Geant4 Simulations for the Radon Electric Dipole Moment Search at

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Logarithmic
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γ-ray Energy (keV)
Figure 4.13: γ-ray energy spectrum from the β decay of 120 million 223 Rn nuclei from
an initial 8 billion nuclei located inside the EDM cell surround by a ring of eight
BrilLanCe 380 detectors. The EDM cell, oven, magnet and 1 mm of µMetal shielding
were included in the simulation. The initial polarization was 100% and both the spinrelaxation
(T 1 ) and the spin-decoherence (T 2 ) times were simulated to be 30 seconds,
resulting in a combined depolarization time of 15 seconds.
to resolve most individual photopeaks in the 223 Rn decay spectrum. Therefore the
time projections which produce the frequency signal will be “contaminated” with
other photopeaks.
The absolute efficiency of eight BrilLanCe 380 detectors in a ring configuration
is presented in Figure 4.12; the detectors have an efficiency of 20.5% at 100 keV
and 6.9% at 1 MeV. Figure 4.13 illustrates the γ ray singles spectrum from the β
decay of 120 million 223 Rn nuclei, from an initial 8 billion nuclei inside the EDM cell.
The EDM cell, oven, magnet and 1 mm of µMetal shielding were also included in
this simulation. The simulation had identical properties to that of the simulation of
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