Massive clusters: Secondary emission from qkeV to qMeV. New emission processes? New SIMS probe?

Abstract

We report on the secondary ion emission under massive cluster (from 100 to 1600 atoms) impacts from different organic samples. The study has been preformed at the Orsay Tandem Accelerator equipped with a Liquid Metal Ion Source (LMIS) using a time of flight (ToF) mass spectrometer (MS) with a multianode localization detector. The influence of the projectile mass and energy is studied in order to investigate the new hydrodynamic regime of the solid-particle interaction related to the use of these massive clusters. We shall present this study, the energy range of which extends from 10 qkeV up to 4 qMeV. The results show that the ionic emission intensities increase with the energy and the mass of the projectiles (from n/q = 25 to n/q = 400) which allows the simultaneous emission of a few tens ions of the same mass per impact, what had never before been observed in SIMS. The study of the positive ionic emission is surprising. There is an important emission (also a few tens ions) of H + , H 2 + , H 3 + and C + . The setup permits to determine the angular velocity distributions of the ejected ions. We present the results which permit to distinguish four classes of ionic emission. The molecular ions and molecular clusters are preferentially pushed from the surface by a pressure wave which rises perpendicularly to the beam trajectory.

Light‐Mediated Heterogeneous Cross Dehydrogenative Coupling Reactions: Metal Oxides as Efficient, Recyclable, Photoredox Catalysts in CC Bond‐Forming Reactions

“…A new way was thus opened to increase the molecular ion emission yields by a factor 1000 compared to those obtained by the bombardment with an atomic projectile16 at low energy. Moreover, the damage cross‐section measurements for different cluster beams including massive clusters show clearly a low damage cross‐section for Au 400 4+ ,16 and the ratio between the molecular ion emission yield and damage cross‐section increases with the energy and the mass of the cluster 17. Recently, a study of the influence of the projectile energy from 20 qkeV to 4 qMeV18 permits to reach ion emission rates higher than a few tens of molecular ions per impact.…”

Analysis of Native Biological Surfaces Using a 100 kV Massive Gold Cluster Source

“…Recent efforts have focused on the use of higher energy and larger cluster projectiles (e.g., C 60 and Au 400 ) to increase the secondary ion signal. 25–28 …”

Characteristics of positive and negative secondary ions emitted from Au3+ and Au400+4 impacts

“…[16] Such simulations as well as experimental results have shown that molecular ion emission occurs from the rim of the impact crater resulting in ions with internal energies sufficiently low that they survive for analysis. [17,18] …”