Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

EXAM: A search for extragalactic antimatter

Thesis/Dissertation ·
OSTI ID:5185264
This thesis presents results from a search for extragalactic antimatter in the cosmic rays (the EXAM experiment). The reasons for undertaking a search for antimatter are given, along with various arguments that indicate that a antimatter fraction of 10{sup {minus}6} {minus} 10{sup {minus}7} in the cosmic-ray flux at earth would not be inconsistent with current antimatter limits obtained from cosmic-ray experiments or with limits set by gamma-ray observations. An experimental technique sensitive to antinuclei with charge Z near iron (Z = 26) is reviewed. This technique uses a combination of active detectors (scintillators, Cerenkov counters) and CR-39 track-etch detectors to provide a unique signature for antimatter detection at a level consistent with the flux estimates given above. This is followed by description of the implementation of this technique (the EXAM detector), along with a summary of the data analysis to date. Directions for future work are described. A detailed description of the microscope system used in the automated analysis of the CR-39 plastic is presented.
Research Organization:
Michigan Univ., Ann Arbor, MI (United States)
OSTI ID:
5185264
Country of Publication:
United States
Language:
English