Physics Commons^™

Physics Department News, December 2003, College Of Arts And Sciences

Physics Newsletter

Contents from Volume 2, Issue 2:

• A Note from the Editor
• From the Chair
• What’s New at the University
• Faculty Highlights
• Staff Highlights
• Accelerator Upgrade 5
• PhysTEC
• Distinguished Alumni Award
• Alumni News
• Recent Guest
• Goldwater Scholar
• New Grants
• Student Awards
• Recent Graduates
• Department Roster
• Photo Gallery
• Feedback/Update Reply Form

“Don’T Tell Me, I’Ll Find Out”: Robert Karplus—A Science Education Pioneer, Robert Fuller

Robert G. Fuller Publications

Robert Karplus (1927–90), who began his career as a brilliant theoretical physicist, switched to science education in the early 1960s. He made many substantial contributions to this field in addition to developing a complete K–6 hands-on science curriculum. Karplus provided his curriculum with a sound epistemological foundation, based on the work of Piaget. He developed an effective classroom teaching strategy, the learning cycle. He and his team used a scientific approach to curriculum development. They focused on teacher development. Karplus was committed to science for ALL students. Through science activities he sought to share the joy of discovery. A recent …

Monte Carlo Simulations And Analysis Of Single-Molecule Detection And Imaging, Peter Williams

Masters Theses

Computer modeling and analysis methods are developed for two modes of operation of an instrument for sensitive fluorescence detection of individual dye-labeled molecules in solution. First, Monte Carlo simulations of experiments for single-molecule imaging (SMI) are extended to include effects of sample flow, sticking of molecules to surfaces, and the finite depth-of-focus of the optics. The results have a bearing on a patented method for high-speed single-molecule DNA sequencing. They indicate that the imaging of freely moving fluorescent labels within a microfluidic flowcell will be considerably more involved than that of immobilized molecules at a surface, which is the usual …

Irradiation Induced Order-Dis Order Transformations In Ni-Mo Alloys, Ovidiu F. Toader

Dissertations

No abstract provided.

Probing Scattering Wave Functions Close To The Nucleus, Don H. Madison, Daniel Fischer, Matthew S. Foster, Michael Schulz, Robert Moshammer, Stephenie J. Jones, Joachim Hermann Ullrich

Physics Faculty Research & Creative Works

Recently, three-dimensional imaging of the ejected electrons following 100  MeV/amu C⁶⁺ single ionization of helium led to the observation of a new structure not predicted by theory [M. Schulz et al., Nature (London) 422, 48 (2003)]. Instead of the usual “recoil lobe” centered on the momentum-transfer axis, a ring-shaped structure centered on the beam axis was observed. New measurements at 2  MeV/amu exhibit a similar structure, which is now predicted by theory. We argue that the same theory failed at 100  MeV/amu because the faster projectiles probe distances much closer to the nucleus, where our multiple-scattering model is expected …

Measurement Of Conductivity And Charge Storage In Insulators Related To Spacecraft Charging, A. R. Frederickson, John R. Dennison

All Physics Faculty Publications

Improved experimental methods are discussed for laboratory measurement of conductivity and electric field in insulating spacecraft material intended for space radiation and plasma environments. These measurement techniques investigate the following features: 1) measurements of conductivity are up to four orders of magnitude smaller than those determined by existing standard methods. 2) Conductivity is altered as radiation accumulates and trapping states fill with electrons. 3) With intense kiloelectronvolt electron irradiation, electrons are continually emitted for hours from the irradiated surface after the irradiation ceases. 4) Charging induced by electron irradiation is strongly modified by the electron-hole pairs that the irradiation generates …

Spatial Frequency Response Of Acrylamide Based Holographic Photopolymer, Raghavendra Jallapuram, Izabela Naydenova, Vincent Toal, Suzanne Martin, Robert Howard

Conference Papers

It has been shown that photopolymers are useful in holographic optical elements [1] and holographic interferometry [2]. However, the list of potential applications increases greatly if reflection holography is possible. Reflection holography requires a material that has the potential to record high spatial frequencies. Here we studied the spatial frequency response of an acrylamide based dye sensitized holographic photopolymer. We have investigated the effect of molecular weight of the binder and concentration of crosslinking monomer on diffusion using real time monitoring of the holographic grating formation. The effect of uniform pre-exposure on diffusion was also investigated. We have also demonstrated …

Charge Transfer In Slow Collisions Of C⁴⁺ With H Below 1 Kev/Amu, Chen-Nan Liu, Anh-Thu Le, C. D. Lin

Physics Faculty Research & Creative Works

We reexamined charge-transfer cross sections for C⁴⁺ + H collisions for energies from 1 meV/amu to 1 keV/amu using the recently developed hyperspherical close-coupling method. Our results agree with several previous theoretical calculations using molecular-orbital expansion. However, these converged theoretical predictions do not agree with total cross sections from the merged-beam experiments.

Measurement Of High-Q2 Charged Current Cross Sections In E +P Deep Inelastic Scattering At Hera, S. Chekanov, M. Derrick, D. Krakauer, J. H. Loizides, S. Magill, B. Musgrave, J. Repond, R. Yoshida, Margarita C. K. Mattingly, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, S. De Pasquale, P. Giusti, G. Iacobucci, A. Margotti, R. Nania, F. Palmonari, A. Pesci, G. Sartorelli, A. Zichichi, G. Aghuzumtsyan

Faculty Publications

Cross sections for e+p charged current deep inelastic scattering at a centre-of-mass energy of 318 GeV have been determined with an integrated luminosity of 60.9 pb-1 collected with the ZEUS detector at HERA. The differential cross sections dσ/dQ2, dσ/dx and dσ/dy for Q2 > 200 GeV2 are presented. In addition, d2σ/dxdQ2 has been measured in the kinematic range 280 GeV2 < Q2 < 17 000 GeV2 and 0.008 < x < 0.42. The predictions of the Standard Model agree well with the measured cross sections. The mass of the W boson propagator is determined to be MW = 78.9 ± 2.0 (stat.) ± 1.8 (syst.) -1.8+2.0 (PDF) GeV from a fit to dσ/dQ2. The chiral structure of the Standard Model is also investigated in terms of the (1-y)2 dependence of the double-differential cross section. The structure-function F2CC has been extracted by combining the measurements presented here with previous ZEUS results from e-p scattering, extending the measurement obtained in a neutrino-nucleus scattering experiment to a significantly higher Q2 region.

Laser-Energy Transfer And Enhancement Of Plasma Waves And Electron Beams By Interfering High-Intensity Laser Pulses, P. Zhang, N. Saleh, Shouyuan Chen, Z.M. Sheng, Donald P. Umstadter

Donald Umstadter Publications

The effects of interference due to crossed laser beams were studied experimentally in the high-intensity regime. Two ultrashort (400 fs), high-intensity (4×10¹⁷ and 1.6×10¹⁸ W/cm²) and1µm wavelength laser pulses were crossed in a plasma of density 4×10¹⁹ cm³. Energy was observed to be transferred from the higher-power to the lower-power pulse, increasing the amplitude of the plasma wave propagating in the direction of the latter. This results in increased electron self-trapping and plasma-wave acceleration gradient, which led to an increased number of hot electrons (by 300%) and hot-electron temperature (by 70%) and a …

Criss-Crossing Laser Beams Zoom Electrons Along, P. Zhang, N. Saleh, Shouyuan Chen, Z.M. Sheng, Donald P. Umstadter

Donald Umstadter Publications

Crossing two high-intensity laser beams in a plasma (a collection of charged particles) can have some interesting effects. In a recent experiment performed by researchers at the University of Michigan and the Institute of Physics in China, energy from a higher-power laser pulse was transferred to a lower-power laser pulse. The lower-power pulse had been accelerating electrons with its "wakefield" (like a wave accelerating a surfer). The extra energy to this lower-power pulse enhanced the electron acceleration and decreased the divergence of the electron beam. These features are desirable for proposed "laser particle accelerators" that would be powered by relatively …

Giant Metamagnetic Moments In A Granular Fecl2-Fe Heterostructure, Sarbeswar Sahoo, Christian Binek, Wolfgang Kleemann

Christian Binek Publications

Giant moments are observed at low temperatures in a granular FeCl₂-Fe heterostructure owing to a local metamagnetic transformation of the antiferromagnetic (AF) FeCl₂ matrix due to dipolar interactions. A model of metamagnetically (MM) "dressed" single-domain Fe particles is suggested to explain the observations. These include polydispersive ac susceptibility induced by AF-MM domain configurations and weak exchange bias due to non-spin-flipped AF crystallites.

Search For The Flavor-Changing Neutral Current Decay D0→Μ +Μ - In Pp̅ Collisions At √S =1.96 Tev, Darin Acosta, Kenneth A. Bloom, Collider Detector At Fermilab Collaboration

Kenneth Bloom Publications

We report on a search for the flavor-changing neutral current decay D⁰→µ⁺µ^- in pp̅ collisions at √s =1.96 TeV using 65 pb^-1 of data collected by the CDF II experiment at the Fermilab Tevatron Collider. A displaced-track trigger selects long-lived D⁰ candidates in the D⁰→µ⁺µ^- search channel, the kinematically similar D⁰→ π⁺ π^- channel used for normalization, the Cabibbo-favored D⁰→ K^-π⁺ channel used to optimize the selection criteria in an unbiased manner, and their charge conjugates. Finding no signal …

Exclusive Electrodisintegration Of Three-Nucleon Systems, Tigran Abrahamyan

FIU Electronic Theses and Dissertations

The purpose of this research was to develop a theory of high-energy exclusive electrodisintegration of three-nucleon systems on the example of 3He(e, e'NN)N reaction with knocked-out nucleon in the final state.

The scattering amplitudes and differential cross section of the reaction were calculated in details within the Generalized Eikonal Approximation(GEA). The manifestly covariant nature of Feynman diagrams derived in GEA allowed us to preserve both the relativistic dynamics and kinematics of the scattering while identifying the low momentum nuclear part of the amplitude with a nonrelativistic nuclear wave function. Numerical calculations of the residual system's total and relative momentum distribution …

Twin-Rainbow Metrology. I. Measurement Of The Thickness Of A Thin Liquid Film Draining Under Gravity, Charles L. Adler, James A. Lock, Ian P. Rafferty, Wayne Hickok

Physics Faculty Publications

We describe twin-rainbow metrology, a new optical technique used to measure the thickness of thin films in a cylindrical geometry. We also present an application of the technique: measurement of the thickness of a Newtonian fluid draining under gravity. We compare these measurements with fluid mechanics models. (C) 2003 Optical Society of America.

Domain Wall Solutions With Abelian Gauge Fields, J. S. Rozowsky, R. R. Volkas, K. C. Wali

Physics - All Scholarship

We study kink (domain wall) solutions in a model consisting of two complex scalar fields coupled to two independent Abelian gauge fields in a Lagrangian that has $U(1)\times U(1)$ gauge plus $\mathbb{Z}_2$ discrete symmetry. We find consistent solutions such that while the U(1) symmetries of the fields are preserved while in their respective vacua, they are broken on the domain wall. The gauge field solutions show that the domain wall is sandwiched between domains with constant magnetic fields.

Long Coherence Times At 300 K For Nitrogen-Vacancy Center Spins In Diamond Grown By Chemical Vapor Deposition, John S. Colton, T. A. Kennedy, J. E. Butler, R. C. Linares, P.J. Doering

Faculty Publications

Electron-spin-echo experiments reveal phase-memory times as long as 58 μs at 300 K for nitrogen-vacancy centers in chemical vapor deposition (CVD) single crystals. The spins were optically polarized and optically detected. Two high-quality CVD samples were studied. From the current results, it is not clear whether these phase-memory times represent a fundamental limit or are limited by an external source of decoherence.

Labview Interface For School-Network Daq Card, Hans Berns, T. H. Burnett, Richard Gran, Graham Wheel, R. Jeffrey Wilkes, Daniel R. Claes, Jared Kite, Gregory R. Snow

Gregory Snow Publications

A low-cost DAQ card has been developed for school-network cosmic ray detector projects, providing digitized data from photomultiplier tubes via a standard serial interface. To facilitate analysis of these data and to provide students with a starting point for custom readout systems, a model interface has been developed using the National Instruments LabVIEW(R) system. This user-friendly interface allows one to initialize the trigger coincidence conditions for data-taking runs and to monitor incoming or pre-recorded data sets with updating singles- and coincidence-rate plots and other user-selectable histograms.

Low-Cost Data Acquisition Card For School-Network Cosmic Ray Detectors, Sten Hansen, Thomas Jordan, Daniel R. Claes, Gregory R. Snow, Hans Berns, T. H. Burnett, Richard Gran, R. Jeffrey Wilkes

Gregory Snow Publications

The Cosmic Ray Observatory Project (CROP) at University of Nebraska/Lincoln and the Washington Area Large-scale Time coincidence Array (WALTA) at University of Washington/Seattle are among several outreach projects siting cosmic-ray detectors at local high schools in cities around North America, to study the origins and interactions of highenergy cosmic rays. In a collaboration between QuarkNet, the outreach program based at Fermilab, CROP, and WALTA, a low-cost data acquisition electronics card has been developed to collect and synchronize the data from each detector site. The cost for each card is under US$500 for parts, functionally replacing much more expensive electronics crates …

Mean Field Theory Of Collective Transport With Phase Slips, Alan Middleton, Karl Saunders, J. M. Schwarz, M. Cristina Marchetti

Physics - All Scholarship

The driven transport of plastic systems in various disordered backgrounds is studied within mean field theory. Plasticity is modeled using non-convex interparticle potentials that allow for phase slips. This theory most naturally describes sliding charge density waves; other applications include flow of colloidal particles or driven magnetic flux vortices in disordered backgrounds. The phase diagrams exhibit generic phases and phase boundaries, though the shapes of the phase boundaries depend on the shape of the disorder potential. The phases are distinguished by their velocity and coherence: the moving phase generically has finite coherence, while pinned states can be coherent or incoherent. …

Measurement Of The Open-Charm Contribution To The Diffractive Proton Structure Function, S. Chekanov, M. Derrick, D. Krakauer, J. H. Loizides, S. Magill, B. Musgrave, J. Repond, R. Yoshida, Margarita C. K. Mattingly, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, S. De Pasquale, P. Giusti, G. Iacobucci, A. Margotti, R. Nania, F. Palmonari, A. Pesci, G. Sartorelli, A. Zichichi, G. Aghuzumtsyan

Faculty Publications

Production of D*±(2010) mesons in diffractive deep inelastic scattering has been measured with the ZEUS detector at HERA using an integrated luminosity of 82 pb-1. Diffractive events were identified by the presence of a large rapidity gap in the final state. Differential cross sections have been measured in the kinematic region 1.5

Mode Structure Of Diffusive Transport In Hydroxypropylcellulose:Water, George D.J. Phillies, Robert O. Connell, Paul Whitford, Kiril A. Streletzky

Physics Faculty Publications

A systematic analysis of the mode structure of diffusive relaxations in 1 MDa hydroxypropylcellulose(HPC):water is presented. New methods and data include (1) use of integral spectral moments to characterize nonexponential decays, (2) spectra of small probes in concentrated HPC solutions, (3) temperature dependence of the mode structure, and (4) comparison of optical probe spectra and spectra of probe-free polymer solutions. We find that (1) probe and polymer relaxations are in general not the same; (2) the apparent viscometric crossover near ct≈6 g/l is echoed by probe behavior; (3) our HPC solutions have a characteristic dynamic length, namely the 50 nm …

State-To-State Rotational Rate Constants For Co+He: Infrared Double Resonance Measurements And Simulation Of The Data Using The Sapt Theoretical Potential Energy Surface, Tony C. Smith, David A. Hostutler, Gordon D. Hager, Michael C. Heaven, George C. Mcbane

Peer Reviewed Articles

An extensive data set of 54 time-resolved pump-probe measurements was used to examine CO+He rotational energy transfer within the CO v=2 rotational manifold. Rotational levels in the range J_i=2-9 were excited and collisional energy transfer of population to the levels J_f=1-10 was monitored. The resulting data set was analyzed by fitting to numerical solutions of the master equation. State-to-state rate constant matrices were generated using fitting law functions and ab initio theoretical calculations that employed the SAPT potential energy surface of Heijmen et al. [J. Chem. Phys. 107, 9921 (1997)]. Fitting laws based on …

Magnetoresistance In Boron Carbide Junctions, L. Bernard, J. Monson, Andrei Sokolov, Zong-Yuan Liu, C.S. Yang, Peter A. Dowben, Bermard Doudin, A. Harken, P. Welsch, B. W. Robertson

Peter Dowben Publications

Photoemission and electric transport properties of ferromagnet–insulator–ferromagnet junctions with boron carbide (C₂B₁₀) dielectric barrier are presented. Using a non-oxide barrier confidence avoids oxidation of the interfaces with the ferromagnetic layers. Photoemission confirms chemical abruptness of the interface. Magnetoresistance ratios reaching 50% are observed at low temperatures, and large nonlinearity in the current–voltage curves show that impurities in the junctions play a key role. © 2003 American Institute of Physics.

Computer-Controlled In-Class Feedback System For Interactive Lectures, Thomas J. Bensky

Physics

Instructors who wish to implement an interactive lecture style, such as peer instruction, have the need to collect feedback from students in a lecture environment. We present a computer-controlled electronic circuit that allows for quick, rigorous, and accurate measurement and reporting of student feedback in the lecture environment.

Equatorial Counterelectrojetsduring Substorms, T. Kikuchi, K. Hashimoto, T. I. Kitamura, H. Tachihara, Bela G. Fejer

Bela G. Fejer

[1] Equatorial counterelectrojet (CEJ) events are analyzed in association with changes in the interplanetary magnetic field (IMF), polar cap potential (PCP), and electric field measured in the equatorial ionosphere. In one event on 16 July 1995, the equatorial CEJ was observed at the afternoon dip equator during the recovery phase of the substorm when the IMF turned northward. Rapid decreases in the PCP and in the auroral electrojet occurred simultaneously with the equatorial CEJ, suggesting instantaneous equatorward penetration of the rapid decrease in the electric field associated with the region 1 field-aligned currents (R1 FACs) under the condition of a …

Evidence Of The Zn Vacancy Acting As The Dominant Acceptor In N-Type Zno, F. Tuomisto, V. Ranki, K. Saarinen, David C. Look

Physics Faculty Publications

We have used positron annihilation spectroscopy to determine the nature and the concentrations of the open volume defects in as-grown and electron irradiated (E_el=2   MeV, fluence 6×10¹⁷   cm^-2) ZnO samples. The Zn vacancies are identified at concentrations of [V_Zn]≃2×10¹⁵   cm^-3 in the as-grown material and [V_Zn]≃2×10¹⁶   cm^-3 in the irradiated ZnO. These concentrations are in very good agreement with the total acceptor density determined by temperature dependent Hall experiments. Thus, the Zn vacancies are dominant acceptors in both as-grown and irradiated ZnO.

Statistics Of Transmission In One-Dimensional Disordered Systems: Universal Characteristics Of States In The Fluctuation Tails, Lev I. Deych, Mikhail V. Erementchouk, Alexander A. Lisyansky, Alexey Yamilov, Hui Cao

Physics Faculty Research & Creative Works

We numerically study the distribution function of the conductance (transmission) in the one-dimensional tight-binding Anderson and periodic-on-average superlattice models in the region of fluctuation states where single parameter scaling is not valid. We show that the scaling properties of the distribution function depend upon the relation between the system's length L and the length l_s determined by the integral density of states. For long enough systems, L ≫ l_s, the distribution can still be described within a new scaling approach based upon the ratio of the localization length l_loc and l_s. In an intermediate …

Review Of "Liquid Crystals: Fundamentals" By S. Singh, Peter J. Collings

Physics & Astronomy Faculty Works

No abstract provided.

Test Particle Acceleration In Three-Dimensional Magnetohydrodynamic Turbulence, P. Dmitruk, W. H. Matthaeus, N. Seenu, Michael R. Brown

Physics & Astronomy Faculty Works

We perform numerical experiments of test particle acceleration on turbulent magnetic and electric fields obtained from pseudospectral direct numerical solutions of the compressible three-dimensional MHD equations. We find consistent acceleration of the particles to many times the plasma characteristic (Alfven) speed and extended power laws in the density distribution of energies. Scaling laws of maximum and mean energy of particles with the nominal gyrofrequency and the MHD electric field are observed and a simple estimate is presented.