Hi to all Radsafers. I'm finally deciding to find a check source for a Victoreen 450 P-SI Ionization chamber. I think that a Sr90 one could be OK. Does anybody have any experience? Thanks, Mauro *********************************************** Mauro Campoleoni Health Physicist Istituti Clinici di Perfezionamento Milan, Italy, tel. +35 +2 +57992166 ***********************************************