Neutron and Proton Tests of Different Technologies for the Upgrade of Cold Readout Electronics of the ATLAS Hadronic Endcap Calorimeter

The expected increase of total integrated luminosity by a factor ten at the sLHC compared to the design goals for LHC essentially eliminates the safety factor for radiation hardness realized at the current cold amplifiers of the ATLAS Hadronic Endcap Calorimeter (HEC). New more radiation hard technologies have been studied: SiGe bipolar, Si CMOS FET and GaAs FET transistors have been irradiated with neutrons up to an integrated fluence of 2.2 x 10^16 neutrons/cm^2 and with 200 MeV protons up to an integrated fluence of 3.4 x 10^14 protons/cm^2. Comparisons of transistor parameters such as the gain for both types of irradiations are presented.