Towards sub-centimetre resolution in bore–core logging

The relatively low signal-to-background ratio is an important impedance in obtaining spatial resolution better than 1 cm in bore–core logging systems. Reducing detector background will improve this ratio and therefore an assessment of the background components is made for a BGO detector that is used in an operational core-logging system and methods to reduce this background are investigated. The cosmic radiation-induced background is recognised as the main component. The improvement of the efficiency of the core logger focuses on the reduction of this background by means of an anticoincidence system surrounding the BGO detector. The intrinsic background of the detector found from underwater measurements was about 1.6 cps.