Three Neutron User Teams from Japan’s Quake-Damaged Accelerator Facilities Working at SNS
“This facility is very user friendly,” enthusiastic researchers say
Research Contact: Georg Ehlers
June 2011, Written by Agatha Bardoel
Left to right: Tokyo University researchers Maiko Kofu, research associate, Atsushi Nagoe, postdoc, and Professor Osamu Yamamuro. The material studied is attached to the bottom of the cryostat stick held by Kofu.
Three teams of Japanese neutron sciences researchers deprived of their own neutron facility by the earthquake that hit northeastern Japan on March 11 are doing experiments this month at the Cold Neutron Chopper Spectrometer (CNCS) at SNS.
The Japan Proton Accelerator Research Complex (J-PARC), located at Tokai on Japan’s east coast, 125 miles south of Sendai, has been closed since the disaster. Sendai is one of the areas worst hit by the 8.9 magnitude quake and tsunami.
The earthquake shifted the mercury target at the massive complex several inches from its base. SNS and other J-PARC partners around the world invited proposals from users of the complex’s Materials and Life Science Experimental Facility (MLF). The first users, from Tohoku University in hard-hit Sendai, arrived on June 13 at CNCS, a high-resolution, direct-geometry multichopper inelastic spectrometer. Georg Ehlers, lead instrument scientist for CNCS, said the instrument is at the users’ disposal until the end of the month.
Road in front of linac building of J-PARC.
After the earthquake, Ehlers received and reviewed five proposals originally submitted for the J-PARC facility and recommended four projects for the CNCS instrument. SNS management then approved these experiments to run at the Oak Ridge facility. The entire process was remarkably quick. “I advised management, and it was smooth sailing from there. You don’t want them to have to wait until a year later,” he said. The fourth Japanese user group will be at CNCS in August.
The research teams are from the University of Tokyo and Tohoku University. The week of June 20, a collaboration that included Dr. Osamu Yamamuro, his research associate Maiko Kofu, and postdoctoral student Atsushi Nagoe, all from the University of Tokyo, conducted experiments. Ehlers and fellow instrument scientist Andrey Podlesnyak guided them on use of the instrument.
Yamamuro was enthusiastic about the user facility at SNS and about CNCS. “This facility is very user friendly,” he said. “From preparing the sample, to the support from the instrument scientists, to the data collection, everything is available to us when we need it. We can see the data right here at the instrument.”
“In Japan, the user process is much more complicated. One must fill out many, many forms. Here everything is much easier.”
The $1.5 billion J-PARC complex, opened two years ago, produces a range of particles including neutrons, muons, kaons, and neutrinos from three accelerators: a 200 MeV linear accelerator; a 3 GeV proton synchrotron; and a 50 GeV proton synchrotron.
J-PARC is working on the diagnosis and repair of its instruments and ancillary systems since the earthquake. Yamamuro said the “most optimistic view” of when J-PARC will be taking neutron users again is December of 2011.
Yamamuro's team investigated the collective dynamics of the boson peak in imidazolium-based ionic liquids. The work, which is an important component in understanding the fundamental science of conductivity in ionic liquids, will help develop more efficient batteries and fuel cells.
“Ionic liquids are good, glass-forming liquids,” Kofu explained. “Usually in glassy materials, excess low-energy excitations characteristic of glasses, called boson peaks, are observed. But the origin of the boson peak is still unknown and a major subject in research in glass transitions. To study this, we investigate the Q-dependence of BP.” Q is typically momentum transfer in a scattering experiment and gives the scattering angle.
On June 27, a third collaboration from the University of Tokyo arrived to conduct research on the electromagnon of multiferroic TbMnO.
