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Proposal to join NEMO-3 decay experiment
P. Adamson, R. Saakyan, J. Thomas
UCL27 January 2003
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Outline Motivation decay basics Short term future for experiments NEMO-III detector Future experiments Possible UK involvement in NEMO-III Costs
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Motivation
Neutrino oscillations
2.510-3 eV2
510-5 eV2
510-5 eV2
2.510-3 eV2
mscale = 0.01 eV mscale = 0.05 eV
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Motivationneutrino oscillations can not measure:
Nature of neutrino mass = bar (Majorana) OR bar (Dirac)
Absolute mass scale decayDirect kinematic searches (3H decay)
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UK Involvement. Current Picture
M IN O S S N O S ou d an II
N eu tirn o O sc illa tion s
K A TR IN(P rop osa l)
Trit iu m D ecay
N O IN V O L V E M E N T
D ou b le B eta D ecay
M ass ive N eu trin o P h ys ics
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decay basics
T0.5~ 1020 yr T0.5 > 1025 yr
Find isotopes where (A,Z)(A,Z+2) is energetically allowed, but forbidden in steps (A,Z)(A,Z+1)(A,Z+2)
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decay basics Average Majorana mass:
m depends on sum over U
2*m
If large, could be dominated by Ue32m3
(depends on hierarchy)
2 222 2 i
N N
ei i ei ii i
m U m U e m
Majorana CP phasesMixing matrix
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1 20 0 0 21/ 2 ( )T G Q M m
Phase spaceNuclear matrix elementQ
48Ca, 76Ge, 100Mo, 150Nd,136Xe, 116Cd, 96Zr, 82Se,130Te
Due to uncertainties in M0 we have to study as manyisotopes as possible!
(0.35 – 1 eV)
Tkin(e-+e-)
(A,Z) (A,Z+2) + e- + e- + bar + bar 2
(A,Z) (A,Z+2) + e- + e- 0
(A,Z) (A,Z+2) + e- + e- + 0 0(Majoran)
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A look at short term future decay experiments
3H expts sensitivity in ~ 2008
Future projects: CUORE, Majorana, EXO, etc to have 0.05 eV sensitivity (~ 2008 – 2010)
mscale ~ 0.01 – 0.05 eVfrom oscillation expts
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Short-term future: now - 2007
<m> = 0.4 eVHeidelberg-Moscow Experiment“Evidence” strongly criticized by community
Not background free region
NEMO-3
CUORICINOby 20070.1 – 0.7 eV 130Te (34%) natural abundance, good bolometric properties
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NEMO-3 Collaboration
50 physicists and engineers
12 Laboratories/Universities
5 Countries
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250ps t timing from plasma propagation in tracker, z = 1cm x, y = 100m,
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Data taking2e events
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Data takingBackground events
208Th <.02mBq/kg
214Bi < .3mBq/kg
These have HE electron, but not same topology,or timing
Excited states O() less common, used to measure NME
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October visit summary: Significant shortage in manpower for data analysis. We are welcome to start right away
Somewhat involved analysis• detection (105 2 events/y !!! for 100Mo)• BG rejection techniques• Source contamination measurements (for future developments)
Running since June’02 but only 200 hrs 100Mo carefully analysed
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Possible UK involvement in data analysis
Isotopes “distributed” between institutions
We are suggested to take up analysis of 82Se (NEMO3 upgrade isotope)
Isotope Mass, g100Mo 7200130Te 130082Se 1000
116Cd 600150Nd 5096Zr 2048Ca 10
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NEMO-3 0 sensitivity5 years
100Mo
7 kg Q =3.034 MeV
External BG: 0 Internal BG:
radioactivity < 0.04 event/y/kg = 0.11 event/y/kg
T1/2 > 5 × 1024 yr
<m> < 0.2 – 0.7 eV
E = 2.8 – 3.2 MeV 82Se
1 kg Q =2.995 MeV
External BG: 0 Internal BG:
radioactivity < 0.01 event/y/kg = 0.01 event/y/kg
T1/2 > 1 × 1024 yr
<m> < 0.6 – 1.2 eV
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Possible UK involvementUpgrade of NEMO-3
2 821/ 22 1001/ 2
( )10
( )
T Se
T Mo
12 kg 82Se Why 82Se?
And theory says there isNO 2 0
1/ 2 1/ 2T T scaling
Improve S/B by ~10 Sensitivity <m>~0.14 eV in 5 yr
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SuperNEMO
Sensitivity <m> ~ 0.05 eV in 5 yr
~ 100 kg 82Se (or other)
4 supermodules, planar geometry
Feasible if:a) BG only from 2 (NEMO3)b)E/E = 10-11% at 1 MeV
(R&D needed)
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Future projects comparison“Conservative” approach
Experiment Source and Mass
Sensitivity toT1/2 (y)
Sensitivity to<m> (eV)*
Majorana$50M
76Ge, 500kg
3×1027 0.03 – 0.07
CUORE$25M,long
130Te, 750kg(nat)
2×1026 0.05 – 0.17
EXO(or other Xe-expt)
136Xe1 ton
8×1026 0.05 – 0.12
SuperNEMO$20M
82Se(or other)
100 kg2×1026 0.05 – 0.11
* 5 different latest NME calculations
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SuperNEMO – UK involvementScintillator R&D
Improving E/E from 9% to 6% (at 3 MeV) will reduce BG by a factor of ~ 10
Increase light output Scintillator studies Light collection PMT-scintillator optical couplingPMT studies
matches our experience (MINOS)
6
(2 )E
FractionQ
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Responsibilities2003-2004 MC of 2e and BG events from 82Se (Saakyan, New
PostDoc) Off-line DA for 82Se, cross-check with other isotopes
(Adamson, NewPostDoc, Saakyan, Thomas) Laser LI calibration/monitoring (Adamson, Thomas) Scintillator R&D for SuperNEMO (Saakyan, Thomas,
NewPostDoc, Technician) DAQ/electronics for R&D setup (Adamson,
NewPostDoc, Software Engineer) DA from R&D setup (Adamson, NewPostDoc,
Saakyan, Thomas)
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Costs
Item 2003 2004
Rolling Grant Costs
UCL staffSaakyan
05%30%
05%30%
Extra costs to PPARC
EquipmentTravelResponsive RA
£10K£5K£50K
£10K£5K£50K
PPARC Fellows
AdamsonThomas
30%30%
30%30%
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Concluding Remarks is the only practical approach for
Majorana ‘s Participation in NEMO-3 is a good
opportunity to understand feasibility of this technique…
…and to put UK in the DBD arena NEMO-3 will confirm or rule out H-M result
(0.1-0.2eV depending on Se availability) Next generation DBD experiments to probe
~ 0.05 eV scale NEMO technology orthogonal to other
competitors
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Concluding Remarks II
Window of opportunity with MINOS for authors (beam due end of 04)
Possibility to analyse data this week!
Results will be competitive (many isotopes, orthogonal approach)
This proposal does not commit us to Super-NEMO