Development of a Liquid Scintillator and of Data ... - Borexino - Infn
Development of a Liquid Scintillator and of Data ... - Borexino - Infn
Development of a Liquid Scintillator and of Data ... - Borexino - Infn
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
3 The Counting Test Facility (CTF) <strong>of</strong> <strong>Borexino</strong><br />
pressed in U <strong>and</strong> Th equivalents [Ali98c]:<br />
<br />
<br />
ÈÓ<br />
Í ¦ ¢ <br />
ÈÓ Ì ¦ ¢ <br />
There were, however, strong indications that the observed Po coincidence rate was<br />
not due to the scintillator intrinsic radioactivity, but rather due to the diffusion <strong>of</strong> Rn from<br />
the shielding water through the nylon vessel into the scintillator, as the coincidence rate increased<br />
with the Rn level in the shielding water.<br />
By studying the radial distribution <strong>of</strong> all the background events, they could be divided into<br />
an internal <strong>and</strong> external contribution. The total internal background with energies in the neutrino<br />
window (250 - 800 keV) went down from ( ¦ ) counts/day before purification to<br />
( ¦ ) counts/day after the purification operations (nitrogen sparging, water extraction, distillation)<br />
[Ali98c].<br />
40<br />
Figure 3.3: Low energy spectrum measured in the CTF, with the fit <strong>of</strong>a C beta spectrum.<br />
Taken from [Ali98b].
Change language