XMASS is a multipurpose physics experiment in Japan. It is a large cryogenic storage dewar, a tank of liquid xenon equipped with photosensors monitoring flashes of light that might be caused by interactions with hypothetical dark matter particles. Unlike a cryogenic particle detector, it operates at temperatures relatively far from absolute zero (specifically, 165 K (−163 °F)).[1] In addition to searching for dark matter, XMASS is also studying neutrinoless double beta decay and solar neutrinos. The project is conducted by a team at Institute for Cosmic Ray Research, University of Tokyo.[2]

Its results have not confirmed the annual variation seen in some earlier experiments.[3]

History

edit

Construction started in April 2007. The detector was completed in September 2010. Commissioning run was conducted between October 2010 and June 2012. Scientific data taking begun in November 2013. The detector is sometimes called XMASS-I, as it is planned to be superseded by an upgrade called XMASS-1.5 (a 5-ton detector) and eventually XMASS-II (24 ton detector).

The XMASS-I experiment shut down and ceased data taking 20 February 2019.

Results were published in 2021.[4]

Detector

edit

The detector is located 1000m underground in the Kamioka Observatory in Japan. It contains about 800 kg of xenon.[5]

See also

edit

References

edit
  1. ^ XMASS overview
  2. ^ "実験代表者挨拶 | XMASS". www-sk.icrr.u-tokyo.ac.jp. Retrieved 2024-03-08.
  3. ^ XMASS continues dark matter debate. Oct 2015
  4. ^ Ichimura, Koichi (2021). "Latest results from the XMASS experiment". Proceedings of the 14th Asia-Pacific Physics Conference. Vol. 2319. p. 040011. doi:10.1063/5.0037305. S2CID 234068033.
  5. ^ About XMASS : Detector
edit