117977604
Building for Discovery: Strategic Plan for U.S. Particle Physics in the Global Context
Beginning in 2013, the U.S. particle physics community embarked on a community study to explore our opportunities to move forward into the next era of discovery. The results of this yearlong study were distilled into five intertwined scientific drivers: use the Higgs boson as a new tool for discovery; pursue the physics associated with neutrino mass; identify the new physics of dark matter; understand cosmic acceleration: dark energy and inflation; and explore the unknown via new particles, interactions, and physical principles. As a member of the panel charged with providing an updated strategic plan for U.S. particle physics over a ten-year timescale, I will present a summary of the report describing the field's updated and exciting vision for the future in a global context, while dealing with the realities of constrained budgets.
118559630
Inner Structure and Outer Limits: Precision QCD and Electroweak Tests from Neutrino Experiments
121978152
Neutrino Scattering in Liquid Argon TPC Detectors
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.
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.
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.
1601826
Calibration and flight performance of the long-slit imaging dual order spectrograph
We present preliminary results for the calibration and flight performance of the Long-Slit Imaging Dual Order Spectrograph (LIDOS), a rocket-borne instrument with a large dynamic range in the 900 - 1650 Å bandpass. The instrument observes UV-bright objects with a CCD channel and fainter nebulosity with an MCP detector. The image quality and the detector quantum efficiencies were determined using the calibration and test equipment at the Johns Hopkins University, and further monitored using an on-board electron-impact calibration lamp. We review results from each of the three flights of the instrument.
119275441
Spitzer Mapping of PAHs and H2 in Photodissociation Regions
The mid-infrared (MIR) spectra of dense photodissociation regions (PDRs) are typically dominated by emission from polycyclic aromatic hydrocarbons (PAHs) and the lowest pure rotational states of molecular hydrogen (H2); two species which are probes of the physical properties of gas and dust in intense UV radiation fields. We utilize the high angular resolution of the Infrared Spectrograph on the Spitzer Space Telescope to construct spectral maps of the PAH and H2 features for three of the best studied PDRs in the galaxy, NGC 7023, NGC 2023 and IC 63. We present spatially resolved maps of the physical properties, including the H2 ortho-to-para ratio, temperature, and Go/nH . We also present evidence for PAH dehydrogenation, which may support theories of H2 formation on PAH surfaces, and a detection of preferential self-shielding of ortho-H2. All PDRs studied exhibit average temperatures of ∼ 500 – 800 K, warm H2 column densities of ∼ 10 cm, Go/nH ∼ 0.1 – 0.8, and ortho-to-para ratios of ∼ 1.8. We find that while the average of each of these properties is consistent with previous single value measurements of these PDRs, when available, the addition of spatial resolution yields a diversity of values with gas temperatures as high as 1500 K, column densities spanning ∼ 2 orders of magnitude, and extreme ortho-to-para ratios (ROP ) of ROP < 1 and ROP > 3. Subject headings: ISM:clouds — ISM: lines and bands — ISM: photon-dominated region — ISM: individual (NGC 7023, NGC 2023, IC 63) — ISM: molecules — infrared: ISM