Academician Olli Viktor L o u n a s m a a, born on August 20, 1930, earned his Bachelor's Degree in physics from the University of Helsinki in 1953 and his D. Phil. Degree from the University of Oxford in 1958. His thesis was on the thermodynamic properties of fluid 4He. After two years of research on liquid 4He at the University of Turku in Finland he became, in 1960, Resident Research Associate of the Argonne National Laboratory near Chicago. There he built a 3He refrigerator and completed an extensive series of measurements on the nuclear heat capacity of rare earth metals. During this period he also did some research on liquid 4He near the l-transition.

In 1965 Lounasmaa returned to Finland. He was appointed Professor of Technical Physics at the Helsinki University of Technology where he founded the Low Temperature Laboratory (LTL) and became its director. Since then he has specialized in research at milli-, micro-, nano- and even picokelvin temperatures. In 1970 he was appointed Professor of the Academy of Finland. Government rules forced him to retire in January 1996. Three refrigerators, employing adiabatic nuclear demagnetization techniques for cooling, have been operating under Lounasmaa's directorship in the Low Temperature Laboratory. In two of them, rotating 3He can be investigated between 0.4 and 3 mK: extensive NMR, superfluid flow, ion mobility, ultrasonic, and optical measurements have been carried out on vortices in rotating 3He-A and 3He-B. The first demonstration of superfluidity in 3He was made and eight different vortices, including a vortex sheet, were discovered.

The third cryostat, intended for research on nuclear cooperative phenomena in metals, has two nuclear cooling stages working in series. This apparatus and its modifications have held many world's low temperature records, currently 100 pK in the nuclear spin system of rhodium. The same cryostat has produced "record-high" negative spin temperatures, first in silver and then in rhodium (—750 pK). Three antiferromagnetic phases have been discovered in copper and antiferromagnetic and ferromagnetic phases in silver.

Another double nuclear refrigerator, constructed in Helsinki for neutron diffraction studies at nanokelvin temperatures, was operating first at the Risø National Laboratory in Denmark in 1985 — 90 and then at the Hahn-Meitner-Institute in Berlin in 1991 97; this was a joint Danish-Finnish-German research effort, partially financed by the European Community's SCIENCE program. Nuclear ordering in copper at T > 0 was studied in Risø and investigated in silver in Berlin. The LTL is also participating in the Spin-Muon Collaboration at CERN by being responsible for the construction of a very powerful dilution refrigerator. Much work has also been done by Lounasmaa and his students on the Mössbauer effect, on thermometry below 1 K, and on the use of SQUIDs for low temperature and brain research. Large scale uses of superconductivity have been investigated as well, including the construction of a 0.17 — T superconducting solenoid for whole-body MR imaging. A 1.5 T magnet, 2 m long and with an 0.8 m bore, was completed in 1988.

In 1977 Lounasmaa worked for a year at Saclay near Paris. He has also spent 1 to 2 months as Visiting Professor in the United States, Japan, India, Germany and Denmark. During the Academic Year 1982 — 83 he pursued research first in the University of California at Berkeley and later in the New York University. Most of 1996 he was working in the Hahn-Meitner-Institut in Berlin. Since the beginning of 1997 he came back in his old laboratory in Finland as an Academy Professor Emeritus.

Prof. Lounasmaa is the author of 250 scientific papers, including a book entitled Experimental Principles and Methods below 1 K. He has given almost 300 seminar or colloquium talks at low temperature laboratories throughout the world and attended about 100 international conferences, presenting over 40 plenary or invited papers. He has also given 20 series of lectures abroad, many of them at international schools of physics. Lounasmaa has supervised the Ph.D. theses of 48 students and written expert's opinions on the qualifications of candidates for many professorships in Finland and abroad. While he was the director of the LTL, a total of 58 Ph.D. theses were approved. In 1994 — 96 Lounasmaa was the Coordinator of two Large-Scale Facilities, BIRCH in neuro- and cardiomagnetism and ULTI in ultralow temperature physics, established by the European Union's Human Capital and Mobility Program. He has also been active in science policy in Finland having served, for example, in 1980 and in 1984 as Chairman of Ministry of Education's working groups on basic research. At the Ministry's request he prepared in 1995 a 70-page evaluation of the departments of mathematics, physics, chemistry, and computer sciences in Finnish universities.

Prof. Lounasmaa has participated extensively in international collaboration among low temperature physicists. He has been President of the Commission on Cryophysics of the International Institute of Refrigeration and Chairman and Member of the Very Low Temperature Physics Commission of the International Union of Pure and Applied Physics; he has also been a member of the International Cryogenic Engineering Committee. For four years he served on the Executive Committee of the European Physical Society. In 1992 — 99 he was member of Comité International des Poids et Mesures. He was in 1975 President of the 14th International Conference on Low Temperature Physics (LT-14) and in 1984 President of the 10th International Cryogenic Engineering Conference (ICEC-10). He was President of the 7th General Conference of the European Physical Society (EPS-7), held in Helsinki in 1987. He has organized six smaller international conferences and several winter schools with foreign participation. He has been a member of the International Committees of over 20 scientific conferences held abroad. He has been member of the Editorial Boards of many scientific journals; currently Europhysics Letters and, most importantly, Proceedings of the National Academy of Sciences of the USA.