THE RAPIDLY CHANGING LANDSCAPE FOR MaRIE
Much has changed in the year since we last discussed Matter-Radiation Interactions in Extremes (MaRIE), LANL's proposed signature-facility concept. In this point of view, we provide a brief glimpse into these exciting times.
President Obama and his administration have made clear their commitment to ensure a nuclear deterrent that is safe, secure, reliable, and as small as possible. Active efforts include ratifying a New Strategic Arms Reduction Treaty (START) and Comprehensive Nuclear Test Ban Treaty. There is also growing consensus that effectively stewarding a shrinking stockpile will require investing in a sustained science and technology capability. Personnel involved with current budget deliberations are making strides in funding this vision, with Los Alamos playing a key role.
We have made significant technical strides. For example, we successfully executed the first hydrotests at the Dual-Axis Radiographic Hydrodynamic Test facility and participated in many experiments helping the National Ignition Campaign work towards its goal of attempting fusion in a laboratory setting—proposed to occur later this year.
In addition, our capabilities in proton radiography continue to deepen our understanding in areas such as high-explosive burn, and we are now defining a set of first experiments that will be fielded at the Advanced Photon Source for the proposed Dynamic Compression-Collaborative Access Team beamline. To gain process-aware understanding, we are (1) designing and conducting experiments that test material properties (such as strength) under dynamic-loading conditions and (2) evaluating how such processed materials respond within the context of microstructural changes.
LANL's MaRIE Project Program Director John Sarrao and Mary Hockaday, Weapons Directorate deputy, overlook the neutron science center.
Roadrunner's petascale-computing speed provides previously unimaginable resolution—and achieving exascale computation is actively underway. Recognized by the broader scientific community, the leadership of both NNSA and Los Alamos in experimentally validated simulation science plays a central role in defining exascale codesign centers and advances the frontiers of computational materials design.
As an example of the type of capability necessary for Los Alamos to retain this leadership, MaRIE stands to revolutionize materials in extremes, a challenge that spans a variety of DOE missions. For example, MaRIE will play a role in our energy and weapons programs by providing unprecedented in situ, transient measurements of real materials under relevant extremes, particularly dynamic loading and irradiation. Following is how MaRIE will address specific weapons needs:
- Sustaining the current stockpile by developing much better predictive capabilities for materials lifetimes
- Weapons System rebuild and life extension by providing materials "by design" to overcome costly "relearning" of old processes and myriad attempts to duplicate old materials.
- Validating weapon performance by better understanding the relationship between material microstructure (through material performance) and nuclear performance.
To meet these weapons needs, MaRIE will consist of a high-energy, low-average intensity source of x-ray photons (preconceptually a 50- to 100-keV x-ray free-electron laser) coupled to an existing high-intensity proton linear accelerator at the Los Alamos Neutron Science Center (LANSCE). There will be three measurement facilities: the Multi-Probe Diagnostic Hall; the Fission-Fusion Materials Facility; and the Making, Measuring, and Modeling Materials Facility. MaRIE will leverage existing DOE investments at LANSCE, the Laboratory's materials infrastructure, and the Office of Basic Energy Sciences national user facilities. MaRIE will also leverage current and planned investments, such as NNSA's LANSCE Linac Risk Mitigation Effort and the Materials Test Station.
Recently, DOE Under Secretaries Thomas D'Agostino, Kristina Johnson, and Steven Koonin acknowledged the importance of LANSCE's role in stockpile stewardship over the next decade. The Under Secretaries requested that the Laboratory Director provide a plan for the full suite of issues that must be addressed to sustain LANSCE's current level of operations through the next decade. They also asked the Laboratory to address the longer-term need for high-quality experimental science capabilities, as well as suggested materials-in-extreme conditions as a possible focus area. As part of LANL's response, Director Anastasio asserted, "MaRIE…is the appropriate signature experimental facility for LANL," and "we believe that a mission need for a materials-in-extreme facility focused on in situ transient measurements exists."
Director Anastasio made these assertions based in part on a series of five workshops sponsored by LANL in 2009, culminating with the December 2009 workshop, entitled "Decadal Challenges for Predicting and Controlling Materials Performance in Extremes." At these workshops, more than 225 scientists from 80 institutions worked to identify scientific challenges and research directions to achieve predictive materials performance in extreme environments, focusing specifically on needed capabilities and tools. Workshop reports are available at http://www.lanl.gov/source/projects/marie/workshops.shtml.
Recently, MaRIE's External Advisory Board concluded that "outreach and engagement with the scientific community couldn't be better. It is particularly noteworthy that these workshops were not LANL-centric; i.e., were not focused on the use of MaRIE as a tool but rather were focused on defining technical challenges in broad areas of research, identifying needs."
Many scientific challenges are directly relevant to our mission, such as understanding the mechanisms of failure under dynamic-loading conditions. To better understand such mechanisms, Los Alamos scientists will use MaRIE's proposed x-ray free-electron laser and proton radiography simultaneously to probe well-characterized samples that are shock- or ramp-loaded. We also will use dynamic x-ray diffraction or ankylography to track defect generation and annihilation, with the resultant data used to validate atomistic to mesoscale models of dynamic response.
This past year, we experienced much activity focused on science and technology capabilities necessary for stockpile stewardship. Accelerating these activities holds great promise for sustaining important LANL capabilities. We can only hope that the upcoming year is as exciting as the last.