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Full-Text Articles in Physics
Cellular Track Model For Study Of Heavy Ion Beams, Judy L. Shinn, Robert Katz, Francis A. Cucinotta, John W. Wilson, Duc M. Ngo
Cellular Track Model For Study Of Heavy Ion Beams, Judy L. Shinn, Robert Katz, Francis A. Cucinotta, John W. Wilson, Duc M. Ngo
Robert Katz Publications
Track theory is combined with a realistic model of a heavy ion beam to study the effects of nuclear fragmentation on cell survival and biological effectiveness . The effects of secondary reaction products are studied as a function of depth in a water column. Good agreement is found with experimental results for the survival of human T-1 cells exposed to monoenergetic carbon, neon, and argon beams under aerobic and hypoxic conditions. The present calculation, which includes the effect of target fragmentation, is a significant improvement over an earlier calculation because of the use of a vastly improved beam model with …
Experimental And Theoretical Cross Sections For Escherichia Coli Mutants B, B/R, And BS-1 After Heavy-Ion Irradiation, Robert Katz, Rashidah Zachariah
Experimental And Theoretical Cross Sections For Escherichia Coli Mutants B, B/R, And BS-1 After Heavy-Ion Irradiation, Robert Katz, Rashidah Zachariah
Robert Katz Publications
Data for the inactivation of three Escherichia coli mutants by energetic heavy ions are fitted by the track theory of a one-hit detector in an extended target mode. The respective E0’s are 46, 36.5, and 12.6 Gy for E. coli B, B/r, and Bs-1, and a0, the assumed target radius, is 0.5 μm for all three. The parameter E0, the D37 with γ rays, is measured directly, while a0 is fitted to the data. It is significant that neither a point target model nor calculations with a0= 0.2 …
Relative Effectiveness Of Mixed Radiation Fields, Robert Katz
Relative Effectiveness Of Mixed Radiation Fields, Robert Katz
Robert Katz Publications
For all one-hit detectors the relative effectiveness of a mixed radiation field may be found as the dose-weighted average of the relative effectiveness of its components, segregated according to the atomic number Z and the energy T. We emphasize that this procedure is incorrect for mammalian cells, whatever the nature of the segregation.
A Track Physics Retrospective, Robert Katz
A Track Physics Retrospective, Robert Katz
Robert Katz Publications
Many condensed matter dosimeters and detectors respond to the perspectives of track physics, a parametric model which relates their response to gamma rays to their response to heavy ions through the radial distribution of dose about a heavy ion’s path. Most dosimeters are treated as 1-hit detectors, a classification which includes emulsions, scintillators, TLDs, the Fricke dosimeter, alanine, and some biological substances: enzymes and Eschericia coli, among others. We have discovered many hit detectors. An extended model describes the killing, transformation, and mutation of biological cells after gamma and heavy ion irradiation. A detector is treated as a black box, …
A Model Of Cell Damage In Space Flight, Robert Katz, F. A. Cucinotta, J. W. Wilson, J. L. Shinn, Duc M. Ngo
A Model Of Cell Damage In Space Flight, Robert Katz, F. A. Cucinotta, J. W. Wilson, J. L. Shinn, Duc M. Ngo
Robert Katz Publications
Cell damage by high LET radiations has been described by a phenomenological model (track theory) for 20 years and more. Molecules of biological significance (dry enzymes and viruses) act as 1 hit detectors. Recent additions to the class of I-hit detectors are E. Coli B, and the creation of both single and double strand breaks in SV-40 virus in EO buffer, where indirect effects predominate. The response of cells (survival, transformation, chromosome aberration) to these radiations is typically described by a 4-parameter model whose numerical values are determined by fitting the equations of the theory to experimental data at high …