The present invention provides an improved gamma ray detector module and a method of operating such a detector module for more accurately determining the position of a gamma ray interaction within the detector. The detector module includes an induction array arranged at an offset angle relative other arrays utilized in the detector, whereby the relative timing of the detection of ionization electrons by the induction array and a collector or anode indicate at least one coordinate corresponding to the location of the interaction that produced the ionization electron. This secondary locating apparatus and method supplements or replaces conventional locating apparatus and methods for improving the accuracy or reducing the complexity of the detection apparatus.