Bulletin of the American Physical Society
APS April Meeting 2011
Volume 56, Number 4
Saturday–Tuesday, April 30–May 3 2011; Anaheim, California
Session L7: Applications and Instrumentation |
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Sponsoring Units: DNP Chair: Elise Martin, University of Kentucky Room: Grand E |
Sunday, May 1, 2011 3:30PM - 3:42PM |
L7.00001: In-Situ Preparation of Radioactive Tracers in NIF Capsules Mark Stoyer Inertial Confinement Fusion (ICF) experiments at the National Ignition Facility (NIF) will probe fundamental high energy density physics of plasmas. Radiochemical diagnostics will provide information on ablator and fuel rho-R, yield, asymmetry, and mix by collecting both gaseous and solid debris samples following an implosion. Many experiments utilize ratios of produced activities, but full utilization of the technique requires knowledge of sample collection efficiencies. Gaseous samples are expected to be collected with high efficiency, but solid sample collection is typically limited by location of the collecting apparatus. Activation of ICF capsules has been utilized at other laser facilities [1-2] to produce a radioactive tracer in the ablator of the capsule that can be used to measure the solid collection efficiency. This talk will describe preliminary experiments activating CH(Ge) NIF capsules and Au hohlraums in the High Flux Isotope Reactor (HFIR) at ORNL in order to produce Ge, As, and Au isotopes for determination of collection efficiency, spatial distribution of the debris, efficacy of various collectors, and if there are preferred locations for debris collection. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. [1] S.M. Lane and M.B. Nelson, Rev. Sci. Inst. 61 (1990) 3298. [2] E.M. Campbell, H.G. Hicks, W.C. Mead, et al. J. Appl. Phys. 51 (1980) 6065. [Preview Abstract] |
Sunday, May 1, 2011 3:42PM - 3:54PM |
L7.00002: Production of $^{13}$N Using a 400keV Van de Graaff Positive Ion Accelerator Christopher Prokop, John Clymer, Nicholas Compton, Henry Dam, Adam Hanson, Justen Pautzke, Andrew Roberts A target system has been developed to study the production and extraction of $^{13}$N, a short-lived radioisotope of nitrogen (t$_{1/2} \quad \approx $ 9.6 minutes), formed via the $^{12}$C(d,n)$^{13}$N reaction. The target is comprised of a graphite rod positioned in a custom-built target chamber where it is irradiated by a deuteron beam. Post irradiation, the target is flushed with H$_{2}$ or CO$_{2}$ gas, and heated via a large applied current producing $^{13}$NH$_{3}$ or HC$^{13}$N and $^{13}$NO$_{2}$ respectively. Radiolabeled $^{13}$N compounds are used for physiological imaging using Positron Emission Tomography (PET). The production system used the 400keV Van de Graaff Positive Ion Accelerator housed in the Applied Nuclear Science Lab at Minnesota State University, Mankato. While this energy, slightly above threshold, is too low to make sufficient amounts of $^{13}$N for imaging work, the system and procedure can be implemented on higher energy machines. Preliminary system results will be presented as well as accelerator calibration and reaction data. [Preview Abstract] |
Sunday, May 1, 2011 3:54PM - 4:06PM |
L7.00003: Cerenkov Radiation as a New In Vivo Imaging Modality Nicole Ackerman, Rehan Ali, J. Matt Noll, Edward Graves \v{C}erenkov radiation has been used in particle detectors for years, but has recently been ``rediscovered" by biologists working with radioactive isotopes. \v{C}erenkov Light Imaging (CLI) can be done with CCD devices typically used for fluorescence or bioluminescence imaging. This provides the first opportunity for \emph{in vivo} imaging of beta emitting isotopes, such as those used for radiation therapy. The GEANT4 simulation package has been used to simulate the properties and limitations of CLI. The simulation begins with the radioactive decay, generates the \v{C}erenkov photons, propagates the optical light through tissue and other materials, and allows for different detection geometries. The simulation results are compared to \emph{in vivo} and \emph{in vitro} data taken in the Stanford Small Animal Imaging Core Facility. [Preview Abstract] |
Sunday, May 1, 2011 4:06PM - 4:18PM |
L7.00004: Comparison of the Angular Dependence of Monte Carlo Particle Transport Modeling Software Jeff Chancellor, Stephen Guetersloh Modeling nuclear interactions is relevant to cancer radiotherapy, space mission dosimetry and the use of heavy ion research beams. In heavy ion radiotherapy, fragmentation of the primary ions has the unwanted effect of reducing dose localization, contributing to a non-negligible dose outside the volume of tissue being treated. Fragmentation in spaceship walls, hardware and human tissue can lead to large uncertainties in estimates of radiation risk inside the crew habitat. Radiation protection mandates very conservative dose estimations, and reduction of uncertainties is critical to avoid limitations on allowed mission duration and maximize shielding design. Though fragment production as a function of scattering angle has not been well characterized, experimental simulation with Monte Carlo particle transport models have shown good agreement with data obtained from on-axis detectors with large acceptance angles. However, agreement worsens with decreasing acceptance angle, attributable in part to incorrect transverse momentum assumptions in the models. We will show there is an unacceptable angular discrepancy in modeling off-axis fragments produced by inelastic nuclear interaction of the primary ion. The results will be compared to published measurements of 400 MeV/nucleon carbon beams interacting in C, CH2 , Al, Cu, Sn, and Pb targets. [Preview Abstract] |
Sunday, May 1, 2011 4:18PM - 4:30PM |
L7.00005: A Dual-Phase Argon Ionization Detector for the Measurement of Nuclear Quench Factors and Coherent Neutrino Scattering Samuele Sangiorgio, Adam Bernstein, Michael Foxe, Chris Hagmann, Tenzing Joshi, Igor Jovanovic, Kareem Kazkaz Dual-phase detectors based on noble elements are widely used for measuring low-energy nuclear recoils, for example in Dark Matter or Coherent Neutrino Scattering (CNS) searches. We have constructed a dual-phase Argon detector to measure the nuclear ionization quench factor of Argon from 10 keV down in the sub-keV range using a neutron beam and also a newer technique based on nuclear resonance fluorescence. The detector is also a prototype for a larger one to measure CNS at a nuclear reactor. We will present an overview of our program and report on the commissioning of the dual-phase prototype, with details on the proposed techniques for the quench factor measurements. [Preview Abstract] |
Sunday, May 1, 2011 4:30PM - 4:42PM |
L7.00006: Development and First Tests of the SuperORRUBA Silicon Detector Array D.W. Bardayan, K.Y. Chae, S.D. Pain, M.S. Smith, S.H. Ahn, K.L. Jones, J.C. Blackmon, L. Linhardt, M. Matos, J.A. Cizewski Studies of transfer reactions on radioactive beams are critical for elucidating the structure of nuclei away from stability and constraining nuclear reaction rates of astrophysical interest. The requirement of performing such studies in inverse kinematics, however, places difficult requirements on the detection system for reaction products. The detectors must provide large solid angle coverage near 90 degrees in the laboratory along with good position and energy resolution. To meet these requirements, we are developing the SuperORRUBA silicon detector array for experiments at the Holifield Radioactive Ion Beam Facility. The array will make use of approximately 1600 strips of 1.2 mm pitch in order to accurately determine the positions of detected particles. The detector design and the results of first tests will be presented. [Preview Abstract] |
Sunday, May 1, 2011 4:42PM - 4:54PM |
L7.00007: BetaCage: an Ultra-sensitive Screener for Surface Contamination Zeeshan Ahmed, Sunil Golwala, Darren Grant, Mark Kos, Robert Nelson, Richard Schnee, Boqian Wang Commercial radioactivity counting techniques for alpha and beta particles are unable to meet the stringent screening requirements for next-generation low-background rare-event search experiments because of inadequate sensitivity. To meet this need, we are developing a new screener, BetaCage, a gaseous neon time-projection chamber. Using radiopure materials for construction, active and passive shielding from extrinsic backgrounds, large counting area and minimal detector mass, BetaCage will be able to achieve sensitivities of $10^{-5}$counts keV$^{-1}$kg$^{-1}$day$^{-1}$ in a few days of running time. We present the status of a prototype we are currently building and testing, to inform the design and construction of the final version. [Preview Abstract] |
Sunday, May 1, 2011 4:54PM - 5:06PM |
L7.00008: MINER$\nu$A Experiment Magnetic Spectrometer Characterization and Simulation Edgar Valencia, Julian Felix MINER$\nu$A experiment (http://minerva.fnal.gov) is a high statistics scattering neutrino experiment, installed 105 meters down the Fermilab NuMI line. For calibration it was planned, constructed and commissioned a test beam line experiment, consisted of a target, a collimator, a time of flight system, four multiwire chambers, two identical dipole magnets, and a test beam detector. The entire test beam line was simulated. Here we present details and results of the dipole magnets simulations, which are in excellent agreement with measurements. [Preview Abstract] |
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