The collimator system in the High Intensity Proton Accelerator (HIPA) at PSI is responsible for stopping the 590 MeV protons that are in the halo of the beam. The halo beam comes from the 4 cm graphite target about 5 meters upstream of the collimator system. It is estimated that 14% of the total beam power will be intercepted by the adopted collimating scheme and the maximum temperature of the collimator system may exceed 400 °C at a beam intensity of 2.5 mA. The KHE2 collimator is exposed to the highest heat load caused by energy deposition from the proton beam and it has been in operation since 1990. A replacement of KHE2 equipped with sample plates was built and successfully inserted in the beam line. The sample plates consist of two parts made of OFE copper and Glidcop® AL-15. They will be used for material property analyses after irradiation. This paper presents experimental and numerical thermal analyses, which have been carried out to characterize the thermal efficiency of the system.