Rolf Siemssen

Rolf Hendrik Siemssen (15 March 1933 – 29 January 2021) was a Dutch -German nuclear physicist. He was a professor of experimental nuclear physics at the University of Groningen between 1971 and 1998. Siemssen was director of the Kernfysisch Versneller Instituut (nl) between 1972 and 1991.

Life Siemssen was born on 15 March 1933 in Fuzhou, China. During his youth he also spent a period in Shanghai. At the age of 14 he moved to Germany. In 1953, he started studying physics, first at the University of Tübingen and later the Ludwig-Maximilians-Universität München and ultimately the University of Hamburg. From 1963 to 1966 he was a research associate at Argonne National Laboratory. From 1966 to 1968 he was an assistant professor at the laboratory of D. Allan Bromley at Yale University. Between 1968 and 1971, he was a scientific employee at Argonne National Laboratory. He was tasked with making the institute a formal research institute. During the summer of the same year Akito Arima also visited the KVI for a three-month period on Siemssen's invitation. Iachello and Arima subsequently laid the base for the interacting boson model during their time at the KVI.

During Siemssen's time as director the spectrum of research at the KVI was broadened, with atomic physics being added in the 1980s. And in 1985 in a joint Dutch-French effort the decision was made to build a new cyclotron. In 1988 Siemssen was re-appointed as director for a three-year term. In August 1990 he asked to be relieved of his position per 1 January 1991. In 1998 he retired as professor. He was elected a member of the Royal Netherlands Academy of Arts and Sciences in 1987. Siemssen became a foreign member of the Polish Academy of Arts and Sciences in 2006. He was an officer in the Order of Orange-Nassau. He died on 29 January 2021 in Haren, Groningen, Netherlands.