Precision measurement of the boron to carbon ratio in cosmic rays with AMS-02
Name
922889351-MIT.pdf
Description
Full printable version
Size
11.87 MB
Format
Adobe PDF
Checksum (MD5)
aed1dd715f857771de259fe58a011ac4
Author(s)
Sun, Wei, Ph. D. Massachusetts Institute of Technology
Advisor(s)
Ulrich J. Becker.
Date Issued
2015
Publisher
Massachusetts Institute of Technology
Abstract
A precision measurement of the Boron to Carbon ratio in cosmic rays is carried out in the range 1 GeV/n to 670 GeV/n using the first 30 months of flight data of AMS-02 located on the International Space Station. Above 20 GeV/n, it is the first accurate measurement. About 5 million clean Boron and Carbon nuclei are identified. The experimental and analysis challenges in achieving a high precision measurement are addressed. Boron is exclusively produced as a secondary particle by spallation from primary elements like Carbon in collisions with interstellar medium. The unprecedented precision and energy range of this measurement deepen the knowledge of cosmic ray propagation. Using this measurement, the diffusion coefficient in Gal-Prop model is determined to be (6.05 ± 0.05)10 28 cm2/s, and the Alfven velocity is (33.9 ± 1.0) km/s. This makes the prediction of secondary anti-proton background in dark matter search one order of magnitude more accurate.
Description
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Physics, 2015.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 163-170).
Subjects
Physics.
MIT Department
Massachusetts Institute of Technology. Department of Physics
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