QEMSCAN Measurement Modes

Depending on the area of application and the project task, five various measurement modes can be selected for a QEMSCAN analysis. It is differentiated between modes that analyze the full sample area and modes that capture only specific phases. For the latter, BSE gray scale trigger values are defined which start the analytical detection of certain phases.


BMA - Bulk Mineral Analysis

BMA mode is a line scan measurement mode which collects X-ray data from one direction only. Before X-ray acquisition the background is distinguished from the particles using a BSE threshold. Only analysis points falling on a particle are measured. As not the full sample area is measured, but lines of intersection, BMA is a very fast mode. However, only modal mineralogy, calculated assay, estimated particle and grain sizes and mineral association data is obtained.

PMA - Particle Mineral Analysis

PMA mode is an X-ray mapping measurement mode which analyses the full sample area. A custom mapping resolution can be set. A false color mineral map is stored for every single particle, but not a full field map as in FieldImage mode. Before X-ray acquisition the background is distinguished from the particles using a BSE threshold, so that particles are analyzed, but not the background. From the PMA measurement mode the full range of results provided by the QEMSCAN software can be extracted.

SMS - Specific Mineral Search

The SMS measurement mode is a search mode using a custom BSE grey value triggers to find minerals of interest which are present in low amounts in the sample material. Only particles containing matching mineral grains will be analyzed but not the full sample area. For these the analytical procedure is similar to PMA. Typical examples for areas of application are the investigation of sulfides in tailings or the search for penalty element-bearing minerals in concentrates. As only a subpopulation of particles in the sample is analyzed, SMS does not provide bulk mineral information. However, the list of results is similar to PMA, with respect to the mineral selective acquisition of data.

TMS - Trace Mineral Search

The TMS measurement mode is a search mode using a custom BSE grey value triggers to find minerals of interest which are present in trace amounts in the sample material. Only particles containing matching mineral grains will be analyzed but not the full sample area. For these the analytical procedure is similar to PMA. A typical example for an area of application is the search for precious metals in the sample material. As only a subpopulation of particles in the sample is analyzed, TMS does not provide bulk mineral information. However, the list of results is similar to PMA, with respect to the mineral selective acquisition of data.

FieldImage (Field Scan)

The FieldImage mode is an X-ray mapping measurement mode which is typically applied to thin sections or coarse-grained particles. FieldImage analyses the full sample area. From each field a false color mineral map is stored, so that a composite image of the sample can be produced after measurement. Before X-ray acquisition the background is distinguished from the particles using a BSE threshold, so that only measurement points falling on particles are analyzed.