skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: The first balloon flight and accelerator calibration of the scintillating optical fiber isotope experiment

Miscellaneous ·
OSTI ID:7071700

The Scintillating Optical Fiber Isotope Experiment (SOFIE) is a balloon-borne experiment designed to measure the isotopic abundances of Si through Fe in the galactic cosmic rays (GCR) with energies between 460 and 1200 MeV/nucleon. The SOFIE incorporates there organic scintillation detectors, a fused silica Cherenkov detector, a scintillating optical fiber range detector, and a novel scintillating optical fiber trajectory (SOFT) detector to measure the mass of incident cosmic ray nuclei using the Cherenkov-Range method. A full-scale balloon-borne version of the SOFIE was developed. This included the design, development, and test of the instrument based on calculations of the anticipated event rate, nuclear interactions in the instrument, and the response of each detector to the cosmic rays. The SOFIE was flown on a high-altitude balloon from Prince Albert, Canada, in August of 1988. Although problems with the fiber detectors prevented determination of isotopic abundances in the cosmic rays, the function and performance of the instrument were verified. Analysis of data obtained in flight and on the ground enabled determination of the cause of the fiber problem. A calibration was performed of the SOFIE balloon scintillation and Cherenkov detectors at the LBL Bevalac heavy-ion accelerator using [sup 56]Fe nuclei with energies between 415 MeV/n and 785 MeV/n at the top of the instrument. The author also calibrated a test model of the SOFT detector at the Bevalac using a beam of [sup 56]Fe nuclei, and obtained a position resolution of 75 [mu]m with 200 [mu] square fibers. Laboratory data on the properties of scintillating optical fibers are presented and a formalism developed for predicting their response, including such effects as self-absorption, reflection losses, and energy-loss conversion efficiency.

Research Organization:
Washington Univ., Seattle, WA (United States)
OSTI ID:
7071700
Resource Relation:
Other Information: Thesis (Ph.D.)
Country of Publication:
United States
Language:
English