Electromagnetic shower profile measurements in iron with 500 MeV electrons

The longitudinal and lateral shower profiles for 500 MeV electrons in iron are studied using dosimetry and activation techniques. The results are comp ared with Monte Carlo simulations and other previously published data. The agreement between the data and the EGS4 simulation results is good; a simpl e shower profile parametrization of type kz(x-1) exp(-betaz) does not repre sent the experimental data well at and around the shower maximum. The diffe rences observed in the activation and dose profiles clearly show the role o f photons in electromagnetic showers. The photon fraction increases as the shower develops deeper and they carry a larger energy fraction farther into the absorber. Photodisintegration reactions are responsible for the activa tion of the iron and we identified Mn-54, Fe-53 and Mn-56 as more active is otopes among several others. These studies were performed for estimating th e dose and its profile for the CMS quartz fiber calorimeter radiation damag e work performed at LIL (CERN). (C) 2001 Elsevier Science B.V. All rights r eserved.