Capillary array as an effusive molecular beam source for high resolution recoil ion momentum spectrometry

The role of a capillary array as a molecular beam source for use in recoil ion momentum spectrometry in ion-atom collisions is investigated. Numerical simulations show that by using a capillary array it is possible to obtain a half-width of 1 meV at room temperature, while the sensitivity could be in the range as low as 100 μeV. Preliminary measurements with electron impact ionisation showed the effectiveness of this technique by providing an energy resolution of about 2 meV at room temperature, which is superior to the resolution reported using a gas cell cooled to 30 K. (orig.)