The Melbourne Thermochronology Group currently operates five comprehensively equipped laboratories for Fission Track analysis, (U-Th)/He analysis, Laser-Ablation Quadrupole ICP-Mass Spectrometry, 252Cf fission track irradiation and Cosmogenic Isotope Target preparation and is supported by comprehensively equipped sample preparation facilities.
Digital Fission Track Laboratory
The state-of-the-art Melbourne Digital Fission Track Laboratory is based on three Zeiss Axio-Imager Microscope Workstations – one Z1m and two M1m systems, all fitted with Physik Instrumente piezo-motor scanning stages and IDS µEye 4MP square-format, fast CMOS digital cameras.
The (U-Th)/He laboratory was established in 2000 with apatite, zircon and titanite being routinely analysed. He outgassing is conducted using a semiconductor diode Coherent Quattro FAP laser with fibre optic coupling to the sample chamber, with He content measured using a Balzers quadrupole (QMS 200-Prisma) mass spectrometer. Analysis for parent U, Th and Sm isotopes is carried out using an Agilent 7700X inductively coupled plasma mass spectrometer (ICP-MS).
Laser-Ablation Quadrupole ICP-Mass Spectrometry
Laser-Ablation Quadrupole ICP-Mass Spectrometry offers low detection limits, highly sensitive and rapid multi-element determinations at ultra-trace level, and has been widely applied on earth materials in geological studies. The Melbourne Thermochronology LA-ICP-MS laboratory is equiped with a New Wave UP213 Laser Ablation System and an Agilent 7700x ICP Mass Spectrometer, delivering high precision trace element analysis.
252Cf Fission Track Irradiation
A separate dedicated laboratory houses a well-shielded 252Cf fission track source for vacuum implantation of collimated Cf fission tracks into polished mineral surfaces. This procedure is used to enhance the number of confined fission tracks for length measurement in selected samples, as required.
Sample Preparation Facilities
The Digital Fission Track Laboratory is supported by comprehensively equipped sample preparation facilities for rock crushing, mineral separation and mount preparation. Slide mounts for analysis are prepared using epoxy mounting and diamond polishing prior to controlled etching. For automatic fission track counting, the prepared slide mounts have a thin gold coating added in a sputter coating unit to enhance the surface reflectivity while maintaining good optical transmissivity.