Klaus Halbach, a long-time staff physicist with the Lawrence Berkeley National Laboratory (LBNL) and an international expert in magnetic systems for particle accelerators, died on 11 May 2000 following a long and courageous battle with prostate cancer.
Born on 3 February 1925 in Wuppertal, Germany, Klaus received his PhD in nuclear physics from the University of Basel, Switzerland, on work involving nuclear magnetic resonance (NMR). After a three-year stint teaching at the University of Fribourg in Switzerland, Klaus came to the US in 1957 on a grant from the Swiss National Fund to work at Stanford University with a pioneer of NMR, Nobel laureate Felix Bloch. Klaus revered Bloch as both a colleague and a teacher.
In 1960, Klaus joined the precursor to LBNL, the University of California Radiation Laboratory. There, he worked in the magnetic fusion group in the area of plasma physics. Following a nearly one-year return to Fribourg, where he was an assistant professor and started a plasma physics group, Klaus returned to LBNL permanently, where his first assignment was to lead the homopolar plasma generator project. His work with plasma physics led him into accelerator design. In one of his first design endeavors, he made a major contribution to the Omnitron; that design laid the groundwork for the Bevelac.
For all his success as an accelerator designer, Klaus is probably best known for his later work on magnetic systems for particle accelerators. He and his colleague (and later son-in-law) Ron Holsinger developed the famous POISSON package of computer codes for solving the Laplace equation—codes still in use today. Building on the expertise he developed in analyzing and designing conventional magnets, Klaus went on to become one of the world’s premier designers and developers of permanent magnet systems, primarily for use in wigglers and undulators. His contribution to the development of these permanent magnet insertion devices as synchrotron radiation sources was instrumental in the worldwide development of so-called third-generation light sources such as the Advanced Light Source and Advanced Photon Source. In 1995, in recognition of this work, the Advanced Photon Source Users Organization at Argonne National Laboratory awarded the Arthur H. Compton Prize jointly to Klaus and Nikolai Vinokurov.
Klaus was a consultant on accelerator projects and synchrotron light sources around the world, including the accelerator divisions at the Nuclear Physics Institute Jülich—now called the Research Center Jülich—in Germany and Los Alamos National Laboratory; the Stanford Synchrotron Radiation Laboratory; and the Advanced Photon Source at Argonne National Laboratory.
Although the only formal teaching position Klaus actually held was during his brief appointment at Fribourg, his contributions as a teacher were probably as significant as those he made as an applied researcher. The technical lectures he delivered were of outstanding clarity and presented in a way that invariably held the attention and interest of his audience. But more important was his ability—one might almost say his compulsion—to impart his ideas to anyone willing to listen, and even occasionally to those who weren’t.
The occasion for such one-on-one teaching was often one’s approaching Klaus with a difficult physics problem. He would supply the solution (which he invariably described as “trivial”) a day or so later, accompanied by an offer to explain further if there was any need. There almost always was. So Klaus would proceed to give a tutorial, not merely on the example at hand, but on a variety of related subjects, delivered with the enthusiasm and excitement he must have felt upon first learning it himself. He showed one the wonderful physics, and he made it fun. As a result, among the practicing physicists around the world are dozens who are, to use Klaus’s colleague Brian Kinckaid’s phrase, “alumni of Halbach U.”
Klaus’s inquisitiveness and enthusiasm as a physicist and teacher allowed him to work passionately and productively until a few months before his death. In the last year of his life, despite his illness, Klaus avidly continued to work. Nothing delighted him more during this time than to have colleagues come by to discuss their scientific work.
After Klaus’s death, numerous tributes from physicists around the world were shared at a memorial service. Perhaps none of them summarized the impact of his loss as well as the following: “In some ways, [it] is like losing both a friend and a father. Many times, when you have a question or a new idea, you think, ‘What would Klaus think about or say to that?’ Now there is no one to turn to.”
