ITRAX: description and evaluation of a new multi-function X-ray core scanner

Abstract

A new automated multi-function core scanning instrument, named ITRAX, has been developed that records optical, radiographic and elemental variations from sediment half cores up to 1.8 m long at a resolution as fine as 200 μm. An intense micro-X-ray beam focused through a flat capillary waveguide is used to irradiate samples to enable both X-radiography and X-ray fluorescence (XRF) analysis. Data are acquired incrementally by advancing a split core, via a programmable stepped motor drive, through the flat, rectangular-section X-ray beam. Traditional XRF determination of element composition in sediments provides high-quality data, but it takes a considerable time and normally consumes gram quantities of material that is often only available in limited quantities. The ITRAX core scanner non-destructively collects optical and X-radiographic images, and provides high-resolution elemental profiles that are invaluable for guiding sample selection for further (destructive) detailed sampling. This paper presents a description of the construction, characteristics and capabilities of the ITRAX system. High-resolution ITRAX data obtained from sediment cores are also presented and compared with results from traditional wavelength-dispersive XRF analysis at lower resolution. Finally, some recent technical developments linked to the second-generation ITRAX are presented