Daya Bay (Neutrino)

Reynolds Polymer acrylic cylinders allow highly sensitive photosensors to clearly read everything that the team measures. The result – the scientists became the first ever to measure a very elusive neutrino in a very short amount of time.

The search for elusive neutrinos outside of a nuclear power complex in China achieved unexpected early success utilizing a design requiring Reynolds Polymer acrylic cylinders from Reynolds Polymer. In only two months of data taking in the field and with only two-thirds of the acrylic cylinders up and running, scientists measured for the first time ever one of the key descriptors of the neutrino’s elusive behavior.

“We were certainly surprised how fast we made the first measurement,” explained Karsten Heeger, University of Wisconsin-Madison physics professor and U.S. manager for the Daya Bay project. “It turns [out] this neutrino oscillation probability we measured was much bigger than expected. After only a couple of weeks of data taking with detectors a mile away from the nuclear power plant we started seeing a disappearance effect.”

Reynolds Polymer assisted in the development of eight custom-designed precision acrylic tanks that allow scientists from the University of Wisconsin-Madison and the Daya Bay Collaboration in China to detect antineutrinos called Theta-13 (pronounced theta-one-three) from a nuclear power plant outside of Hong Kong. The proprietary acrylic cylindrical tanks measure 13 feet tall, 13 feet in diameter, 0.75 inches thick and form the inner center of the antineutrino detectors resting inside a larger steel chamber with photomultiplier tube (PMT) light sensors. The entire assembly sits in pairs in pools of ultrapure water to shield the antineutrino detectors from environmental interference.

Heeger’s team selected Reynolds Polymer’s acrylic for this project because acrylic, in general, is compatible with the scintillating fluids that fill the detectors and that make up the target medium for the experiment.

“When neutrinos interact in the detector they produce little flashes,” explained Heeger. “The acrylic vessels allow the light to pass through so that it can be detected with highly sensitive photosensors outside the vessels.”

The Daya Bay experiment built tanks at the China Guangdong Nuclear Power Group power plant which has six reactors. It is among the top 5 most powerful reactor complexes in the world. The antineutrino detectors are located in three underground experimental halls specifically built for this experiment under a mountain. The detectors sit at varying distances from the power plant so that the team can detect the transformation of one kind of neutrino into another as a function of distance from the power plant.