 |
|
Listening to dark matter
October 16, 2008A team of researchers in Canada have made a bold stride in the struggle to detect dark matter. The PICASSO collaboration has documented the discovery of a significant difference between the acoustic signals induced by neutrons and alpha particles in a detector based on superheated liquids.
Since neutron induced signals are very similar to dark matter induced signals, this new discovery, published today, Thursday, 16 October, in the New Journal of Physics, could lead to improved background suppression in dark matter searches with this type of detector.
So far, alpha particles have been an obstacle to the detection of dark matter's weakly interacting massive particles (WIMPs) in PICASSO. This detector, which is based on the operation principle of the classic bubble chamber, is sensitive to alpha particles over exactly the same temperature and energy range, therefore making it very difficult to discriminate between the two types of particles.
Alpha particles are relatively common on Earth, emitted by radioactive nuclei such as uranium, and thorium, and are therefore also present in traces in the detector material itself. WIMPs are thought to fill the large spaces between galaxies, concentrating around them in gigantic clouds. As the Earth moves together with the sun through the Milky Way's dark matter cloud, researchers hope to detect occasional collisions of a WIMP particle with an atom in their detectors.
Teams of researchers around the globe work deep underground to create the best conditions to isolate WIMPs from their travelling companions, namely neutrons, which are created by cosmic rays. Underground, teams in the US, Canada, England, Italy, Japan, Korea and Russia have long been sparring over the best detection methods for WIMPs.
The Canadian-American-Czech team based at SNOLAB, using their PICASSO detector, experimented with very sensitive Fluorine-based superheated liquids and analysed acoustic signals following phase transitions induced by alpha particles and WIMP like, neutron induced recoil nuclei. To their surprise they found a significant difference in amplitudes of the acoustic signals, which has never been observed before.
As experiment spokesperson Viktor Zacek (Université de Montréal) said, "When we looked at our calibration data taken with neutrons and compared them with our alpha background data we saw a peculiar difference which we attributed first to some detector instabilities or gain drifts in our electronics. However when we checked the data and refined the analysis the discrimination effect became even more pronounced."
Detection of WIMPs is the first challenge in the struggle to understand dark matter. Much of our understanding until now has been hypothetical. There is convincing astronomical evidence to suggest that 23 per cent of the Universe is made up of dark matter - different from the matter with protons, neutrons and electrons that we are accustomed to.
This dark matter is between a hundred to a thousand times heavier than a proton and interacts extremely weakly with itself and 'ordinary' matter. It is believed it was created during the Big bang and that it now surrounds most galaxies, and also our Milky Way in gigantic clouds.
Institute of Physics
Alpha particles are relatively common on Earth, emitted by radioactive nuclei such as uranium, and thorium, and are therefore also present in traces in the detector material itself. WIMPs are thought to fill the large spaces between galaxies, concentrating around them in gigantic clouds. As the Earth moves together with the sun through the Milky Way's dark matter cloud, researchers hope to detect occasional collisions of a WIMP particle with an atom in their detectors.
Teams of researchers around the globe work deep underground to create the best conditions to isolate WIMPs from their travelling companions, namely neutrons, which are created by cosmic rays. Underground, teams in the US, Canada, England, Italy, Japan, Korea and Russia have long been sparring over the best detection methods for WIMPs.
The Canadian-American-Czech team based at SNOLAB, using their PICASSO detector, experimented with very sensitive Fluorine-based superheated liquids and analysed acoustic signals following phase transitions induced by alpha particles and WIMP like, neutron induced recoil nuclei. To their surprise they found a significant difference in amplitudes of the acoustic signals, which has never been observed before.
As experiment spokesperson Viktor Zacek (Université de Montréal) said, "When we looked at our calibration data taken with neutrons and compared them with our alpha background data we saw a peculiar difference which we attributed first to some detector instabilities or gain drifts in our electronics. However when we checked the data and refined the analysis the discrimination effect became even more pronounced."
Detection of WIMPs is the first challenge in the struggle to understand dark matter. Much of our understanding until now has been hypothetical. There is convincing astronomical evidence to suggest that 23 per cent of the Universe is made up of dark matter - different from the matter with protons, neutrons and electrons that we are accustomed to.
This dark matter is between a hundred to a thousand times heavier than a proton and interacts extremely weakly with itself and 'ordinary' matter. It is believed it was created during the Big bang and that it now surrounds most galaxies, and also our Milky Way in gigantic clouds.
Institute of Physics
Dark Matter Current Events and Dark Matter News RSSIowa State astrophysicist helps map the Milky Way's four spiral arms
Iowa State University's Martin Pohl is part of a research team that has developed the first complete map of the Milky Way galaxy's spiral arms.
New detector will aid dark matter search
Several research projects are underway to try to detect particles that may make up the mysterious "dark matter" believed to dominate the universe's mass.
Crash Test-Iconic Rings and Flares of Galaxies Created by Violent, Intergalactic Collisions, Research by Pitt and Partners Finds
The bright pinwheels and broad star sweeps iconic of disk galaxies such as the Milky Way might all be the shrapnel from massive, violent collisions with other galaxies and galaxy-size chunks of dark matter, according to a multi-institutional project involving the University of Pittsburgh.
Memory mission explores new territory in neuroscience
Astrophysicists peer into the far corners of deep space for dark matter, but for neuroscientists at the Queensland Brain Institute (QBI) exploring the unknown is much closer to home.
Oak Ridge supercomputer is the world's fastest for science
A Cray XT high-performance computing system at the Department of Energy's (DOE) Oak Ridge National Laboratory is the world's fastest supercomputer for science.
New gene silencing pathway found in plants
Biologists at Washington University in St. Louis have made major headway in explaining a mechanism by which plant cells silence potentially harmful genes.
Giant simulation could solve mystery of 'dark matter'
The search for a mysterious substance which makes up most of the Universe could soon be at an end, according to new research.
Ghostly glow reveals galaxy clusters in collision
A team of scientists, including astronomers from the Naval Research Laboratory (NRL), have detected long wavelength radio emission from a colliding, massive galaxy cluster which, surprisingly, is not detected at the shorter wavelengths typically seen in these objects.
Spallation Neutron Source sends first neutrons to 'Big Bang' beam line
New analytical tools coming on line at the Spallation Neutron Source, the Department of Energy's state-of-the-art neutron science facility at Oak Ridge National Laboratory, include a beam line dedicated to nuclear physics studies.
Scientists Detect Cosmic 'Dark Flow' Across Billions of Light Years
Using data from NASA's Wilkinson Microwave Anisotropy Probe (WMAP), scientists have identified an unexpected motion in distant galaxy clusters. The cause, they suggest, is the gravitational attraction of matter that lies beyond the observable universe.
More Dark Matter Current Events and Dark Matter News Articles
 | Dark Side of the Universe: Dark Matter, Dark Energy, and the Fate of the Cosmos by Iain Nicolson Once we thought the universe was filled with shining stars, dust, planets, and galaxies. We now know that more than 98 percent of all matter in the universe is dark. It emits absolutely nothing yet bends space and time; keeps stars speeding around galaxies; and determines the fate of the universe. But dark matter is only part of the story. Scientists have recently discovered that the expansion of... |
 | Dark Matters: Unifying Matter, Dark Matter, Dark Energy, and the Universal Grid by Dr. Percy Seymour One of the most important unsolved problems of current physics, astronomy, and cosmology is the nature of dark matter and dark energy. These two invisible components of the universe seem to control the behavior of galaxies, clusters of galaxies, and the accelerating expansion of the universe, but we do not know what they are. Dark Matters offers a unified explanation for dark matter and dark... |
 | In Search of Dark Matter (Springer Praxis Books / Space Exploration) by Ken Freeman, Geoff McNamara The dark matter problem is one of the most fundamental and profoundly difficult problems in the history of science. Not knowing what makes up most of the mass in the Universe goes to the heart of our understanding of the Universe and our place in it. In Search of Dark Matter is the story of the emergence of the dark matter problem, from the initial 'discovery' of dark matter by Jan Oort to... |
 | Einstein's Telescope: The Hunt for Dark Matter and Dark Energy in the Universe by Evalyn Gates Cutting-edge astrophysics that builds on Einstein's theories to find the unseen matter that fills the Universe. Dark energy. Dark matter. These strange and invisible substances don't just sound mysterious: their unexpected appearance in the cosmic census is upending long-held notions ... |
 | Dark Matter, Missing Planets and New Comets: Paradoxes Resolved, Origins Illuminated Second Edition by Tom Van Flandern Tom Van Flandern's book adds a new dimension to cosmology--not only does it present a novel approach to timeless issues, it stands up to the closest scientific scrutiny. Even the most respected scientists today will readily admit that the Big Bang Theory is full of holes. But it takes a new look, like Dark Matter, Missing Planets, and New Comets, to explain not only why the theory is wrong but... |
 | From 'Now' to Dark Matter: A new approach to Time and Cosmic evolution by Noel Eberz Considering and exploring two major ideas, 'Time as only Now' and 'Mass as the confinement of Energy', gives a new interpretation to numerous cosmological problems in standard Big bang evolution including a unique suggestion on the nature of Dark Matter. This profound change does not refute Relativity, rather merely requires a variable exchange. Yet, it does resolve a few tired paradoxes of... |
 | Dark Matter In The Universe If standard gravitational theory is correct, then most of the matter in the universe is in an unidentified form which does not emit enough light to have been detected by current instrumentation. This book is the second editon of the lectures given at the 4th Jerusalem Winter School for Theoretical Physics, with new material added. The lectures are devoted to the "missing matter" problem in the... |
 | Dark Matter: Poems of Space Poets have long been stargazers, moved by the strange infinities of the universe to translate them into metaphor and song. For "Dark Matter", the third in the Gulbenkian's trilogy of poetry and science anthologies, leading poets were commissioned to create new work inspired by their discussions with eminent space scientists. Their meditations on the light and dark matters of the skies have been... |
 | Dark Matter by S. W. Ahmed Dark matter constitutes the bulk of all matter in the known universe. Yet to this day, its true nature remains one of science's greatest mysteries. But what if dark matter actually is just ordinary matter purposely hidden from our view? What if we are only allowed to see a small fraction of the stars in every galaxy, because the vast majority of star systems in our own galaxy are teeming with... |
 | Dark Matter: The Private Life of Sir Isaac Newton: A Novel by Philip Kerr In 1696, Christopher Ellis, a young, hot-tempered gentleman, is sent to the Tower of London, but not as a prisoner. A sudden twist of fate has led him there to assist the renowned scientist Sir Isaac Newton, who as Warden of the Royal Mint has accepted an appointment to hunt down counterfeiters who threaten to topple the shaky, war-weakened economy. Armed with Newton’s superior intellect and... |
| © 2009 BrightSurf.com |