Abstract
The atomic beam apparatus has been employed to observe the Sodium spectrum using two step laser excitation schemes. The first dye laser pumped by the second harmonic generation (SHG) 532nm excites the atom from the 3s S-2(1/2) ground state to the 3p P-2(1/2) or 3p P-2(3/2) multiplets of the first excited state which are further ionized by a photon from the third harmonic 355nm of the Nd-YAG laser. The ions are directed to the channeltron by applying a positive voltage to the lower ion deflecting plate. The ions signal from the channeltron has been recorded on a computer after processing through a box car averager. The ionization peaks and the calculation of Full width Half Maximum (FWHM) of Sodium are studied by varying the voltage on the lower ion deflecting plates.