Klaus Winter (1930 - 2015)

We learned with great sadness that Klaus Winter passed away on 9 February 2015, after a long illness.

Klaus was born in 1930 in Hamburg, where he obtained his diploma in physics in 1955. From 1955 to 1958 he held a scholarship at the Collège de France, where he received his doctorate in nuclear physics under the guidance of Francis Perrin. Klaus joined CERN in 1958, where he first participated in experiments on π⁺ and K⁰ decay properties at the PS, and later became the spokesperson of the CHOV Collaboration at the ISR.

Starting in 1976, his work focused on experiments with the SPS neutrino beam. In 1984 he joined Ugo Amaldi to head the CHARM experiment, designed for detailed studies of the neutral current interactions of high-energy neutrinos, which had been discovered in 1973 using the Gargamelle bubble chamber at the PS. The unique feature of the detector was its target calorimeter, which used large Carrara marble plates as an absorber material.

From 1984 to 1991, Klaus headed up the CHARM II Collaboration. The huge detector, which weighed 700 tonnes and was principally a sandwich structure of large glass plates and planes of streamer tubes, was primarily designed to study high-energy neutrino-electron scattering through neutral currents.

In recognition of the fundamental results obtained by these experiments, Klaus was awarded the Stern-Gerlach Medal in 1993, the highest distinction of the German Physical Society for exceptional achievements in experimental physics. In 1997, he was awarded the prestigious Bruno Pontecorvo Prize for his major contributions to neutrino physics by the Joint Institute for Nuclear Research in Dubna.

The last experiment under his leadership, from 1991 until his retirement, was CHORUS, which used a hybrid emulsion-electronic detector primarily designed to search for ν_μ− ν_τ oscillations in the then-favoured region of large mass differences and small mixing angle.

Among other responsibilities, Klaus served for many years as editor of Physics Letters B and on the Advisory Committee of the International Conference on Neutrino Physics and Astrophysics. He was also the editor of two renowned books, Neutrino Physics (1991 and 2000) and Neutrino Mass with Guido Altarelli (2003).

An exceptional researcher, he also lectured physics at the University of Hamburg and – after the reunification of Germany – at the Humboldt University of Berlin, supervising 25 PhD theses and seven Habilitationen.

Klaus was an outstanding and successful leader, dedicated to his work, which he pursued with vision and determination. His intellectual horizons were by no means limited to science, extending far into culture and the arts, notably modern painting.

We have lost an exceptional colleague and friend.
 

His friends and colleagues from CHARM, CHARM II and CHORUS