Thursday, January 12, 2012

Seeking tantalising particles!

Neutrinos, the tiny particles unrecognized by man until the past century, are tantalising in their elusiveness and promise. Scientists are constructing huge, elaborate traps in the race to observe the sub-atomic particles that may unlock secrets of our universe. (Neutrinos are the particles that were observed travelling faster than the speed of light at the European CERN facility, and announced in September 2011 - see Wikipedia article "Faster-than-light neutrino anomaly!")

Tiger Optics is contributing its expertise to the effort. Electrically neutral, a tiny neutrino can travel great distances, and at great speed, through ordinary matter. Scientists are keen to use neutrinos to explore environments - such as the Sun’s core, to name one - that cannot be probed by light or radio waves. Indeed, scientists hope to use neutrinos to deepen understanding of the fundamental laws of physics. Several particle physics laboratories, including the Fermi National Accelerator Laboratory in Illinois (USA), are using Tiger Optics’ LaserTrace and Halo instruments to monitor the level of oxygen and moisture in the detector medium that such labs employ to study the ghost-like neutrino particles.

One detection method involves the use of a huge vessel containing a network of detector wires surrounded by an electric field, submerged in vast quantities of liquid argon. These liquid argon timeprojection chambers (LArTPC) may be located deep beneath the earth’s surface, with the intention of reducing interference from cosmic rays and background radiation. If - as a neutrino passes through the liquid argon—an interaction with an argon nucleus occurs, the interaction produces charged particles. Those particles spawn electrons that drift with the electric field until they are received by the wire network, whereupon the signals they produce can be used to produce an image and detailed 3D reconstruction of the interaction. In that process, the unwelcome presence of trace electronegative impurities - such as water and oxygen in the liquid argon, even at extremely low concentrations - has an adverse effect by intercepting the electrons before they reach the detector wires. For this reason, Tiger’s instruments are being pressed into service.

Fermilab uses the company’s Halo and LaserTrace instruments to monitor the gaseous release of water from detector elements in the vapor space above the liquid argon. LaserTrace instruments are also used to monitor the oxygen level in both the argon vapour and liquid. “We have always taken pride in blazing the frontiers of science,” said Lisa Bergson, Tiger Optics’ founder and chief executive. “The neutrino chase exemplifies that mission.”

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