3HE 3H B- DECAY 15NDS 201512
3HE H TYP=FUL$AUT=J.E. Purcell{+#}, C.G. Sheu{+*}$CIT=NDS 130 1 (2015)$
3HE2 H CUT=30-Jun-2015$
3HE c Measurements of the |b-decay spectrum of tritium in solid
3HE2c tritiated valine by (1981Lu06,1985Bo34) indicated a nonzero electron
3HE3c antineutrino mass within the limits from 20 eV to 45 eV.
3HE cB $The Q value for this decay process is given in (2012Wa38) to be
3HE2cB 18.591 keV {I1}. The |b decay of {+3}H is 100% to the ground state of
3HE3cB {+3}He. As stated earlier, the half-life of {+3}H is 12.32 y {I2}. This
3HE4cB gives log| {Ift}=3.0524 {I7} and the average E{-|b}=5.68 keV.
3HE cB $Measurements of {+3}H |b-decay end point energy (EPE) or {+3}H-{+3}He
3HE2cB mass difference (MD): [Note: Table VII in (1950Ho80) lists eight
3HE3cB measurements of EPE prior to 1950 ranging from 12 keV {I5} to 18.9 keV
3HE4cB {I5}.]
3HE cB E A review of early work is found in (1973Pi01).
3HE TB
3HE4TB Reference Energy (KEV) Comment
3HE2TB 1950JE60 18.6 2 Calorimetry, measured average energy, deduced
3HE+TB \ ^EPE
3HE5TB 1959Po78 18.61 10 ^EPE, double lens spectrometer
3HE3TB 1969SA21 18.72 5 ^EPE; retarding electrostatic field
3HE4TB 1970LE15 18.540 95 ^EPE, 3H implantation
3HE5TB 1972BE11 18.610 16 ^EPE, magnetic-electrostatic spectrometer
3HE6TB 1972BE11 18.651 16 ^MD, magnetic-electrostatic spectrometer
3HE7TB 1973PI01 18.538 0 ^EPE, magnetic spectrometer
3HE8TB 1974RO08 18.648 26 ^EPE, magnetic spectrometer
3HE9TB 1975SM02 18.600 7 ^MD, mass spectrometer, 3H, 3HE masses measured
3HEaTB 1976TR07 18.575 13 ^EPE, magnetic spectrometer
3HEbTB 1981LU07 18.577 13 ^EPE, magnetic spectrometer
3HEvTB 1981SI18 18.567 5 ^EPE, 3H implantation
3HEdTB 1981SM02 18.573 7 ^MD, mass spectrometer; reconsider (1975SM02)
3HE+TB \ results
3HEeTB 1982DI01 18.594 25 ^EPE, ion implantation reconsider
3HEfTB 1983DE47 18.562 6 ^EPE, thermal diffusion
3HEhTB 1984NI16 18.584 4 ^MD, ion cyclotron resonance
3HEiTB 1985BO34 18.5842 16 ^EPE, magnetic-electrostatic spectrometer
3HEjTB 1985LI02 18.599 2 ^MD, ion cyclotron resonance
3HEkTB 1985SI07 18.577 7 ^EPE, 3H implantation
3HElTB 1985TAZK 18.582 3 ^MD
3HEmTB 1986FR09 18.5823 1 ^EPE, magnetic spectrometer
3HEoTB 1987BO07 18.5793 8 ^EPE, |b spectrometer
3HEpTB 1987KA51 18.593 5 ^EPE, |b spectrometer; also see
3HE+TB \ (1988KA12,1988KA32)
3HEqTB 1989RE04 18.590 8 ^EPE, reconsideration of earlier results
3HErTB 1989ST05 18.5890 26 ^MD, |b spectrometer
3HEsTB 1991BU12 18.595 6 ^MD, bremsstrahlung
3HEtTB 1992HO09 18.57332 18 ^EPE, |b spectrometer
3HEuTB 1993VA04 18.5901 17 ^MD, Penning trap mass spectrometer
3HEvTB 1993WE03 18.5748 6 ^EPE, |b spectrometer, also see (1993BA08)
3HEwTB 1995HI14 18.597 14 ^MD, magnetic spectrometer
3HExTB 2006NA49 18.5898 12 ^MD, Penning trap mass spectrometer
3HEyTB 2015MY03 18.59201 7 ^MD, cyclotron frequency ratio
3HEzTB
3HE cB $The |b spectrum end point energy differs from the {+3}H-{+3}He mass
3HE2cB difference due to the recoil energy, the final state of the residual
3HE3cB system and the mass of the emitted but not detected anti-electron
3HE4cB neutrino. In the table above, most of the references that measured the
3HE5cB end point energy (EPE) also put upper limits on the neutrino mass. An
3HE6cB early history of the role that the |b decay of {+3}H has played in
3HE7cB attempts to measure the neutrino mass can be found in (1988Ro21). Fig.
3HE8cB 1 in this article is a graph of the {+3}H |b spectrum near the EPE for
3HE9cB the electron neutrino masses of 0 and 30 eV. Fig. 1 in (2006We03) and
3HEacB Fig. 3 in (2013Dr11) show the |b spectrum near the end point energy
3HEbcB for electron neutrino masses of 0 and 1 eV. Modern refinements of these
3HEccB measurements have resulted in the upper limit of the electron neutrino
3HEdcB mass being just over 2 eV; see (2005Kr03,2010Ot02,2011As10,2013Dr11).
3HE cB $Studies of atomic and molecular effects on the {+3}H |b spectrum near
3HE2cB the end point energy are reported in (1971Sc23,2010Ot02,2015Bo02).
3HE N 1.0 1.0
3H P 0.0 1/2+ 12.32 Y 2 18.5906 32
3HE L 0.0 1/2+ STABLE
3HE B 100.0 3.0524 8
3HES B EAV=5.6817 12
3HE cB EAV weight-average heat output 0.3233 {I10} W/|g from
3HE2cB (0.321 {I3} (1950Je60)), (0.321 {I1} (1958Gr93)), (0.312 {I1}
3HE3cB (1958Po64)), (0.3240 {I9} (1961Pi01)), (0.3244 {I13} (1961Jo22)).