Spectrally resolved ion imaging from laser produced plasmas using CR-39 detectors

The field of intracellular ion concentration measurement expanded greatly in the 1980's due primarily to the development by Roger Tsien of ratiometric fluorescence dyes. These dyes have many applications, and in particular they make possible to image ion concentrations: to produce maps of the ion concentration within living cells. Ion imagers comprise a fluorescence microscope, an imaging light detector such as a video camera, and a computer system to process the fluorescence signal and display the map of ion concentration.Ion imaging can be used for two distinct purposes. In the first, the imager looks at a field of cells, measuring the mean ion concentration in each cell of the many in the field of view. One can then, for instance, challenge the cells with an agonist and examine the response of each individual cell. Ion imagers are not necessary for this sort of experiment: one can instead use a system that measures the mean ion concentration in a just one cell at any one time. However, they are very much more convenient.

Download Full-text

Calcium ion imaging in plant cells

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100146503 ◽

1993 ◽

Vol 51 ◽

pp. 132-133

Author(s):

Peter K. Hepler ◽

Dale A. Callaham

Keyword(s):

Plant Cell Wall ◽

Cytoplasmic Membrane ◽

Fluorescent Dyes ◽

Free Acid ◽

Methyl Esters ◽

Free Calcium ◽

Local Concentration ◽

Ion Imaging ◽

Membrane Compartments ◽

Free Acid Form

Calcium ions (Ca) participate in many signal transduction processes, and for that reason it is important to determine where these ions are located within the living cell, and when and to what extent they change their local concentration. Of the different Ca-specific indicators, the fluorescent dyes, developed by Grynkiewicz et al. (1), have proved most efficacious, however, their use on plants has met with several problems (2). First, the dyes as acetoxy-methyl esters are often cleaved by extracellular esterases in the plant cell wall, and thus they do not enter the cell. Second, if the dye crosses the plasma membrane it may continue into non-cytoplasmic membrane compartments. Third, even if cleaved by esterases in the cytoplasm, or introduced as the free acid into the cytoplasmic compartment, the dyes often become quickly sequestered into vacuoles and organelles, or extruded from the cell. Finally, the free acid form of the dye readily complexes with proteins reducing its ability to detect free calcium. All these problems lead to an erroneous measurement of calcium (2).

Download Full-text

Toward The Simultaneous Correction of Spherical and Chromatic Aberration in Electron Optics by Means of an Electrostatic Electron Mirror

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100179786 ◽

1990 ◽

Vol 48 (1) ◽

pp. 206-207

Author(s):

Gertrude. F. Rempfer

Keyword(s):

Chromatic Aberration ◽

Transverse Magnetic ◽

Objective Lens ◽

Ion Imaging ◽

Corrected Image ◽

Electric And Magnetic Fields ◽

Chromatic Aberrations ◽

Improved Performance ◽

Electron Microscopes ◽

Image Planes

Optimum performance in electron and ion imaging instruments, such as electron microscopes and probe-forming instruments, in most cases depends on a compromise either between imaging errors due to spherical and chromatic aberrations and the diffraction error or between the imaging errors and the current in the image. These compromises result in the use of very small angular apertures. Reducing the spherical and chromatic aberration coefficients would permit the use of larger apertures with resulting improved performance, granted that other problems such as incorrect operation of the instrument or spurious disturbances do not interfere. One approach to correcting aberrations which has been investigated extensively is through the use of multipole electric and magnetic fields. Another approach involves the use of foil windows. However, a practical system for correcting spherical and chromatic aberration is not yet available.Our approach to correction of spherical and chromatic aberration makes use of an electrostatic electron mirror. Early studies of the properties of electron mirrors were done by Recknagel. More recently my colleagues and I have studied the properties of the hyperbolic electron mirror as a function of the ratio of accelerating voltage to mirror voltage. The spherical and chromatic aberration coefficients of the mirror are of opposite sign (overcorrected) from those of electron lenses (undercorrected). This important property invites one to find a way to incorporate a correcting mirror in an electron microscope. Unfortunately, the parts of the beam heading toward and away from the mirror must be separated. A transverse magnetic field can separate the beams, but in general the deflection aberrations degrade the image. The key to avoiding the detrimental effects of deflection aberrations is to have deflections take place at image planes. Our separating system is shown in Fig. 1. Deflections take place at the separating magnet and also at two additional magnetic deflectors. The uncorrected magnified image formed by the objective lens is focused in the first deflector, and relay lenses transfer the image to the separating magnet. The interface lens and the hyperbolic mirror acting in zoom fashion return the corrected image to the separating magnet, and the second set of relay lenses transfers the image to the final deflector, where the beam is deflected onto the projection axis.

Download Full-text

Colloidal Plasmonic Nanostar Antennas with Wide Range Resonance Tunability

10.26434/chemrxiv.6552743 ◽

2019 ◽

Cited By ~ 1

Author(s):

Theodoros Tsoulos ◽

Supriya Atta ◽

Maureen Lagos ◽

Michael Beetz ◽

Philip Batson ◽

...

Keyword(s):

Single Particle ◽

Structural Complexity ◽

Field Enhancement ◽

Hot Electron ◽

Structure Property ◽

Plasmon Band ◽

Gold Nanostars ◽

Wide Range ◽

Particle Level ◽

Spectrally Resolved

<div>Gold nanostars display exceptional field enhancement properties and tunable resonant modes that can be leveraged to create effective imaging tags or phototherapeutic agents, or to design novel hot-electron based photocatalysts. From a fundamental standpoint, they represent important tunable platforms to study the dependence of hot carrier energy and dynamics on plasmon band intensity and position. Toward the realization of these platforms, holistic approaches taking into account both theory and experiments to study the fundamental behavior of these</div><div>particles are needed. Arguably, the intrinsic difficulties underlying this goal stem from the inability to rationally design and effectively synthesize nanoparticles that are sufficiently monodispersed to be employed for corroborations of the theoretical results without the need of single particle experiments. Herein, we report on our concerted computational and experimental effort to design, synthesize, and explain the origin and morphology-dependence of the plasmon modes of a novel gold nanostar system, with an approach that builds upon the well-known plasmon hybridization model. We have synthesized monodispersed samples of gold nanostars with finely tunable morphology employing seed-mediated colloidal protocols, and experimentally observed narrow and spectrally resolved harmonics of the primary surface plasmon resonance mode both at the single particle level (via electron energy loss spectroscopy) and in ensemble (by UV-Vis and ATR-FTIR spectroscopies). Computational results on complex anisotropic gold nanostructures are validated experimentally on samples prepared colloidally, underscoring their importance as ideal testbeds for the study of structure-property relationships in colloidal nanostructures of high structural complexity.</div>

Download Full-text

Failure Analysis and Defect Inspection of Electronic Devices by High-Resolution Cathodoluminescence

ISTFA 2017: Conference Proceedings from the 43rd International Symposium for Testing and Failure Analysis ◽

10.31399/asm.cp.istfa2017p0349 ◽

2017 ◽

Author(s):

C. Monachon ◽

M.S. Zielinski ◽

D. Gachet ◽

S. Sonderegger ◽

S. Muckenhirn ◽

...

Keyword(s):

Failure Analysis ◽

Electronic Materials ◽

Electronic Devices ◽

Optical Emission ◽

Large Field ◽

Nanometer Scale ◽

Defect Analysis ◽

Defect Inspection ◽

Spectrally Resolved ◽

Non Destructive

Abstract Quantitative cathodoluminescence (CL) microscopy is a new optical spectroscopy technique that measures electron beam-induced optical emission over large field of view with a spatial resolution close to that of a scanning electron microscope (SEM). Correlation of surface morphology (SE contrast) with spectrally resolved and highly material composition sensitive CL emission opens a new pathway in non-destructive failure and defect analysis at the nanometer scale. Here we present application of a modern CL microscope in defect and homogeneity metrology, as well as failure analysis in semiconducting electronic materials

Download Full-text

Photon Emission Spectral Signatures of AlGaN/GaN HEMT for Functional and Reliability Analysis

ISTFA 2008: Conference Proceedings from the 34th International Symposium for Testing and Failure Analysis ◽

10.31399/asm.cp.istfa2008p0220 ◽

2008 ◽

Author(s):

Arkadiusz Glowacki ◽

Christian Boit ◽

Richard Lossy ◽

Joachim Würfl

Keyword(s):

Reliability Analysis ◽

Gate Voltage ◽

Near Infrared ◽

Photon Emission ◽

Electrical Characterization ◽

Spectral Signatures ◽

Operating Modes ◽

Gan Hemt ◽

Spectrally Resolved ◽

Performance Variations

Abstract Non-degraded and degraded AlGaN/GaN HEMT devices have been characterized electrically and investigated in various operating modes using integral and spectrally resolved photon emission (PE). In degraded devices the PE dependence on the gate voltage differs from the non-degraded devices. Various types of dependencies on the gate voltage have been identified when investigating local degradation sites. PE spectroscopy was performed at various bias conditions. For both devices broad spectra have been obtained in a wavelength regime from visible to near-infrared, including local performance variations. Signatures of the degradation have been determined in the electrical characterization, in integral PE distribution and in the PE spectrum.

Download Full-text

A white light confocal microscope for spectrally resolved multidimensional imaging

Journal of Microscopy ◽

10.1111/j.1365-2818.2007.01803.x ◽

2007 ◽

Vol 227 (3) ◽

pp. 203-215 ◽

Cited By ~ 60

Author(s):

J. H. FRANK ◽

A. D. ELDER ◽

J. SWARTLING ◽

A. R. VENKITARAMAN ◽

A. D. JEYASEKHARAN ◽

...

Keyword(s):

White Light ◽

Confocal Microscope ◽

Multidimensional Imaging ◽

Spectrally Resolved

Download Full-text

Ultraviolet photodissociation dynamics of PCl3 at 235 nm: three-dimensional ion imaging and theoretical analysis

Physical Chemistry Chemical Physics ◽

10.1039/d1cp01396c ◽

2021 ◽

Author(s):

Alexei Chichinin ◽

Christof Maul ◽

Karl-Heinz Gericke

Keyword(s):

Theoretical Analysis ◽

Ground State ◽

Multiphoton Ionization ◽

Three Dimensional ◽

Ion Imaging ◽

Ultraviolet Photodissociation

The photodissociation dynamics of PCl3 at 235 nm has been studied by monitoring ground state Cl(2P3/2) and spin-orbitally excited Cl(2P1/2) atoms by resonance enhanced multiphoton ionization(REMPI). Also, the PCl+n (n=0,1,2)...

Download Full-text