André Rousset 1930-2001
André Rousset, who played a major role in heavy-liquid bubble chamber physics at CERN, died on 1 July.
After studying at the Ecole Polytechnique, Rousset joined Louis Leprince-Ringuet's research laboratory in 1954, collaborating in pioneer cosmic-ray studies at the Pic du Midi de Bigorre. In 1960 he became professor at the Ecole des Mines, Paris, and was nominated a director of Leprince-Ringuet's laboratory from 1964 to 1969 before moving to CERN to lead work on heavy-liquid bubble chambers. There he managed the arrival of the big Gargamelle chamber, of which he had been one of the major constructors under the direction of André Lagarrigue, and its subsequent use for experiments in CERN's neutrino beam.
At Gargamelle the weak neutral current was discovered in 1973, signalling the unification of electromagnetic and weak interactions, which merited a Nobel Prize for the theoreticians who had made the prediction. André Rousset was one of the major players in this discovery, along with other physicists of the international Gargamelle collaboration, including André Lagarrigue and Paul Musset. He served as a member of CERN's Scientific Policy Committee from 1974 to 1980.
Returning to Paris in 1974, Rousset became a governmental scientific advisor, before moving to Aérospatiale in 1985, where he was to remain the chairman's scientific advisor until 1995. He retained his physics teaching post at the Ecole des Mines until he retired in 1968.
André Rousset was an enthusiastic and dynamic physicist who was gifted with keen intuition and a strong critical sense. His collaborators will remember a warm and cheerful man, full of spirit and humour, with whom it was always very pleasant to work.
Violette Brisson, LAL.Orsay and Ung Nguyen Khac, Ecole Polytechnique.
Christoph Schmelzer 1908-2001
Christoph Schmelzer, one of the pioneers of German particle accelerators and of CERN, a founding father of the GSI Darmstadt laboratory and from 1969 to 1979 its first scientific director, died on 10 June in Heidelberg at the age of 92.
Born in Lichtentanne, Saxony, and schooled in Zwickau, Schmelzer began his university studies at Munich's Technische Hochschule, initially in chemistry, before switching subject and university to study physics at Jena, where he submitted his thesis on high-frequency measurements in 1935.
After a short time at Jena as assistant to Max Wien, Schmelzer went to the US, but had to return in 1939, working until 1945 with Georg Goubeau in Jena on 10 cm wavelength physics and technology. In 1948 he became Walther Bothe's assistant in Heidelberg. In 1952 he turned his attention to particle accelerators at the time when the idea of CERN as a major European laboratory was being launched, becoming a key member of the group designing - and eventually building - the Proton Synchrotron (PS), which was then one of the world's two highest-energy accelerators.
From 1954 to the end of construction, Schmelzer served as deputy to PS Division leader John Adams. However, he is best remembered as the creator and inspiring leader of the group responsible for the PS radiofrequency acceleration system.
The construction of the world's first large alternating gradient accelerator, controlled by beam feedback, was new scientific territory, calling for imaginative new radiofrequency techniques, and many experts doubted that the result would be successful. The accelerating frequency had to follow a nonlinear function of the magnetic guide field with a precision that could not possibly be achieved by external programming. Moreover, a potentially fatal transition energy in mid-acceleration, at which the synchronous phase jumps from one side of the accelerating wave to the other, had to be overcome. Finally, precision frequency tracking of the ferrite-tuned accelerating cavities was required. All of these problems were solved by the first application of multiple feedback systems, deriving their input from the beam itself. Schmelzer was one of the inventors of this new technology.
The 1959 commissioning of the PS was described by Robert Jungk in his book The Big Machine (1968 Scribners, New York). After documenting a series of headaches, Jungk continued: "hardly had this [latest] disorder been cured when an extremely complicated radiofrequency system, geared to high-speed switching within ten-thousandths of a second, acted up. The method of beam control, invented in Heidelberg, in which the acceleration of the proton beam is regulated by its own feedback signals, would not listen to reason, and its master, Christoph Schmelzer, ordinarily easygoing, for the first time showed a nervousness that not even his beloved beer could control."
However, soon afterwards, everything came together, and on 24 November 1959 the PS protons sailed through the critical transition energy barrier without difficulty and reached 24 GeV with a transmission factor of 90%.
In 1959, Schmelzer became professor of applied physics at Heidelberg. He pushed the establishment of the GSI heavy-ion laboratory, equipped with the UNILAC linear accelerator, which was formally founded in December 1969 with him as its first scientific director. He furthered the development of the laboratory's installations with a ring accelerator to reach higher energies. Thanks to his vision and wisdom, the GSI laboratory went on to become a world player in heavy-ion research.
Christoph Schmelzer was an honorary professor at Heidelberg and a member of the Heidelberg Academy of Science. In 1978 he was awarded the German Bundesverdeinstkreuz. He is remembered as a warm-hearted and modest man, and his death represents the loss of a leading figure in scientific research.
Vladimir L Solovianov 1940-2001
Outstanding high-energy experimental physicist Vladimir L Solovianov died suddenly on 26 June at the age of 60 as a result of a tragic accident.
Born on 17 December 1940 in Dnepropetrovsk in the Ukraine, Solovianov received his diploma degree in physics at Moscow State University in 1964. That year he began his 37 year career at the Institute for High Energy Physics in Protvino, where he earned his candidate (PhD) and doctorate degrees in high-energy spin physics.
Early in his career, Solovianov helped to create the hodoscope detectors for one of the first elastic scattering experiment at the 70 GeV U-70 accelerator. He then made important contributions to the IHEP-SEN (Saclay) experiment, which made precision measurements of Coulomb-nuclear- interference cross-sections, inclusive cross-sections and spin-polarization effects. He was also a co-author of the key discovery at U-70 in the late 1960s for evidence of an increase in the proton's radius in high-energy strong interactions.
During the past 15 years, Solovianov was a leader in developing three spin-polarization experiments: NEPTUN at the 400 GeV - 3 TeV UNK, and RAMPEX and SPIN@U-70 at the 70 GeV U-70. These experiments form a major part of the Russia-US Physics Collaboration Program in Russia and a major part of IHEP-Protvino's large Polarization Program.
Solovianov was an unusually active and talented physicist. He also made significant contributions to several other CERN-Russia and US-Russia experiments, such as the SPS high-energy elastic polarization experiment at CERN and the E-704 lambda-decay polarized-proton experiment at Fermilab.
His death occurred while he was, as usual, working too many hours each day to ensure that his new and well loved SPIN@U-70 polarized high-momentum-transfer elastic proton-proton scattering experiment would be fully installed and ready to take data in the 70 GeV extracted beam in March 2002. His many colleagues in Russia and around the world will remember him as an outstanding scientist and a wise and loyal friend.
N E Tyurin, M N Oukhanov, A D Krisch.
* Jefferson Laboratory chief scientist and eminent theorist Nathan Isgur died on 23 July, aged 54. A tribute will follow