XENON

42.42056613.516424Koordinaten: 42 ° 25 ' 14 " N, 13 ° 30' 59.1 " W The XENON Dark Matter Project is an experiment to search for WIMPs, a variant of the dark matter. The experiment is set up in the Gran Sasso underground laboratory. At XENON several universities and laboratories worldwide involved ( see below). The scientific collaboration has been chaired since 2002 by Elena Aprile ( Columbia University ).

  • 3.1 XENON10
  • 3.2 XENON100
  • 3.3 XENON1T

Operation

The detector is a two-phase time projection chamber (dual phase time projection chamber, TPC) with liquid xenon as a detector material and gaseous xenon at the top of the detector. Liquid xenon is particularly well suited for the search for WIMPs, because it is both high density ( 3 g/cm3 ) and high atomic number (Z = 54). At the top and at the bottom of the detector are disposed photomultipliers ( PMTs ). In an interaction of a particle with xenon produced scintillation and ionization. Prompt the scintillation light is detected by the PMTs (primary scintillation light, S1 ) signal. The free charges from the ionization drift due to an electric field to the surface of liquid xenon de. If they occur in the gaseous phase, they also produce scintillation light, which is detected by the PMTs (secondary scintillation S2 signal ).

From the time difference between the S1 and the S2 signal and from the sample, with which the secondary scintillation light is incident on the upper PMTs, the position of the point of interaction can be determined. As a result, events can be selected in the center of the detector and background suppress ( the increasingly occurs at the edge of the detector ). The ratio of the size of S2 signal and S1 signal provides information on the nature of the event. Since WIMPs are electrically neutral, they would interact with a xenon nucleus. The ratio of the magnitude of the S2 signal and the S1 signal is smaller at these events, than particles that would interfere with the electron shell of the xenon atoms ( gamma rays or electrons). This underground events can be filtered out.

Phases

XENON10

In the first phase XENON10 15 kg liquid xenon were used. The structure of XENON10 began in March 2006; the first experiments started in October 2007 At this stage, no evidence could be provided for WIMPs. ; the cross section is thus under 9 × 10-44 cm2 for an assumed particle mass of 30 GeV/c2.

XENON100

In the second phase XENON100 therefore 150 kg liquid xenon are used, which showed about 50 times higher sensitivity results. The detector was commissioned in February 2008. The published in July 2012 limit is 2 × 10-45 cm2 for WIMP masses of 55 GeV/c2 at 90 % confidence level which is currently the strongest limit on the WIMP -nucleon cross section.

XENON1T

The construction of the follow-up project called XENON1T is launched in the summer of 2013. Here are 1000 liters of liquid xenon are used in order to extend the range studied a cross -section of 2 × 10-47 cm2 at a WIMP mass of 100 GeV/c2.

Other major experiments to search for dark matter in the 2000s are the SuperCDMS experiment in Sudbury and EDELWEISS in the Frejus tunnel.

Participating universities and laboratories

XENON10

  • University of Columbia, USA
  • Brown University, USA
  • Rice University, USA
  • Case Western Reserve University, USA
  • RWTH Aachen, Germany
  • Yale University, USA
  • Lawrence Livermore National Laboratory, USA
  • Laboratori Nazionali del Gran Sasso, Italy
  • University of Coimbra, Portugal

XENON100

  • University of Columbia, USA
  • Rice University, USA
  • University of Zurich, Switzerland
  • Laboratori Nazionali del Gran Sasso, Italy
  • University of Coimbra, Portugal
  • University of California, USA
  • Subatech, France
  • Westfälische Wilhelms-Universität Münster, Germany
  • Max Planck Institute for Nuclear Physics, Germany
  • Jiaotong University, Shanghai, China
  • Johannes Gutenberg University Mainz, Germany

XENON1T

  • University of Columbia, USA
  • Rice University, USA
  • University of Zurich, Switzerland
  • University of Bern, Switzerland
  • Laboratori Nazionali del Gran Sasso, Italy
  • University of Bologna, Italy
  • University of Coimbra, Portugal
  • University of California, USA
  • Purdue University, USA
  • Weizmann Institute of Science, Israel
  • NIKHEF, The Netherlands
  • Subatech, France
  • Westfälische Wilhelms-Universität Münster, Germany
  • Max Planck Institute for Nuclear Physics, Germany
  • Johannes Gutenberg University Mainz, Germany
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