Recent results obtained with a pulsed nanosecond IR laser system to automatically test single event latch-up effects in laboratory are presented. In particular, the capabilities of this system to perform detailed mapping for ICs sensitivity to radiation are discussed. Two VLSI ASIC circuits were used for sensitivity mapping. The results are compared with those obtained in heavy ion tests at GSI (Darmstad, Germany). © 2003 Elsevier Science Ltd. All rights reserved.