The NWR193UC laser ablation system (Electro Scientific Industries/New Wave Research) was installed in May 2015 and represents the latest addition to PCIGR’s laser-based micro-sampling infrastructure. The core of the instrument is a Coherent ExciStar XS ArF Excimer laser (wavelength of 193 nm), which delivers pulses of high energy light (up to 8 mJ) at a repetition rate up of 200 Hz, with an average 1 W of power per pulse. The laser can be can be dynamically attenuated, and focussed to spot sizes of 2–150 μm, allowing flexible micro-sampling of solid materials. The system is equipped with a TwoVol2 ablation cell. The cell comprises a main cell capable of containing samples of various shapes and sizes, and is fitted with a small cyclonic cup for efficient aerosol transport and washout.
The RESOlution M-50-LR laser ablation system (Australian Scientific Instruments) is a Class I laser device equipped with a UV excimer laser source (Coherent COMPex Pro 110, 193 nm). The powerful laser head and sophisticated optical system allow for the ablation of a wide range of geological and environmental materials at high resolution and low absorbance. High sampling resolution is assured with spot sizes from 5 to 200 µm. The sample stage (z-stage) enables an accurate beam focus even on rough sample surfaces. In addition, a unique two-volume cell developed by Laurin Technic Pty. Ltd. (Australia) provides high sensitivity, low fractionation and short wash-out times as well as fast sample throughput. PCIGR keeps at hand a second complete sample chamber and introduction accessories in order to separate high-matrix work from measurements at ultra-low levels and hence avoid cross-contamination. Samples of various dimensions such as microscopic slides, mineral mounts, thick rock sections, slices of speleothems, drill cores and samples of irregular shape may be investigated using multiple sample holders.
At PCIGR, the RESOlution laser system can be connected to the Agilent 7700 Series quadrupole ICP-MS and to the HR-SF-ICPMS Nu AttoM (Nu Instruments, Inc.). The quadrupole ICP-MS incorporates a 3rd-generation collision/reaction cell used in helium mode and offers higher sensitivity, lower backgrounds and more effective polyatomic interference removal of complex sample matrices. The HR-SF-ICPMS Nu Attom enables high-precision elemental and isotopic analyses at low concentration levels. Most applications comprise the analyses of low-level trace element concentrations in quartz veins and mineral grains, investigations of mineral zonation and geochronological work on zircons. We have also analyzed growth rings of mussel shells and ototliths for their trace element variations. One focus of the laser work at PCIGR is the development and testing of appropriate standard and reference materials for the application in microanalytical work by laser ablation.