Engineering topics
Publications and source records attributed to Abe, Ko.
XMASS is a single phase liquid xenon scintillator detector. The project is designed for multi purposes, dark matter, neutrinoless double beta decay and {sup 7}Be/pp solar neutrino. As the first step of project, XMASS-I detector with 832 kg sensitive volume started operation from Dec. 2010. In this paper, recent obtained physics results from commissioning data, refurbishment of detector and future step of experiment are presented.
The spectra of low-energy cosmic-ray protons and antiprotons have been measured by BESS in nine high-latitude balloon flights between 1993 and 2004. These measurements span a range of solar activity from the previous solar minimum through solar ma>:im%am and the onset of the present solar minimum, as well as a solar magnetic field reversal from positive to negative in 2000. Because protons and antiprotons differ only in charge sign, these simultaneous measurements provide a sensitive probe of charge dependent solar modulation. The antiproton to proton ratio measured by BESS is consistent with simple spherically symmetric models of solar modulation during the Sun's positive polarity phase, but favor charge-sign-dependent drift models during the negative phase. The BESS measurements will be presented and compared to various models of solar modulation.