2 Decay of 150 Nd, Preliminary Results (PhaseI data). Nasim Fatemi-Ghomi. Introduction. Background study of 150 Nd 2 A study of the 207 Bi and 214 Bi background in the e -channel. A study of the 210 Bi, 207 Tl+ 211 Pb and 234m Pa background in the e-channel.
Used UCL OO framework written by V.Vasiliev.
cos(e) < 0.9
Activity of 207Bi
In addition to the pre-selection criteria described there should not be any single or
group delayed hit(s) in the tracker.
Fit 207Bi with the data minus background
where 207Bi dominated over all other backgrounds.
A207Bi=13.4 ± 0.3 mBq ~ 235 ± 5 mBq/kg
Activity of E214Bi
Find the activity looking at events with an (delayed or single hits.)
A214Bi = 0.87 0.17 mBq ~ 15.26 2.98 mBq/kg
A214Bi = 0.86 0.06 mBq ~ 15 1 mBq/kg
The external background activity found by V.Vasiliev is checked with looking at the energy distribution of the energy of e- events coming from the Cu foil.
Data = 35524±188, Total Background=34251± 382
Data-Background= 1273 ± 425 -> has to be added to the systematic uncertainty.
Background on the Surface
of the Wires and Foils.
with Cu foil
150 ENd Half-life
Pre-selection for 150Nd to 2 events:
Number of data events: 1011
Number of total background: 315
Efficiency =133643/2000000 6.68%
T12= 9.04 -0.57+0.63(stat) 0.51 (act) 0.78 (syst) x 1018 y