Comparative radiation hardness results obtained from various neutron sources and the Niel problem

Starting from systematics on the current related damage constant α(0) for Si detectors irradiated in various neutron fields, we analyze the Niel scaling of the results to 1 MeV equivalent neutrons. The discrepancies present in the data obtained with reactor or spallation sources need a detailed discussion regarding the energy cuts used for the fluence measurements and calculations of the hardness parameter. A more attentive approach to the interpretation of the radiation hardness data is outlined.