INTERACTIONS OF IONS WITH
MATTER
This website contains
software on TWO Topics:
SRIM - The Stopping and Range of Ions in Matter
SER - Soft Error Rates from Cosmic
Rays (see bottom of this page)
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Software
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� Science
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Download TRIM Manual |
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Above
links
in Green are links to other websites.
The Stopping
and Range
of Ions in Matter
Software -
SRIM is a collection
of software packages which calculate many features of the transport of ions in
matter. Typical applications include:
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Ion
Stopping and Range in Targets:
Most aspects of the energy loss of ions in matter are calculated in SRIM, the Stopping and Range
of Ions in Matter. SRIM
includes quick calculations which produce tables of stopping powers, range and
straggling distributions for any ion at any energy in any elemental target.
More elaborate calculations include targets with complex multi-layer configurations.
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Ion
Implantation: Ion beams are
used to modify samples by injecting atoms to change the target chemical and
electronic properties. The ion beam also causes damage to solid targets by atom
displacement. Most of the kinetic effect s associated with the physics of this
kind of interactions are found in the SRIM
package.
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Sputtering:
The ion beam may knock out
target atoms, a process called ion sputtering. The calculation of
sputtering, by any ion at any energy, is included in the SRIM
package.
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Ion
Transmission: Ion beams can be followed through mixed gas/solid target layers,
such as occurs in ionization chambers or in energy degrader blocks used to
reduce ion beam energies.
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Ion
Beam Therapy: Ion beams are widely used in medical therapy, especially in
radiation oncology. Typical applications are included.
Science -
The science of
ion beams goes back almost a century to the earliest explanations of
radioactive particles transiting thin films (1904). The field is so rich that
it is difficult for a non-expert to understand any of the current papers in the
field. But basically, the stopping of ions in
matter can not be calculated from first principles. Hidden in stopping theories
are parameters which normalize calculated stopping powers to existing data. The "Science" section of SRIM will
review the basic theories of the stopping of ions in matter. Then some of the
major parameters are reviewed and it will be shown how they are derived from
experimental data. Examples are shell corrections, mean ionization
potentials, the effective charge of ions and the Fermi velocity
of solids.
Over 2000 papers
have been published in the experimental stopping of ions in solids.
Experimental measurements of stopping powers is a difficult task, and there is
wide variation in the results.. Plots will show how
existing stopping calculations compare to experimental data from these
papers. Since the stopping calculations are based in great part on
theory, the interpolation of stopping powers between various ions and targets
is often more accurate than individual measurements, especially for difficult
targets.
Soft Errors in
Electronics from Cosmic Rays
Electronic Reliability -
Effects of Terrestrial Cosmic Rays
Technology
Soft Error
Rates
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Science of
Terrestrial
Cosmic Rays
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Introduction |
History |
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Neutron Sea Level Flux |
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History of Accelerated Testing |
Neutron Spectrometers |
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Current Status Accelerated Testing |
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Above links in Green are not yet active.
Although this
subject is more about the effects of energetic hadrons on terrestrial
electronics than about ion beams, it is scientifically in a similar field
(hadrons = protons, neutrons and pions, i.e. particles which respond to the
nuclear force / strong interaction). The science and technology about cosmic
ray induced soft fails was considered proprietary by IBM for more than 15
years. In 1996, a complete issue of the IBM Journal of Research and Development
was devoted to reviewing this work. A summary of the issue, and the complete
first article (the 15 year history of the development of the IBM scientific
understanding of soft fails from radiation) is given at IBM J. R.& D.
The scientific
history of this field is reviewed in detail. The
field is not static because the technology of integrated circuits is still
rapidly changing and the effects of cosmic rays on integrated circuits (ICs) show
trends which are not well understood. The trends in the sensitivity of ICs to
cosmic rays are reviewed for SRAMs, DRAMs and logic over the last 15 years.
Fundamental to any estimates of the fail rate of ICs is an
understanding of the ambient flux of cosmic rays in the environment. As this
flux has been investigated over the last 15 years, it has become fuzzier rather
than more precise. Previous measurements of the ambient flux which were
considered reliable have been shown to be suspect. New measurements rarely
agree with past measurements. Recent reports of the flux of sea level cosmic
ray hadrons vary by more than 10x, even though they
were performed by highly competent scientists. The problem will probably be
resolved by understanding that the immediate materials nearby an experiment can
have significant effect on the measured flux. The field of the terrestrial flux
of cosmic rays will be reviewed.
About the author:
James F.
Ziegler
e-mail :
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