50SC 50CA B- DECAY (13.45 S) 2017GA25,1984AL18 19NDS 201906
50SC H TYP=FUL$AUT=Jun Chen and Balraj Singh$CIT=NDS 157, 1 (2019)$
50SC2 H CUT=15-Apr-2019$
50SC c 2017Ga25: {+50}Ca was produced by spallation reaction using 500 MeV
50SC2c proton beam from TRIUMF cyclotron on a 22.49 g/cm{+2} thick Ta target.
50SC3c Selected ions were ionized, accelerated to 20 keV, mass separated and
50SC3c delivered to the experimental station. Measured E|g, I|g, |g|g-coin
50SC4c using GRIFFIN array of 15 HPGe clover detectors and five 1 in x 1 in
50SC5c LaBr{-3}(Ce) scintillators for fast timing. The |b{+-} particles were
50SC6c detected by plastic scintillator array SCEPTAR. Deduced levels,
50SC7c |g-ray branching ratios, level lifetimes, and transition strengths.
50SC8c Comparison with shell-model calculations, with special emphasis on
50SC9c B(M3) transition strengths.
50SC c 1984Al18: measured E|g, I|g, |b|g(t); pneumatic transfer system used
50SC2c for radioactive {+50}Ca source.
50SC c Others: 1970Wa29, 1968Ch11
50SC c 1970Wa29: measured T{-1/2}, E|g, I|g
50SC c 1968Ch11: measured E|g, I|g.
50SC c 1964Sh14: first identification of {+50}Ca nuclide. Measured E|g, I|g.
50SC2c Two |g rays of 72 and 258 keV reported using scintillation detector,
50SC3c and placed in a |g|g cascade
50SC cB $The |b feeding to 257 and 328 levels from higher levels (including
50SC2cB those from known (1+) states) is estimated as <0.75% (1984Al18)
50SC cG E$From 1984Al18, except where noted. Authors used different
50SC2cG reference sources whose E|g values were known precisely, and
50SC3cG final E|g values were weighted averages of three runs for 71.6|g and
50SC4cG 256.9|g, and seven runs for 1519.3 and 1519.8 |g rays
50SC cG E(a)$E|g=1562.302 {I5} (1979He19) from the decay of {+110m}Ag was used
50SC2cG as reference (1984Al18)
50SC cG M,MR$From |g|g(|q) in 2017Ga25 and RUL. The same values are adopted in
50SC2cG Adopted Levels
50SC cL E$From a least-squares fit to |g-ray energies.
50SC cL T(A),J$From Adopted Levels.
50CA P 0.0 0+ 13.45 S 5 4958 15
50CA cP T$From Adopted Levels, where value is adopted from 2017Ga25
50CA cP QP$From 2017Wa10
50SC N 0.997 15 1 1
50SC cN NR,NT$from |SI|g(from 1848)=99 {i1}. Lower lying states will not be
50SC2cN directly fed (|DJ|p|>2,no). Gamma feeding from higher states to
50SC3cN observed states estimated to be <2% by 1984Al18.
50SC PN 3
50SC L 0.0 5+ 102.5 S 5 A
50SC L 256.895 10 2+ 0.35 S 4 AM
50SC2 L %IT=99.5 5 $ %B-<1.0 (2017Ga25)
50SC cL J$spin=2 from (1519|g)(71|g)(|q) (2017Ga25)
50SC cL $Upper limit of %|b{+-} estimated in 2017Ga25 from examining
50SC2cL |g-intensities in {+50}Sc and {+50}Ti
50SC G 256.894 10 99.4 20(M3) 0.0356
50SCS G KC=0.0321 5$LC=0.00306 5$MC=0.000378 6$ NC=2.02E-5 3
50SC cG E$264.0755 {I8} (1979He19) from decay of {+182}Ta used as
50SC2cG reference, supplemented by lines from decays of {+133}Ba and
50SC3cG {+152}Eu (1984Al18); 256.94 {I10} (1970Wa29); 257 {I1} (1968Ch11)
50SC cG RI$weighted average of 100 {I2} (2017Ga25) and 98 {I3} (deduced from
50SC2cG I(|g+ce)=102 {I3} and |a(257|g,M3)=0.0366 in 1984Al18)
50SC L 328.447 12 3+ 600 PS LT
50SC cL J$spin=3 from (1519|g)(71|g)(|q) (2017Ga25)
50SC cL T$upper limit is based on the sensitivity of the experimental setup,
50SC2cL as no non-prompt component was seen by LaBr{-3} detectors (2017Ga25).
50SC3cL Other: <10 ns from |b|g(t) (1984Al18, authors obtained 5 ns {I2}, but
50SC4cL cited an upper limit of 10 ns as possible systematic uncertainties
50SC5cL were not properly monitored)
50SC G 71.552 5 54.6 50 M1(+E2) +0.015 25 0.0386 17
50SCS G KC=0.0350 15$LC=0.00319 14$MC=0.000395 17$ NC=2.16E-5 9
50SC cG E$72.8042 {I8} (1967Be65) from K|a{-2} x ray of Pb was used as
50SC2cG reference (1984Al18); 71.54 {I20} (1970Wa29); 72 {I1} (1968Ch11)
50SC cG RI$weighted average of 58.4 {I60} (2017Ga25) and 52 {I5} (deduced
50SC2cG from I(|g+ce)=54 {I5} and |a(71|g,M1)=0.0396 in 1984Al18)
50SC cG MR$from (1519|g)(71|g)(|q) (2017Ga25). Other: <0.5 from
50SC2cG |a(exp)=0.13 {I+13-11} deduced by evaluators from intensity balance
50SC G 328 0.46 5
50SC cG E,RI$from 2017Ga25. In 1984Al18, only an upper limit of 0.7 for I|g
50SC2cG was given.
50SC L 1847.772 20 1+ 2 NS LT
50SC cL T$upper limit obtained using generalized centroid difference method
50SC2cL in |b|g-coin data (2017Ga25). Other: <10 ns from |b|g(t) (1984Al18,
50SC3cL authors obtained 5 ns {I2}, but cited an upper limit of 10 ns as
50SC4cL possible systematic uncertainties were not properly monitored)
50SC B 99 1 4.12 1
50SCS B EAV=1349.9 73
50SC cB IB$|g feeding from higher states to this level was estimated as
50SC2cB <1% (1984Al18)
50SC G 1519.300 20 61.8 8 a
50SC cG E$1519.44 {I30} (1970Wa29); 1519 {I1} (1968Ch11)
50SC cG RI$weighted average of 59.6 {I17} (2017Ga25) and 62.1 {I6} (1984Al18)
50SC G 1590.850 30 37.5 7 a
50SC cG E$1591.00 {I30} (1970Wa29); 1591 {I1} (1968Ch11)
50SC cG RI$weighted average of 36.3 {I10} (2017Ga25) and 37.9 {I6} (1984Al18)