Bulletin of the American Physical Society
2013 Joint Meeting of the APS Division of Atomic, Molecular & Optical Physics and the CAP Division of Atomic, Molecular & Optical Physics, Canada
Volume 58, Number 6
Monday–Friday, June 3–7, 2013; Quebec City, Canada
Session H5: Focus Session: Applications of Atomic Collisions and Spectroscopy |
Hide Abstracts |
Chair: Morty Khakoo, California State University, Fullerton Room: 301 |
Wednesday, June 5, 2013 10:30AM - 11:00AM |
H5.00001: EBIT spectroscopy of highly charged heavy ions relevant to hot plasmas Invited Speaker: Nobuyuki Nakamura An electron beam ion trap (EBIT) is a versatile device for studying highly charged ions. We have been using two types of EBITs for the spectroscopic studies of highly charged ions. One is a high-energy device called the Tokyo-EBIT, and another is a compact low-energy device called CoBIT. Complementary use of them enables us to obtain spectroscopic data for ions over a wide charge-state range interacting with electrons over a wide energy range. In this talk, we present EBIT spectra of highly charged ions for tungsten, iron, bismuth, etc., which are relevant to hot plasmas. Tungsten is considered to be the main impurity in the ITER (the next generation nuclear fusion reactor) plasma, and thus its emission lines are important for diagnosing and controlling the ITER plasma. We have observed many previously unreported lines to supply the lack of spectroscopic data of tungsten ions. Iron is one of the main components of the solar corona, and its spectra are used to diagnose temperature, density, etc. The diagnostics is usually done by comparing observed spectra with model calculations. An EBIT can provide spectra under a well-defined condition; they are thus useful to test the model calculations. Laser-produced bismuth plasma is one of the candidates for a soft x-ray source in the water window region. An EBIT has a narrow charge state distribution; it is thus useful to disentangle the spectra of laser-produced plasma containing ions with a wide charge-state range. [Preview Abstract] |
Wednesday, June 5, 2013 11:00AM - 11:12AM |
H5.00002: Momentum Imaging of the Dynamics of Dissociative Electron Attachment to Uracil Dan Slaughter, Yu Kawarai, Thorsten Weber, Yoshiro Azuma, Carl Winstead, Vince McKoy, Ali Belkacem Observation of the dynamics of dissociative electron attachment (DEA) in biomolecules has recently become possible by momentum imaging of the fragments resulting from the dissociating transient anion resonance. A momentum spectrometer featuring a 4$\pi$ solid angle of detection is combined with a pulsed electron beam and effusive molecular beam in a crossed geometry to measure the full 3D momentum distribution of dissociating negative ions. Guided by electronic structure calculations that indicate the most likely orientation of the molecule at the time of attachment, we present key aspects of the dynamics of ring-breaking dissociation of the transient anion formed upon DEA to the nucleobase uracil. [Preview Abstract] |
Wednesday, June 5, 2013 11:12AM - 11:24AM |
H5.00003: SELF: Fast Ion Surface Energy Loss in the Wake Fields of Solid Foils Gordon Berry, Tapan Nandi, Kumar Haris We have measured the stopping powers of several fast, highly-ionized atoms passing through thin bi-layer targets made up of metals and non-conductors. We were surprised to find that the energy loss depends on the ordering of the target is significantly different on bi-layer reversal. We ascribe this new energy-loss (the SELF -- the Surface Energy Loss Field) effect to the differing wake fields as the beam exits the target in the two cases. This finding is validated with several different bi-layer targets. Further, besides the highly charged ion beams, molecular ions also reveal similar results in the forward/backward coulomb explosions. We compare our energy loss results with those of previous theoretical predictions for the wake potential for fast ions in solids; lighter ions show better agreements: some theories show large discrepancies with our measurements. Further theoretical work is needed to better quantify our conclusions. [Preview Abstract] |
Wednesday, June 5, 2013 11:24AM - 11:54AM |
H5.00004: High precision atomic data for halo nuclei and related nuclear structure Invited Speaker: Wilfried N\"ortersh\"auser The observation of extremely large nuclear interaction cross sections for the isotopes $^{6,8}$He, $^{11}$Li, and $^{11,14}$Be demonstrated that one of the paradigms of nuclear structure -- a constant nuclear matter density throughout the nucleus -- is not necessarily fulfilled. It turned out that the large cross section of these isotopes is caused by a ``halo'' of dilute neutron matter around a central core nucleus that obeys the usual nuclear density. A large deformation, as another possible explanation, was soon ruled out by laser spectroscopic investigations of the hyperfine structure of $^{11}$Li and $^{11}$Be, showing that their nuclear moments are in accordance with a nearly spherical nucleus. Since then, a measurement of the nuclear charge radii of these exotic isotopes was considered of high importance. Only atomic isotope shift measurements can provide reliable nuclear charge radii of short-lived isotopes so far. This technique has been used on long isotopic chains of heavier elements above neon (Z$=$10) for decades. However, the isotope shift in light elements is dominated by huge mass-dependent shifts whereas the nuclear volume shift is only on the scale of a few 10 ppm. Semi-empirical techniques -- that proofed to be successful in separating mass-dependent and finite-size effects for heavier elements -- are therefore not sufficiently accurate in these cases. A clear separation of the nuclear size effect became possible only with the emergence of new techniques in high-accuracy atomic structure calculations of two-electron and three-electron systems, allowing the calculation of the mass-dependent isotope shift with accuracy of 1 ppm and better. Isotope shifts, hyperfine structure splitting and absolute transition frequencies have now been determined for all isotopes of helium, lithium and beryllium -- except $^{14}$Be -- in several experiments at various on-line facilities world-wide. In my talk I will present a few examples for the techniques that are applied in such measurements and discuss how their results have influenced our picture of halo nuclei. [Preview Abstract] |
Wednesday, June 5, 2013 11:54AM - 12:06PM |
H5.00005: A microfabricated hyperpolarized Xe source Ricardo Jimenez-Martinez, Daniel Kennedy, Michael Rosenbluh, Elizabeth Donley, Svenja Knappe, Scott Seltzer, Hattie Ring, Brian Patton, Vikram Bajaj, Alexander Pines, John Kitching Spin-exchange collisions offer an efficient way to transfer spin orientation from optically pumped alkali-metal atoms to the nuclei of noble gas atoms. Of particular interest in NMR spectroscopy is the polarization of xenon gas, which due to its physical properties is an amenable sensor in fields ranging from medical imaging to analytical chemistry. There is current interest in developing portable NMR instrumentation combining hyperpolarized Xe. Here we demonstrate a microfabricated platform for the optical production and detection of polarized Xe gas. The device is implemented in a 3 cm X 1cm X 0.1 cm silicon preform with two micromachined chambers connected by a 300 $\mu $m X 300 $\mu $m X 1000 $\mu $m channel. One chamber is used to orient Xe nuclei spin through spin-exchange collisions with optically pumped Rb atoms. Characterization of the polarized Xe is carried out in the second chamber by measuring its magnetic field using a Rb magnetometer. [Preview Abstract] |
Wednesday, June 5, 2013 12:06PM - 12:18PM |
H5.00006: Recent advances in the use of laser-induced breakdown spectroscopy (LIBS) as a rapid point-of-care pathogen diagnostic Steven Rehse, Daniel Trojand, Russell Putnam, Derek Gillies, Ryan Woodman, Khadija Sheikh, Andrew Daabous There is a well-known and urgent need in the fields of medicine, environmental health and safety, food-processing, and defense/security to develop new 21st Century technologies for the rapid and sensitive identification of bacterial pathogens. In only the last five years, the use of a real-time elemental (atomic) analysis performed with laser-induced breakdown spectroscopy (LIBS) has made tremendous progress in becoming a viable technology for rapid bacterial pathogen detection and identification. In this talk we will show how this laser-based optical emission spectroscopic technique is able to sensitively assay the elemental composition of bacterial cells in situ. We will also present the latest achievements of our lab to fully develop LIBS-based bacterial sensing including simulation of a rapid urinary tract infection diagnosis and investigation of a variety of autonomous multivariate analysis algorithms. Lastly, we will show how this technology is now ready to be transitioned from the laboratory to field-portable and potentially man-portable instrumentation. The introduction of such a technology into popular use could very well transform the field of bacterial biosensing -- a market valued at approximately {\$}10 billion/year world-wide. [Preview Abstract] |
Wednesday, June 5, 2013 12:18PM - 12:30PM |
H5.00007: Elastic and inelastic transmission of electrons through tapered glass capillaries S.J. Wickramarachchi, D. Keerthisinghe, B.S. Dassanayake, J.A. Tanis, T. Ikeda The transmission of electrons through tapered borosilicate glass capillaries has been studied for 500 and 1000 eV incident electrons. The energy and angular dependence of the transmitted electrons as well as the temporal charge deposition has been investigated. The capillaries had inlet/outlet diameters of 800 $\mu $m/100 $\mu $m and 700 $\mu $m/20 $\mu $m and lengths of 35 mm. Transmission was observed for tilt angles up to 9.5$^{\mathrm{o}}$, and 1.5$^{\mathrm{o}}$, respectively, for the two capillaries. The transmitted electrons were found to have both elastic and inelastic behavior as was observed for electrons through PET [1] and single straight glass capillaries [2]. The charge deposition with time consisted of stable transmission, fluctuations, blocking, and self discharging for both capillaries depending on the sample tilt angle. \\[4pt] [1] S. Das \textit{et al}., \textit{Phys. Rev. A }\textbf{76}, 042716 (2007).\\[0pt] [2] B.S. Dassanayake \textit{et al}., \textit{Phys. Rev. A }\textbf{81}, 020701(R) (2010). [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700