CAMS

Summary

Big Ideas Lab: CAMS

Podcast: Big Ideas Lab (Mission.org)
Episode: CAMS
Date: November 18, 2025

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Episode Overview

This episode dives into the pioneering work of the Center for Accelerator Mass Spectrometry (CAMS) at Lawrence Livermore National Laboratory. With immersive storytelling and direct accounts from scientists, listeners are taken inside investigations ranging from cracking cold cases with atomic precision to rewriting the timeline of North American prehistory. What emerges is a portrait of boundary-pushing science, powered by world-class technology and a deeply collaborative ethos.

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Key Discussion Points & Insights

The Power of Accelerator Mass Spectrometry (AMS)

• CAMS is a world leader in measuring ultra-rare isotopes, which enables research in archaeology, national security, public health, and forensics. (03:23)
• Diverse expertise: The lab's staff, including a dozen PhDs across disciplines, contribute to a wide array of research using AMS’s unparalleled sensitivity.

  "We all come with different scientific backgrounds." — Bruce Buchholz (04:00)

AMS in Cold Case Forensics

British Columbia John Doe Case

• In 1968, detectives found a child's remains whose identity stumped authorities for decades (00:04–01:38).
• Detailed forensic work decades later—combining DNA analysis and AMS-based radiocarbon dating—revealed the child was actually about four and a half years old, not 7–9 as initially thought (01:03).
• Lawrence Livermore’s team used fallout from Cold War nuclear testing as a “bomb pulse” timestamp to pinpoint dates of birth and death:

  "It was actually amazing." — Bruce Buchholz (01:33)

• The case closure exemplified how modern scientific tools can bring closure to families even decades later.

Newfoundland Murder Case

• In 2007, AMS helped identify Temistoko Fernandez Casas, a murder victim whose remains had been discovered in the Canadian woods six years earlier (06:20–08:24).
• Key insight: Global nuclear testing increased atmospheric carbon-14, allowing researchers to date organic remains with tremendous precision if the individual died after 1955.

  "That pulse basically started in 1955, went up and reached a peak in 1963, and has been coming down since then." — Bruce Buchholz (07:39)

• Date of death estimated to ~1996 and birth to 1958–1962, narrowing down the ID window and allowing for closure in a 15-year-old case.

Instrumentation and Lab Culture

• CAMS utilizes a powerful 10 MV particle accelerator—repurposed from nuclear physics—making it unique among facilities focused on advanced radiocarbon work.

  "Some of the big machines like that were modified from their nuclear physics backgrounds to do AMS." — Susan Zimmerman (09:39)

• The mission encompasses not just science, but applications in national security and forensics.

  "So our mission... is all, I think, different from other labs that do AMS." — Susan Zimmerman (09:59)

Rewriting North American Prehistory

The White Sands Footprints Discovery

• Scientists used AMS to analyze seeds from aquatic plants embedded with ancient footprints in White Sands National Park, NM.
• The surprising result: The analyzed seeds—and thus the footprints themselves—date to between 21,000 and 23,000 years ago, overturning the previous consensus that humans arrived in North America only 13,000–16,000 years ago (13:24–14:01).

  "No one was expecting dates 23,000 years old." — Susan Zimmerman (14:01)

• Pollen dating confirmed the results, after technical hurdles in isolating sufficient, uncontaminated pollen.

  "It turned out that the pollen dates pretty much confirmed the rupia seed dates." — Susan Zimmerman (15:29)

• This work adds 7,000 years to the established timeline and challenges archaeologists to rethink human migration.

  "There has to be so much humility to say we don't know anything, anything about what people were doing..." — Susan Zimmerman (15:56)

Biomedical Breakthroughs

Dating the Age of Neurons

• AMS was used to date DNA in brain cells, leading to the discovery that most neurons do not renew—except for those in the hippocampus, which is vital for memory formation (16:44–17:10).

  "Do turn over, and hippocampus is where memories get transformed from short term to long term." — Bruce Buchholz (17:10)

• The technique enables detailed studies of neuron life spans and offers insights into neurobiology and diseases.

  "Some of the projects that we've been involved in really changed the way people think of things." — Bruce Buchholz (17:33)

Scientific Curiosity & Ongoing Innovation

• The team views scientific progress as an ongoing process, always looking for ways to extract more nuanced data and challenge assumptions.

  "We're always trying to figure out what we can do better, what kind of scientific measurements we can make that we can't do now." — Susan Zimmerman (17:58)

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Notable Quotes & Memorable Moments

• On scientific humility:

  "There has to be so much humility to say we don't know anything, anything about what people were doing in the Western hemisphere for those 7,000 years..."
  — Susan Zimmerman (15:56)

• On technological advancement:

  "There’s just lots of things that can be done now that couldn’t be done 20 years ago. They're new tools all the time."
  — Bruce Buchholz (17:52)

• On the lab’s collaborative nature:

  "We all come with different scientific backgrounds."
  — Bruce Buchholz (04:00)

• Surprise in the evidence:

  "No one was expecting dates 23,000 years old."
  — Susan Zimmerman (14:01)

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Important Timestamps

• British Columbia cold case intro (00:04–01:38)
• Overview of AMS and CAMS's multifaceted work (03:23–04:49)
• Bruce Buchholz describes AMS applications and composition of staff (04:00–04:49)
• Newfoundland cold case and the bomb pulse (06:20–08:24)
• Susan Zimmerman on White Sands footprints (10:40–15:56)
• Breakthrough in dating DNA in brain cells (16:44–17:16)
• Reflections on scientific curiosity and future innovation (17:52–18:23)

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Episode Tone

The episode maintains a curious, awe-inspired, and collaborative tone, interspersed with rigor and humility. The scientists’ voices reveal both pride in their breakthroughs and an ongoing sense of wonder at how much remains to be discovered.

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Summary prepared for those seeking the essential insights into this powerful episode, weaving together stories of forensic breakthroughs, cultural history, and scientific curiosity at CAMS.

Transcript

[Narrator]

British Columbia, 1968 detectives were at a loss. Come in Dispatch. I think we found something. A child's remains were discovered along the riverbank with no clear cause of death and no indication of who the child was. Copy that, Dispatch.

[Bruce Buchholz]

Alert Central. They couldn't figure out where the child was from.

[Narrator]

Initial forensics at the time concluded that they had found the body of a 7 to 9 year old and there.

[Bruce Buchholz]

Wasn'T anybody in the area that match that. There was no DNA at that time.

[Narrator]

With no name, no missing persons match and no DNA analysis available, the case faded into the archives of the John and Jane does stories suspended in silence. Years passed. But in 2005, a forensic DNA analysis at Simon Fraser University reopened the case with a new discovery.

[Bruce Buchholz]

They misidentified the age.

[Narrator]

The child wasn't even seven years old. He was about four and a half. Hundreds of miles away, Lawrence Livermore National Laboratory took the next step with an advanced radiocarbon dating technique. Scientists used the atomic signature of Cold War nuclear tests to pinpoint when the child was born and when he died. Key information that led to the end of the search and a legal identification for the child finally declared.

[Bruce Buchholz]

And it was like 40 years from the time that they found it. It was actually amazing.

[Narrator]

It wasn't guesswork, it wasn't luck. It was a technique that hadn't even existed when the child's remains were first discovered. A technique perfected with the ultra precise instruments at the center for Accelerator Mass Spectrometry. Welcome to the Big Ideas Lab.

[Recruitment Announcer]

Your exploration inside Lawrence Livermore National Laboratory. Hear untold stories, meet boundary pushing pioneers.

[Narrator]

And get unparalleled access inside the gates. From national security challenges to computing revolutions, discover the innovations that are shaping tomorrow. Today.

[Recruitment Announcer]

Lawrence Livermore National Laboratory is hiring. If you're passionate about tackling real world challenges in science, engineering, business or skilled.

[Narrator]

Trades, there's a place for you at the lab.

[Recruitment Announcer]

Right now, positions are open for a field engineer, safety basis analyst and and an electric utility distribution electrician. These are just a few of the more than 100 exciting roles available at Lawrence Livermore. You'll work on projects that matter. From national security to cutting edge scientific advancements. Join a team that values innovation, collaboration and professional growth. Explore opportunities at LLNL where your next career move could make history.

[Narrator]

The center for Accelerator Mass Spectrometry, or CAMS at Lawrence Livermore National Laboratory is one of the most advanced and prestigious facilities in the world for measuring various ultra rare isotopes and investigating the information they provide. It houses an array of powerful machines that analyze Tiny atomic markers and discover answers to questions that have long eluded science, from archaeology to national security to public health and forensic investigation. But one of cam's most unique strengths comes from its people.

[Bruce Buchholz]

We all come with different scientific backgrounds.

[Narrator]

That's Bruce Buchholz, a staff scientist at.

[Recruitment Announcer]

Lawrence Livermore National Laboratory and a lead on multiple CAMS research initiatives.

[Bruce Buchholz]

We have some very specialized things that we can do.

[Narrator]

The lab operates with a flat structure where a dozen PhDs from a wide range of disciplines all work hands on with the machines, pursuing their own lines of scientific inquiry and creating a diverse, multifaceted team.

[Bruce Buchholz]

It could be soil, it could be coral, wood, charcoal, anything. And the reason carbon is so useful is that everything that's alive has carbon.

[Narrator]

Carbon 14 in particular plays a key role in radiocarbon dating. And that's where accelerator mass spectrometry, or AMS, comes in.

[Bruce Buchholz]

99% of carbon is carbon 12. About 1% of carbon is carbon 13. About 1 part per trillion of carbon out in the environment is carbon 14. So we're measuring variations off the one part per trillion natural concentration of carbon 14.

[Recruitment Announcer]

AMS is designed to detect and count those rare atoms by turning them into.

[Narrator]

Charged particles, accelerating them and separating them based on their mass. When traveling through a magnetic field, heavier isotopes like carbon 14 bend less, while lighter ones like carbon 13 and carbon 12 bend more. By measuring how much radioactive carbon 14 is left compared to stable carbon 13 and carbon 12, scientists can determine a sample's age, whether it's 400 or 4,000 years old. However, Bruce and the other CAM scientists use this process for far more than dating ancient charcoal or wood.

[Bruce Buchholz]

And I will do nuclear forensics and bomb pole stuff and a wide variety of things.

[Recruitment Announcer]

In many cases, AMS can help unlock.

[Narrator]

The hidden history of human remains, breathing new life into cold cases and long forgotten lives. That's exactly what happened in 2007, when police from Newfoundland, Canada, were six years into an investigation with nothing but dead ends.

[Bruce Buchholz]

I was approached by inspector in Newfoundland about a case. Hunters found some remains in the woods somewhere in Newfoundland. They knew it was a murder Based on other information. They had no idea who the person was.

[Narrator]

The body had been deep in the Canadian woods for six years. Local investigators had done everything they could, but the leads had dried up and the evidence, what little there was, was inconclusive. Authorities decided to try something different. Investigators in Newfoundland contacted Bruce after encountering research he had published alongside collaborators from the Karolinska Institute in Sweden on using carbon dating to estimate the age of human remains. Bruce Used the advanced machines At Lawrence Livermore national laboratory not to analyze fingerprints, but to analyze the atoms that history had left its fingerprints on. Beginning in 1955, above ground, nuclear testing Released Increased amounts of neutrons into the atmosphere. These neutrons reacted with nitrogen to create carbon 14, which created a spike in the atmosphere, the radiocarbon bomb pulse. In 1963, the partial test ban treaty was signed, and the carbon 14 supply began decreasing.

[Bruce Buchholz]

That pulse basically started in 1955, went up and reached a peak in 1963, and has been coming down since then.

[Narrator]

For scientists like Bruce, the bomb pulse acts as a timestamp. The surge in carbon 14 gives post1955 samples a precise fingerprint that narrows the age range of an organic sample as close as a few months. It's a level of chronological precision Otherwise impossible With older remains, where timelines blur and the age uncertainties can stretch across decades.

[Bruce Buchholz]

We were able to determine that date of Death was about 1996, approximately dated a couple of teeth. And we were able to determine a date of birth was 1958 to 1962.

[Narrator]

The unidentified person in Newfoundland was likely born in 1958, plus or minus a few years, and died sometime between 1994 and 1997, placing him in his 30s at the time of death. Combined with advances in genetic genealogy, Investigators were eventually able to identify the unidentifiable Temistoko Fernandez Casas, A man originally from Cuba. A case spanning 15 years could finally be closed. The machines that made it possible Contain their own history. A powerful lineup of accelerator systems, each one designed to perform A different kind of scientific investigation.

[Recruitment Announcer]

Their principal Machine is a 10 MV.

[Narrator]

Particle accelerator, the most versatile and productive AMS system in the world. Susan Zimmerman is a staff scientist At Lawrence Livermore National Laboratory.

[Susan Zimmerman]

The big accelerator that we have, the 10 MV machine, is a kind of equipment that was used by nuclear physicists.

[Narrator]

Accelerators like this underground installation. In the late 1960s, nuclear physicists moved on to bigger facilities, Leaving machines like the 10 MV to find new missions.

[Susan Zimmerman]

Some of the big machines like that Were modified From their nuclear physics backgrounds to do ams.

[Narrator]

Most radiocarbon work is done in universities and institutes that are focused on doing science, not nuclear physics and other national security work, Positioning cams to take on more unique challenges.

[Susan Zimmerman]

So our mission and the kinds of things that we do and the support that we have from engineering and from the safety people Is all, I think, different from other labs that do AMs.

[Narrator]

The diversity of tasks CAMs accepts extends far beyond cold cases. The same scientific techniques that Help law enforcement identify a missing person can also reach far deeper into the past. Sometimes the mystery isn't who someone was, but when someone was. That was the question geologists were trying to answer when they turned to Susan, who led the team at CAMS on investigating the age of the footprints discovered at White Sands National Park.

[Susan Zimmerman]

Radiocarbon is the most widespread fundamental way of dating things that happened in the last about 50,000 years.

[Narrator]

A set of fossilized footprints were originally discovered in the park in 2006. Footprints that told a story far more complex than we imagined about the first humans in North America.

[Susan Zimmerman]

The biggest thing when you're trying to reconstruct the past is to understand the timing of things. That would turn out to be much harder than we actually anticipated.

[Narrator]

For the U.S. geological Survey team invited by the Park Service to investigate, dating the White Sands footprints presented a huge challenge. Researchers needed to find organic material that was not only reliable, but also clearly connected to the event itself.

[Susan Zimmerman]

This is, from my perspective as a geochronologist, one of the really hard things about archaeology.

[Narrator]

You can't just date the dirt around a footprint. The most accurate radiocarbon dating requires an organic sample that was growing using carbon from the atmosphere around the time the print was made.

[Susan Zimmerman]

If you find an arrowhead or something, the arrowhead is made of stone and you can't date the arrowhead with radiocarbon. And so you date a little piece of plant material from the rope that was associated with the arrowhead or some other organic material.

[Narrator]

Without organic material containing carbon, radiocarbon dating can't be done. But buried in the same sediment layers containing the footprints, scientists discovered something small and powerful. Seeds from an aquatic plant called Rupia serosa that were both directly associated with the fossilized footprints and radiocarbon dateable.

[Recruitment Announcer]

These seeds were the key.

[Narrator]

They became the organic timestamp that scientists could use to peer into the past. And when the analysis was complete, the dates shocked everyone.

[Recruitment Announcer]

Join a team where expertise makes a difference. Lawrence Livermore National Laboratory is hiring for a safety basis analyst, a full stack developer, and a target diagnostics engineer. And the list of open positions doesn't end there. There are more than 100 job openings across science, engineering, IT, HR and the skilled trades. This is more than a job. It's an opportunity to help shape the future. Explore all open positions and start your next career adventure [e-mail]. that's llnl.govcareers.

[Narrator]

New evidence confirms that humans were walking.

[Susan Zimmerman]

Across North America more than 20,000 years ago.

[Narrator]

According to the rupiah seed measurements, the footprints found in White Sands national park were between 21,000 and 23,000. For decades, the scientific consensus had been that humans crossed into the North American continent around 13,000 years ago. After the last ice age began to thaw, newer investigations at various sites had begun pushing that date back to about 16,000 years ago. However, the new evidence that emerged from dating organic material showed these footprints were laid down during the ice Age, not after.

[Susan Zimmerman]

No one was expecting dates 23,000 years old.

[Narrator]

It sparked immediate debate. Academic minds questioned whether the plant material truly reflected the age of the footprints or if it had been affected by a chemical disequilibrium between the water the root beer was growing in and the atmosphere. The U.S. geological Survey had to go deeper. The team continued searching for terrestrial materials that could be dated using ams, and eventually they found it. Pollen the carbon trees use to make pollen comes from the atmosphere, one way of assuring reliable radiocarbon dates. But analyzing pollen isn't simple. It's a delicate, complex process that requires both precision and patience. This is when the U.S. geological Survey team called Susan. They knew she had been working on developing pollen dating for years.

[Susan Zimmerman]

The really critical thing about dating the pollen is you have to have really pure pollen. You can't have a bunch of algae or other aquatic material or carbonate minerals are things that are made in the lake water.

[Narrator]

To perform AMS measurements on pollen, scientists need at least 50,000 pollen grains. And the more grains, the more precise the date. Thankfully, with the help of a flow cytometer, a machine that separates grains individually, producing pure pollen samples, the team at CAMS was able to isolate clean samples and send them to Susan for, for analysis.

[Susan Zimmerman]

It turned out that the pollen dates pretty much confirmed the rupia seed dates. And so the footprints really are, as far as we know, at the moment with the evidence we have something like 23,000 years old.

[Narrator]

Thanks to the ultra sensitive isotope work at cams, these footprints are now considered the oldest reliable evidence of human presence in North America, rewriting a key chapter in the story of human migration and adding 7,000 years to of their history living there.

[Susan Zimmerman]

There has to be so much humility to say we don't know anything, anything about what people were doing in the Western hemisphere for those 7,000 years and what other people were doing 23,000 years in other places, right? Suddenly we have to go, oh, we know almost nothing. And that is pretty cool.

[Narrator]

Members of the CAMS team at Lawrence Livermore National Laboratory aren't just a unlocking the past, they're contributing to the future. Their work extends into biomedical research and drug development like the new compound to aid in fentanyl recovery and prevention mentioned in part two of our Forensic Science center episode, or the biomedical breakthrough on what most scientists assumed was dating DNA.

[Bruce Buchholz]

No one had ever tried to date DNA because we always said, oh, it's too small, there's not enough there, you can't purify it.

[Narrator]

However, Bruce Buchholz and his collaborators Jonas Friesian and Kirsty Spalding at the Karolinska Institute decided to try. By dating DNA in the brain, they found that neurons don't turn over. The neurons you're born with are the ones you keep. With one exception, neurons in the hippocampus.

[Bruce Buchholz]

Do turn over, and hippocampus is where memories get transformed from short term to long term.

[Narrator]

By using accelerator mass spectrometry, scientists can trace the lifespan of brain cells with incredible precision, revealing when neurons are formed, how they age, and whether they regenerate. This discovery has helped shape how scientists understand the brain.

[Bruce Buchholz]

Some of the projects that we've been involved in really changed the way people think of things.

[Narrator]

Accelerator mass spectrometry is helping scientists navigate concepts that find feel unreachable, identifying unknown individuals, rewriting human history, tracing how our brains age and beyond.

[Bruce Buchholz]

There's just lots of things that can be done now that couldn't be done 20 years ago. They're new tools all the time.

[Susan Zimmerman]

We're always trying to figure out what we can do better, what kind of scientific measurements we can make that we can't do now. If we would just modify or improve the accelerator system, what new science, what more science, what better science we can do?

[Recruitment Announcer]

Lawrence Livermore National Laboratory is hiring. If you're passionate about tackling real world challenges in science, engineering, business or skilled.

[Narrator]

Trades, there's a place for you at the lab.

[Recruitment Announcer]

Right now, positions are open for a field engineer, safety basis analyst and an electric utility distribution electrician. These are just a few of the more than 100 exciting roles available at Lawrence Livermore. You'll work on projects that matter, from national security to cutting edge scientific advancements. Join a team that values innovation, collaboration and professional growth. Explore [e-mail] careers where your next career move could make history.

[Narrator]

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[Recruitment Announcer]

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