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 Breakthrough with a chain of gold atoms
17.02.2017 | Universität Konstanz

nachricht New functional principle to generate the „third harmonic“
16.02.2017 | Laser Zentrum Hannover e.V.

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: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

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”...

Im Focus: Dresdner scientists print tomorrow’s world

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...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Biocompatible 3-D tracking system has potential to improve robot-assisted surgery

17.02.2017 | Medical Engineering

Real-time MRI analysis powered by supercomputers

17.02.2017 | Medical Engineering

Antibiotic effective against drug-resistant bacteria in pediatric skin infections

17.02.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>