Key Parameters:

Base Vacuum for main chamber:  ~ 1×10-10 Torr
Base Vacuum for ionization chamber:  < 5×10-12 torr
Temperature range for sample:  100 - 1000 K ;
Surface preparation tool:  ion gun;
Surface detection tool:  AES and LEED
Mass range for mass spectrometer:  1-60 amu
Sensitivity for mass spectrometer:  8-12 mA/Torr
Filament for mass spectrometer:  Thoriated Iridium
Electron energy for ionization:  0.1-100V

Functions & Applications

This apparatus devoted to study kinetics and mechanism of photochemical processes with various signal crystal surfaces has been constructed. Extremely high vacuum (～2x10-12 Torr) for the detector’s ionization region is maintained using multiple ultrahigh vacuum pumps. Compared with previously built similar instruments, the H2, CH4 background in the ionization region can be reduced by about two orders of magnitude; other residual gases in the ionization region can be reduced by about an order of magnitude. Therefore, the signal-to-noise ratio for the temperature programmed desorption (TPD) and time of flight (TOF) spectra is substantially enhanced, making experimental studies of photocatalytic processes on surfaces much easier. In addition, combination with tunable femtosecond laser source, we could study the effect of photon energy on photocatalysis.