A balloon measurement of the isotopic composition of galactic cosmic ray boron, carbon and nitrogen

Technical Report · Thu Jan 01 04:00:00 EST 1981

OSTI ID:5439433

Zumberge, J F

The isotopic compositions of galactic cosmic ray boron, carbon, and nitrogen were measured at energies near 300 MeV amu, using a balloon-borne instrument at an atmospheric depth of approximately 5 g/sq cm. The calibrations of the detectors comprising the instrument are described. The saturation properties of the cesium iodide scintillators used for measurement of particle energy are studied in the context of analyzing the data for mass. The achieved rms mass resolution varies from approximately 0.3 amu at boron to approximately 0.5 amu at nitrogen, consistent with a theoretical analysis of the contributing factors. Corrected for detector interactions and the effects of the residual atmosphere the results are B-10/B 0.33 (+0.17, -0.11), C-13/C 0.06 (+0.13, -0.11), and N-15/N 0.42 (+0.19, -0.17). A model of galactic propagation and solar modulation is described. Assuming a cosmic ray source composition of solar-like isotopic abundances, the model predicts abundances near Earth consistent with the measurements.

• Research Organization: California Inst. of Tech., Pasadena (USA)
• OSTI ID: 5439433
• Report Number(s): NASA-CR-164013
• Country of Publication: United States
• Language: English

Related Subjects

640101* -- Astrophysics & Cosmology-- Cosmic Radiation
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABUNDANCE
AIRSHIPS
BALLOONS
BORON ISOTOPES
CALIBRATION
CARBON ISOTOPES
COSMIC RADIATION
ENERGY RANGE
IONIZING RADIATIONS
ISOTOPES
MEASURING INSTRUMENTS
MEV RANGE
MEV RANGE 100-1000
NITROGEN ISOTOPES
RADIATION DETECTORS
RADIATIONS
SCINTILLATION COUNTERS