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Instruments and equipment
Crushing and mineral separation
LIG (Laboratory for Isotope Geology) has the basic equipment for crushing, milling and sieving of rock samples, as well as for mineral separation using Wilfley table, Frantz Isodynamic Separators and heavy liquids.
There are also microscopes and binoculars for handpicking of minerals, and equipment for photo-documentation of individual mineral grains.
Clean chemistry lab
The clean chemistry laboratory of LIG is used for dissolution of whole rock and mineral samples and separation of the elements of interest by ion exchange chromatography. These include U and Pb, Sm and Nd, as well as Sr. Other types of samples, such as water and sediment samples, may also be treated. In order to keep contamination at low levels and make it possible to prepare and analyse small U-Pb samples, the laboratory is built as a cleanroom with an overpressure of filtered air inside.
Finnigan MAT261 Thermal ionization mass spectrometer
LIG has a thermal ionization mass spectrometer (TIMS), a Finnigan MAT261, originally delivered in 1982 but upgraded several times since that. The MAT261 has an ion source that can house a turret with 13 samples, loaded on Re filaments, at a time. It has a multi-collector system encompassing five Faraday detectors for simultaneous analysis of five masses / isotopes, as well as one secondary electron multiplier for analysis of small samples. The MAT261 is used to analyse the isotopic composition of solid elements such as uranium, lead, strontium, samarium and neodymium, but is also used for the analysis of chlorine isotopes in the form of cesium chloride.
Triton Thermal ionization mass spectrometer
In February 2006, a new thermal ionization mass spectrometer (TIMS), a Triton from Thermo Finnigan, was installed at LIG. It is equipped with nine Faraday detectors and one secondary electron multiplier with RPQ filter for small signals. The sample magasin can house 21 samples. It is used for isotope analysis of solid substances, principally the same elements as our old machine (MAT261), uranium and lead, strontium, samarium and neodymium.
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Isoprobe ICP mass spectrometer
Since 1999 LIG has also an inductively coupled plasma mass spectrometer (ICP-MS), a Micromass Isoprobe, equipped with a collision cell and a multi-collector system encompassing nine Faraday detectors and one Daly detector for analysis of small samples. Samples are introcuced in solution, evaporated and passed through a hot plasma, where the atoms are ionized and accelerated into the mass spectrometer unit. Energy filtering of ions takes place in a collision cell, prior to mass separation by the electromagnet. Because of the efficient ionization, the Isoprobe has the potential of analysing isotopic composition on a wide range of elements; so far analytical work has concentrated on Sr, Nd, Pb, Sn, Fe, Si, Hf and Th.
NORDSIM ion microprobe
The Nordic ion microprobe facility (NORDSIM) is also located at LIG. NORDSIM is a joint Nordic resource, funded by four of the Nordic countries (Sweden, Finland, Norway and Denmark) and governed by a special board with members from these countries.
It is centred around a large geometry Cameca IMS1280 ion microprobe. The original instrument was installed in 1995, and underwent a major upgrade in 2009. This complex and advanced instrument enables high spatial resolution (typically 10-30 micrometer) microanalysis of a wide range of elements and isotopes in different materials.
The most common application to date has been U-Th-Pb geo-chronology of complex polyphase zircons whose history would be unobtainable by other methods. In addition trace-element studies in zircons as well as other silicate minerals, together with analysis of light stable isotopes (e.g. B, C, O) are being performed.
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LIG also has a Beta counter for analysis of 234Th, and a Gamma counter for analysis of 210Pb and 137Cs. Furthermore, LIG has access to the Hitachi scanning electron microscope of the museum. This is equipped with detectors for EDS, Cathodoluminescence and Back Scatter Electrons, enabling studies of the composition and internal structure of individual mineral grains.