LLNL Interns—New Air Force Officers—Support Future NIF Experiments

Two LLNL engineering interns who are newly commissioned officers in the U.S. Air Force collaborated on a diagnostic that will improve future x-ray response experiments at NIF.

Because of COVID-19 restrictions, Air Force ROTC cadets Colt Drew and Nathaniel Feldmann communicated remotely and have yet to meet in person. They’ll have the chance to finally meet face-to-face after Drew graduates from Clemson University in December and joins Feldmann for flight training at Vance Air Force Base in Enid, Oklahoma.

Both second lieutenants were summer interns sponsored by the Defense Threat Reduction Agency (DTRA) and supervised by Brent Blue, NIF’s National Security Applications (NSA) program manager.

“Both Colt and Nathaniel played a critical role in developing a new diagnostic specifically to support Air Force experiments on NIF,” Blue said recently, “and they were in the first batch of Air Force experiments. They’re actually happening today as we speak.”

The Department of Defense and other government agencies use NIF, the world’s largest and most energetic laser, for national-security research. The Lab has been supporting the Air Force and Navy on radiation-effects testing for strategic systems.

The interns were tasked with helping the NSA team redesign a total impulse gauge that meets NIF and Lab radiation-effects user needs. Currently, comparable impulse gauges do not meet experimental and NIF facility requirements. The new optical impulse gauge (OIG) would be used in experiments for the Ground-Based Strategic Deterrent (GBSD) missile program, including the Air Force Mark 21 (Mk21A) reentry vehicle and the W87-1 Warhead Modification Program.

Collaborating only through an online application and in virtual group meetings, Drew and Feldmann began working on the design during the summer of 2020, initially by studying current impulse gauges in NIF on the XTRRA (X-ray Transport and Radiation Response Analysis) platform and an Atomic Weapons Establishment (AWE) design in the United Kingdom.

They continued to refine the gauge in December 2020 and completed a current mathematical model design in May. The parts were fabricated and assembled recently, and the diagnostic is currently being tested.

“One of the things I really enjoyed about it was just being able to see everything throughout the process from no design to design approval,” Drew said. “It was really enjoyable to do that because a lot of my past experience has been a little more focused like a cog in a machine.”

Drew, who is from South Carolina, is a senior mechanical engineering major at Clemson University and will graduate in December. Feldmann, who is from central Missouri, graduated from Missouri University of Science and Technology with a degree in aerospace engineering. Both applied to the Lab for internships and followed the same path through AFROTC.

Blue has worked with ROTC cadets over the years and selects interns who would be a good match for the NSA program.

“It’s not only, ‘Do they have the skills to be able to contribute to our work?’ but also, ‘Can they use it as a growth opportunity and learn something that will help them as well?’” Blue said. “What caught my eye about Colt and Nathaniel was their mechanical and aerospace engineering backgrounds.

“The work we leverage is not just the physicist and the scientist side of NIF, but also the engineering side,” Blue continued. “We do a lot of work to put samples into the NIF Target Chamber to test for radiation effects. We’re putting these samples in pretty hostile and strenuous situations and the hardware to test samples has to survive that environment. It’s a really challenging engineering problem and that’s what attracted me to their backgrounds.“

Blue said it was “a good opportunity to have them pair up so they could learn to work in a remote environment and really help each other. I thought it went very well.”

Feldman came away with positive impressions about his Lab experience.

“I really liked both the people and the tech,” Feldman said. “The tech is really cool, but I’ve liked all the people I’ve had a chance to interact with, even those remotely. I’ve always been impressed with the skill set of the people at the Lab.”

Drew said it was “a great experience” to work at LLNL.

“I have learned more from the Lab than I have been able to give back to it,” he said. “Everything we’ve done at the Lab has been more of a learning process than just the working process. I’m a much better engineer because of the Lab. The people are definitely what makes the Lab, and they were really accommodating and made sure we had everything we needed, especially in this remote setup.”

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