Green, J. Andrew
Fermi National Accelerator Lab., Batavia, IL (United States). Funding organisation: USDOE Office of Energy Research (ER) (United States)2000
Fermi National Accelerator Lab., Batavia, IL (United States). Funding organisation: USDOE Office of Energy Research (ER) (United States)2000
AbstractAbstract
[en] The existence of three families of quarks and leptons suggests the possibility of a substructure for these objects. The hypothetical constituents known generically as preons, interact via a new strong interaction called Metacolor. The characteristic energy scale, Λ, for the new interactions is, of course, unknown. The strength of the interactions through a contact term can be written as cflx s/(αSΛ2), where cflx s is the square of the energy in the center of mass frame of the (normal) interacting partons, and αS is the QCD coupling. The first limit on the size of the atomic nucleus was obtained by Geiger and Mardsen in the Rutherford scattering of α particles from nuclei. In an analogous way, the authors can set a limit on the size of quarks and leptons by observing the scattering of the highest energy quarks and antiquarks at the Fermilab Tevatron at bar pp center-of-mass energy of 1.8 TeV for collider experiments, and proton beam energy of 0.8 TeV for fixed-target experiments. The collider detectors at Fermilab, CDF and D0, have performed searches for compositeness, and this paper gives a summary of those searches. Those detectors are general-purpose, have nearly 4π acceptance, and measure lepton and jet energies to high precision. In addition, the neutrino detector, CCFR, which utilized the 800 GeV proton line at Fermilab has performed a compositeness search
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11 May 2000; 347 Kilobytes; Rencontres de Blois: Summer school of the physics; Blois (France); 27 Jun - 3 Jul 1999; AC02-76CH03000; Available from PURL: https://www.osti.gov/servlets/purl/754710-ImNOgn/webviewable/
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[en] Muon tomography is a technique that uses cosmic ray muons to generate three dimensional images of volumes using information contained in the Coulomb scattering of the muons. Advantages of this technique are the ability of cosmic rays to penetrate significant overburden and the absence of any additional dose delivered to subjects under study above the natural cosmic ray flux. Disadvantages include the relatively long exposure times and poor position resolution and complex algorithms needed for reconstruction. Here we demonstrate a new method for obtaining improved position resolution and statistical precision for objects with spherical symmetry.
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(c) 2013 © 2013 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License.; Country of input: International Atomic Energy Agency (IAEA)
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Chung, Kiwhan; Brockwell, Michael I.; Borozdin, Konstantin N.; Green, J. Andrew; Hogan, Gary E.; Makela, Mark F.; Mariam, Fesseha G.; Morris, Christopher L.
Los Alamos National Laboratory (United States). Funding organisation: US Department of Energy (United States)2010
Los Alamos National Laboratory (United States). Funding organisation: US Department of Energy (United States)2010
AbstractAbstract
[en] Prototypes of radiation detector arrays used for charged-particle radiography require iniliol calibration to correlate the distribution of electron arrival time to the particle track locations. This step is crucial to obtaining the spatial resolution necessary to separate particle tracks traversing the individual proportional counters in the arrays. Our past attempts to use cosmic rays alone for the initial calibration have fallen short of obtaining the desired resolution due to the insufficient cosmic ray flux to provide the necessary number of particle tracks. A theoretical relation between electron drift time and radial drift distance is obtained with Garfield, a CERN gas detector simulation program. This relation is then used as an effective starting point for the initial calibration and results in a shorter calibration period and improved spatial resolution of the detectors.
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1 Jan 2010; 3 p; American Physical Society March Meeting 2010; Portland, OR (United States); 15-19 Mar 2010; LA-UR--10-1520; AC52-06NA25396; Available from http://permalink.lanl.gov/object/tr?what=info:lanl-repo/lareport/LA-UR-10-01520; PURL: https://www.osti.gov/servlets/purl/993120-D2gU6C/
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[en] The passage of muons through matter is dominated by the Coulomb interaction with electrons and nuclei in the matter. The muon interaction with the electrons leads to continuous energy loss and stopping of the muons. The muon interaction with nuclei leads to angular diffusion. Using both stopped muons and angle diffusion interactions allows us to determine density and identify materials. Here we demonstrate material identification using data taken at Los Alamos with a particle tracker built from a set of sealed drift tubes with commercial electronics and software, the Mini Muon Tracker (MMT).
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(c) 2012 Copyright 2012 Author(s). This article is distributed under a Creative Commons Attribution 3.0 Unported License.; Country of input: International Atomic Energy Agency (IAEA)
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Bonal, Nedra; Cashion, Avery Ted; Cieslewski, Grzegorz; Dorsey, Daniel J.; Foris, Adam; Miller, Timothy J.; Roberts, Barry L; Su, Jiann-Cherng; Dreesen, Wendi; Green, J. Andrew; Schwellenbach, David
Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States). Funding organisation: USDOE National Nuclear Security Administration (NNSA) (United States)2016
Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States). Funding organisation: USDOE National Nuclear Security Administration (NNSA) (United States)2016
AbstractAbstract
[en] Muons are subatomic particles that can penetrate the earth 's crust several kilometers and may be useful for subsurface characterization . The absorption rate of muons depends on the density of the materials through which they pass. Muons are more sensitive to density variation than other phenomena, including gravity, making them beneficial for subsurface investigation . Measurements of muon flux rate at differing directions provide density variations of the materials between the muon source (cosmic rays and neutrino interactions) and the detector, much like a CAT scan. Currently, muon tomography can resolve features to the sub-meter scale. This work consists of three parts to address the use of muons for subsurface characterization : 1) assess the use of muon scattering for estimating density differences of common rock types, 2 ) using muon flux to detect a void in rock, 3) measure muon direction by designing a new detector. Results from this project lay the groundwork for future directions in this field. Low-density objects can be detected by muons even when enclosed in high-density material like lead, and even small changes in density (e.g. changes due to fracturing of material) can be detected. Rock density has a linear relationship with muon scattering density per rock volume when this ratio is greater than 0.10 . Limitations on using muon scattering to assess density changes among common rock types have been identified. However, other analysis methods may show improved results for these relatively low density materials. Simulations show that muons can be used to image void space (e.g. tunnels) within rock but experimental results have been ambiguous. Improvements are suggested to improve imaging voids such as tunnels through rocks. Finally, a muon detector has been designed and tested to measure muon direction, which will improve signal-to-noise ratio and help address fundamental questions about the source of upgoing muons .
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1 Nov 2016; 65 p; OSTIID--1333270; AC04-94AL85000; Available from http://prod.sandia.gov/sand_doc/2016/1611650.pdf; PURL: http://www.osti.gov/servlets/purl/1333270/
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