Measurement of the isotopic composition of the iron group elements in the galactic cosmic radiation

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1978

OSTI ID:6249653

Tarle, G

IRIS, a telescope consisting of a large-area, precision Cerenkov detector, scintillators, spark chambers, and a passive stack of Lexan polycarbonate track detectors, was exposed to the primary cosmic radiation for 6.6 m/sup 2/sr h in a balloon flight in 1976. This measurement has yielded the isotopic composition of the iron-group elements Cr, Mn, Fe and Ni with an average mass resolution of 0.65 amu for the energies 320 to 500 MeV/amu at the detector. This experiment places the most severe constraints to date on deviations from solar system composition of the source of the cosmic radiation. Upper limits were placed of 10% on the ratios /sup 54/Fe//sup 56/Fe and /sup 58/Fe//sup 56/Fe, which are inconsistent with large departures from solar system source composition reported by other workers. The isotopic measurements of Fe and Ni preclude the possibility that these cosmic rays were produced in a single e-process zone. The mean mass of Mn is less than 55, indicating the presence of electron capture species produced by spallation.

• Research Organization: California Univ., Berkeley (USA)
• OSTI ID: 6249653
• Country of Publication: United States
• Language: English

Related Subjects

640101* -- Astrophysics & Cosmology-- Cosmic Radiation
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AIRSHIPS
BALLOONS
CHEMICAL COMPOSITION
CHROMIUM
COSMIC RADIATION
ELEMENTS
ENERGY RANGE
IONIZING RADIATIONS
IRON
ISOTOPE RATIO
LIMITING VALUES
MANGANESE
MASS
METALS
MEV RANGE
MEV RANGE 100-1000
NICKEL
NUCLEAR REACTIONS
PRIMARY COSMIC RADIATION
RADIATIONS
SOLAR SYSTEM
SPALLATION
TELESCOPES
TRANSITION ELEMENTS