A Study On Controllable Pulse Neutron Generator With High Temperature And High Yield

As an important method of petroleum logging,radioactive logging has considerable advantages over the other techniques, and therefore it is universally used in this field. However,the utilization of ordinary radioactive americium beryllium neutron source has been put under control due to the progressively-increasing awareness of environmental and health hazard, which proves hindrance to the development of radioactive logging. Therefore using controllable neutron generator to replace conventional radioactive americium beryllium neutron source has become the main focus of the major oil companies.This article introduces the principles and composition of the pulsed neutron generator, and it provides in-depth discussion of the neutron tube, which is the key component of the generator.The related experiments have improved the structure and material of deuterium tritium storage medium, and they also have optimized the configuration and material selection of the ion source.With the contribution of the experiments, the neutron tube is now able to function under high temperatures, and its efficiency of neutron generation also has been improved. In addition, the tube’s service life would be extended.The three major power-supply circuits of the neutron generator are optimized. The improved stability of the equipment and the efficiency of neutron generation are accomplished by upgrading the high-voltage and the voltage-multiplying circuits; The optimization of the anode pulse power supply increases its clock rate up to 20 kHz with fast stop enabled; The filament constant current power supply is modified so that the output of the deuterium tritium storage and the process of ionization are more stable. The feedback circuit is also improved, thus the status of the neutron tube can be adjusted according to the signal sent back by the circuit. The yield of neutron is more stable and the margin of error of the neutron generation is between±3%. This new model of pulsed neutron generator could be used in elemental logging, logging while drilling and other types of logging equipment that has high operating requirement.In conclusion, the performance of the conventional type of neutron generator has been fundamentally improved. The new system is capable of stably functioning at the temperature of175℃ with neutron output of 2×108N/S. It is a reliable and efficient controllable neutron sourcefor neutron logging.