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 Igniting a solar flare in the corona with lower-atmosphere kindling
29.03.2017 | New Jersey Institute of Technology

nachricht NASA spacecraft investigate clues in radiation belts
28.03.2017 | NASA/Goddard Space Flight Center

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: A Challenging European Research Project to Develop New Tiny Microscopes

The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.

To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Researchers shoot for success with simulations of laser pulse-material interactions

29.03.2017 | Materials Sciences

Igniting a solar flare in the corona with lower-atmosphere kindling

29.03.2017 | Physics and Astronomy

As sea level rises, much of Honolulu and Waikiki vulnerable to groundwater inundation

29.03.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>