PC procurement at Sarroch completed
Borexino use a solution of PPO (a flour) in PC (pseudocumene, an organic solvent) as its scintillator (active detector mass) and a solution of DMP (a quencher) in the same solvent as a buffer fluid between the inner vessel and the SSS (the two solutions have almost the same density to minimize buoyancy).
Our PC was produced at an oil refinery in Sarroch (Sardinia island, Italy) using freshly extracted crude oil from specially selected oil field and then quickly brought to the LNGS underground lab to minimize activation by cosmic rays. PC procurement (production and transportation) and detector filling was streamlined (see the relevant published papers for more details).
The last Isotank from Sarroch arrived and was unloaded at LNGS on Apr 16, 2007. With that, Borexino PC procurement completed. One more step toward detector completion was done.