Andrew Yee[_1_]
April 25th 07, 03:00 AM
Royal Astronomical Society
London, U.K.
Issued by RAS Press Officers:
Robert Massey
Tel: +44 (0)20 7734 4582
AND
Anita Heward
Tel: +44 (0)1483 420 904
NATIONAL ASTRONOMY MEETING PRESS ROOM (16 - 20 APRIL ONLY):
Tel: +44 (0)1772 892 613
+44 (0)1772 892 475
+44 (0)1772 892 477
RAS Web site:
http://www.ras.org.uk/
RAS National Astronomy Meeting web site:
http://nam2007.uclan.ac.uk
CONTACTS:
Dr Alexander Murphy
Room 8208
James Clerk Maxwell Building
The King's Buildings
Mayfield Road
Edinburgh
EH9 3JZ
Tel : 0131 650 5285
Fax : 0131 650 7002
Prof. Tim Sumner
Imperial College London
Tel: 020 75947552
Prof. Nigel Smith
Rutherford Appleton Laboratory
PRESS INFORMATION NOTE: RAS PN 07/27 (NAM23)
EMBARGOED FOR 00:01 BST, WEDNESDAY, 18 APRIL 2007
FLEET OF ZEPLIN STEP UP SEARCH FOR DARK MATTER PARTICLES
The race for the first direct detection of dark matter will move into a new
phase in the coming months as the ZEPLIN-II instrument is joined by
ZEPLIN-III, the world's most sensitive dark matter detector.
Dr Alexander Murphy, who is presenting the first results from the ZEPLIN-II
detector at the RAS National Astronomy Meeting in Preston on 18th April
said, "ZEPLIN-II is beginning its second search for dark matter particles,
deep underground in a salt and potash mine in North Yorkshire, and we have
been pouring through the first data looking for possible interactions with
dark matter. Now, just last week, we've had the go-ahead to start operating
our next generation detector, ZEPLIN-III. We will be tweaking both detectors
to improve their sensitivity all the time and, over the next few months,
we'll be able to see signals that are many times fainter. This will give us
a fantastic chance of making the first direct detection of a dark matter
particle."
The ZEPLIN-II instrument holds 31 kg of liquid xenon, cooled to a
temperature of -110 deg Celsius. Theory suggests that, from time to time, a
dark matter particle will scatter from the xenon leaving a very small signal
behind. Extremely sensitive light detectors view the xenon looking for such
a telltale sign. ZEPLIN-II, has proved the world's most sensitive detector
of this type (noble liquid technology) and is surpassed only by the
Cryogenic Dark Matter Search (CDMS), based in Minnesota, which uses a
semiconductor technology. With a few tweaks, the team expects ZEPLIN-II to
be able to match the sensitivity of CDMS within a few months.
The upgraded ZEPLIN-III, although not significantly bigger than ZEPLIN-II,
will be able to achieve a sensitivity that is a factor of 30 better than
CDMS, although it should take about two years to reach this level of
operation. This factor of 30 is especially important because the theoretical
models predict that this is the level of sensitivity needed to have a
realistic chance of seeing a signal.
The major benefit of noble liquid technology over semi-conductor technology
is that it is more easily scalable, which means that it should allow for
bigger detectors in the future. Features of ZEPLIN-III include a much
better ability to reject background events, lower radioactivity of materials
used in construction to minimise contamination and spurious signals, and the
use of higher electric fields to improve discrimination against any
remaining background.
FURTHER INFORMATION
Dark Matter
Since the 1930's it has been apparent that the Universe is made up of more
than just the things we can see. It is now widely accepted that a large
fraction of the Universe consists of 'dark matter' in the form of a new type
of fundamental particle. These dark matter particles constitute about 90% of
the mass of our galaxy and are constantly passing through the Earth itself.
Evidence for this comes from a diverse, yet consistent, array of
astronomical observations and is supported by advanced theories of particle
physics that seek a deeper symmetry to explain the forces of nature.
Crucially however, no direct observation of these dark matter particles has
yet been made.
The ZEPLIN Project
The ZEPLIN Project team is composed of scientists from the Universities of
Edinburgh, Oxford and Sheffield, Imperial College London and the Rutherford
Appleton Laboratory. International collaborators include scientists from the
University of Coimbra, Portugal, the University of California, Los Angeles,
USA, Texas A&M University, USA, and the University of Rochester, USA. UK
funding is provided by the Science and Technologies Facilities Council.
The project's first detector, ZEPLIN-I, ran between 2001 and 2004. It was
the first generation of this style of detector and had a target of 3.2 kg of
liquid xenon. For more information see
http://www.shef.ac.uk/physics/research/pppa/research/dm/zeplin.php
The ZEPLIN detectors have all been located in the Boulby Underground
Laboratory, in the Boulby Mine, near Whitby, Yorkshire, on the North East
coast of England. For more information see
http://www.pppa.group.shef.ac.uk/boulby/boulby.php
A paper on results from ZEPLIN-II, "First limits on WIMP nuclear recoil
signals in ZEPLIN-II: a two phase xenon detector for dark matter detection"
has been submitted to the journal, Journal Astroparticle Physics. The
submitted paper is available at
http://arxiv.org/PS_cache/astro-ph/pdf/0701/0701858v2.pdf
IMAGES
Images of ZEPLIN-II and ZEPLIN-III can be found at:
http://astro.ic.ac.uk/Research/ZEPLIN-III/
London, U.K.
Issued by RAS Press Officers:
Robert Massey
Tel: +44 (0)20 7734 4582
AND
Anita Heward
Tel: +44 (0)1483 420 904
NATIONAL ASTRONOMY MEETING PRESS ROOM (16 - 20 APRIL ONLY):
Tel: +44 (0)1772 892 613
+44 (0)1772 892 475
+44 (0)1772 892 477
RAS Web site:
http://www.ras.org.uk/
RAS National Astronomy Meeting web site:
http://nam2007.uclan.ac.uk
CONTACTS:
Dr Alexander Murphy
Room 8208
James Clerk Maxwell Building
The King's Buildings
Mayfield Road
Edinburgh
EH9 3JZ
Tel : 0131 650 5285
Fax : 0131 650 7002
Prof. Tim Sumner
Imperial College London
Tel: 020 75947552
Prof. Nigel Smith
Rutherford Appleton Laboratory
PRESS INFORMATION NOTE: RAS PN 07/27 (NAM23)
EMBARGOED FOR 00:01 BST, WEDNESDAY, 18 APRIL 2007
FLEET OF ZEPLIN STEP UP SEARCH FOR DARK MATTER PARTICLES
The race for the first direct detection of dark matter will move into a new
phase in the coming months as the ZEPLIN-II instrument is joined by
ZEPLIN-III, the world's most sensitive dark matter detector.
Dr Alexander Murphy, who is presenting the first results from the ZEPLIN-II
detector at the RAS National Astronomy Meeting in Preston on 18th April
said, "ZEPLIN-II is beginning its second search for dark matter particles,
deep underground in a salt and potash mine in North Yorkshire, and we have
been pouring through the first data looking for possible interactions with
dark matter. Now, just last week, we've had the go-ahead to start operating
our next generation detector, ZEPLIN-III. We will be tweaking both detectors
to improve their sensitivity all the time and, over the next few months,
we'll be able to see signals that are many times fainter. This will give us
a fantastic chance of making the first direct detection of a dark matter
particle."
The ZEPLIN-II instrument holds 31 kg of liquid xenon, cooled to a
temperature of -110 deg Celsius. Theory suggests that, from time to time, a
dark matter particle will scatter from the xenon leaving a very small signal
behind. Extremely sensitive light detectors view the xenon looking for such
a telltale sign. ZEPLIN-II, has proved the world's most sensitive detector
of this type (noble liquid technology) and is surpassed only by the
Cryogenic Dark Matter Search (CDMS), based in Minnesota, which uses a
semiconductor technology. With a few tweaks, the team expects ZEPLIN-II to
be able to match the sensitivity of CDMS within a few months.
The upgraded ZEPLIN-III, although not significantly bigger than ZEPLIN-II,
will be able to achieve a sensitivity that is a factor of 30 better than
CDMS, although it should take about two years to reach this level of
operation. This factor of 30 is especially important because the theoretical
models predict that this is the level of sensitivity needed to have a
realistic chance of seeing a signal.
The major benefit of noble liquid technology over semi-conductor technology
is that it is more easily scalable, which means that it should allow for
bigger detectors in the future. Features of ZEPLIN-III include a much
better ability to reject background events, lower radioactivity of materials
used in construction to minimise contamination and spurious signals, and the
use of higher electric fields to improve discrimination against any
remaining background.
FURTHER INFORMATION
Dark Matter
Since the 1930's it has been apparent that the Universe is made up of more
than just the things we can see. It is now widely accepted that a large
fraction of the Universe consists of 'dark matter' in the form of a new type
of fundamental particle. These dark matter particles constitute about 90% of
the mass of our galaxy and are constantly passing through the Earth itself.
Evidence for this comes from a diverse, yet consistent, array of
astronomical observations and is supported by advanced theories of particle
physics that seek a deeper symmetry to explain the forces of nature.
Crucially however, no direct observation of these dark matter particles has
yet been made.
The ZEPLIN Project
The ZEPLIN Project team is composed of scientists from the Universities of
Edinburgh, Oxford and Sheffield, Imperial College London and the Rutherford
Appleton Laboratory. International collaborators include scientists from the
University of Coimbra, Portugal, the University of California, Los Angeles,
USA, Texas A&M University, USA, and the University of Rochester, USA. UK
funding is provided by the Science and Technologies Facilities Council.
The project's first detector, ZEPLIN-I, ran between 2001 and 2004. It was
the first generation of this style of detector and had a target of 3.2 kg of
liquid xenon. For more information see
http://www.shef.ac.uk/physics/research/pppa/research/dm/zeplin.php
The ZEPLIN detectors have all been located in the Boulby Underground
Laboratory, in the Boulby Mine, near Whitby, Yorkshire, on the North East
coast of England. For more information see
http://www.pppa.group.shef.ac.uk/boulby/boulby.php
A paper on results from ZEPLIN-II, "First limits on WIMP nuclear recoil
signals in ZEPLIN-II: a two phase xenon detector for dark matter detection"
has been submitted to the journal, Journal Astroparticle Physics. The
submitted paper is available at
http://arxiv.org/PS_cache/astro-ph/pdf/0701/0701858v2.pdf
IMAGES
Images of ZEPLIN-II and ZEPLIN-III can be found at:
http://astro.ic.ac.uk/Research/ZEPLIN-III/