In all-hands meetings on Oct. 23, NIF & Photon Science Principal Associate Director Jeff Wisoff described the directorate’s chief goals for Fiscal Year 2015 and the organizational changes now under way to support them. The goals include executing the FY15 NIF Facility Use Plan to support the directorate’s Stockpile Stewardship, National Security Applications, and Discovery Science missions while continuing exploratory experiments in pursuit of ignition and developing advanced photonics technology.
NIF’s first experiments using targets with a small amount (about half a milligram) of plutonium-242 “will provide important data in support of the Stockpile Stewardship Program,” Wisoff said, adding that alpha particle monitoring, along with radiological controls already established for the use of beryllium targets, will minimize the operational impact on the facility.
The FY15 plan includes a stretch goal of firing 300 target shots or more, including 35 Discovery Science shots in support of users, compared to 191 target shots in FY14. The shot-rate increase was made possible by a variety of efficiency and scheduling improvements recommended by the “120-day Study” completed earlier this year. “Eighteen Discovery Science shot days are planned for FY15, about three times the FY14 number,” Wisoff said. This will enable NIF to meet its commitments from previous calls for experimental proposals during FY15 and pave the way for new experiments beginning in FY16. Wisoff said the recent call for FY16 yielded 42 proposals, which will be reviewed next month by a technical review committee.
The National Nuclear Security Administration (NNSA) will conduct a review in the July 2015 time frame to assess progress on NNSA’s “go-forward” inertial confinement fusion ignition strategy outlined in a December 2012 report to Congress. Wisoff said NIF’s strategy has been to improve understanding of the challenges to achieving ignition and to improve predictive capability through the use of integrated and focused experiments and alternate x-ray drive concepts.
“Significant progress has been made in understanding and controlling capsule hydrodynamic stability,” he said. Principal directions of the go-forward strategy include increasing the performance of high-foot (high initial laser pulse) experiments; aggressively developing near-vacuum hohlraums with diamond ablators to minimize laser-plasma interactions; understanding why previous implosions did not perform as expected and why high-foot shots perform well; using this information to set requirements for staged improvements toward ignition; and developing additional plausible paths based on new learning.
Wisoff also outlined other elements of the directorate’s short- and long-term strategies, including commissioning the Advanced Radiographic Capability and developing new diagnostic capabilities for FY15 and beyond; continuing NIF’s transition to a more efficient and supportive user facility with the goal of creating a “world-class user experience”; broadening the directorate’s capabilities to address the future of lasers and associated missions by creating a leading international laser capability at LLNL for high-energy, high-average-power and high-peak-power lasers, high-repetition-rate lasers, and new photonic sources; and “investing in our people to provide sustainability of our core capabilities.”
NIF & Photon Science Chief Technology Officer Chris Barty gave a talk titled, “Photonics for Fusion and Nuclear Science,” at an ASET (Advances in Science, Engineering and Technology) Forum colloquium at the Tata Institute of Fundamental Research (TIFR) in Mumbai, India, on Oct. 10. The ASET Forum, established nearly 30 years ago in TIFR, organizes colloquia, workshops, product presentations, and other programs under the broad spectrum of fields covered by ASET.
In his talk, attended by more than 100 faculty members, staff and students, Barty traced the long history of lasers and optics activities at LLNL and described two ongoing efforts at the Laboratory that utilize lasers to enable nuclear-related science and applications. He discussed how research on NIF is pursuing the science and potential applications of laser-driven nuclear fusion, while at LLNL’s laser-Compton facilities, lasers and state-of-the-art particle accelerators are being used to create tunable gamma-ray sources whose peak brilliance can exceed that of the world’s largest synchrotrons by more than 15 orders of magnitude. Barty noted that laser-Compton machines can enable precision spectroscopy of the nucleus with photons and the detection, assay and imaging of materials based on their isotopic as opposed to elemental signatures.