East coast scientists anxious to get back into Homestake

 

BY WENDY PITLICK, Black Hills Pioneer
No Online Source

LEAD - University of Pennsylvania physics professor Dr. Kenneth Lande just can't wait to get back into the Homestake Mine.

Lande, who had been conducting neutrino experiments in the Homestake Mine from the early 1970s until 2000 when the mine shut down, said he has big plans for expanding his research. Now, he just has to get back into the mine.

"I am pretty much experienced at the 4,850 foot level because that's where I lived a long time," Lande said.

When Lande started his original experiments he had a detector in the mine which he used to observe the fusion of protons in helium at the core of the sun, a process which produced neutrinos. But through the course of his research, Lande said he discovered that he was only detecting about one-third of the neutrinos which pass through any type of matter undetected. The reason - the neutrinos had changed from one flight path from the sun to another, with most of them passing through the earth's core virtually undetected. "That transformation was a totally unexpected phenomenon," Lande said. "Nobody thought that was going to happen. It's very exciting because it now opens up a whole new window of how particles behave."

That's a window that Lande hopes to open when he can get back to the mine. By conducting a more controlled experiment that shoots a beam of neutrinos not from the sun, but from the FERMI National Laboratory in Chicago, down to several enormous detectors at the 4,850 foot level of Homestake, Lande hopes to simultaneously conduct a series of experiments.

But first he needs to build his detectors. At between 160 to 170 feet, the huge vertical cylinders will be the largest in the world at about half the size of a football field in diameter and about 15 stories high. They will be filled with purified water from the mine, and lined with light detecting electronic circuitry. "So they will see the pulses of light created by the neutrino attractions in that water," Lande said.

Once the detectors are in place Lande said he will have many different experiments going at the same time. One experiment will analyze whether the protons and neutrons in the neutrinos are stable particles, or if they are like other particles and decay after long periods of time. Another experiment, Lande said will look for the signals of neutrinos which come from the collapse of large stars, from existing stars' neutrino emissions to those which come from old supernova which exploded several thousand years ago. This research, Lande said, will provide a better understanding of the early universe. "These would be bursts of neutrinos but instead of coming from the Chicago area they would come from somewhere in the sky," Lande said. "One of these was seen in 1987 in the Japanese detector."

The final experiment Lande is planning is more practical in nature because it will examine the decay of uranium and uranium products in the earth. This decay, Lande said, emits anti-neutrinos which are also produced by nuclear power reactors. Since the nearest nuclear power plant is about 500 kilometers (about 310 miles) away from Homestake, and the other sites are much closer to the plants, Lande said the local mine would be ideal for this type of research which will essentially be a survey of the natural radioactivity of the earth.

Besides Homestake's obvious strengths in its location, its depth and its existing infrastructure, Lande said his experience in the mine is one of the biggest reasons he is pulling for Lead in the DUSEL selection process. "I have a long association with Lead and with the Homestake Mine," he said. "So clearly that is where I want to do it. The Homestake Mine is ideally suited for this purpose. It would be the ideal location from many points of view."

While Lande is very excited about his pending research projects and experiments, the practical applications that result from his work has yet to be seen. "(I'll use) an example of a paper Einstein wrote in 1905 ... on photoelectric effect," he said. "This was an obscure observation that was made in the late 1800s and Einstein explained what was happening. Particles of light were hitting metal films and out came electrons. It was some strange phenomenon that nobody quite understood and nobody quite knew what to do with. (Today) it's the thing that happens in all the cameras that we have and our entire electronics industry is based on that particular 1905 paper.

"The point is that there is a very large body of research which does not have immediate applications but which very well might have applications decades or half a century from now."

After having conducted neutrino experiments for nearly 30 years in the mine until it shut down in 2000.