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.
Exploring the mysteries of supercooled water
01.03.2017 | American Institute of Physics
Optical generation of ultrasound via photoacoustic effect
01.03.2017 | American Institute of Physics
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
On January 15, 2009, Chesley B. Sullenberger was celebrated world-wide: after the two engines had failed due to bird strike, he and his flight crew succeeded after a glide flight with an Airbus A320 in ditching on the Hudson River. All 155 people on board were saved.
On January 15, 2009, Chesley B. Sullenberger was celebrated world-wide: after the two engines had failed due to bird strike, he and his flight crew succeeded...
In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport
Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...
The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.
The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...
13.02.2017 | Event News
10.02.2017 | Event News
09.02.2017 | Event News
01.03.2017 | Health and Medicine
01.03.2017 | Physics and Astronomy
01.03.2017 | Life Sciences