We present a summary of recent tests and measurements of hadronic interaction properties with air showers. This report has a special focus on muon density measurements. Several experiments reported deviations between simulated and recorded muon densities in extensive air showers, while others reported no discrepancies. We combine data from eight leading air shower experiments to cover shower energies from PeV to tens of EeV. Data are combined using the z-scale, a unified reference scale based on simulated air showers. Energy-scales of experiments are cross-calibrated. Above 10 PeV, we find a muon deficit in simulated air showers for each of the six considered hadronic interaction models. The deficit is increasing with shower energy. For the models EPOS-LHC and QGSJet-II.04, the slope is found significant at 8 sigma.

The idea of a novel type detector array is the following: delayed thermal neutrons generated by hadronic component of Extensive Air Showers (EAS) can be detected over the whole array area using special electron-neutron detectors (en-detectors). The array PRISMA-32 consists of 32 en-detectors, deployed over the area of 450 m 2 . En-detectors are able to detect two main EAS components: electromagnetic one in a case of a synchronous passage of several charged particles, and hadronic component through thermal neutron captures. Detectors are based on a specialized inorganic scintillator, being a granulated alloy of ZnS(Ag) with LiF, enriched up to 90% with 6 Li isotope. The array is triggered by the electromagnetic component of EAS, and provides information about the energy deposit (mostly electrons) and delayed neutrons accompanying the EAS within 20 ms after the trigger. During 2 years of operation more than 10 5 events were recorded. Examples of EAS detection are presented.

The purposes, tasks and design features of the new measuring system of the Cherenkov water detector NEVOD are discussed

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