Cosmic ray physics began in Łódź when new higher education schools started there after the war (in the fifties). Aleksander Zawadzki was the person who, following the advice of prof. Marian Miesowicz from Kraków, started to build an extensive air shower array for cosmic rays with E ~ (1015 - 1016) eV being then one of the first in Europe. A new branch of the Institute of Nuclear Research from Warsaw was installed in Łódź to develop these studies, together with the group at the University of Łódź. The array was based on the Maze type Geiger-Mueller counters, some of them being covered by iron and lead for muon content studies. It has been developed and modernized over several years, e.g. adding timing and an 36 m2 underground muon detector, 14m underground to search for muon poor (gamma induced) showers.
Later on, particularly when prof. Zawadzki stayed in France, the trend was to develop more theoretical work in high energy astrophysics and high energy interactions. George Wdowczyk was the one who led this, collaborating closely with Arnold Wolfendale from the University of Durham and his co-workers. Some of the University people (a group led by Alojzy Tomaszewski) were for many years members of the Pamir Collaboration. There was also a fruitful collaboration of our both institutions in hardware while the KASCADE experiment was being built, and it has been continuing in data analysis and KASCADE-Grande till now. There were three European Cosmic Ray Symposia organized here, in 1968 - the first one, 1974 and 2000.
At present the group at the University works in the Pierre Auger Collaboration (highest energy cosmic rays) and in MAGIC Collaboration (TeV gamma-ray astrophysics). The group in the A. Sołtan Institute for Nuclear Studies works in KASCADE-Grande and LOPES Collaborations, it develops neutron detection in high energy cosmic rays still using Łódź underground facility, and builds the Roland Maze Project - cosmic ray detectors on the roofs of the high schools in Łódź.
Text: Maria Giller