  The properties of 60-{\mu}m thick Ultra-Fast Silicon Detectors (UFSD)
detectors manufactured by Fondazione Bruno Kessler (FBK), Trento (Italy) were
tested before and after irradiation with minimum ionizing particles (MIPs) from
a 90Sr \b{eta}-source . This FBK production, called UFSD2, has UFSDs with gain
layer made of Boron, Boron low-diffusion, Gallium, Carbonated Boron and
Carbonated. The irradiation with neutrons took place at the TRIGA reactor in
Ljubljana, while the proton irradiation took place at CERN SPS. The sensors
were exposed to a neutron fluence of 4*10e14, 8*1014, 1.5*10e15, 3*10e15,
6*10e15 neq/cm2 and to a proton fluence of 9.6*10e14 p/cm2, equivalent to a
fluence of 6*10e14 neq/cm2. The internal gain and the timing resolution were
measured as a function of bias voltage at -20C. The timing resolution was
extracted from the time difference with a second calibrated UFSD in
coincidence, using the constant fraction method for both.
