Construction of a quartz spherical analyzer: application to high-resolution analysis of the NiKα emission spectrum

The construction and characterization of a focusing X-ray spherical analyzer based on α-quartz 4{\bar 4}04 are presented. The performance of the analyzer was demonstrated by applying it to a high-resolution X-ray spectroscopy study of theKα1,2emission spectrum of Ni. An analytical representation based on physical grounds was assumed to model the shape of the X-ray emission lines. Satellite structures assigned to 3dspectator hole transitions were resolved and determined as well as their relative contribution to the emission spectrum. The present results on 1s−13d−1shake probabilities support a recently proposed calculation framework based on a multi-configuration atomic model.

Initial Results with Low Energy Single Stage AMS

The National Electrostatics Corporation has built and tested a prototype low energy, open-air, single stage carbon accelerator mass spectrometry (AMS) system (patent pending). The configuration tested has a standard 40-sample, multi-cathode SNICS source on a 300-kV deck. The beam is mass analyzed before acceleration to a gas stripper located at ground. The 14C+ ions are separated from 13C+ and 12C+ arising from the molecular breakup by a 90° analyzing magnet immediately after the gas stripper which acts as a molecular dissociator. The 14C+ beam passes through an electrostatic spherical analyzer before entering the particle detector. The observed 14C/12C precision is better than 5% with a sensitivity of better than 0.05 dpm/gmC. A first single stage AMS system has been ordered. The configuration of this system will be discussed.

Retarding-field electron energy analyzer with a two-tube adapting lens for voltage contrast

In order to obtain a quantitative voltage contrast in SEMs various secondary electron energy analyzers are applied, often of a very sofisticated design. However, retarding field analyzers with planar or spherical fields are most popular because of their small dimensions which enable to place them below the objective lens. Spherical analyzers ensure better energy resolving power but contain too many grids (3-4) shadowing a sample when it is scanned.It is possible to design an analyzer equipped only with one grid which would save the advantages of the spherical one. Relatively good resolving power of the spherical analyzer results from the fact that electrons approach the retarding grid in perpendicular direction. The same effect can also be obtained for a planar grid when an electron lens is created below it and a sample is placed at the lens focus. The presented analyzer has been equipped with a two tube electron lens (Fig.1). The first tube plays simultaneously a role of the extraction electrode.