New cryostat design has a Halloween feel

Inexpensive, easy to make: It’s the gourd-based neutrino detector. Photo: Rachel Tayse

As the country’s premier particle physics laboratory, Fermilab is always looking for the latest accelerator and detector technology. But a recent breakthrough in detector design has Fermilab’s Neutrino Division getting into the Halloween spirit.

The latest experiment to study those ghostly particles is called PUMPKIN, or Particles Undergoing Magnetic Propulsion de-K Into Neutrinos, and true to its name, it makes use of a strange yet surprisingly effective new design: cryostats made of actual pumpkins.

Like all great discoveries, this one was made by accident: an employee was decorating the tanks of liquid nitrogen with festive Halloween pumpkins, when he accidentally dropped one in. After fishing out the now frozen pumpkin, scientists conducted a few tests and discovered something amazing: cooled to extreme temperatures, pumpkins make excellent neutrino detectors.

“It’s crazy, I know,” said Steve Brice, head of the Neutrino Division. “When I heard about it, I thought they were kidding. But it really works. We’ve canceled all of the liquid-argon research and development and are dedicating all of our resources to freezing pumpkins.”

The pumpkin cryostats work better, Brice said, if the seeds are scooped out first, so he has organized a team of carvers to prepare the pumpkins for freezing. Experimentation is still ongoing, he said – some scientists decided to see if the seeds decayed into any interesting particles.

“Turns out they just decay into a smelly mess,” he said.

Brice went on to talk about the cost savings, explaining that while the average liquid-argon neutrino detector can range from $20 million to half a billion dollars, the average pumpkin costs around three bucks.

“We can make something the size of the MicroBooNE detector for something like $9,000,” he said. “That’s such a good deal, it’s almost scary.”