156SM 156PM B- DECAY (26.70 S) 1990HE11 12NDS 201210
156SM H TYP=FUL$AUT=C. W. REICH$CIT=NDS 113, 2537 (2012)$CUT=1-Mar-2012$
156SM D DATA SET REVISED (AUGUST, 2011) BY CW REICH TO INCLUDE REVISED QP, E,
156SM2D AND JPI VALUES FOR THE GS AND RECOMPUTED CC VALUES.
156SM c {+156}Pm has been produced by thermal-neutron induced fission of
156SM2c {+235}U (1986Ma12,1986Ok01,1990He11) and spontaneous fission of
156SM3c {+252}Cf (1987Gr12), all with isotope separation. All data reported
156SM4c here are from 1990He11 or computed by the evaluator. For shorter lists
156SM5c of |g's, see 1986Ma12, 1986Ok01, and 1987Gr12.
156SM c 1990He11: {+156}Sm, from thermal-neutron fission of {+235}U followed by
156SM2c isotope separation. Source material collected on a movable tape and
156SM3c transported to a counting station. Measured multiscaled |g singles
156SM4c using a large-volume coaxial Ge detector and a LEPS detector. Measured
156SM5c simultaneously low-energy |g's and ce's using the LEPS and an
156SM6c ion-implanted Si detector. System geometry was calibrated using |g's of
156SM7c known multipolarities from the {+124}In decay. Measured |g|g and
156SM8c |b|g(t) coincidences using a small plastic detector and various Ge
156SM9c detectors. Report E|g, I|g, Q(|b{+-}), T{-1/2} values for two excited
156SMac states. The ce data are not reported in 1990He11, but some of the
156SMbc deduced multipolarities are given there.
156SM D Experimental methods (other):
156SM D 1986Ma12: 156PM produced by thermal-neutron induced fission of 235U
156SM2D with isotope separation. |g's measured with Ge detectors.
156SM D 1986Ok01: 156PM produced by thermal-neutron induced fission of 235U
156SM2D with isotope separation. |g's measured with Ge detectors.
156SM D 1987Gr12: 156PM produced by spontaneous fission of 252CF with
156SM2D isotope separation. |g's measured with Ge detectors.
156SM cB The I|b{+-} values have all been computed from the
156SM2cB |g-transition intensity balances and therefore are accurate only
156SM3cB insofar as this decay scheme is correct and complete. There are 3
156SM4cB unplaced |g rays with intensities of |?0.6% and, since the weakest
156SM5cB reported |g's have intensities of 0.3%, it is reasonable to expect
156SM6cB that there are unobserved |g rays with intensites of 0.2% and less.
156SM7cB With a Q value of 5150 keV and the high spin (J=4) of the parent,
156SM8cB it is expected that many levels above that at 2699 keV will be
156SM9cB populated, albeit weakly. Therefore, a minimum uncertainty of 0.4%
156SM0cB has been assigned to each I|b{+-} by the evaluator.
156SM cB $1995Gr19, using total-absorption |g spectroscopy, deduce that the |b
156SM2cB branching to the ground and first excited states is 1.8% 17. These
156SM3cB authors point out that their data do not provide evidence for a nonzero
156SM4cB |b- branch to the first excited state.
156SM cB The I|b{+-} to the 803 and 1009 levels have been set to zero
156SM2cB because the adopted J|p requires that these transitions be negligibly
156SM3cB weak. The values deduced from the intensity balance are 2.0% {I3} and
156SM4cB 2.1% {I8}, respectively.
156SM cG E,RI From 1990He11. Others: 1986Ok01, 1987Gr12.
156SM cG M Based on I|g and Ice data normalized using transitions of
156SM2cG known multipolarity in the {+124}In decay. Multipolarities deduced
156SM3cG from the J|p assignments are omitted if |a<0.01.
156SM cL The level energies are from a least-squares fit to the |g
156SM2cL energies. There are several cases in which the deduced level-energy
156SM3cL difference differs from the corresponding |g energy by more than 2
156SM4cL or 3 times the quoted uncertainty. It is thus reasonable to assume,
156SM5cL for specific |g lines, that there are doublets and/or that the
156SM6cL uncertainties are underestimated, possibly due to difficulties in the
156SM7cL spectral analysis.
156SM cL E(G)$Suggested member of a band by 1990He11. From log| {Ift}
156SM2cL considerations, these authors suggest that |p for the J=3 level is most
156SM3cL likely the same as that of the {+156}Pm g.s., which these authors
156SM4cL propose to be negative. 2011So05, however, indicate that this log|
156SM5cL {Ift} argument may not be a strong one in this case. Based on the
156SM6cL expected nucleonic configurations, the evaluator prefers |p=+ for the
156SM7cL {+156}Pm g.s. The sole decay mode of the 2609 level is to a 4+ level,
156SM8cL consistent with J{+|p}=4-, which is the value listed by 1990He11. In
156SM9cL that case this and the J=3 level would not be members of the same band.
156SM cL E(H)$Suggested member of a band by 1990He11. From log| {Ift}
156SM2cL considerations, these authors indicate that |p for the J=3 level is
156SM3cL most likely the same as that of the {+156}Pm g.s., which they propose
156SM4cL to be negative. However, the evaluator has preferred |p=+ for the
156SM5cL {+156}Pm g.s. The sole decay mode of the 2616 level is to a 4+ level,
156SM6cL consistent with J{+|p}=4-, which is the value listed by 1990He11. In
156SM7cL that case this and the J=3 level would not be members of the same band.
156SM cL J$From the adopted values. These are generally those proposed by
156SM2cL 1990He11. Where there are differences, these are noted.
156SM cL BAND(A)$K{+|p}=0+ ground-state band
156SM cL BAND(B)$Probable K{+|p}=1- octupole band. This band likely contains a
156SM2cL significant component of |n5/2[642]-|n3/2[521].
156SM cL BAND(D)$Possible 3- member of the K{+|p}=0- octupole band. This
156SM2cL suggestion is supported by the observation that the |g branching from
156SM3cL this level to the 2+ and 4+ members of the g.s. band agrees well with
156SM4cL the Alaga-rule expectations for |DK=0 dipole transitions.
156SM cL BAND(E)$K{+|p}=5- bandhead, conf=|n5/2[642]+|n5/2[523]. This is the
156SM2cL dominant conf. See the discussion regarding the 5- state at 1515~keV
156SM3cL regarding possible configuration mixing between these two 5- states.
156SM cL BAND(F)$K{+|p}=5- bandhead, conf=|p5/2[532]+|p5/2[413]. The
156SM2cL preferential |b{+-} feeding of this state relative to the 1397, 5-,
156SM3cL state suggests that it is predominantly two-proton, rather than
156SM4cL two-neutron, in character. These two 5- states are, however, most
156SM5cL likely mixed to some extent. Evidence for such mixing, which is
156SM6cL frequently observed between two-proton and two-neutron bands with the
156SM7cL same K{+|p} values, is evidenced by the existence (albeit with a
156SM8cL sizeable hindrance factor) of the 117-keV M1 transition connecting them
156SM9cL and the possible, but much weaker, |b{+-} feeding of this level.
156SM cL BAND(J)$Probable K{+|p}=4+ bandhead.
156PM P 0 4(+) 26.70 S 10 5150 33
156PM DP J From 156PM Adopted Levels.
156PM DP T From 156PM Adopted Levels.
156PM DP QP From 2011AuZZ.
156SM N 1.00 5 1.00
156SM cN NR calculated to give average |g feeding of levels at 0 and 75
156SM2cN keV as 100%; these feedings are 96% {I6} and 102% {I3}, respectively.
156SM PN 3
156SM G 625.27 20 0.6 1
156SM G 1416.6 5 0.6 1
156SM G 1473.6 4 0.5 1
156SM L 0 0+ A
156SM L 75.89 5 2+ A
156SM G 75.88 5 12.5 7 E2 6.51 C
156SMS G KC=2.38 4$LC=3.20 5$MC=0.745 11$NC+=0.183 3
156SMS G NC=0.1629 24$OC=0.0202 3$PC=9.97E-5 14
156SM L 249.71 7 4+ A
156SM G 173.75 5 52.0 20E2 0.336 C
156SMS G KC=0.232 4$LC=0.0809 12$MC=0.0184 3$NC+=0.00461 7
156SMS G NC=0.00407 6$OC=0.000533 8$PC=1.112E-5 16
156SM L 517.07 8 6+ A
156SM B 3.4 10 8.96 13 1U
156SMS B EAV=1947 16
156SM G 267.32 5 13.3 7 E2 0.0808 C
156SMS G KC=0.0618 9$LC=0.01483 21$MC=0.00332 5$NC+=0.000841 12
156SMS G NC=0.000738 11$OC=0.0001005 14$PC=3.25E-6 5
156SM L 803.69 22 (1-) B
156SM G 727.6 3 0.9 2 C
156SM G 803.9 3 1.1 2
156SM L 875.69 11 (3-) B
156SM B 3.6 5 7.05 7
156SMS B EAV=1805 16
156SM G 626.37 20 0.6 1 C
156SM G 799.70 10 3.6 4 C
156SM L 1009.79 9 (2-) B
156SM G 934.00 10 12.3 6 C
156SM L 1020.62 10 (5-) B
156SM B 1.7 4 7.32 11
156SMS B EAV=1738 16
156SM G 503.37 20 0.3 1 C
156SM G 770.77 10 2.6 3 C
156SM L 1110.11 11 (3-) D
156SM cL J$1990He11 report J{+|p}=(3).
156SM B 2.5 4 7.11 8
156SMS B EAV=1697 16
156SM G 860.26 20 1.1 1 C
156SM G 1034.25 10 1.4 1 C
156SM L 1144.07 9 (4-) B
156SM G 894.35 10 8.4 4 C
156SM L 1256.1 5
156SM B 0.6 4 7.7 3
156SMS B EAV=1629 16
156SM G 380.4 4 0.6 1 C
156SM L 1397.55 9 5- 185 NS 7 E
156SM cL T From 1990He11. Note that 1974ClZX report a half-life of
156SM2cL 160 ns {I40}, but were not able to identify the associated level.
156SM B 3.1 16 6.88 23
156SMS B EAV=1564 16
156SM G 376.75 10 0.9 1 [M1,E2] 0.036 9 C
156SMS G KC=0.030 8$LC=0.0048 4$MC=0.00104 8$NC+=0.000271 23
156SMS G NC=0.000235 18$OC=3.4E-5 4$PC=1.8E-6 6
156SM G 880.39 10 10.4 5 C
156SM G 1147.84 10 20.5 10 C
156SM cG RI$1990He11 report this uncertainty as 0.1. However, this seems
156SM2cG unusually small. The evaluator has assumed that it is a misprint.
156SM L 1509.22 9 4+ J
156SM cL $1990He11 propose the two-proton quasiparticle excitation
156SM2cL |p5/2[413]+|p3/2[411] as the conf of this state (note that the one
156SM3cL shown by them apparently has a misprint), presumably by analogy with
156SM4cL the 1510.5, 4+, state in {+156}Gd. However, the location of the Fermi
156SM5cL surface for protons in {+156}Sm is different from that in {+156}Gd. The
156SM6cL evaluator has proposed a different conf for this state (see the Adopted
156SM7cL Levels data set).
156SM B 11.4 9 6.26 4
156SMS B EAV=1513 16
156SM G 992.0 10 0.3 1 C
156SM G 1259.44 10 12.6 6 C
156SM G 1433.70 10 8.4 4 C
156SM L 1515.04 9 5- 4.5 NS 2 F
156SM cL T$From 1990He11.
156SM B 23.0 15 5.95 4
156SMS B EAV=1510 16
156SM G 117.42 5 13.8 7 M1 1.068 C
156SMS G KC=0.906 13$LC=0.1281 18$MC=0.0275 4$NC+=0.00723 11
156SMS G NC=0.00624 9$OC=0.000935 14$PC=5.78E-5 9
156SM cG M$As assigned by 1990He11. The ce data are also consistent with
156SM2cG mult=E1+M2, with %M2 between 8 and 9. However, from RUL,
156SM3cG |d(M2/E1)|<0.01. Thus, there is no parity change involved in the 117.42
156SM4cG transition.
156SM G 370.94 10 0.6 1 [M1,E2] 0.038 9 C
156SMS G KC=0.032 8$LC=0.0050 4$MC=0.00109 7$NC+=0.000284 22
156SMS G NC=0.000246 18$OC=3.6E-5 4$PC=1.9E-6 6
156SM G 494.4 4 0.3 1 [M1,E2] 0.018 5 C
156SMS G KC=0.015 4$LC=0.0022 4$MC=0.00048 8$NC+=0.000125 20
156SMS G NC=0.000108 17$OC=1.6E-5 3$PC=9.E-7 3
156SM L 1610.30 12
156SM B 1.8 4 7.01 10
156SMS B EAV=1466 16
156SM G 1360.56 10 1.8 2 C
156SM L 1738.35 13
156SM B 1.0 4 7.20 18
156SMS B EAV=1407 16
156SM G 223.31 10 1.0 1 C
156SM L 2033.8 3
156SM B 1.9 4 6.75 10
156SMS B EAV=1271 16
156SM G 518.4 4 0.9 1 C
156SM G 524.9 4 1.0 1 C
156SM L 2199.91 11
156SM B 7.7 4 6.05 3
156SMS B EAV=1195 15
156SM G 684.65 10 2.1 1 C
156SM G 690.90 10 5.6 3 C
156SM L 2265.52 11
156SM B 4.2 4 6.27 5
156SMS B EAV=1165 15
156SM G 750.26 10 2.1 2 C
156SM G 756.51 10 2.1 2 C
156SM L 2341.92 12
156SM B 1.8 4 6.59 10
156SMS B EAV=1131 15
156SM G 827.03 10 0.6 1 C
156SM G 832.08 20 1.2 2 C
156SM L 2482.6 3
156SM B 1.0 4 6.75 18
156SMS B EAV=1067 15
156SM G 2406.7 3 1.0 1 C
156SM L 2519.04 11 3 G
156SM B 8.2 5 5.82 4
156SMS B EAV=1050 15
156SM G 1374.91 10 2.3 2 C
156SM G 1509.12 20 2.8 3 C
156SM G 2269.9 4 0.7 1 C
156SM G 2443.34 20 2.4 2 C
156SM L 2526.22 9 3 H
156SM B 16.5 6 5.51 3
156SMS B EAV=1047 15
156SM G 1382.24 10 5.7 3 C
156SM G 1516.56 10 7.4 4 C
156SM G 2276.18 20 0.7 1 C
156SM G 2450.17 10 2.7 3 C
156SM L 2609.7 3 (4) G
156SM B 1.0 4 6.67 18
156SMS B EAV=1009 15
156SM G 2360.0 3 1.0 1 C
156SM L 2616.51 21 (4) H
156SM B 0.8 4 6.76 22
156SMS B EAV=1006 15
156SM G 2366.78 20 0.8 1 C
156SM L 2699.7 5
156SM B 0.4 4 7.0 5
156SMS B EAV=968 15
156SM G 1555.6 5 0.4 1 C