Charge Transfer and Ionization by Intermediate-Energy Heavy Ions

Journal Article · Wed Nov 01 04:00:00 EST 2006 · Radiation Protection Dosimetry

OSTI ID:931059

Toburen, L H ^[1]; McLawhorn, S L ^[1]; McLawhorn, R A ^[1]; Evans, N L ^[1]; Justiniano, E L. B. ^[1]; Shinpaugh, J L ^[1]; Schultz, David Robert ^[2]; Reinhold, Carlos O ^[2]

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1. East Carolina University
2. ORNL

The use of heavy ion beams for microbeam studies of mammalian cell response leads to a need to better understand interaction cross sections for collisions of heavy ions with tissue constituents. For ion energies of a few MeV u^-1 or less, ions capture electrons from the media in which they travel and undergo subsequent interactions as partially 'dressed' ions. For example, 16 MeV fluorine ions have an equilibrium charge of 7⁺, 32 MeV sulphur ions have an equilibrium charge of approx. 11⁺, and as the ion energies decrease the equilibrium charge decreases dramatically. Data for interactions of partially dressed ions are extremely rare, making it difficult to estimate microscopic patterns of energy deposition leading to damage to cellular components. Such estimates, normally obtained by Monte Carlo track structure simulations, require a comprehensive database of differential and total ionisation cross sections as well as charge transfer cross sections. To provide information for track simulation, measurement of total ionisation cross sections have been initiated at East Carolina University using the recoil ion time-of-flight method that also yields cross sections for multiple ionisation processes and charge transfer cross sections; multiple ionisation is prevalent for heavy ion interactions. In addition, measurements of differential ionisation cross sections needed for Monte Carlo simulation of detailed event-by-event particle tracks are under way. Differential, total and multiple ionisation cross sections and electron capture and loss cross sections measured for C⁺ ions with energies of 100 and 200 keV u^-1 are described.

• Research Organization: Oak Ridge National Laboratory (ORNL)
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 931059
• Journal Information: Radiation Protection Dosimetry, Journal Name: Radiation Protection Dosimetry Journal Issue: 1-4 Vol. 122; ISSN RPDODE; ISSN 0144-8420
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
CROSS SECTIONS
ELECTRON CAPTURE
ELECTRONS
FLUORINE IONS
HEAVY IONS
IONIZATION
PARTICLE TRACKS
SIMULATION
TIME-OF-FLIGHT METHOD