High efficiency purification of liquid scintillators for the solar neutrino experiment Borexino

The neutrino experiment Borexino has been set up to detect solar 7Be neutrinos, anti-neutrinos, supernovae neutrinos, as well as other neutrinos from solar and geological sources. In order to realise these projects, the radiopurity of the liquid scintillator has to be still improved by a factor of 10. The theoretical and experimental examinations carried out in the framework of this thesis concern the silica gel chromatography, a highly efficient scintillator purification method, and thus show a possibility of reaching the mentioned scope. A silica gel purification system as well as two other purification systems, a water extraction and a distillation system, have been set up on the Borexino experimental site to solve the described task. These plants have successfully been tested with the CTF detector, a Borexino prototype detector developed for the measurement of ultra-low activities