Etude et impact du bruit de fond corrélé pour la mesure de l'angle ...

LIST OF FIGURES 169
tel-00821629, version 1 - 11 May 2013
3.14 FADC baseline mean position (left) and RMS (right) as function
of the PMT number. ID PMT are identified by PMT
number smaller that 390 while IV PMT by number bigger
than 390. This monitoring unit allows to identify abnormal
channels through the position and the fluctuation of the
FADC baseline. . . . . . . . . . . . . . . . . . . . . . . . . . . 59
3.15 Schematic view of a PWR nuclear plant. . . . . . . . . . . . . 61
3.16 Chooz reactors thermal power, from EDF measurements, as
function of the day, since the FD data taking has started. The
observed variation of the thermal power reflect the status of
the operation of the reactors. Single reactor o↵ periods (i.e.
thermal power drop to zero) of few days are also visible. . . . 62
3.17 Reference ¯⌫ e spectra from [65, 75] and related uncertainties. . 64
3.18 Fission rates as function of the day since start of data taking,
as obtained by the simulation of the reactor evolution. The
decrease of the U isotopes and the increase of the Pu isotopes
reflect the evolution of the reactor fuel, which burn U isotopes
creating Pu isotopes. . . . . . . . . . . . . . . . . . . . . . . . 66
3.19 Breakdown of simulation uncertainties on the 235 U fission
rate, as obtained by varying di↵erent input parameters of
the simulation. . . . . . . . . . . . . . . . . . . . . . . . . . . 66
3.20 Breakdown of uncertainties on the reactor ¯⌫ e rate prediction
from Eq. 3.3. The main contribution to the total uncertainty
comes from the normalisation of the mean cross section per
fission to the Bugey4 measurement, of about 1.4 %. Nevertheless,
the use of the Bugey4 measurement as anchor point
reduce the overall systematics from 2.7 %to1.7 %. . . . . . . 67
3.21 Schema of the DC reconstruction strategy. Both data and
MC follows the same reconstruction process, performed at
CCIN2P3 by the Common Trunk. . . . . . . . . . . . . . . . 69
3.22 Schema of the reconstructed pulse timing characteristics . . . 71
3.23 Scintillator time response obtained from the PMT pulse start
time, corrected by the time of flight of the light between the
interaction vertex and the PMT itself. . . . . . . . . . . . . . 73
3.24 Linear PE calibration for one channel. The dashed line shows
the constant component of the gain in the multi-PE charge
equivalent region (> 200 a.u.). The calibration utilises a
linear approximation in the SPE charge equivalent region
(< 200 a.u.) to describe non-linearity. at low charges. . . . . 75
3.25 Detector calibration map as sampled with spallation neutrons
captured on H across the ID. The Colour shows energy correction
factors distributed as a function of reconstructed vertex.
A similar map is constructed to calibrate the MC energy. . . 75