Muonography of the structure of the power unit of the Kalinin NPP

A large-area hybrid muon hodoscope for studying the internal structure of large-scale objects using the muonography method was constructed at the National Research Nuclear University MEPhI in 2022. The hodoscope detecting system has a hybrid structure and consists of a scintillation strip detector and a drift tube detector and is designed to record tracks of charged particles, mainly muons. Recording systems, data processing and particle track reconstruction methods have been developed for each detector. Experimental studies of the internal structure of the Kalinin NPP power unit using the muonography method were carried out in 2022–2023. A description of the design of the hybrid muon hodoscope, the method for constructing muonograms, as well as the results of the first experiment conducted under normal operating conditions of the power unit are presented in the article.