The Centrifuge Test Facility’s flash X-ray system. Photo Courtesy LANL
All of the current U.S. nuclear deterrent is composed of weapon systems that are designed to fly, primarily on ballistic missiles, but also carried by aircraft. Part of the stockpile stewardship mission at Los Alamos National Laboratory is assuring that the weapons will work as designed throughout the “stockpile to target sequence” that includes the flight component.
In order to fulfill this mission, the Laboratory conducts a wide variety of tests at its Centrifuge Test Facility (CTF), a one-of-a-kind capability that can create high-gravity environments like those encountered during missile launch and atmospheric re-entry, for example. Opened in 2016, the CTF has now added flash X-ray radiography to its suite of diagnostic tools.
“Radiography conducted on test objects during high g-loadings allows us not only to obtain a very valuable image to help us visualize the effects of these environments, but also offers a new method of mathematical analysis to compliment the other measurements we make,” said CTF test engineer Alex Cusick.
The Laboratory runs tests at the CTF to evaluate the effects of high g-loading on internal components of weapon test assemblies. This facility is unique in that it can accommodate the high-explosive charges, detonators, and associated electronics, where surrogates are used in place of nuclear materials. The test objects are attached to the arm of the centrifuge and spun to high velocities to simulate atmospheric reentry deceleration forces and lateral g-loading. Data are typically acquired using accelerometers, strain gauges, and displacement sensors. With the addition of flash X-ray radiography, the CTF can now image the internal components during these tests which is a new and valuable capability.
“This is at the core of the weapons development objectives,” said Cusick, “because it allows us to feed results back into our computer models and redesign efforts, and allows us to qualify design changes before those changes are made to weapons in our stockpile. Radiography adds to the existing methods, making our analysis capabilities more powerful than ever.”
“This has never been done before at any other weapons complex facility, to the best of our knowledge, and is significant because it offers a completely different approach to our previous evaluation and qualification processes,” he added.
Beyond the nuclear weapons mission, the CTF is also available to help qualify flight electronics and components that will be used for space applications, for example, satellite components that are being developed by the Intelligence and Space Research Division and others at Los Alamos.
The facility can also be used as a user facility to support external organizations for similar non-weapons related work. Los Alamos is currently collaborating with Texas A&M to fine-tune this brand new method, and have been coordinating with Lawrence Livermore National Laboratory, the Air Force Research Laboratory and others about planning future work at Los Alamos using this capability. This new method became operational in October of 2020.
“Up to now, it has been impossible to truly visualize the internal components of a weapon system or space system under a high-g environment. Now we do not need to rely solely on data to understand the effects, but have the ability to look at real images to visualize them which is truly unique and exciting,” said Cusick.
Watch the CTF go for a spin.