Surface detection, characterization, and 3d-imaging using swift-heavy
ions
Z. Insepov, Argonne National Laboratory, USA
J. Matsuo, Kyoto University, Japan
G. Norman, MIPhT, Russia
Executive Summary
Theoretical models based on fundamental and applied results obtained by our partners will be
studied by atomistic and quantum modeling and simulations coupled with mesoscale and
macroscale methods, and the results will be verified by experiments.
Significance and Potential Impact
Swift heavy ion surface detection, characterization, and imaging (HIDI) is an important problem
based on radiation technology that produces high-resolution two-dimensional mass spectra (a
map) of the large organic molecules adsorbed on the surface and a three-dimensional picture of
electronic devices and/or the vital organs in the animal’s body that has an important application
for express analysis of electronic devices, explosives and biological substances for their
identification.
Various microbeam techniques have been recently applied for biological imaging. For example,
focused ion beam and nuclear microprobe are used and elemental imaging in single cells was
performed [1]. Although the techniques provide elemental mapping in biological samples,
knowledge of molecular distribution in organisms such as cells or tissues is still insufficient,
because the organism is composed of various kinds of organic molecules such as peptides,
hormones and lipids. Therefore, better molecular imaging techniques are desired in biology.
The solution of it will also be important for microelectronics, imaging CMOS devices and integral
circuits in electronics for failure and damage, surface analysis in medical applications, and national
security by checking luggage and cargo for contamination, by deploying detection devices at
airports, sea ports and customs.
Art will be benefited by using such devices for discovering authenticity of paintings and artifacts.
Geology and geophysics areas would use express analysis provided by the HIDI for probing the
samples of the natural resources such as sand and rocks. Materials technology will be benefited
from the development of a new technology of 3D mapping of radiation defects in advanced
materials.
Proposed Approach
A new fundamental methodology will be developed based on large scale simulation-assisted
concept that would take into account electronic degrees of freedom in the target materials thus
ensuring better description of electron excitation processes generated by swift heavy ions and
large gas clusters (neutral or ionized), complemented by large scale quantum and atomistic
simulations of the detection of large organic molecules on the solid surfaces supported by
experimental validation and verification.
Various imaging techniques using ion microbeams have been experimentally developed and
applied to biomedical and national security areas. Secondary ion mass spectrometry (SIMS) is one
of the prominent tools for biological and biomedical imaging (Fig.1,2). SIMS can provide data on
molecular distribution in biological samples smaller than 1 micrometer. However, conventional
SIMS has only low sensitivity for molecular ions; therefore there is a considerable need for
1
Fig. 1
Fig.2
development of the beams of more sensitive primary ions. Plasma desorption mass spectrometry
(PDMS) is a method using high energy fission fragments from excitation of a 252Cf source, and it
allows ionization of large molecules (typically up to 20 kDa) due to the dense electronic excitation.
Although PDMS is not in use today because of the development of soft ionization methods,
ionization induced by high energy ion collision still remains the only method which combines high
spatial resolution and sensitive detection of large molecules. In our work, the secondary ion yield
of amino acid and phospholipid was measured for 6 MeV Cu4+ [2]. The yields were compared to
bismuth cluster ions, which achieve relatively high yield. It was experimentally confirmed that the
swift heavy ion has a couple of hundred times higher yield for large molecules than bismuth cluster
ions.
Goals, Deliverables, and Innovation
Development of a new prototype and a new technology of surface detection, characterization and
modification based on using swift heavy and high-energy ions.
References:
[1] G. Parish, S. Keller, S.P. Denbaars, U.K. Mishra, J. Electro. Mater. 29 (2000) 15–20.
[2] Y. Wakamatsu, H. Yamada, S. Ninomiya, B. N. Jones, T. Seki, T. Aoki, R. Webb, J. Matsuo, Nucl. Instr.
Meth. B 269
2