Haymes, Robert C.2018-12-182018-12-181977Djuth, Frank T. (Frank Thomas). "The gamma-ray background at balloon altitudes." (1977) Master’s Thesis, Rice University. <a href="https://hdl.handle.net/1911/103998">https://hdl.handle.net/1911/103998</a>.https://hdl.handle.net/1911/103998On April 2, 1974, a balloon-borne observation of the gamma-ray background at 4 mbar pressure was conducted in the energy band .3-12.27 MeV. The measurements were made at a geomagnetic cutoff rigidity of 11.9 GV. Cosmicray-induced activation of the Nal(Tl) detector was discovered to be a major source of the background count rate in the energy region .15-2.5 MeV. The cosmic diffuse gamma radiation makes a sizable contribution to the background count rate in the low energy region .3 - .15 MeV. At these energies lower limits for the diffuse gamma-ray flux were determined. A search of the detector data for evidence of cosmic gamma-ray bursts proved inconclusive. The conclusions drawn from the background study can be utilized in order to design a very low background gammaray detector for celestial observations.241 ppengCopyright is held by the author, unless otherwise indicated. Permission to reuse, publish, or reproduce the work beyond the bounds of fair use or other exemptions to copyright law must be obtained from the copyright holder.ThesisRICE1624reformatted digitalThesis Sp. Sci. 1977 Djuth