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 Decay of 48 Ca, Preliminary Results Shiva King NEMO Meeting Aussois December 2005.

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Presentation on theme: " Decay of 48 Ca, Preliminary Results Shiva King NEMO Meeting Aussois December 2005."— Presentation transcript:

1  Decay of 48 Ca, Preliminary Results Shiva King NEMO Meeting Aussois December 2005

2 Introduction Selection criteria Analysis Results Runs processed from Feb. 2003 – Sept. 2004, total run time = 28882324s = 0.92yrs

3 Selection Criteria (preliminary) Two tracks with –ve charge associated with different scintillator hits Energy deposit in each scintillator E > 100 keV For counters on petals use front face only Do not use PMTs with a low gain: >6 Two tracks must have a common vertex in the source foil  r| < 4cm |  z| < 4cm TOF cut: int. > 1%; ext. < 0.1% There must be at least 1 hit in layer 0 or 1 Track length > 30cm Alphas:  Refiring time > 70  s  Not more than 2 unused fast geiger hits <20cm from vertex  Single and group hits

4 MC Background BgGen. EventsActivityExp. Events 214 Bi sfoil1.0e70.74mBq/m 2 1.06 214 Bi swire4.7e8857mBq1.61 214 Bi foil2.0e60.254mBq/Kg0.12 152 Eu foil2.0e630mBq/Kg0.38 234 Pa foil2.0e6<15mBq/Kg5.31 214 Pb foil2.0e64.17mBq/Kg0.27 208 Tl foil2.0e60.3mBq/Kg0.08 208 Tl PMT2.0e940.41Bq0.58 90 Y2.0e61746mBq/Kg681.02

5 Eee and Ee (before energy cuts)

6 Cos  (before energy cuts)

7 Eee/Ee (EeeMin>1.5Mev; EeMin>0.6Mev) Events: 61 Bg Events:21.73 S/B:1.81 Events: 41 Bg Events:2.64 S/B:14.54 T 1/2 =3.29 x10 19 yrs

8 Cos  (EeeMin>1.5Mev; EeMin>0.6Mev )

9 Eee/Ee (EeeMin>1.5Mev; EeMin>0.7Mev) Events: 41 Bg Events:11.26 S/B:2.64 Events: 30 Bg Events:2.13 S/B:13.10 T 1/2 =3.46 x10 19 yrs

10 Cos  (EeeMin>1.5Mev; EeMin>0.7Mev )

11 Results E cuts Cos  Half-Life (x10 19 yrs)EvntsBg EvntsS/BEff. EeMin>0.6 All cos  4.77 +0.91 -0.666121.731.813.4% EeMin>0.6 Cos  <0 3.29 +0.63 -0.46412.6414.542.2% EeMin>0.7 All cos  4.79 +1.08 -0.744111.262.642.6% EeMin>0.7 Cos  <0 3.46 +0.81 -0.55302.1313.101.7%

12


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