By the virtue of the decision of the University Senate, the Merentibus Medal, the highest distinction of the Jagiellonian University, was awarded to Professor Walter Oelert from Germany by the University Rector Professor Franciszek Ziejka. The ceremony was held on 25th September 1999 in Stuba Communis, the representative Hall of Collegium Maius, which is the oldest building of the University In his laudatory address, Professor Lucjan Jarczyk described the inestimable merits of Professor Walter Oelert in the development of the exemplary and successful collaboration between physicists from the Jagiellonian University and the Research Centre Jülich in Germany. He stressed that the scientific success of many physisist from our University is due to his enormous personal engagement. Before the Rector invited guests to toast the guest, Professor Walter Oelert expressed his thanks by giving a short speech in Polish and gaining the sympathy of the whole audience.

The ceremony was preceded by a Symposium on ten years of the Jülich - Kraków Collaboration on the accelerator COSY, which took place in the Michal Bobrzyñski Conference Hall in Collegium Maius. The meeting was opened by the talks of Professor Walter Oelert and Professor Lucjan Jarczyk, who presented some of the highlights of the 20 years of the Jülich - Kraków collaboration in the field of a nuclear physics, and 10 years of common research at the high precision particle accelerator COSY. These presentations were followed by contributions from Professors K. Kilian, S. Krewald, A. Szczurek, H. Ströher and A. Magiera on present and future physics at COSY.

Thanks to Professor Walter Oelert, we have managed to create up-to-date equipped laboratories in the Institute of Physics at our University. These eliver high quality particle detectors to many experiments carried out at the European research centers. Many physicists from our University have opportunities to perform experiments at the modern physics facilities of the Research Centre Jülich, and these have resulted in numerous doctoral and habilitation dissertations. The effects of the continuing collaboration can be counted through the impressive number of a common physics works published in the most prestigious journals. The series of conferences, initiated in 1991 by Professor Walter Oelert and Professor Lucjan Jarczyk and organised in Kraków, is well recognised in the international community. The next conference in this series will take place this year and, for the first time, will unite medium and high energy particle physicists.

Being a great personality, Professor Walter Oelert managed to create in our group a real family and creative atmosphere, which results in a perfect performance of many experiments and in the formation of friendly relationships between German and Polish physicists.

As stressed in the diploma, read in Latin by Professor Karol Musiol, Dean of the Mathematics and Physics Faculty, Professor Walter Oelert is distinguished for his many outstanding contributions in physics. These include the successful development of the experimental programme of meson production at the accelerator COSY and the splendid achievement of synthesising atoms of antihydrogen, the very first antimatter atoms created consciously by man in the laboratory. Such antimatter has often been produced in laboratories over the last 40 years. However it was only in 1995 that, under the leadership of Professor Walter Oelert, the international group of physicists in the CERN laboratory managed to show that they had obtained experimentally eleven atoms of antihydrogen. The investigations are being continued and, in the next few years, the colour of light emitted by hydrogen and antihydrogen will be compared with fantastic accuracy. If a difference were observed then this would change the basis of contemporary physics.

Pawel Moskal, Ph.D.
Nuclear Physics Department, JU