The Counting Test Facility (CTF) is the Borexino prototype detector
built by the collaboration to test the large-scale purification of the
liquid scintillator (LS) and shielding water from the natural
radioactive isotopes. After achieving the record purification of liquid
scintillator at the level of 10− 16g/g of U/Th, the CTF became the
world’s biggest (about 4 tones of LS) low-threshold ultrapure detector.
The data collected with an upgraded version of the CTF were analyzed by
the Borexino collaboration in order to search for a number of possible
manifestations of non-standard physics. A review of the main results on
rare physics obtained recently using the CTF data will be presented,
including limits on the solar neutrino magnetic moment, limits on the
solar antineutrino flux, constraints on the electron e → ν + γ decay
and nucleon/dinucleon disappearence, new limits on the non-Paulian
transitions in 12C and 16O nuclei and, the result of searches for the
heavy neutrino decay. These results demonstrate the sensitivity level
of a modern lowbackground low-treshold liquid scintillator detector.
The full-scale 300 tones Borexino detector will approach limits of
great theoretical importance for some of the cited processes.