Gamma Sonification: MIT Students Make Music From Particle Energy


Junior Keldin Sergheyev candidly admits he didn’t know much about Western musical notation before taking 21M.065 (Introduction to Musical Composition) this spring. Most of what he did know about sound, Sergheyev adds, came from 8.03 (Vibrations and Waves), a required physics class for all nuclear science and engineering majors at MIT.

Midway through 21M.065, however, Sergheyev and two fellow MIT students had invented a new technique for generating musical sound — one that uses gamma radiation. Reflecting on the project, Sergheyev says, “The nuclear part was easy. The music part was the larger challenge.”

MIT’s music classes range from conservatory-level tutorials to classes for complete novices. Taught this year by acclaimed composer Keeril Makan, 21M.065 is designed to be within reach of beginners — students such as Sergheyev and junior Nick Lopez, also a nuclear science and engineering major. Because it is taught by master composers, however, the class also appeals to students like sophomore Helen Liu, who had prior experience performing in a choir, jazz band, and orchestra, but had not yet studied composition.

Listening deeply

Makan’s class thus assembled a group of students with varying levels of musical experience, all of whom began to learn how to more fully experience and think about the sonic textures of their everyday lives. Makan also asks his students to make things to express their increased understanding of sound.

In past classes, students have created soundwalks and graphic scores, learning about experimental pieces that broaden conventional ideas about sound. “We start off doing things that are meant to expand what the students think of as being ‘music,’ and get them listening more deeply,” Makan says. In his most recent class, students were asked to design a musical instrument. Some made flutes, chimes, and drums. Sergheyev, Lopez, and Liu decided to make musical textures from nuclear radiation.

One of only two American universities with a nuclear reactor on campus for research, MIT also has a Department of Nuclear Science and Engineering (NSE), where students study the future of nuclear power, learning how to design more efficient reactors, examining nuclear security, and researching applications for radiation.

It is a field that is propelled by the dream of providing the planet with safe, carbon-free energy. “As soon as I knew about nuclear power and the potential it has to provide power so cleanly and elegantly, I was hooked,” says Sergheyev, who grew up in water-starved Tucson, Ariz. “I wanted to be a part of that solution.”

How cool would it be?

“I’ve always been interested in things that were misunderstood,” Liu says, noting that even other MIT students can be leery of the work she does. Usually, she is the only NSE student in any given class outside her department — but as luck would have it, there were three NSE students taking Makan’s composition class.

“How cool would it be if we were in a group?” Lopez recalls thinking. “We could do something nuclear-related and show off our major, you know? Kind of take pride in it.”

Lopez and Sergheyev were also in another class together, studying particle detectors, devices used to spot and measure the high-energy particles fired off in the process of radioactive decay. “With that influencing us, we realized that these detectors are outputting signals based on the energy of the incoming particle,” Lopez says. Let’s try to map that energy to a frequency, the group thought. With that, the students realized that there, in the lab, they had a musical instrument at their fingertips all along.

“When we actually had our ‘recording session,’ if you will — it’s fun to call it that — we used a lanthanum bromide detector,” Sergheyev says.

The lanthanum bromide detector is a type of particle detector called a scintillator. Sealed within a thick aluminum canister, which resembles a coffee thermos, is a crystal that scintillates in proportion to the energy emitted during nuclear decay. One late night in the lab, the group exposed the detector to various sample isotopes, such as cobalt-60 and cesium-137.

They also used cigarettes — which contain polonium and lead — and a vintage orange plate with a slightly radioactive glaze. Because each source emits a characteristic energy, the students found they could “compose” musical sound by placing different combinations of elements near the detector.

The sound of the decaying atom

From there, the students were able to convert these pulses of light to numerical data using software developed by NSE graduate student Zach Hartwig, who served as a mentor. In other words, the energy, in the form of light, was transformed into an electrical signal that was then transmitted to a computer. Using Hartwig’s software, the signals were converted into graphable numbers that represented a measure of the energy released by the decaying atom — gamma radiation.

To transform the numbers into a composition, the group first had to figure out how to decode the data into real-time sound. For this, they experimented with different programming languages, as well as different methods of mapping the energy to distinct sine-wave frequencies.

Liu took on the task of composing the musical sound textures, while Sergheyev and Lopez worked on the programming.

In one version, they assigned each energy level a particular note on the musical scale: The specific energy emitted by cobalt-60 might translate to an E note, for example. In another rendition, the entire graph of energy was correlated to the sound spectrum in a one-to-one fashion. The resulting compositions — which translate silent energy into an audible form — are surprisingly moving, eerie signals, evocative reminders of the vast elemental realms that exist beyond our immediate perception.


The kind of art-science collaboration this project illustrates is encouraged at MIT, where the Center for Arts, Science and Technology was founded in 2012 — and the project has already suggested one immediate practical application to the students.

“We were in the nuclear lab, where they do a lot of radiation testing, and while we were there one of the detectors started going off,” Liu says, mimicking the loud beeping noises of the detector. “We were saying, ‘What is that? What does that mean?’, and we had to figure out what the machine was trying to say to us.”

The human brain processes sound very quickly, and Liu suggests that if a detector were to generate a unique sound in response to a particular stimuli, researchers could know immediately whether something was harmful.

For Lopez, a double-major in NSE and physics who gravitates toward theory, the exploration was a good workout. “Being able to do these abstract projects helps practice the thinking muscles,” he says. “And it’s just nice to sit down and listen to music.”

Turning data into meaning

The arts also offer fresh methodologies for representing and grasping large and complex amounts of information — and for turning data into meaning. Indeed, the students’ project occurs against a backdrop of growing interest across the engineering and science communities in sonifying data, with the idea that engaging multiple senses — including the ear — may lead to new discoveries in the pursuit of knowledge.

“One goal, as a scientist, is to be constantly exposing yourself to new ways of thinking,” Sergheyev says. “So now I’ve been thinking a lot about how sound pressure waves and these sorts of things might affect neutron spectrums in a reactor.” He wouldn’t have been thinking about sound, he says, had he not taken Makan’s class on music composition.

Photo: Jon Sachs.
Posted on July 30, 2014 by Anya Ventura