July 2011 Americas Edition Cover Picture and Story

The cover image is an energy-dispersive X-ray spectroscopic map showing the distribution of nickel (red), oxygen (green) and silicon (blue) in tooth-like sub-µm objects formed from 5 µm x 5 µm x 0.1 µm NiO-ashlars on an oxidized Si-wafer (250 nm SiO₂) by irradiation with 1.45 GeV uranium ions under glancing incidence (80°) and continuous azimuthal sample rotation. The experiment was carried out by Prof. W. Bolse and his doctoral student R. Ferhati (Institut für Halbleiteroptik und Funktionelle Grenzflächen, University of Stuttgart, Germany) using their in-situ SEM irradiation facility at the UNILAC accelerator of the GSI Helmholtz Centre for Heavy Ion Research in Darmstadt, Germany.

The high-resolution element map (4076 x 3072 pixels) was acquired within 5 minutes with a Bruker Nano QUANTAX EDS system using an XFlash^® 5060 silicon drift detector (SDD) in a field-emission SEM with an accelerating voltage of 3.5 kV. The annular XFlash 5060 detector contains four separate SDD segments integrated into one chip resulting in a total active area of 60 mm². It is placed between the microscope pole piece and the sample while the electrons pass through a hole in the centre, allowing mapping of topographic surfaces without shadowing. The large active area and the annular geometry, where the detector is very close to the sample, lead to an extremely large solid angle of more than 1 sr, 100 times larger than for a typical 10　mm² detector in a conventional setup. Therefore extremely high count rates can be achieved easily (with low probe currents) and processed with four separate electronic channels in parallel, leading to maximum output count rates of more than 1,100,000 cps.

Further details can be obtained from:
Bruker Nano, 1239 Parkway Ave, Suite 203, Ewing, NJ 08628, USA
Tel.: +1 (609) 771-4400 Fax: +1 (609) 771-4411 info-ewing@bruker-nano.com www.bruker-nano.com