On 22 June 2023, Prof Mieczysław Zielczyński passed away at the age of 93.

He was a long-time employee of the Nuclear Research Institute, then the Atomic Energy Institute and the National Centre for Nuclear Research. He worked in the field of radiation protection, its effects on the human body, dosimetry and radiation surveying. He was called the father of mixed radiation dosimetry and developed recombinant dosimetry methods, which are still used today. He was remembered as an extremely warm, ever-smiling and kind-hearted man, and a great teacher of two generations of scientists.

The following excerpt from a 2019 interview shows one of his passions - orienteering, which he pioneered in Poland.

"Professor Mieczysław Zielczyński is almost 90 years old, having been born in January 1930. He comes from near Lviv and has lived in Warsaw for a long time. He is a world-renowned nuclear physicist and one of the pioneers of Polish sport orienteering. He is still active all the time, regularly competing in cross-country and orienteering competitions, and this coming weekend he will once again represent Poland in the Masters World Championships. The veteran orienteering championships will be held in Latvia. (...)

- I spent many years in the Soviet Union, working at the United Institute of Nuclear Research near Moscow, then 2 years at the famous CERN in Geneva. We often went hiking with a group, e.g. to Lake Baikal, to the northern Urals, we made the first passes to the Baikal passes. (...)

- Surely you read the map well?

- For so many years I managed to learn (laughs). I worked professionally for a very long time, until I was 82, I worked mentally, because I am a nuclear physicist. So I'm pretty good with a map too.

- Professor, how long do you intend to keep going like this? And run and compete?

- Until I do! That is, as long as I can. I'm sure I won't be able to, but as long as my health and strength allow, I'll keep running. If I live to see it, I would still like to compete in the M95 category.

The team of co-workers remembers 'Mietek' very warmly and will continue to work with the detectors and recombination methods he invented with great satisfaction.

We are not saying goodbye, but see you Professor....

The farewell ceremony for Professor Mieczysław Zielczyński will take place on 7 July 2023 (Friday) at the Northern Cemetery in Warsaw. The ceremony will begin at 12.30 p.m., farewell room "B".

Professor Zielczyński is remembered by Stanisław Pszona

Mieczysław Zielczyński started working at the Institute of Nuclear Research in 1956 and continued working in its successive transformations (IEA, NCBJ) until his retirement in 2012.

In 1959-64, he stayed at ZIBJ Dubna, where he obtained his doctorate in physics (candidate of sciences). While at ZIBJ, he began work on the application of the phenomenon of recombination of ions formed under the influence of ionising radiation in pressurised gas. This phenomenon was used to determine the quality factor of mixed radiation in the radiation fields of nuclear devices. As a result, he developed ionising chambers operating in the recombination regime, which brought him worldwide success. He continued his work on recombination chambers at CERN from 1975 to 1977, successively obtaining the degrees of Dr. Habilitated and Professor of Technical Sciences. During his career, he formed a research team that continues to develop this field of metrology in radiation protection and radiotherapy. The ResearchGate publication list lists 60 papers authored and co-authored by Mieczysław Zielczynski and over 300 citations. Professor was open to collaboration and inspired my research interests with his work.

Together with his wife Helena, they created a Home where we spent many cordial meetings between 1980 and 2018.

You will remain in our memory

Stanisław Pszona