Geant4 Simulations for the Radon Electric Dipole Moment Search at

12
10
linear regression:
y = 0.22432 x - 1.0887e-06
8
σ f
(e-04 Hz)
6
4
2
0
0 1 2 3 4 5 6
N -1/2 (e-03 counts -1/2 )
Figure 4.11: The sensitivity of the fitted frequency versus the number of counts fitted.
The linear behaviour validates the statistical precision equation (see Equation 4.1)
for the RnEDM measurement.
100 seconds of simulation time. Of the 14 signal intensities in the fitting program,
onlythefirst signal intensity (A 7 ) was fit intheanalysis. The EDMcell, oven, magnet
and µMetal were not included in these simulations.
Figure 4.11 can be extrapolated to estimate the sensitivity that will be achieved
by the RnEDM experiment. Estimates for 100 days of counting with the GRIFFIN
detectorsrunning atatotalcount rateof120kHzresults in1×10 12 photopeakcounts.
With a stable electric field of 5 kV/cm an EDM sensitivity of 4.64 × 10 −26 ecm is
calculated from the slope in Figure 4.11 if the spin-decoherence time is 15 seconds
as used in these simulations. Increasing the electric field beyond 5 kV/cm and increasing
the spin-decoherence time beyond the 15 seconds simulated here through
the design of the EDM measurement cell will each improve the EDM sensitivity linearly.
Taking advantage of the predicted EDM enhancement factor of ∼ 600 for
75