JMSSJ On-line

JMSSJ On-line, Vol. 50 (2002) No. 1, pp. 11-14

Simultaneous Measurement of Mass and Velocity Distributions of Cluster Beams by Orthogonal Acceleration Time-of-Flight Mass Spectrometers		>> Full Text PDF >> References
*Naoaki SAITO,^a) Kazuyoshi KOYAMA,^a) and Mitsumori TANIMOTO^a)** ^a) National Institute of Advanced Industrial Science and Technology (AIST Central 2, Umezono 1-1-1, Tsukuba 305-8568, Japan)*

In order to study cluster beams, it is essential to measure their mass and velocity distributions as the fundamental characteristics. We demonstrate an experimental method to simultaneously measure both the mass spectrum and the beam velocities by the orthogonal acceleration time-of-flight mass spectrometer. The method is based on the ion-interruption effect of the electrode wire-mesh in the accelerator. The neutral clusters are photoionized in a small area in the accelerator, accelerated perpendicularly to the cluster beam axis, mass-analyzed and detected. Depending on the mass and the beam velocity, specific ions are interrupted by the wires arranged with a equal spacing and can not reach the detector. This ion-interruption effect modulates the transmittance of the ions, yielding the apparent oscillations in the mass spectra. Unfolding these modulated mass spectra, we have successfully measured both the mass spectrum and the beam velocities as a function of the mass simultaneously.

Key words: Cluster, Ion, Beam, Velocity, Mass, Wire, Mesh, Time-of-flight.