Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Xenon outs WIMPs

02.05.2002


The UK’s Dark Matter Collaboration’s detector lab in Buolby Mine, Yorkshire.


Underneath the mine the WIMP detector is shielded from cosmic rays.


Dark-matter detector could pin down the Universe’s missing mass.

Researchers in London are building a cheap dark-matter detector that should be able to spot the exotic particles called WIMPs that are suspected of hiding most of the Universe’s missing mass1.

A prototype of the detector has just shown, for the first time, that it can spot something as close to a WIMP as it’s possible to produce in the lab.



WIMP stands for ’weakly interacting massive particle’. If WIMPs exist at all, they are thought to be hefty compared to the protons and neutrons in an atomic nucleus, but to barely interact with these components of normal matter.

Physicists believe that WIMPs make up as much as 99% of the total mass of the Universe. Astronomers can’t see this matter - hence its ’dark’ moniker - but they can see its gravitational effects on the way the stars and gas in galaxies rotate.

Even if billions of WIMPs are streaming through our bodies, they don’t have any effect. So WIMP-hunting could be a frustrating affair - like trying to fish for shrimps using the net from a football goal.

Several experiments are currently going to great lengths in the search for WIMPS. The problem is that detectors capable of WIMP-spotting will probably pick up other cosmic particles, too, swamping the WIMP signal. Cosmic rays - high-energy particles of normal matter from space - and radioactive emissions would also register.

To shield a WIMP-detector from cosmic rays, it must be placed deep underground. The UK Dark Matter Collaboration (UKDMC) houses detectors at a depth of 1,100 metres in a salt mine in Yorkshire. Another array in Italy is buried in a tunnel beneath a mountain.

It would all be a lot easier if a detector could differentiate between a cosmic ray and a WIMP. Last year Alex Howard and co-workers at Imperial College, London, proposed a new type of WIMP detector that could, in principle, do just that. The simple device contains liquid and gaseous xenon.

Howard’s team said that WIMPs entering the detector would occasionally collide with the nucleus of a xenon atom, causing a brief flash of light called a primary scintillation and removing an electron from the atom. An electric field would pull these electrons through the liquid into the xenon gas, where they would induce a secondary scintillation flash.

These two distinct events are crucial to WIMP identification. Other particles, such as cosmic rays, induce the same processes. But the brightness of the primary and secondary scintillations would be different for WIMPs, cosmic rays and other particles.

The closest thing to a WIMP that the researchers could use readily to test their device is a neutron. So they teamed up with Farhat Beg and colleagues, also at Imperial, who have developed a cheap and convenient table-top source of neutron beams called a plasma focus. Neutrons for scientific research are usually generated in nuclear reactors.

Using this source, the Imperial researchers show that the xenon detector spots and identifies neutrons, implying that it should be able to do the same with WIMPs. Indeed, neutrons give a signal so much like that of WIMPs that the remaining challenge will be to tell them apart.

"We’re now making a full-scale detector," Howard says. They hope to install it in the UKDMC mine in the next 12 to 18 months.

References

  1. Beg, F. N. et al. Table-top neutron source for characterization and calibration of dark matter detectors. Applied Physics Letters, 80, 3009 - 3011, (2002).

PHILIP BALL | © Nature News Service

More articles from Physics and Astronomy:

nachricht Astronomers release most complete ultraviolet-light survey of nearby galaxies
18.05.2018 | NASA/Goddard Space Flight Center

nachricht A quantum entanglement between two physically separated ultra-cold atomic clouds
17.05.2018 | University of the Basque Country

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

Im Focus: Dozens of binaries from Milky Way's globular clusters could be detectable by LISA

Next-generation gravitational wave detector in space will complement LIGO on Earth

The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...

Im Focus: Entangled atoms shine in unison

A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.

The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...

Im Focus: Computer-Designed Customized Regenerative Heart Valves

Cardiovascular tissue engineering aims to treat heart disease with prostheses that grow and regenerate. Now, researchers from the University of Zurich, the Technical University Eindhoven and the Charité Berlin have successfully implanted regenerative heart valves, designed with the aid of computer simulations, into sheep for the first time.

Producing living tissue or organs based on human cells is one of the main research fields in regenerative medicine. Tissue engineering, which involves growing...

Im Focus: Light-induced superconductivity under high pressure

A team of scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg investigated optically-induced superconductivity in the alkali-doped fulleride K3C60under high external pressures. This study allowed, on one hand, to uniquely assess the nature of the transient state as a superconducting phase. In addition, it unveiled the possibility to induce superconductivity in K3C60 at temperatures far above the -170 degrees Celsius hypothesized previously, and rather all the way to room temperature. The paper by Cantaluppi et al has been published in Nature Physics.

Unlike ordinary metals, superconductors have the unique capability of transporting electrical currents without any loss. Nowadays, their technological...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

 
Latest News

Supersonic waves may help electronics beat the heat

18.05.2018 | Power and Electrical Engineering

Keeping a Close Eye on Ice Loss

18.05.2018 | Information Technology

CrowdWater: An App for Flood Research

18.05.2018 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>