DESIREE as a new tool for interstellar ion chemistry

2008 ◽  
Vol 7 (3-4) ◽  
pp. 205-208 ◽  
Author(s):  
Henning T. Schmidt ◽  
Henrik A.B. Johansson ◽  
Richard D. Thomas ◽  
Wolf D. Geppert ◽  
Nicole Haag ◽  
...  
Keyword(s):  
Cross Sections ◽  
Ion Beam ◽  
Storage Rings ◽  
Rate Coefficients ◽  
Storage Device ◽  
Straight Section ◽  
Ion Chemistry ◽  
Under Construction ◽  
Charged Ions ◽  
Oppositely Charged

AbstractA novel cryogenic electrostatic storage device consisting of two ion-beam storage rings with a common straight section for studies of interactions between oppositely charged ions at low and well-defined relative velocities is under construction at Stockholm University. Here we consider the prospect of using this new tool to measure cross-sections and rate coefficients for mutual neutralization reactions of importance in interstellar ion chemistry in general and specifically in cosmic pre-biotic ion chemistry.

Near-field plume properties of an ion beam formed by alternating extraction and acceleration of oppositely charged ions

2016 ◽  
Vol 25 (5) ◽  
pp. 055013 ◽  
Author(s):  
N Oudini ◽  
A Aanesland ◽  
P Chabert ◽  
S Lounes-Mahloul ◽  
A Bendib
Keyword(s):  
Ion Beam ◽  
Near Field ◽  
Charged Ions ◽  
Oppositely Charged

scholarly journals Photorecombination and Photoionization Experiments at Heavy-Ion Storage-Rings and Synchrotron-Light Sources

2005 ◽  
Vol 13 ◽  
pp. 640-643
Author(s):  
Stefan Schippers
Keyword(s):  
Cross Sections ◽  
Theoretical Calculations ◽  
Accurate Determination ◽  
Heavy Ion ◽  
Storage Rings ◽  
Rate Coefficients ◽  
Light Sources ◽  
Ion Storage ◽  
Synchrotron Light ◽  
Synchrotron Light Sources

AbstractRecent experimental work on the photorecombination and the photoionization of astrophysically relevant atomic ions employing the merged-beams technique at heavy-ion storage-rings and synchrotron-light sources, respectively, is summarized. The resulting absolute photoionization cross sections and recombination rate coefficients benchmark corresponding theoretical calculations and are needed for the accurate determination of ionization equilibria in astrophysical plasmas.

Laboratory studies of electron attachment and detachment processes of aeronomic interest

1969 ◽  
Vol 47 (10) ◽  
pp. 1783-1793 ◽  
Author(s):  
A. V. Phelps
Keyword(s):  
Cross Sections ◽  
Ion Beam ◽  
Electron Attachment ◽  
Negative Ions ◽  
High Energy ◽  
Low Energy ◽  
Rate Coefficients ◽  
Dissociative Attachment ◽  
Three Body ◽  
Energy Processes

Techniques for the study of electron attachment and detachment are reviewed. The rate coefficients for the various processes of aeronomic interest are then discussed. The rates of three-body and dissociative attachment by thermal electrons have been successfully determined by swarm techniques and by high frequency studies of electrons produced by high energy particles and by photoionization. Collisional and associative detachment rates for thermal energy negative ions have been measured using the swarm and flowing afterglow techniques. Radiative attachment rates for some atmospheric negative ions have been calculated from measurements of photodetachment cross sections using crossed photon and ion beam techniques. Electron beam studies and measurements of ion kinetic energy have provided much useful information regarding the dissociative attachment process and the structure of molecular negative ions. Rate coefficients for low energy processes such as the three-body attachment to O2, the radiative attachment to O, and the associative detachment of O− in collisions with various atmospheric gases are reasonably well known. Other possibly important low energy processes, such as dissociative attachment to O3, radiative attachment to O2, and the associative detachment of O2− are less well known.

scholarly journals The morphology of oxygen greenline dayglow emission

1998 ◽  
Vol 16 (12) ◽  
pp. 1599-1606 ◽  
Author(s):  
S. Tyagi ◽  
V. Singh
Keyword(s):  
Cross Sections ◽  
Cosmic Ray ◽  
Rate Coefficients ◽  
Emission Rates ◽  
Ion Chemistry ◽  
Modeling And Forecasting ◽  
Volume Emission ◽  
Qualitative Nature ◽  
Ion Chemistry And Composition ◽  
Good Agreement

Abstract. In this study, the morphology of the oxygen greenline dayglow emission is presented. The volume emission rate profiles are obtained by using Solomon's glow model. The glow model is updated in terms of recent cross sections, reaction rate coefficients and quantum yield of greenline emission. Throughout most of the thermosphere the modelled and observed emission rates are in reasonably good agreement. In the region between 98 and 120 km, the modelled emission rates are substantially higher (about a factor of 1.7) than the observed emission rates. This discrepancy is discussed in terms of scaling of solar fluxes which accounts the variation of solar activity for the day on which calculations are made. The modelled morphology of greenline emission is compared with those cases where WINDII data is available. The modelled and observed morphology is in reasonably good agreement at most of the latitudes above 120 km. In the mesosphere the qualitative nature of morphology is very similar to those of WINDII observation except the modelled emission rates are about a factor of 1.7 higher than the observed emission rates.Keywords. Ionosphere (ion chemistry and composition; modeling and forecasting; solar radiation and cosmic ray effects).

scholarly journals Microcalorimeters for X-Ray Spectroscopy of Highly Charged Ions at Storage Rings

Atoms ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 59 ◽  
Author(s):  
Saskia Kraft-Bermuth ◽  
Daniel Hengstler ◽  
Peter Egelhof ◽  
Christian Enss ◽  
Andreas Fleischmann ◽  
...  
Keyword(s):  
Heavy Ions ◽  
Lamb Shift ◽  
Ion Beam ◽  
Heavy Ion ◽  
Storage Rings ◽  
Highly Charged Ions ◽  
Semiconductor Detectors ◽  
X Ray ◽  
Charged Ions

X-ray spectroscopy of highly charged heavy ions is an important tool for the investigation of many topics in atomic physics. Such highly charged ions, in particular hydrogen-like uranium, are investigated at heavy ion storage rings, where high charge states can be produced in large quantities, stored for long times and cooled to low momentum spread of the ion beam. One prominent example is the determination of the 1s Lamb Shift in hydrogen-like heavy ions, which has been investigated at the Experimental Storage Ring (ESR) at the GSI Helmholtz Centre for Heavy Ion Research. Due to the large electron binding energies, the energies of the corresponding photon transitions are located in the X-ray regime. To determine the transition energies with high accuracy, highly resolving X-ray spectrometers are needed. One concept of such spectrometers is the concept of microcalorimeters, which, in contrast to semiconductor detectors, uses the detection of heat rather than charge to detect energy. Such detectors have been developed and successfully applied in experiments at the ESR. For experiments at the Facility for Antiproton and Ion Research (FAIR), the Stored Particles and Atoms Collaboration (SPARC) pursues the development of new microcalorimeter concepts and larger detector arrays. Next to fundamental investigations on quantum electrodynamics such as the 1s Lamb Shift or electron–electron interactions in two- and three-electron systems, X-ray spectroscopy may be extended towards nuclear physics investigations like the determination of nuclear charge radii.

An Study of Influence of Imperfections on the Delamination of Diamond-Like Carbon Films

2002 ◽  
Vol 719 ◽  
Author(s):  
Myoung-Woon Moon ◽  
Kyang-Ryel Lee ◽  
Jin-Won Chung ◽  
Kyu Hwan Oh
Keyword(s):  
Cross Sections ◽  
Focused Ion Beam ◽  
Imaging System ◽  
Ion Beam ◽  
Carbon Films ◽  
Diamond Like Carbon ◽  
Glass Substrates ◽  
Atomic Force ◽  
Initiation And Propagation

AbstractThe role of imperfections on the initiation and propagation of interface delaminations in compressed thin films has been analyzed using experiments with diamond-like carbon (DLC) films deposited onto glass substrates. The surface topologies and interface separations have been characterized by using the Atomic Force Microscope (AFM) and the Focused Ion Beam (FIB) imaging system. The lengths and amplitudes of numerous imperfections have been measured by AFM and the interface separations characterized on cross sections made with the FIB. Chemical analysis of several sites, performed using Auger Electron Spectroscopy (AES), has revealed the origin of the imperfections. The incidence of buckles has been correlated with the imperfection length.

FIB Enhancement of Mechanically Polished Cross-sections

2019 ◽  
Author(s):  
Becky Holdford
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Scanning Electron Microscope ◽  
Cross Sections ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
High Resolution Imaging ◽  
Chemical Attack ◽  
Resolution Imaging ◽  
Scanning Electron

Abstract On mechanically polished cross-sections, getting a surface adequate for high-resolution imaging is sometimes beyond the analyst’s ability, due to material smearing, chipping, polishing media chemical attack, etc.. A method has been developed to enable the focused ion beam (FIB) to re-face the section block and achieve a surface that can be imaged at high resolution in the scanning electron microscope (SEM).

Yield Enhancement Study: Process Variation and Design Margins Leading to Timing Issues in the RAM

2000 ◽  
Author(s):  
Srikanth Perungulam ◽  
Scott Wills ◽  
Greg Mekras
Keyword(s):  
Cross Sections ◽  
Digital Signal Processor ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Random Access ◽  
Digital Signal ◽  
Yield Enhancement ◽  
Final Conclusion ◽  
Stage Separation ◽  
Study Process

Abstract This paper illustrates a yield enhancement effort on a Digital Signal Processor (DSP) where random columns in the Static Random Access Memory (SRAM) were found to be failing. In this SRAM circuit, sense amps are designed with a two-stage separation and latch sequence. In the failing devices the bit line and bit_bar line were not separated far enough in voltage before latching got triggered. The design team determined that the sense amp was being turned on too quickly. The final conclusion was that a marginal sense amp design, combined with process deviations, would result in this type of failure. The possible process issues were narrowed to variations of via resistances on the bit and bit_bar lines. Scanning Electron Microscope (SEM) inspection of the the Focused Ion Beam (FIB) cross sections followed by Transmission Electron Microscopy (TEM) showed the presence of contaminants at the bottom of the vias causing resistance variations.

Rotational de-excitations of C3H+ (1Σ+) by collision with He: new ab initio potential energy surface and scattering calculations

2020 ◽  
Vol 494 (4) ◽  
pp. 5675-5681 ◽  
Author(s):  
Sanchit Chhabra ◽  
T J Dhilip Kumar
Keyword(s):  
Potential Energy ◽  
Potential Energy Surface ◽  
Ab Initio ◽  
Cross Sections ◽  
Energy Surface ◽  
Molecular Ions ◽  
Basis Set ◽  
Rate Coefficients ◽  
Close Coupling ◽  
Collisional Rate Coefficients

ABSTRACT Molecular ions play an important role in the astrochemistry of interstellar and circumstellar media. C3H+ has been identified in the interstellar medium recently. A new potential energy surface of the C3H+–He van der Waals complex is computed using the ab initio explicitly correlated coupled cluster with the single, double and perturbative triple excitation [CCSD(T)-F12] method and the augmented correlation consistent polarized valence triple zeta (aug-cc-pVTZ) basis set. The potential presents a well of 174.6 cm−1 in linear geometry towards the H end. Calculations of pure rotational excitation cross-sections of C3H+ by He are carried out using the exact quantum mechanical close-coupling approach. Cross-sections for transitions among the rotational levels of C3H+ are computed for energies up to 600 cm−1. The cross-sections are used to obtain the collisional rate coefficients for temperatures T ≤ 100 K. Along with laboratory experiments, the results obtained in this work may be very useful for astrophysical applications to understand hydrocarbon chemistry.

Sign in / Sign up

Export Citation Format

Share Document