions. The PMTs are the main detector component and must be well understood. They underwent a series of tests to determine their functionality and figures of merit in order to be placed in the detector, as described here.
18440205
Photomultiplier tubes in the MiniBooNE experiment
The detector for the MiniBooNE [Proposal for the MiniBooNE experiment: hhttp://www-boone.fnal.gov/publicpages/proposal.psi] experiment at the Fermi National Accelerator Laboratory employs 1520 8 in. Hamamatsu models R1408 and R5912 photomultiplier tubes with custom-designed bases. Tests were performed to determine the dark rate, charge and timing resolutions, double-pulsing rate, and desired operating voltage for each tube, so that the tubes could be sorted for optimal placement in the detector. Seven phototubes were tested to find the angular dependence of their response. After the Super-K phototube implosion accident, an analysis was performed to determine the risk of a similar accident with MiniBooNE. r 2006 Elsevier B.V. All rights reserved.
121182187
From ArgoNeuT to MicroBooNE
The final unknowns in the neutrino oscillation mixing matrix, including the search for CP Violation in the neutrino sector, offer extraordinary physics opportunities, which make a compelling case for developing the best possible detectors. Liquid Argon Time Projection Chambers (LArTPCs) combine fine-grained tracking with total absorption calorimetry to achieve sensitivities well beyond conventional neutrino detectors. The ArgoNeuT and MicroBooNE projects serve as steps in a development path towards massive kiloton scale LArTPCs for long baseline electron neutrino appearance physics. These experiments combine development goals with exploration of low energy neutrino interaction physics. Progress on ArgoNeuT and MicroBooNE en route to massive LArTPCs for the LBNE program are presented here.
55097706
The Yale Liquid Argon Time Projection Chamber
In this paper we give a thorough description of a liquid argon time projection chamber designed, built and operated at Yale. We present results from a calibration run where cosmic rays have been observed in the detector, a first in the US.
110951547
Designs of Large Liquid Argon TPCs — from MicroBooNE to LBNE LAr40
Abstract Liquid argon time projection chamber (LArTPC) is a unique technology well suited for large scale detectors of neutrinos and other rare processes. Its combination of millimeter scale 3D precision particle tracking and calorimetry with good dE/dx resolution provide excellent efficiency of particle identification and background rejection. MicroBooNE is a LArTPC about to enter its final design phase and is scheduled for construction in 2012. Its active volume contains 86 ton of LAr. It has a 2.6m drift distance, 8256 sense wires connected to cold CMOS analog front–end electronics. Most of the TPC design features improve upon existing tried and true techniques. The LAr40 is one of the two far detector options under consideration for the Long Baseline Neutrino Experiment (LBNE). Its conceptual design has 40 kton active liquid argon mass, to be installed underground at a moderate depth. Due to its large scale, and underground siting, great emphasis was placed on the detector cost and reliability. A modular TPC design is the key to achieve these goals. The LAr40 consists of two 20 kton detectors in one underground cavern. Each detector is in turn constructed from an array of TPC modules. Innovative concepts enable the modules to be tiled with minimal dead space. An overview of both detectors is presented. The designs of key elements in these two TPCs are described in detail.
1526145
A regenerable filter for liquid argon purification
A filter system for removing electronegative impurities from liquid argon is described. The active components of the filter are adsorbing molecular sieve and activated-copper-coated alumina granules. The system is capable of purifying liquid argon to an oxygen-equivalent impurity concentration of better than 30 parts per trillion, corresponding to an electron drift lifetime of at least 10 ms. Reduction reactions that occur at �250 ◦ C allow the filter material to be regenerated in-situ through a simple procedure. In the following work we describe the filter design, performance, and regeneration process.
5665227
Project Lyman
We explore the design of a space mission called Project Lyman that has the goal of quantifying the ionization history of th e universe from the present epoch to a redshift of z∼ 3. Observations from WMAP and SDSS show that before a redshif t of z∼> 6 the first collapsed objects, possibly dwarf galaxies, emit t d Lyman continuum (LyC) radiation shortward of 912 Å that reionized most of the universe. Theoretical estimates of the LyC escape fraction ( fesc) required from these objects to complete reionization isfesc∼ 10%. How LyC escapes from galactic environments, whether it induces positive or negative feedback on the local and global collapse of structures, and the role played by clumping, molecules, metallicity and dus t are major unanswered theoretical questions, requiring observ ational constraint. Numerous intervening Lyman limit syst ems frustrate the detection of LyC from high z objects. They thin below z∼ 3 where there are reportedly a few cases of apparently very highfesc. At low z there are only controversial detections and a handful of upp er limits. A wide-field multi-object spectroscopic survey with moderate spectral and spatial resolution can quantify esc within diverse spatially resolved galactic environments over redshifts with signifi cant evolution in galaxy assemblage and quasar activity. It can also calibrate LyC escape against Ly α escape, providing an essential tool to JWST for probing the b eginnings of reionization. We present calculations showing the evolution of the charac te istic apparent magnitude of star-forming galaxy lumino s ty functions at 900Å, as a function of redshift and assumed escape fraction. The se calculations allow us to determine the required aperture for detecting LyC and conduct trade studi es to guide technology choices and balance science return against mission cost. Finally we review our efforts to build a pathfinding dual order multi-object spectro/telescope wi th a (0.5◦)2 field-of-view, using a GSFC microshutter array, and crossed delay-line micro-channel plate detector.