Use of LaBr3 for downhole spectroscopic applications

The use of lanthanum bromide (LaBr₃) in commercial applications has increased rapidly over the last few years owing to its very favorable properties, e.g., excellent spectral resolution, high speed, high light output, and efficiency. In addition to these properties, the ability of LaBr₃ to work at temperatures up to 200°C without a significant loss in performance is of particular interest to the well logging industry. The use of the new scintillator together with a 175-°C photomultiplier, a high throughput spectroscopy pulse-height analyzer, and a high-performance pulsed neutron generator allows new downhole gamma-ray spectroscopy measurements with unprecedented precision and accuracy. The instrument measures gamma-rays from both inelastic neutron interactions and neutron capture at logging speeds up to 18 m/min (3600 ft/h) resulting in a 0.5-s acquisition time for the typically used 15 cm (6-in) depth intervals.