Allan S. Jacobson (1932–1997)

Although Allan S. (Bud) Jacobson will be remembered by many of us for his pioneering work in nuclear gamma ray spectroscopy, his life and career were unusually rich. His service in the Air Force kindled a lifelong interest in military history and war games; his beautiful bass voice led him to an early career in show business; and his love of art resulted in the development of award-winning software for the visual display of scientific data. All who knew him will also remember his banjo playing and singing, which enlivened long balloon field trips and numerous social events.

Bud was born on 18 June 1932 in Chattanooga, Tennessee. He joined the Air Force soon after graduating from high school there, and considered it as a possible career, but his interest in show business was stronger. He performed some 200 night club shows while stationed in Japan and cut a demonstration record after coming to California. By 1957, Bud had concluded that show business was not for him, either, and he enrolled in night school in engineering at Los Angeles City College. Transferring to UCLA in 1959, he completed a bachelor's degree in three years and was elected to Phi Beta Kappa.

Jacobson began graduate studies in physics at UCSD, intending to pursue solid state and plasma physics, but quickly developed an interest in astronomy, becoming one of the first graduate students to work with Laurence Peterson. He designed, built, and flew (on a balloon) an actively shielded germanium detector, recording a featureless spectrum from the Crab Nebula and receiving MS and PhD degrees in 1964 and 1968. After another year at UCSD as an Assistant Research Physicist, responsible for the instrument concept of the Cosmic X-ray Experiment flown on OSO-7, he moved on to the Jet Propulsion Laboratory.

In 1973, Jacobson became supervisor of the High Energy Astrophysics Group at JPL, where he was engaged primarily in low-energy gamma ray spectroscopy from both balloons and satellites. For the next decade, he pioneered the use of germanium detectors for high-resolution gamma ray spectroscopy, leading the development of the High Spectral Resolution Gamma Ray Spectrometer, which was launched on HEAO-3 in September 1979. Perhaps the most significant discovery by HEAO-3 was that of the decay line from several solar masses of Al-26 in the interstellar medium. This fulfilled Bud's original goal of providing experimental evidence for ongoing nucleosynthesis in stars. This work resulted in Dr. Jacobson receiving the NASA Exceptional Scientific Achievement Medal in 1980 and the first Bruno Rossi Prize from the High Energy Astrophysics Division of the AAS in 1986.

Even before the launch of HEAO-3, Bud began to have doubts about the future of gamma ray astrophysics, at least high resolution spectroscopy, which doubts were confirmed by the removal of the high-resolution spectrometer from the original CGRO package. This, together with Bud's lifelong interest in art, colors, an4 visual effects led him to a new career in computer graphics, which continued for the rest of his life. His Linked Windows Interactive Data System (LinkWinds) was the co-winner of the NASA Software of the Year award in 1996. At various times, he also collaborated with the Air Force and Army to employ gamma ray sensing for military surveillance and developed several war games, as well as acquiring an extensive collection of literature on military history.

Bud died at his home in Altadena, California on 6 May 1997, as the result of heart failure. He is survived by his wife, Laura, his sister, Doris Rae Friedman, and dozens of colleagues, friends, and associates, all of whom will miss him deeply.

Photo (available in the PDF version) courtesy Jet Propulsion Laboratory.