external exposure facility CERF Paul Schofield website The CERN-EU high-energy Reference Field (CERF) facility, located in the North Experimental Area of CERN and served by a secondary beam from the Super Proton Synchrotron (SPS), reproduces the mixed radiation field encountered near high-energy particle accelerators and at commercial flight altitudes. A 120 GeV/c positively charged hadron beam (approximately 2/3 pions and 1/3 protons) strikes a copper target to produce a neutron-dominated mixed field; ambient dose equivalent rates range from 5–250 μSv/h on the concrete roof and 18–360 μSv/h on the iron roof. The facility is used for calibrating and testing dosimeters and radiation protection instruments for aviation, space and accelerator applications, with around ten international user groups per year. Located at CERN. The CERN-EU high-energy Reference Field (CERF) facility for dosimetry at commercial flight altitudes and in space, A. Mitaroff and M. Silari, Radiation Protection Dosimetry 102, 7-22, 2002