Lowell Bollinger

In Memoriam: Lowell Bollinger

Lowell Bollinger, a pioneer in nuclear physics research and recipient of the Bonner Prize of the American Physical society, died on September 25 at the age of 91 in Harpswell, Maine. Bollinger was brought up in India, educated at Oberlin College receiving his BA in 1943, and from ’43 to ’46 worked at the Aircraft Engine Research Laboratory as a physicist. After World War II, he attended Cornell, where he received his Ph.D. in 1951. His thesis research was one of the earliest underground cosmic ray measurements, observing muons 600-m deep in a salt mine.

Bollinger joined the Physics Division at Argonne National Laboratory in 1951 and during his long, distinguished career, played an important role in many areas of nuclear and accelerator physics. Developing a fast chopper at the CP5 reactor, he did definitive work on the properties of neutron resonances and their capture widths, and pioneered gamma-ray spectroscopy, establishing systematics in the decay of neutron resonances and the characteristics of gamma-ray cascades in the de-excitation of compound nuclei.

In 1963 he became director of the Physics Division, serving for over a decade. During this time he built up a strong research staff in the Division focused on nuclear physics research – and Argonne is a major center in nuclear physics to this day. Bollinger stepped down as director of the Division to lead a small group exploring the possible applications of superconductivity to the acceleration of beams of nuclei. The result was the first successful utilization of superconducting radio frequency technology for the acceleration of sub-relativistic particles aimed at investigations of nuclear structure.

The extremely high “Q” of a superconducting resonator made phase and frequency control a challenge. One of the major accomplishments of Bollinger’s group was the development of the combined use of a slow frequency-tuning system and a fast reactance system, to stabilize against vibrations and achieve the required synchronization of the RF fields to enable precisely controlled acceleration. Another was to develop a multi-stage harmonic buncher to shape the time profile of a dc beam to match the acceleration window of the linac. The hands-on involvement of Bollinger in all aspects of the development, including setting up the required cryogenic system, was crucial. Under his leadership, first a prototype (funding was a patchwork, from a variety of sources), then a fully funded and successful accelerator, ATLAS, were constructed. ATLAS has evolved in its capabilities to become a major international user facility for nuclear structure research.

The pioneering work of Lowell Bollinger, Ken Shepard, and their coworkers was followed by a number of other nuclear physics facilities using RF superconductivity for accelerating sub-relativistic particles, at Florida State, Kansas State, Stony Brook, the University of Washington, and TRIUMF in North America, as well as in Europe, Asia, and Australia. This demonstration of using Superconducting RF technology for accelerating sub-relativistic particles continues to have a major influence on research facilities. It is currently being applied in FRIB, a major new facility for nuclear physics, under construction at Michigan State University and a number of similar projects worldwide. It is also the basis of the high-intensity linac injector project at Fermilab.

Bollinger citation accompanying the 1986 Tom W Bonner Prize of the American Physical Society reads: