The Spectron UV (266µm) laser is focused through a Leica DM microscope to a spot size of around 10 microns across. This laser is used to ablate areas of sample a few 10s of microns across and extracts small gas samples for geochronology or noble gas analyses.
The system is used for high spatial resolution analysis of minerals such as detrital and pegmatitic white micas, and ‘thick sections’ of rock, such as sandstones with K-feldspar cements or overgrowths, or deformed metamorphic rocks. Another major use of this system has been the determination of the diffusion and partition paramaters for noble gases from He to Xe laboratory experiments, and helium diffusion in apatite. A programmable motorised XY stage facilitates laser rasters across small areas of the sample surface and regions of 50µm2 or less are routinely analysed. The resulting gas is extracted via an all metal extraction line and cleaned by 3 AP-10 getters. The system is entirely automated and is operated via Labview software. The Spectron IR (1064µm) and Synrad CO2 (25W, 1064µm) lasers are both attached to an automated extraction system and an MAP 215-50 mass spectrometer. This system is used for single spot and single grain or multi-grain stepped heating experiments. Single spot analyses are produced in either individual mineral grains or ‘thick sections’ of rocks – for example pseudotachylite material from fault zones or meteorite impacts. Both lasers are also used for incrementally heating single mineral grains or bulk mineral separates – for example from young volcanoes and flood basalts – and analysing ultra-small encapsulated illite samples. The extracted gas is cleaned via 2 AP-10 getters and a cold finger (IR laser) and 2 GP-50 getters and cold finger (CO2 laser). This system is also fully automated and is operated via Labview software.
Contact Information
Lead Academic - Dr Sarah Sherlock
Telephone: +44 (0) 1908 659559 (office), +44 (0) 1908 659505 (Lab)
