The electromagnetic component of large air showers

Nine scintillators each of area 1.1 m2 and 7.8 g cm-2 thickness have been placed 500 m from the centre of the Haverah Park array. Comparison of the signals from these detectors with the Haverah Park Cerenkov tanks near them, and analysis of the energy-loss spectra measured by the scintillators at larger distances from the cores of showers of nominal size 2*107 particles, has yielded the lateral distributions of number and energy flux of the incident electromagnetic component from 200 to 1100 m. It is found that the energy flux of this component, mainly photons, varies over this distance from 1000 MeV m-2 to of the order of 1 MeV m-2 and the photon number from 1000 m-2 to of the order of 1 m-2. Spectra of the photons incident at the larger core distances can be obtained in fair approximation.