The New ANL Materials Science HVEM Facility

Abstract

A new transmission HVEM facility has been completed at Argonne National Laboratory. The ANL HVEM provides the beginning of a dedicated materials research laboratory which will subsequently include an interface with a 2 MV tandem accelerator and a low energy ion injector for iri situ ion irradiation and ion beam analysis experiments (Figure 1).The microscope, an improved version of the AEI EM-7, has an accelerating voltage of 1.2 MeV. Moreover, a number of exceptional features have been designed into the instrument which will significantly enhance its usefulness in materials research: 1. High vacuum specimen chamber with direct ion pumping. 2. Instrumentation for two independent and alternatively selectable dark field conditions. 3. Negative ion trap. 4. Ion beam interface. In addition, a helium temperature, side entry, cooling stage is being developed at ANL . The negative ion trap and the ion beam interface are features that have not been previously included in HVEM designs.