The tale of the two cyclotrons at the National Superconducting Cyclotron Laboratory begins all the way back in 1911 when British-New Zealand physicist Ernest Rutherford first came up with the idea of the nucleus. Within a couple of decades, the first accelerators came on the scene. As the technology became more refined, more institutions began building them. Each had its own strengths and energy levels, providing the world with a more comprehensive view of the nucleus than any single type could.
Different accelerator energies are necessary for studying objects of different sizes. As former NSCL Director Henry Blosser put it, “A hammer is a very unuseful tool to the biologist probing the internal structure of a fly, whereas it is a very useful tool for the geologist interested in the internal structure of a rock. The most useful projectile energy for a nuclear study is then fixed by the nucleus itself, namely, an energy high enough to dislodge fragments from the nucleus—to dissect the nucleus—but not so high that the nucleus is totally destroyed, so that the structure of the nucleus has little effect on the final result (just as the internal structure of the fly has little effect on the final result when the fly is smashed with a hammer.)”
As the world was building its nuclear physics industry, Michigan State University decided to join the party. No written records exist, but Professor Richard Schlegel, the head of the Physics Department at the time, believes the idea was passed down through the administrative ranks by former President John A. Hannah. Though Hannah claimed no recollection of this, the idea was supported, and Professor J. Ballam formed a study committee in 1954 that recommended adding positions and setting up funding to begin the planning of a cyclotron-based nuclear research facility.
Two types of accelerators were seriously considered: a 10 million electron volt (MeV) Van de Graaff electrostatic generator and a 30 MeV cyclotron. Though the former could be purchased commercially for less money, the committee settled on the latter, assuming the process of designing and constructing a cyclotron from scratch would help develop the new program.
Recruiting a director for the new program proved challenging as no established physicists wanted to leave stability and security for a new program. The search ended in 1958 when MSU took a chance on a young Oak Ridge physicist named Henry Blosser. Though just three years out of graduate school, Blosser was the group leader in a cyclotron design project and the perfect man for the job.
The newly born MSU nuclear physics program had a great advantage during its infant years. The campus was home to one of the best computers in the country called MISTIC. The computational power allowed Blosser and his new team to design a new technique for extracting the accelerated nuclei from the cyclotron. Instead of a broadly fanned out beam, the new technique created a finely collimated, precise pencil of particles, which is a great advantage in nuclear physics.
Armed with this new technique, Blosser set out to get funding. Though the proposal received a glowing review from the Massachusetts Institute of Technology, the Atomic Energy Commission had too tight of a budget to finance the project. Sherwood K. Haynes, chairman of the Department of Physics, worried that if the project was left unfunded, other institutions would use MSU’s design first and steal members of Blosser’s team in the process.
But the fears were unfounded because MSU was able to land a National Science Foundation (NSF) grant to build its first 40 MeV cyclotron in 1961. Four years later, the first beam was accelerated. Because the device outperformed its design and provided beams of 50 MeV, it was called the K-50. Along with the new accelerator, a building was erected to house the laboratory and the people working on it.
Three sites were considered: an addition to the old Physics-Mathematics Building on north campus, a site on Service Road where a power plant now resides and a site on South Shaw Lane—where the laboratory still stands—in the middle of what had been a fine alfalfa field. Coupled with a device known as the Split Pole Spectrograph, which provided unique, high-precision studies of nuclear structure, the MSU facility was being described in peer reviewed papers as the best of its kind in the world.
The laboratory attempted to expand in 1969 and build a new cyclotron designed to produce both high energy protons and heavy ion beams, but was turned down by the Nixon administration. Though the scientific community agreed such a device should be built, nobody was willing to allow a different lab to host it.
Then, in 1973, came the idea of using superconducting technology to create a more powerful yet smaller and cheaper accelerator.
Superconducting materials are chilled below 450˚F, causing electricity to flow with zero resistance in certain materials such as niobium. This makes electromagnets, which rely on the flow of electricity to produce magnetic fields, much stronger. The technology reduced the volume of wire needed by 10 to 20 times. For example, Blosser wrote, “the 500 MeV cyclotron being constructed in East Lansing has a magnet which weighs approximately 100 tons; the magnet of the next most recent cyclotron in this country, a 240 MeV room temperature cyclotron, in contrast, weights 1600 tons or 16 times more for a cyclotron of only half the energy.”
Since the Canadians didn’t have any expertise building cyclotrons, they took their idea to the faculty at MSU, who agreed it seemed like a splendid idea. Studies of superconducting cyclotrons were then enthusiastically renewed in the fall of 1973.
Making a superconducting cyclotron isn’t as easy as simply replacing the magnets, though. Because the magnets are smaller but more powerful, all of the bells and whistles must be made smaller as well. And as Henry Blosser pointed out, “many parts prefer to melt when reduced in size rather than to perform their assigned function; others break under added stresses, and a broad array of problems associated with the change of scale must be handled and solved.”
But solve them they did before hitting another bump in the road. Who would get to build this new device?
To skirt the problem, Blosser submitted a proposal to only build a magnet for the new accelerator to prove it would work. Everyone agreed this was a good idea, so work began in 1975 and two years later, the magnet containing 25 miles of niobium wire was operational. When it came time to decide which laboratory got to host the actual accelerator, though, each facility thought they themselves should. But the fact that the superconducting magnet had already been built removed the option of doing nothing with it.
After a round of proposals, the NSF made the decision to award it to MSU in mid-1977 due to the fact the East Lansing team had built the magnet and had a strong program with the proven K-50.
The funding was given as the first phase of a grander scheme. The newly formed Midwest Consortium of collaborating Nuclear Scientists, which represented 21 midwestern universities, proposed a $13,195,000 project to form a coupled superconducting cyclotron facility at MSU. The second phase would link a new 800-MeV superconducting cyclotron to the 500-MeV superconducting cyclotron already being designed.
The initial appropriations bill for the giant project went through the House and Senate and was signed by President Carter in September 1979, only months after the original K-50 cyclotron was shut down to allow the construction of the K-500. After hammering out the details, a contract between MSU and the Department of Energy was signed early in 1980, work on a second superconducting cyclotron began and the National Superconducting Cyclotron Laboratory—formerly called the MSU/NSF Heavy Ion Laboratory—was born.
The K-500—the world’s first superconducting cyclotron—was launched at 3:00 p.m. on Saturday, November 21, 1981 and the first beam of particles was extracted in August of 1982, just five years after the team was given the go-ahead.
Two years later in 1984, the superconducting magnet for the second cyclotron was tested successfully. However, the original plan to couple the two cyclotrons together was revised so that the second cyclotron would operate independently, at least for the short term. The new plan was successful and the K-800 was online by early 1988 and, due to its excellent focusing power, renamed the K-1200 a year later.
It was also around this time that the laboratory completed a program launched in 1984 to use its knowledge of accelerators to build a different sort of device. By then it had been discovered that neutron radiation could be used as a more precise alternative to cancer treatment than chemotherapy.
Because neutrons are much heavier than the x-rays or electrons used in more traditional radiation therapies, they stop in a person’s flesh much more quickly. This allows doctors to target tumors without the radiation continuing through to damage other parts of the body. Also, neutrons damage cells using high linear-energy-transfer (LET), which does not give a cell the chance to heal like low LET radiation can. This results in about one-third as many doses as other forms of therapy.
Since the lab knew how to construct accelerators to produce the needed neutrons, it partnered with the Gershenson Radiation Oncology Center at Harper Hospital in Detroit to provide a small, medicinal accelerator. The first superconducting cyclotron for medicinal use was designed and constructed at NSCL and delivered in 1990. Since that time, the lab also has designed the concept for a 250 MeV superconducting cyclotron for proton cancer therapy that was licensed through an agreement with ACCEL Instruments Gmbh in Germany.
As the demands of the nuclear physics community matured, the technique of secondary beam physics slowly emerged. This involves colliding a beam of nuclei with a target to create a range of new isotopes; some with a very strange number of neutrons. The exact isotope that scientists want to study is filtered out and a second beam is created. These rare, exotic isotopes that don’t occur naturally on Earth are studied before they decay into a more stable form.
In order to do this type of research, though, more power was needed from the cyclotrons. So the original plans to couple the K-500 and the K-1200 together finally began receiving funding in late 1998. By using the K-500 as an injector, scientists can give isotopes a higher charge, which means they can be accelerated to higher speeds. The combination of the two cyclotrons would allow heavier particles to be accelerated to higher energies—ten times more energy than the K-500 produces alone.
The cyclotrons were shut down on July 2, 1999 so that work on the coupling system could begin. By October 1, 2000, the laboratory successfully produced its first beam of ions from the new facility. The power of the new facility allowed the lab to explore new isotopes, some of which can only be found in astronomical phenomena like supernova and neutron stars. Because of its newfound expertise in astrophysics, NSCL joined the University of Notre Dame’s Nuclear Structure Laboratory and the University of Chicago to establish the Joint Institute for Nuclear Physics (JINA) in 2003.
Through the first half of the 1990's, a project of enormous proportions was being advocated by many nuclear physicists, most notably Konrad Gelbke, Director of NSCL and chairman of the Nuclear Science Advisory Committee. The idea was to construct a Rare Isotope Accelerator (RIA) more powerful than the coupled cyclotron facility at NSCL. But instead of a cyclotron, RIA would consist of many units in a line accelerating the nuclei as they pass from one to the next; a linear accelerator.
After years of advocating for the device, the DOE put out a call for proposals for a $1 billion RIA in 2004. However, due to budget restraints, the project was shelved for three years until a new call went out for a $550 million project dubbed the Facility for Rare Isotope Beams (FRIB). At that time, MSU entered a proposal competition - primarily with Argonne National Laboratory – for the right to host the new accelerator.
After a lot of hard work and dedication, the DOE announced that FRIB would be hosted by MSU on December 11, 2008. Included in the grant were several upgrades to be completed within a few years so that the laboratory would be ready for the new accelerator scheduled to be completed in 2018. One such upgrade was a new device called the Low Energy Beam Ion Trap (LEBIT), capable of stopping, trapping and studying rare isotopes.
Work continues today on the FRIB project. Besides carefully planning, designing and researching the new facility, NSCL is becoming an expert in linear accelerators. For example, a new experimental device capable of stopping and reaccelerating rare isotopes is underway; a device using technology very similar to the accelerators that FRIB will require.
Over the years, NSCL and MSU have developed into one of the best nuclear physics programs in the country and its premier facility for studying rare isotopes. But with the addition of FRIB over the coming decade, the entire world will be playing catch-up.