High flux directional laser driven neutron sources for static radiography applications

Laser-driven neutron sources offer an attractive, alternative approach for generation of short, intense bursts of multi-MeV neutrons, especially desirable for neutron radiography applications. High repetition-rate petawatt lasers driving novel neutron sources could outperform existing conventional sources with respect to peak brilliance¹. These high repetition-rate, high flux sources show great promise for applications of radiography of static or slowly evolving systems (seconds-to-minutes) such as nondestructive evaluation of manufactured materials or compounds or water uptake in biological or structural systems.

Here, we present results of high flux directional neutron beam generation at the Texas Petawatt (TPW) Laser at the University of Texas, Austin (1 um, 150 fs, 100 J) on a single shot basis using a pitcher-catcher setup² implementing a cryogenic liquid deuterium jet target as well as subsequent experiments using a similar platform showing reliable neutron generation in a laser-driven pitcher catcher setup for the first time at a repetition rate of 0.5 Hz. These were performed using a converging heavy water sheet target³ with the ALEPH laser at Colorado State University (400 nm, 45 fs, 4.6 J). We observe peak neutron yields of 7.2x10⁹ neutrons/sr/shot within 20 deg from target normal direction at the TPW. At lower laser energy (ALEPH) but higher repetition rate the average measured neutron yield is 2.5x10⁵ neutrons/sr/s. Both results show the potential of achieving a high flux, high repetition-rate laser-driven neutron source suitable for radiography applications when scaled to high repetition-rate Petawatt laser systems such as the MEC-U project at SLAC.



References

¹ S. N. Chen et al., Matter and Radiation at Extremes 4, 054402 (2019)

² F. Treffert et al., Instruments 5, 38 (2021)

³ F. Treffert et al., Appl. Phys. Lett. 121, 074104 (2022)



This work was supported by the U.S. DOE Office of Science, Fusion Energy Sciences under FWP 100182 and Contract No. DE-SC0021246: the LaserNetUS initiative at Colorado State University. This work was partially performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 and was supported by the LLNL-LDRD Program under Project No. 22-ERD-022. LLNL-ABS-851233