The North Physics Laboratory (NPL) and Cyclotron Shop sit inconspicuously on the Northeast end of campus, below both Haggett and McCarty Halls. Save for the rustling of leaves by a breeze cascading toward Union Bay, the facility is oddly quiescent. Partially built into a hill, it seems to shrink from contact with the broader campus, keen on keeping its contents obscure.
Such unimposing yet intriguing facilities beg further inspection. Who and what lies within their mysterious confines? What is a cyclotron, and what can it tell us about the universe?
The answers illuminate two devices run by people asking even more complex questions.
After receiving his Ph.D. at the University of California at Berkeley, a young physicist named Fred Schmidt joined the physics faculty at the UW in 1946. World War II had just ended and interest in nuclear physics was widespread. Among those charged with building the nuclear physics program at Washington, Schmidt installed a cyclotron at NPL soon after his arrival.
"The Cyclotron was a cylindrical vacuum chamber wherein particles were accelerated using a high power high frequency oscillator to alternate voltages between two half-cylinder electrodes called 'Dees,'" said Greg Harper, a research engineer at NPL. "Particles injected into the cyclotron were accelerated each time they crossed the intervening layer between the Dees." The particles took on more and more energy as they accelerated, and eventually were directed out of the chamber toward a target, Harper said.
At a fundamental level, particle accelerators smash atoms into one another, producing nuclear reactions that interest scientists. The device at the UW was used for experiments ranging from the ordinary to the peculiar.
Local diamond dealers brought gems to the NPL for radiation treatment. When exposed to the cyclotron's radiation, the stones were altered slightly, making them more valuable. The neutron therapy project it supported made various isotopes for area hospitals. They were used as tracers in medical treatments. Patients were admitted for treatment, but studies on cadavers caused the most stir.
One night after a party, UW professor of physics John Cramer stopped by the labs with his wife to pick up some things. Hoping to offer her a glimpse of the corpses and the cyclotron, Cramer led his wife to the room where the cadavers were kept. To their surprise, the bodies were gone, and the light in the cyclotron chamber was on.
As they peeked into the large room, the two saw a medical researcher using a shop drill with one hand and positioning a corpse on a vertical board with the other. The scientist took no notice of the couple, busily preparing whatever experiment he had planned.
"It looked eerily similar to something out of Shelley's Frankenstein," Cramer reminisced. "My wife certainly got more than she bargained for."
When Cramer arrived on campus in the fall of 1964, he knew exactly what attracted him to the UW. The University had begun installing a cutting edge FN Van de Graff particle accelerator. Built into a new wing of the NPL, the Van de Graff held the promise of offering physicists a powerful new tool in their investigations.
The Van de Graff accelerates particles linearly from a terminal to a target. It works just the same as the toy of the same name. Instead of charging a metal sphere fondly known to cause a person's hair to stand on end, the Van de Graff charges the source of the particles, set inside a giant purple chamber, to millions of volts.
The particles originating at the terminal are positively charged and are accelerated away from the similarly charged terminal at a high velocity. The beam of particles speeds out of the chamber, is filtered and directed by magnets and eventually arrives at a target set in another room. When the particles collide, a spray of energy is given off in the form of radiation. Detectors measure this energy, providing quantitative description of the collision and resulting matter.
Cramer now considers himself the oldest member of the nuclear physics group at the UW. His work has expanded to larger accelerators at Brookhaven National Laboratory in New York and CERN, an international collaboration in Switzerland. Their accelerators span miles in diameter.
While he no longer uses the accelerator on campus, Cramer finds utility in having it at the UW.
"On campus, projects involve a comparatively small number of people who get to make their own decisions," Cramer said. "The disadvantage of doing research with the larger accelerators at Brookhaven or CERN is having to study out of a suitcase."
A real advantage of having an accelerator here is being able study and work in the same place. That's incredibly advantageous to students, Cramer said.
Young researchers at NPL agree. Anne Sallaska, a doctoral candidate in the physics department, once did research at Los Alamos National Laboratory in New Mexico.
"I hated the traveling and being away from home," Sallaska said. "It's a bad idea for a graduate student to work on an experiment that they're not present for. Besides learning more from being immersed in the physics I'm studying, I appreciate being able to go back to my own bed at night."
Sallaska spends her days at NPL working under the guidance of Alejandro Garcia, a UW professor of physics. His group is engaged in an experiment he describes as a detective story. Using the accelerator, they are attempting to recreate reactions occurring in exploding stars.
"Theory predicts that supernovae should produce a particular isotope, Sodium-22, in great abundance," Garcia said. "However, observations using gamma ray telescopes find that it has disappeared. Our hypothesis is that hydrogen consumes the sodium, producing magnesium."
To begin to reconcile theory and observation, Garcia's group slams hydrogen protons into a Sodium-22 target and observes the resulting reactions. The Sodium-22 experiment should help shed light on how the heavier elements in our universe came to be, giving some tangibility to the phrase, 'We are all made of stars.'
Today, research continues at the NPL under the auspices of the Center for Experimental Nuclear Physics and Astrophysics. The cyclotron lays dormant and largely disassembled, only a shell of its former self. A product of late 1940s technology, it was eventually decommissioned in the mid-1980s. The Van de Graff accelerator is used regularly by a variety of experimenters, including Garcia's group. They continue to collect data on the Sodium-22 experiment today, striving to solve their mystery and shed light to curious onlookers.
[Reach reporter Brian Smoliak at email@example.com.]