Establishing a Laser-Driven Megaelectronvolt X-Ray and Neutron Radiographic Capability

Project Overview

The goal of this project was to establish a unique new laser-driven mega electron Volt (MeV) radiographic capability for dynamic radiography of explosively driven materials. Laser driven MeV radiography enables simultaneous neutron and MeV x-ray radiography of explosively driven materials. Both these new radiographic capabilities could provide a compelling alternative to accelerator driven MeV radiography sources such as the Dual Axis Radiography Hydro Test facility at Los Alamos National Laboratory and Flash X-Ray (FXR) Source at Lawrence Livermore National Laboratory. Importantly, being driven by a common laser front-end, this new capability represents a powerful and highly flexible way to augment and extend the capabilities of existing facilities, especially with respect to the number of view angles and temporal frames.

We carried out experiments on the high-power laser facilities at the National Ignition Facility (NIF), the Texas Petawatt at University of Austin, and the OMEGA EP laser at the University of Rochester. These experiments showed that innovative targets could increase the brightness of laser driven MeV x-ray sources by a factor of approximately two to three times over conventional planar slab targets. Coupling these results to new laser architectures, identified during the course of the project, would yield an increase in MeV x-ray brightness by a factor of nine times the prior state of the art. This is very close to our pre-proposal goals (10x). Experimental radiographs of dense objects were obtained during these experiments, which are being used to develop a quantitative understanding of the utility of laser driven sources for radiographing explosively driven materials for the weapons program. NIF experiments on laser-driven neutrons also demonstrated high brightness (1x10^13, 14 MeV neutrons / steradian) source with 100-kilojoule laser drive, which met the original goal of the project.

Mission Impact

The MeV radiography sources developed in this proposal will be very interesting for dynamic radiography of explosively driven materials and have the potential to provide flexible radiography sources for tomography. Radiography programs at Livermore have recognized the potential of these sources and have funded follow-on work. The targets developed in this project are also now being used by other high-energy-density science programs to optimize laser to high-energy electron coupling for x-ray and proton generation. The project was awarded a patent for the laser architecture concept.

Publications, Presentations, and Patents

"Burst-mode Chirped Pulse Amplification for increased laser-driven MeV hot electron and secondary photon and particle generation." Worldwide Patent: WO2020014684A1.

Kerr, Shaun, invited talk, American Physical Society 2020.

MacKinnon, Andrew invited Seminar, Atomic Weapons Establishment, Sep 2019.

MacKinnon, Andrew, invited Seminar, Los Alamos National Laboratory, Jan 2020.

MacKinnon, Andrew, invited Seminar, General Atomics, May 2019.

A. J. Kemp and S. C. Wilks, "Direct electron acceleration in multi-kilojoule, multi-picosecond laser pulses," Physics of Plasmas 27, 103106 (2020).

D. R. Rusby, P. M. King, A. Pak, N. Lemus, S. Kerr, G. Cochran, I. Pagano, A. Hannah, H. Quevedo, M. Spinks, M. Donovan, A. Link, A. Kemp, S. C. Wilks, G. J. Williams, M. J. Manuel, Z. Gavin, A. Haid, F. Albert, M. Aufderheide, H. Chen, C. W. Siders, A. Macphee, and A. Mackinnon,"Enhancements in laser-generated hot-electron production via focusing cone targets at short pulse and high contrast," Physical Review E 053207, 1 (2021).

M. Hohenberger, N. B. Meezan, W. M. Riedel, N. Kabadi, C. J. Forrest, L. Aghaian, M. A. Cappelli, M. Farrell, S. H. Glenzer, B. Heeter, R. Heredia, O. L. Landen, A. J. Mackinnon, R. Petrasso, C. M. Shuldberg, F. Treffert, and W. W. Hsing, Rev. Sci. Instrum. 92, 033544 (2021).

A. MacPhee, A. David, C. Hui, G. Cochran, M. R. Hermann, D. H. Kalantar, A. J. Kemp, S. M. Kerr, A. J. Link, T. Ma, A. J. Mackinnon, D. A. Mariscal, D. J. Schlossberg, R. Tommasini, S. Vonhof, C. C. Widmayer, S. C. Wilks, G. J. Williams, W. H. Williams, and K. Youngblood, Optica 7, 129 (2020).

G. J. Williams, A. Link, M. Sherlock, D. A. Alessi, M. Bowers, B. P. Golick, M. Hamamoto, M. R. Hermann, D. Kalantar, K. N. Lafortune, A. J. Mackinnon, A. Macphee, M. J. Manuel, D. Martinez, M. Mauldin, L. Pelz, M. Prantil, M. Quinn, B. Remington, R. Sigurdsson, P. Wegner, K. Youngblood, and H.Chen, Physical Review E 103, 1 (2021).

K. D. Meaney, S. Kerr, G. J. Williams, H. GeppertKleinrath, Y. Kim, H. W. Herrmann, D. H. Kalantar, A. Mackinnon, M. Bowers, L. Pelz, D. Alessi, D. Martinez, M. Prantil, S. Herriot, M. R. Hermann, T. E. Lanier, M. Hamamoto, J. M. Di Nicola, S. Yang, W. Williams, C. Widmayer, and R.Lowe-Webb, Physics of Plasmas 28, 1 (2021).