Studies of electrodynamic processes of relativistic heavy ions in solids
A variety of detectors used (inter alia) in cosmic ray physics have been exposed to 600 MeV/amu /sup 20/Ne, /sup 40/Ar, and /sup 56/Fe provided by the Bevalac in order to measure their response to relativistic heavy ions and improve understanding of the physics of these detectors in the regime of high ion charge and energy. The detectors discussed here are Cerenkov radiators, range detectors, and alkali halide scintillators. Classically, and to first order in QED, the Cerenkov emission due to an above threshold ion of charge Z/sub 1/ has a Z/sub 1//sup 2/ dependence. Certain higher order QED terms suggest a Z/sub 1//sup 4/ contribution as well. Our experimental results are consistent with a pure Z/sub 1//sup 2/ response, and limits are placed on Z/sub 1//sup 3/ and Z/sub 1//sup 4/ contributions to Cerenkov emission. The accuracy of higher order Mott, Bloch, and polarization correction terms to the Bethe expression for stopping power has been tested with measurements of range of our three ion species in a variety of absorbers. The theoretical state-of-the-art gives an acceptable (<2sigma) fit to energies determined by time-of-flight methods. Should the relativistic Bloch correction be smaller than is presently calculated, an improved fit would result. A model of scintillation in alkali halides is presented along with our data showing Nal:T1 response to relativistic heavy ions. In the model, a prompt dose profile is calculated, followed by simultaneous exciton diffusion and biexciton (second-order) annihilative interactions, the latter quenching part of the electronic excitation energy. An excellent qualitative fit to collected data spanning two orders of magnitude in stopping power results. The absence of an activator depletion mechanism in alkali halide scintillation saturation is explained.
- Research Organization:
- California Univ., Berkeley (USA)
- OSTI ID:
- 6126196
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
ALKALI METAL COMPOUNDS
CHARGED PARTICLE DETECTION
CHARGED PARTICLES
CHARGED-PARTICLE REACTIONS
CHERENKOV COUNTERS
COSMIC RAY DETECTION
DATA
DETECTION
ELECTRODYNAMICS
ENERGY RANGE
EXPERIMENTAL DATA
FIELD THEORIES
FUNCTIONS
HALIDES
HALOGEN COMPOUNDS
HEAVY ION REACTIONS
HEAVY IONS
INFORMATION
IONS
MEASURING INSTRUMENTS
NUCLEAR REACTIONS
NUMERICAL DATA
QUANTUM ELECTRODYNAMICS
QUANTUM FIELD THEORY
RADIATION DETECTION
RADIATION DETECTORS
RANGE
RELATIVISTIC RANGE
RESPONSE FUNCTIONS
SCINTILLATION COUNTERS
SHOWER COUNTERS
SOLID SCINTILLATION DETECTORS