Muon Capture Rates for Double Beta Decay

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Muon Capture Rates for Double Beta
Decay
?CR42?

• Status report

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?CR42?
2n?2p 2? 2? (Dirac) 2n?2p 2? 0?
(Majorana)
??
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Probability of the 2?0? - decay
?CR42?
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(No Transcript)
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?CR42?
OMC
?
??
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Ordinary Muon Capture (OMC)
?CR42?

• Electron Capture
• e- (A,Z) ? (A, Z-1) ?e
• Q
  me ? 0.5 MeV
• Muon Capture
• ?- (A,Z) ? (A, Z-1) ??
• Q m?
  ? 100 MeV

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?CR42?
OMC
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?CR42?
95.8 -enriched Is available
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Nuclei candidates for measurement
?CR42?

• 2?-decaying nuclei 48Ca,
  150Nd, 96Zr, 100Mo, 82Se, 116Cd, 106Cd, 130Te,
  136Xe, 136Ce, 76Ge,
• Enriched targets availability
• (not available today) 100Ru
• (probably) 82Kr, 130Xe
• (sure) 48Ti, 76Se, 106Cd, 116Sn, 150Sm

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Set-up
?CR42?
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Spectra measured with 48Ti target
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Muon Life Time in 48Ti
370 keV
1297 keV
808 keV
767 keV
780 keV
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?CR42?
Total ?-Capture Rates
48Ca 5992 ns
40Ca 3622 ns
48Ti 3601 ns
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Partial OMC rates in 48Ti target
?CR42?
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Unfortunately,

• it is not the case for the 76Se, 106Cd,
  116Sn and 150Sm targets

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Spectra measured with 76Se target
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Failures and mistakes

• Detection system was optimized only for light
  targets. For the heavier we need
• Lower energy region (smaller Ge-detectors)
• Better timing (suppress µX-rays)
• Better E-resolution (instead of regular RF)
• Hot summer.
• We did not take enough care about temperature and
  voltage stability (separate feeding of
  acquisition electronics)

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We would like

• 2004 remeasure 76Se, 106Cd, 116Sn with the
  above improvements (1 week per target)
  
• 2005 82Kr (µE4 special gas target)

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MEDEX2003 Workshop

• Nuclear wave functions involved in ?? and OMC
  are the same.
• But operators not exactly.
• To clarify their role, theorists asked us to
  measure PCR for any light easy-calculatable
  nucleus.
• 12C ? (? Significant disagreement)

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(No Transcript)
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? -spectrum in 12C(?,? n)11B
2125
4445
5021
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(No Transcript)
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?-lines observed with 76Se target
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Beam-time required in 2004 (?E1)

• 1 week SetUp
• 1 week 76Se (for 2? of 76Ge)
• 1 week 106Cd (for 2K of 106Cd)
• 1 week 116Sn (for 2? of 116Cd)
• 2 weeks 12C (C4H10?)