In Memoriam
Josef Kemmer
March 2, 1938 – October 16, 2007
Submitted by Pavel Rehak,
Brookhaven National Laboratory, Upton, NY 11973-5000, USA.
Josef Kemmer passed away after a three year battle with colon cancer. He will be missed in the detector community, in which he pioneered the planar technology of silicon radiation detectors.
Josef was born as the second youngest child of a family of ten children in the small farming village of Burgerroth, close to Würzburg in Germany. In 1959 Josef started studying physics at the University of Würzburg where he obtained the German equivalent of a Bachelor’s Degree. He continued at the famous University of Heidelberg where he obtained the equivalent of a Master’s Degree in 1965. There, he started his seminal career in semiconductor detectors. His diploma thesis was titled “Development of a combined dE/E counter by boron implantation in n-silicon”. After obtaining this degree, Josef spent two years at the Max Planck Institute (MPI) for Nuclear Physics in Heidelberg where he designed and constructed lithium drifted germanium detectors Ge(Li). In 1966 he moved to Munich and started to work on his PhD at the Institute for Radiochemistry of Technical University (TU)-Munich. The title of his PhD thesis was “Analysis of the mass distribution of the fission products of Pa-231 and U-232 by irradiation of reactor neutrons.” The measurements were done with an experimental-setup of Ge(Li) detectors built by Josef himself.
After obtaining his PhD in 1970, Josef stayed at TU Munich where he headed the detector laboratory until 1992. At the beginning of his time at TU Munich, Josef improved Ge(Li) detectors, however, soon his attention moved toward silicon detectors. During this period Josef produced the most important contribution to the field of silicon detectors. In 1980 he published the now classical paper [1] in Nuclear Instrument and Methods (NIM). Josef is the sole author of the publication, which is slightly longer than three pages. The paper describes a new, yet relatively simple way to produce superior silicon detectors. The technology used to produce silicon radiation detectors described in this paper was a radical departure from the accepted technology. In the conclusion of his paper, Josef modestly claimed: “Using the planar process it is possible to fabricate Si radiation detectors of extremely low reverse current by the improvement of the charge carrier lifetimes and by elimination of surface leakage currents.” The development of many new kinds of silicon radiation detectors was made possible by the technology introduced by Josef. It was immediately recognized that Josef’s technology was ideally suited for producing finely segmented silicon detectors for position sensing. Precise position sensing became an important requirement for an increasing number of experiments in elementary particle physics and it is Josef’s achievement that silicon detectors today are essential for all experiments in high energy physics. It was also recognized that this technology was capable of producing new semiconductor detectors with complex design, like drift and pixel detectors.
After the publication of [1], Josef collaborated closely with physicists of MPI Munich for more than 20 years. During that time Josef was in charge of a team of people working in several semiconductor laboratories. The first laboratory was at TU Munich in Garching, the next in the central research laboratory of MBB in Ottobrunn, and then in the semiconductor laboratory of the MPI in München-Pasing and Neuperlach. In 1990 Josef founded and managed his own company KETEK. In this period several hundred publications document Josef’s activities and simultaneously the progress of silicon radiation detectors. The peak achievement came in December 1999 when a satellite called X-ray Multi Mirror mission (XMM) was launched. One of the principal X-ray detectors in the focal plane of the X-ray mirrors was the fully depleted, back illuminated pn-Charge Coupled Device (pnCCD) designed and produced by the MPI semiconductor laboratory in Munich [2]. Josef’s contributions were critical to the success of the project.
Josef was a colleague and mentor to many younger professionals in the field of silicon detectors. He was an excellent teacher and a dedicated tutor for many students (PhD and diploma) and postgraduates. When his students are asked to characterize Josef, the most often mentioned word is “creator”. It fits into several aspects of Josef’s life. It aptly describes his contributions to silicon detector technology, his bright new ideas, passion for truth, scientific curiosity, and permanent search for beauty not only in his professional activities but in all aspects of life as well. He remained creative to the very end of his days and he was constantly inspiring others. Moreover his inspiration was not an end in itself. Josef was always there to support the constructive ideas to their largest possible extent. Josef’s enthusiasm and pioneering spirit motivated many younger people to join KETEK. KETEK was always ready to give chances to many young scientists and technicians to start their professional carriers. Josef was a careful manager, planning for long-term goals, aiming for sustained growth, security and stability, and a family working atmosphere. Although Josef was often faced with obstacles and setbacks, he never lost his realistic evaluation of the current situation and his optimism to find solutions.
Josef’s interests extended well beyond his professional field. Josef was actively interested in art, performed music, and dedicated his time to his garden. He was an excellent sketch artist and sponsored young artists, including the now famous artist Jutta Bosch. He loved classical music and played the organ, piano, and harmonica. He enjoyed working in his Japanese-style garden with domestic and exotic plants. Josef travelled extensively and was an ambitious photographer and filmmaker. Josef had a clearly defined life philosophy. He was determined, aspiring, diligent, modest, down to earth, religious, humanistic, humorous, and noble. He sponsored, within his relatively modest means, students as well as scientific and ecclesiastic projects. The following is an incomplete list of activities which Josef enjoyed: exceptional paintings, good poems, scientific or philosophic discussions, organ concerts of J.S. Bach, the statue “Riemenschneider-Madonna” from St. Burkhard church, and his gardens.
Josef’s fight against cancer was the most tragic part of his life. Josef’s first cancer of the colon was diagnosed at the end of 2004. He went through surgery and decided against chemotherapy but tried other methods of fighting the disease. Josef recovered and worked in 2005 and 2006. One bright, colourful autumn day in 2007, Josef died very peacefully.
Josef will be missed by the radiation detector community, by his many friends, and by his family, especially his wife of 42 years, Traute, his two daughters, Silvia and Susanne, and two grandsons, Josef and Konrad. Josef will be missed but never forgotten.
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