The relaxation dynamics of jet cooled naphthalene (NPH) has been studied by mass-resolved transient ionization, following excitation to the S-1(L-b) and S-2(L-a) states and further single/multi photon ionization at a variety of probe wavelengths. Time-dependent signals were collected from the parent C10H8+ and the C10H7+ fragment ions. The relaxation transients include two lifetimes of 30 and 800 fs. The short decay suggests the presence of a conical intersection nearby the L-a state surface minimum that is crossed in one single passage by most part of the population, whereas the long lifetime is tentatively assigned either to internal vibrational redistribution (IVR) within the L-b state, or to the decay of coherent recurrences. (C) 2008 Elsevier B. V. All rights reserved.