Secondary ion statistics and determination of nanocluster (m>107amu) ion registration efficiency

The m/q spectra of gold nanocluster ions (NCI) ((D) = 18.1 nm and (m) = 4.6 x 10(7) amu) desorbed from nanodispersed targets with Cf-252 fission fragments were measured using a tandem time-of-flight mass spectrometer at acceleration of 38 W In parallel, the statistics of secondary ions (SI) emitted with NCI from various converters (Au and CsI) were measured and the registration efficiency (RE) of NCI was determined. It was shown that distribution of SI number is most adequately described by the geometric distribution. The resulting values of RE are less by a factor of 1.5-2 than those predicted by the Poisson distribution for the m/q range from 3.1 x 10(6) to 8.2 x 10(6) amu/e. (c) 2006 Elsevier B.V. All rights reserved.