LAUSR

With the rapid development of ultrashort-pulse laser technology, short-pulse, high-flux neutron sources based on the interactions of laser plasmas have become increasingly important. However, the extremely strong gamma rays generated by the interaction between a picosecond laser beam and a target make it difficult to apply traditional neutron-diagnostic methods. Here, we introduce a neutron-diagnostic method that employs a BF3 detector array for use in the strong-gamma-ray environments associated with ultrashort-pulse-laser neutron sources. This method determines the neutron yield by collecting signals from each of six independent BF3 counting tubes, effectively reducing statistical-fluctuation uncertainties. We first propose a time-partition calibration method for the BF3 detector array that uses counts in different time intervals. With this calibration method, the dynamic range for neutron-yield measurements is expanded from 1× 103~ 1× 108 to 1× 103~ 1× 1010 neutrons (in 4π space). We have applied this neutron-diagnostic method for the first time to the ultrashort-pulse-laser neutron source at the SG-II upgrade facility.