In the wake of the departed

Leonid Tkachev 20.01.1939 - 11.10.2024

On 11 October, Advisor to Directorate of the Dzhelepov Laboratory of Nuclear Problems of the Joint Institute for Nuclear Research Leonid Tkachev passed away at the age of 85. He started working at JINR in 1963 as a postgraduate student seconded to the Laboratory of Theoretical Physics and in 1966, he joined the Laboratory of Nuclear Problems of JINR as a researcher.

From the beginning of his scientific activity, Leonid Tkachev was actively engaged in the preparation of the project of a multi-cube liquid hydrogen chamber and later, he was involved in theoretical and methodological research on the basics of the operation of an ultrasonic bubble chamber. Based on the results of these papers, in 1972, Leonid Tkachev successfully defended his PhD thesis.

From 1975 to 1984, Leonid Tkachev worked at the RISK facility. He made a significant contribution to processing of the experimental data, as well as to development of a number of key units of the facility: the gas system, the data acquisition system and a number of other systems. In addition, he successfully participated in organizing the work of the international staff at all stages of preparing and implementing the experiment on the RISK spectrometer at IHEP, starting with the design of the spectrometer and ending with the analysis of the obtained data.

In 1986-1992, Leonid Tkachev headed the topic COCOS - a satellite communication channel between JINR and Western scientific centres. Since 1984, he has been participating in the DELPHI collaboration. Twice (in 1986-1987 and 1993-1997) he headed a group of JINR specialists at CERN.

Recently, Leonid Tkachev has been actively engaged in the NUCLEON, TOUS, TAIGA collaborations and in the scheduled HERO and SAHEAS experiments as leader of the topic "Astrophysical research in space experiments".

Leonid Tkachev was a highly qualified physicist with an excellent theoretical base, he was distinguished by his wide scientific interests, independence and initiative in defining and meeting tasks, passion for science, dedication to work and the ability to work in the staff. He is the author of more than 700 scientific papers, a significant part of which were reported at international conferences.

Leonid Tkachev successfully passed on his knowledge to the younger generation, teaching a course in cosmic ray physics at the Department of Nuclear and Elementary Particle Physics at Dubna University.

Working at the Joint Institute for Nuclear Research, he demonstrated his best qualities - the ability to delve deeply into a task, diligence, discipline, initiative and efficiency. With his organizational talent and conscientious work, he won authority and respect. His workmates, colleagues and friends knew him as a responsive person, not indifferent to the misfortunes of others, capable of providing support in difficult times. Eternal memory to our colleague.

Management and staff of the Laboratory of Nuclear Problems