A day in the life of an accelerator engineer

At the Department of Energy’s SLAC National Accelerator Laboratory, a kilometer-long accelerator sends bursts of electrons hurtling at over 99.9999992% the speed of light. Meanwhile, from a support building above the accelerator, Shweta Saraf peers at a control panel lined with glowing computer screens. Each monitor provides real-time data about the Linac Coherent Light Source (LCLS), which operates 30 feet beneath her feet. 

She gestures to the controls instrumentation. “These are programmable logic controllers, or PLCs, and they tell us everything we need to know about the current pressures and temperatures of the beamline,” Saraf explained. “If they sense anything has gone wrong, they will trigger that section of the beamline to isolate itself, then send an alert to my team.” 

As head of Industrial Controls & Construction Engineering, Saraf coordinates essential systems that keep LCLS running smoothly. Although her team supports the world’s most advanced X-ray free-electron laser, their focus isn’t on pushing technology to the extremes. “Stability is our goal,” she said. “With hundreds of scientists from universities and labs across the world lined up to conduct experiments with LCLS, we want to do what we can to avoid disruptions and support science every day.” 

The road to SLAC 

Saraf’s interest in engineering came at an early age. Growing up in Pune, India, she remembers sitting with her father, himself an engineer, as he took apart and fixed household appliances at the kitchen table. “When it came time for university, he encouraged me to study engineering,” Saraf said. 

She did so, earning an electrical engineering degree in India, then moving to the U.S. for graduate studies at Stony Brook University in New York. She got her start in light source technology at Brookhaven National Laboratory, where she helped build the controls system for the National Synchrotron Light Source II. In 2014, she brought her experience to SLAC, working first with the Stanford Synchrotron Radiation Light Source. 

“I remember interviewing at SLAC and meeting so many incredible women in leadership roles and thinking, ‘I can really see myself working and growing here.’ It was a very inspiring place to walk into,” Saraf recalls. “From the start, my mentors encouraged me to take on challenging projects and apply for new opportunities.”

In 2016, she came to LCLS. Like an incredibly powerful microscope, LCLS gives researchers insight into minuscule atomic and molecular reactions, which can lead to big advances in medicine, energy and manufacturing. It starts by accelerating bursts of electrons nearly to the speed of light, then uses magnets to make them wiggle and emit ultrabright X-ray light. Saraf’s team ensures that nothing interferes with the electrons speeding down the kilometer-long beamline – not even air. 

“Even just the molecules in the air we breathe can block and absorb electrons, so the entire beam is under vacuum,” Saraf explained. Her team designed the electronics for the vacuum system, which reduces the pressure from regular atmospheric levels by almost a factor of a trillion, clearing the beamline for electrons to stream through undeterred. 

The vacuum system is just one of the many subsystems that come together to support the beamline. “The subsystems support the generation and acceleration of the beam, maintain its speed and direction, keep the environments – like temperature and pressure – stable, and protect the beam from damaging the beamline hardware in any way,” Saraf said. 

Of these subsystems, Saraf directly manages teams for industrial controls and oversees teams responsible for infrastructure support systems, including the cable plant and cable shop operations.  “My days consist of a lot of planning and coordination with other teams, and we’re always ready to pivot to address any issues that arise at a moment’s notice,” Saraf said. 

Tackling new projects 

Today, Saraf is also playing a pivotal role in the upcoming LCLS-II-HE upgrade, which will double the energy of the electron beam from the superconducting accelerator, dramatically increasing the brightness of high-energy X-rays for experiments. During the two-year upgrade, the copper accelerator, which runs in parallel to the superconducting accelerator, will continue operating. 

As the technical lead for controls, Saraf is coordinating the upgrade of all the subsystems. For her teams, the challenge is twofold: continue delivering uninterrupted support for ongoing science operations while implementing new systems for a state-of-the-art upgrade. 

“We’re in the planning stages now, but when the upgrade begins, we’ll have to do a very large amount of work in close coordination with multiple divisions across the lab in a finite amount of time,” Saraf said. 

It’s a big task, but she’s looking forward to the challenge. 

“I started at SLAC as an individual contributor, and I was always looking for ways to develop and expand my skill set,” Saraf said. “I’m lucky to have had mentors who saw that desire and gave me these projects that stretch and challenge me. This upgrade is another opportunity for our team to grow – to improve on what we’ve done in the past.” 

Giving back 

Though much of her days are spent in coordination meetings, planning out timelines and budgets and remotely monitoring the beamline, Saraf tries to carve out time to build meaningful connections with colleagues. 

She hopes to help make the field welcoming for aspiring engineers, including her seven-year-old son Daniel. “He says he wants to be an engineer at SLAC, which may be largely due to the fact that both of his parents work here,” Saraf said with a laugh. Whether or not that desire sticks, she wants this field to be one where everyone belongs. 

“I want to turn around and tell the next generation, especially young women like myself, that this path is open to them, too. I want to do what I can to make the field seem less scary, less intimidating, and to make it a space for everyone to feel welcome. Yes, there is hard work along the way, but the effort is well worth it.”

For questions or comments, contact SLAC Strategic Communications & External Affairs at communications@slac.stanford.edu.