We present ultra low energy results taken with the novel Spherical Proportional Counter. The energy threshold has been pushed down to about 25 eV and single electrons are clearly collected and detected. To reach such ...We present ultra low energy results taken with the novel Spherical Proportional Counter. The energy threshold has been pushed down to about 25 eV and single electrons are clearly collected and detected. To reach such a performance two low energy calibration systems have been successfully developed: a pulsed UV lamp extracting photoelectrons from the inner surface of the detector and various radioactive sources allowing low energy peaks through fluorescence processes. The bench mark result is the observation of a well resolved peak at 270 eV due to carbon fluorescence, which is a unique performance for such large massive detector. It opens up a new window in dark matter and low energy neutrino searches and it may allow the detection of neutrinos from a nuclear reactor or from supernova via neutrino-nucleus elastic scattering.展开更多
26.1. Theory 26.1.1. Evidence for Dark Matter ： The existence of Dark （i.e., non-luminous and non-absorbing） Matter （DM） is by now well established [1,2]. The earliest, and perhaps still most convincing, evidenc...26.1. Theory 26.1.1. Evidence for Dark Matter ： The existence of Dark （i.e., non-luminous and non-absorbing） Matter （DM） is by now well established [1,2]. The earliest, and perhaps still most convincing, evidence for DM came from the observation that various luminous objects （stars, gas clouds, globular clusters, or entire galaxies） move faster than one would expect if they only felt the gravitational attraction of other visible objects. An important example is the measurement of galactic rotation curves.展开更多
文摘We present ultra low energy results taken with the novel Spherical Proportional Counter. The energy threshold has been pushed down to about 25 eV and single electrons are clearly collected and detected. To reach such a performance two low energy calibration systems have been successfully developed: a pulsed UV lamp extracting photoelectrons from the inner surface of the detector and various radioactive sources allowing low energy peaks through fluorescence processes. The bench mark result is the observation of a well resolved peak at 270 eV due to carbon fluorescence, which is a unique performance for such large massive detector. It opens up a new window in dark matter and low energy neutrino searches and it may allow the detection of neutrinos from a nuclear reactor or from supernova via neutrino-nucleus elastic scattering.
文摘26.1. Theory 26.1.1. Evidence for Dark Matter ： The existence of Dark （i.e., non-luminous and non-absorbing） Matter （DM） is by now well established [1,2]. The earliest, and perhaps still most convincing, evidence for DM came from the observation that various luminous objects （stars, gas clouds, globular clusters, or entire galaxies） move faster than one would expect if they only felt the gravitational attraction of other visible objects. An important example is the measurement of galactic rotation curves.
