Division of Analytics
Staff
Equipment
- XRF
- SEM
- P-XRD
- High-Speed-PIXE
- Ion microprobe
- AMS
- Super-SIMS
Projects
Publications
Ion Beam Analysis Group

Contact

Dr. Axel Renno
Group Leader Ion Beam Analysis
Phone: +49 351 260 - 3274

Eye catcher

Super-SIMS

Super-SIMS (SIMS = Secondary ion mass spectrometry) - also called Accelerator-SIMS or Trace Element AMS (TREAMS) - is an ultrasensitive analytical method for the determination of stable elements and isotopes.

Actually, a Super-SIMS-Set-up is developed at the HZDR ion beam centre by connecting a conventional SIMS-source (Cameca IMS 6f, formerly installed at the Helmholtz-Zentrum Potsdam Deutsches GeoForschungsZentrum GFZ) to a 6 MV tandem accelerator. A similar set-up has been yet realised at the ETH Zürich.

Due to the acceleration of the extracted sample ions to MeV-energies and their charge reversal from negative to positive ions, Super-SIMS can reach about 2 to 3 orders of magnitude lower detection limits (up to 10^-12 or ppt, highly depending on analyte and matrix) as conventional SIMS.

The HZDR Super-SIMS will be part of an anticipated HGF-SIMS-Network called SIGMA. Other partners are the Helmholtz Centre for Environmental Reasearch in Leipzig (NanoSIMS & TOF-SIMS under installation) and the GFZ Potsdam (High-resolution 1280-HR SIMS under installation).

Anticipated characteristics:

Measurable Elements:
all but noble gases
Lateral resolution:
- 10 - 20 µm
- 3 µm (minimum beam size)
Scanning area: < some mm²
Detection limits: 10^-9 -10^-12 (ppb - ppt)
Analysing depth (max.): some hundreds µm
Depth resolution: ~ 5 nm

Limitations:

only solid and vacuumstable samples
destructive
standard/reference materials needed

Lab

To reach the SIMS-lab please call:

lab: +49-351-260-3590

sample preparation: +49-351-260-3591

Cesium ion source - SIMS.

How does Super-SIMS work?

A sputter source is used to focus a Cs⁺-beam onto a as smooth as possible sample surface. The extracted negative ions (elements or molecules) of keV-energy are electrostatically and magnetically separated leading to a mass resolution (m/Δm) of about 5000. A first isobar suppression is gained right in the ion source, if these do not form any negative ions (e.g. no formation of Mg^- when analysing Al).	Super-SIMS-source (actually at GFZ).
Selected ions with the correct energy, mass and charge are injected into the 6 MV accelerator and accelerated to the positively charged high-voltage terminal. Negative ions are passing an area filled with argon gas, thus, loosing electrons from the outer shell. Thereby, all existing molecules are destroyed. The henceforth multiple-positively charged ions (e.g. Al³⁺) are accelerated a second time in the direction of the other end of the accelerator, which is on ground potential.	6 MV tandem accelerator.
At the so-called high-energy site all ions are again magnetically and electrostatically separated before they are finally detected by Faraday-Cups (major elements) and gas ionisations detectors (trace elements, respectively.	Gas ionisation counter.