Simulations for CMS hadron endcap calorimeter upgrade at HL-LHC

The upgrade of the present endcap calorimeters is foreseen to prepare the CMS experiment for the High Luminosity LHC. Integrated doses at the location of the front layers of the hadron endcap calorimeter are expected to reach 20 Mrad. Studies of radiation fields are presented in this report. At the same time, the effects of pileup will become more severe, making the identification of jet objects more challenging. We estimated the effects of different transverse segmentations of back hadron calorimeter (BH) for CMS upgrade.