Relaxation of 5s22D3/2 states of Cd ions in He atom collisions in a He-Cd medium excited by fission fragments

Efforts to obtain lasing at the 325 nm CdII transition in a high pressure He-Cd medium pumped by the nuclear reactions products were unsuccessful, in contrast with the same 441.6 nm transition. Experiments carried out at the fast burst nuclear reactor in order to obtain information about the relative intensities of the 441.6 and 325 nm luminescence lines as a function of pressure have allowed to evaluate the constant of the reaction Cd+ (5s22D3/2) + He → Cd+ (5s22D5/2) + He, which has been found to be about 1.5×10−13 cm3/s. Thus the intensities of the 441.6 and 325 nm luminescence lines measured in a nuclear pumped He-Cd medium are almost equal and the hypothesis about the strong deexcitation of the Cd+(5s22D3/2) state by He has not been confirmed.