Experimental and Computational Methods
Here you find a list of techniques available at the Institute of Resource Ecology with short descriptions of their in house applications. Additional details as well as the respective contact persons can be found by following the links provided with each method.
- Databases, Modelling and Quantum Mechanics
- Synchroton Based Techniques
- Microbiology, Molecular Biology and Biochemistry
- Reactive Transport and Tomography
- Computational Codes fur Reactor Safety calculations
- Microscopic Materials Characterization
- Radiochemistry and Spectrometry
- Macroscopic Techniques
- In situ vibrational spectroscopy
The molecular processes of dissolved metal ions at mineral-water interfaces are monitored in real time by in situ IR spectroscopy using the ATR technique. Metal complexes of biomolecules in aqueous solution can be characterized. Complementary vibrational spectroscopic information can be obtained from FT-Raman spectroscopy. Peak assignments are complemented by quantum chemical calculations (DFT, MP2).
- Time-resolved laser-induced fluorescence spectroscopy (TRLFS)
Luminescence spectroscopy is a key experimental technique for speciation studies of the actinides in solids, in solution, and at interfaces. Our institute applies seven tunable and fixed wavelength laser systems to study the coordination environment of the actinides Am, Cm, U(VI) and U(IV), as well as multiple lanthanides, especially Eu(III). Speciation is trace concentration sensitive, and can be performed down to ~10-9 M depending on the fluorescent probe, with detection limits approximately two orders of magnitude lower. For heterogeneous natural samples a setup for µTRLFS with spatial resolution ~10 µm is available.
- Magnetic spectroscopy (NMR, EPR, SQUID)
Two NMR spectrometers (Agilent DD2 600 MHz, Agilent MR 400 MHz) are available for studying the interaction of lanthanides and early actinides in solution and in solid state. An Agilent MR 400 MHz NMR spectrometer is installed in the controlled area to investigate samples that contain transuranic elements in solution. State-of-the-art multinuclear 1D- and 2D-NMR methods are applied to investigate complexes of the actinides with biologically and environmentally relevant complexing agents.
In addition, a Bruker ELEXSYS E500-10/12 EPR spectrometer is installed in the controlled area labs and available for use with actinides including transuranic elements. The magnetic methods are complemented by a QuantumDesign MPMS3 SQUID magnetometer also within the controlled area laboratories.
- UV-Vis-NIR absorption spectroscopy
Absorption spectra of aqueous samples can be recorded in the wavelength range from 190 – 3300 nm. Temperature control (0 °C – 70 °C) and measurements in inertgas/radionuclide glove boxes are optional. Long path flow cells (50 – 250 cm) are available for samples with low extinction. Time-dependent DFT (TD-DFT) calculations are used to reproduce experimental absorption spectra.
- Single-crystal X-ray diffraction (SC-XRD)
Our single-crystal X-ray diffractometer, D8 Venture from Bruker, is installed in a controlled area for radioactive materials. The diffractometer is equipped with dual micro-focus X-ray tubes for Mo or Cu Kα radiation and a high-end Charge-Integrating Pixel Array (CIPA) detector, PHOTON II. This instrument is one of the few single-crystal X-ray diffractometers in the world, which enables SC-XRD measurements on highly radioactive actinide compounds with proper precautions for radiation safety.
- THEREDA offers evaluated thermodynamic data for all compounds of dose relevant elements according to the present state of research.
- RES³T is a digitized version of a thermodynamic sorption database as required for the parameterization of Surface Complexation Models (SCM).
- Quantum chemical calculations
Quantum chemical calculations are used to predict the molecular structures of various organic and inorganic complexes of the actinides, including calculations of IR spectra and luminescence properties.
The Institute of Resource Ecology operates the Rossendorf Beamline (ROBL) at sector 20 of the European Synchrotron Radiation Facility (ESRF) in Grenoble, France. In two hutches various spectroscopic and diffraction techniques are available:
- X-ray absorption spectroscopy in a dedicated hutch equipped as a controlled area for radioactive samples with activities up to 187 MBq.
- X-ray emission spectroscopy: a Johann-type spectrometer is currently under construction for high-resolution X-ray emission studies.
- Surface X-ray diffraction: a diffraction setup consisting of a Huber six-circle diffractometer, a PILATUS 100K diode array area detector, and the corresponding beamline components is available for e.g. Crystal Truncation Rod (CTR) and Resonant Anomalous X-ray Reflectivity (RAXR) experiments.
- X-ray diffraction: the diffractometer will also be suitable for Synchrotron Powder X-ray Diffraction, and equipped with the necessary detectors and components.
Analysis of microbial diversity in water and rock samples
Extraction of high molecular DNA from water and rock samples by using our in-house protocol, followed by amplification of 16S rRNA gene fragments or fragments of other functional genes by PCR using a thermocycler. Analysis of microbial diversity in the samples by sequencing of the amplified 16S rRNA gene fragments by using Next Gen sequencing technologies.
Isolation and characterization of microorganisms
Using classical bacteriological methods to enrich and isolate microorganisms from environmental samples and their characterization by DNA analyses and DNA sequencing.
Cultivation of microorganisms
Aerobic and anaerobic cultivation of microorganisms in bioreactors under controlled pH, pO2 and temperature in volumes of 0.5 to 50 L for the production of biomass and the isolation of cell components, biopolymers or biomolecules.
Cell harvesting and disruption
Multi-scale cell harvesting with large volume centrifuges and continuous flow centrifuges combined with multi-scale cell disruption e.g. by ultra-sonic, mixer mill, high pressure homogenizers.
Protein isolation and purification by using different chromatographic methods such as FPLC and HPLC and characterization of protein solutions and purified proteins by gel electrophoresis, isoelectric focusing and western blotting.
Transmitted light microscopy, fluorescence microscopy and confocal laser scanning microscopy
Light microscopy and confocal laser scanning microscopy including phase contrast and dark filed techniques for the investigation of prokaryotic cells, biofilms or eukaryotic organisms. In combination with fluorescence microscopy or spectroscopy visualization and localization of cell components and fluorescent metals as well as identification of metal species.
Atomic force microscopy
Visualization of biogenic and geogenic surfaces, surface modifications and biomolecules in the range of micro- to nanometers to investigate the interaction of microorganisms, mineral phases and biomolecules with metals by using a high resolution AFM and a coolable/heatable liquid cell.
We develop conservative and reactive radionuclide tracers using our cyclotron laboratory.
We have adopted positron emission tomography (PET) for the purpose of flow field tomography in opaque materials, particularly geomaterials.
We analyze the heterogeneity of crystal surface reactivity by various microscopic methods, such as vertical scanning interferometry, in combination with µ-focus X-ray CT, and use these data to calculate reaction rate maps.
We use and develop numerical methods for the analysis of crystal surface reactivity and for transport analysis at the pore scale and above.
- 3D reactor dynamics core simulator DYN3D developed by HZDR
- Advanced thermal hydraulic system codes ATHLET and ATHLET-CD (developed by GRS)
- Plant dynamics, accident and severe accident analysis
- Integral code ASTEC (joint development by IRSN and GRS)
- Accident and severe accident analysis
- Monte Carlo code SERPENT2 developed by VTT Finland
- Reference calculations for DYN3D verification
- Cross section generation for the DYN3D code
- Lattice code HELIOS2 developed by Studsvik-Scandpower
- Cross section generation for the DYN3D code
- Monte Carlo code TRAMO developed by HZDR
- Fluence calculations of reactor pressure vessels
- Monte Carlo code MCNP6
- Fluence calculations of reactor pressure vessels
Small-angle neutron scattering (SANS)
Nanodisperse chemical, structural and magnetic inhomogeneities scatter neutrons (n) or X-rays (X) at small angles. Information on nature, size, number and chemical composition of the inhomogeneities can be obtained from the angular dependence of the intensity of the scattered neutrons. The SANS experiments are performed at the Helmholtz-Zentrum Berlin, the neutron source FRM II at Munich, the Institute Laue-Langevin (ILL) at Grenoble, the Laboratoire Leon Brillouin at Saclay and at KFKI Budapest.
Transmission electron microscopy (TEM)
Irradiation-induced defects such as dislocation loops can be observed by TEM at nm-resolution. With respect to radiation damage, TEM and SANS represent complementary techniques. The application of TEM is also important for the characterization of size, concentration and composition of ODS particles.
Positron annihilation spectroscopy (PAS)
Positrons are self-searching, defect-specific probes for open-volume type defects of sub-nm size and in this respect supplementary to SANS, TEM and Atom probe. PAS experiments are performed in collaboration at the Institute of Radiation Physics.
Depth-sensing nanoindentation in combination with atomic force microscopy (AFM)
Neutrons are able to penetrate deeply into materials and consequently damage samples as a whole. In contrast, ions are stopped within a surface layer of only a few µm thickness. These small volumes cannot be probed with SANS and other bulk methods, but require alternative characterization tools. This is achieved by using a combination of TEM, depth-resolution PAS, and nano-indentation. The sub-µm indentation structures created by this method are then visualized using atomic force microscopy (AFM).
- Radioanalytical methods
α-spectrometry: Grid ionization chamber (GIK 800S, MAB) allows the analysis of thin layers up to ~300 cm² (limit of detection ~10−2 Bq).
Semiconductor detector (PIPS: PH 450-21-100AM, Canberra) allows the analysis of thin layers up to ~4.5 cm² (limit of detection ~10−3 Bq).
β-spectrometry: Liquid scintillation counting (LSC) with α/β discrimination (1400 Wallac Win Spectral, Tri-Carb 3100 TR, Perkin-Elmer).
γ-spectrometry: High Purity Germanium Detection (Gamma-X HPGe, Coaxial Photon Detector, Ortec).
- Colloid characterization techniques
Light scattering: Dynamic and static light scattering (CGS-3 (ALV) and Zetasizer Nano ZS (Malvern Instruments) allows determination of size distributions of colloidal nanoparticles and molecular weights of macromolecules.
Zeta-Potential: The zeta potentials of nanoparticles in dependence on pH can be determined by laser Doppler velocimetry using a Zetasizer Nano ZS (Malvern).
- Mass spectrometry
Inductively coupled plasma-mass (ICP-MS) spectrometry is highly sensitive for the quantification of elements in solid and liquid samples.
- Hot Cell Testing Facilities
- Calorimetric methods are used to determine the thermodynamic parameters of protein stability and metal-ligand interactions using Differential Scanning Calorimetry and Isothermal Titration Calorimetry, respectively. The impact of heavy metals and radionuclides on the physiology of living organisms is monitored by Microcalorimetry.
- Thermogravimetry / Differential Scanning Calorimetry (TG/DSC): Investigation of solid phase transformation, crystallization, melting, removal of water etc. in dependence of temperature (maximum 1600 °C) under air or inertgas atmosphere using a STA 449 F5 Jupiter (Netzsch).
- Batch sorption experiments
Sorption properties of different minerals towards inorganic and organic pollutants depending on various factors (e.g. pH, ionic strength, redox potential, temperature, presence of organic matter, microbes or competing species) are determined by batch experiments and thermodynamic parameters (Kd, ΔRH, ΔRS) are derived.
- Determination of transport parameters (De, Kd, porosity)
Small-scale stainless steel diffusion cells are used for investigation of radionuclide migration through minerals or rock materials.
- Specific surface area analysis
Determination of the specific surface area (m²/g) of solids based on the so-called BET (Brunauer, Emmett and Teller) method, by measuring N2(g) physical adsorption onto cleaned surfaces.