AVS 50th International Symposium
    Surface Science Wednesday Sessions
       Session SS-WeP

Paper SS-WeP3
A Laser Plasma Vacuum Ultraviolet Light Source for Photo Desorption Studies

Wednesday, November 5, 2003, 11:00 am, Room Hall A-C

Session: Poster Session
Presenter: I. Arakawa, Gakushuin University, Japan
Authors: I. Arakawa, Gakushuin University, Japan
J. Sato, Gakushuin University, Japan
T. Miura, Gakushuin University, Japan
T. Hirayama, Rikkyo University, Japan
Correspondent: Click to Email
We have developed a laser-plasma vacuum ultraviolet light source (LPLS) as an excitation light source for the experimental studies of desorption induced by electronic transitions(DIET). Radiation from metal plasma, which is produced by laser beam focused on a metal surface, has a wide spectrum from infrared to X-ray and can provide a substitute for a conventional synchrotron radiation. In comparison with the synchrotron light source, LPLS has the advantage of being intense in short duration: the pulse width is the order of 10 ns, which is determined by a laser pulse. This distinctive feature makes it possible to obtain higher time resolution in a time-of-flight measurement of desorbed particles. The specifications of the Q-switched Nd-YAG laser we used in our LPLS are the followings; wave length: 532 nm with a second harmonic generator, maximum power: 210 mJ/pulse, pulse width: 10 ns, and repetition rate: 50 Hz. The radiation from the metal plasma is monochromatized by the three toroidal type gratings which cover the wavelength ranges of 4 - 12, 12 - 36, and 36 - 108 nm. We have choose Ta as the target metal for plasma source. This is because (1) a continuum like spectrum of primary radiation from plasma is expected in VUV range and (2) evaporated Ta will act as a getter pump in a vacuum chamber. The photon intensity of our LPLS apparatus is 10@super 7@ - 10@super 8@ photon/pulse in the pulse width less than 15 ns and with the resolution @lambda@/@DELTA@@lambda@ = 50 - 100 in the range of 12 - 108 nm. On application of our apparatus to the PSD experiment of a solid Ne, it was proved that the performance was satisfactory both in photon intensity and in time resolution for the DIET study.