220AC 224PA A DECAY 1996LI05 26NDS 202609
220AC H TYP=FUL$AUT=J.Chen, M.S. Basunia P.Dimitriou, et al.,$
220AC2 H CIT=NDS 212, 18 (2026)$CUT=31-Mar-2026$
220AC dA HF$Hindrance Factor is calculated by AlphaHF (version 16-Dec-2025)
220AC dG CC$FROM BrIcc v2.3e (17-Jun-2020) 2008Ki07, "Frozen Orbitals" appr.
220AC d Previous modification was done by E. Browne (Jan. 11, 2011) using ICC's
220AC2d from BrIcc, providing a new and consistent interpretation of the decay
220AC3d scheme by introducing a new level at 28-keV. The current dataset is an
220AC4d update based on that modified version.
220AC dL E$Least-squares fitting is done by GLSC (version 19-Aug-2025).
220AC c 1996Li05 (also 1997Sh09): {+224}Pa source was produced by
220AC2c {+209}Bi({+18}O,3n) with 96 MeV {+18}O beam from the Grenoble SARA
220AC3c accelerator on a 1.5 mg/cm{+2} self-supporting {+209}Bi target, and
220AC4c transported by a He-jet system to a tape tation. Measured E|a, I|a,
220AC5c E|g, I|g, |a|g-coin, |g|a-coin, (ce)|a-coin. Deduced levels, J, |p,
220AC6c |g-ray multipolarities, |a-decay branching ratios, hindrace factors.
220AC c 1987FuZT: {+224}Pa source was produced via {+209}Bi({+18}O,3n) with
220AC2c E=88 MeV {+18}O beam from the RIKEN 160-cm cycloton. |a particles were
220AC3c detected with a surface-barrier Si detector. Measured E|a, I|a,
220AC4c |a|a(t). Deduced levels, |a-decay branching ratios.
220AC c 1990An19: {+224}Pa source was produced via {+205}Tl({+22}Ne,X) at JINR.
220AC2c Measured E|a, |a|a(t) of decay daughter {+220}Ac. Deduced {+220}Ac
220AC3c T{-1/2}.
220AC c The decay scheme is that proposed by 1996Li05 based on measured |g, |a,
220AC2c |a|g-coin and (ce)|a-coin measurements. A different decay scheme is
220AC3c available in 1987FuZT which is only based on their measured E|a and is
220AC4c less complete, and those data are given under comments. Note that most
220AC5c levels in 1987FuZT are lower than the corresponding levels in 1996Li05
220AC6c by an offset of about 28 keV.
220AC cA HF$The nuclear radius parameter r{-0}({+220}Ac)=1.5466 {I27} is deduced
220AC2cA from interpolation of radius parameters of the adjacent even-even
220AC3cA nuclides in 2020Si16
220AC cA $1990An19 observed two |a groups with E|a=7460 {I10} with %I|a=25 {I3}
220AC2cA and 7555 {I10} with %I|a=75 {I3}. Their energies are in agreement but
220AC3cA the branching ratios are in disagreement with those reported in
220AC4cA 1996Li05 and 1987FuZT.
220AC cA E$From 1996Li05, unless otherwise noted.
220AC cA IA$Deduced by the evaluators from |g+ce intensity balance at each level
220AC2cA for excited states using conversion coefficients calculated by the
220AC3cA BrIcc code, unless otherwise noted. The original values (with no
220AC4cA uncertainties) in 1996Li05 are deduced by the authors using their
220AC5cA measured |a-gated I|g and I(ce) values, with the latter not given in
220AC6cA 1996Li05. The original values are given under comments where available.
220AC cA E(A),IA(A)$|a energy is not reported in 1996Li05 and 1987FuZT and the
220AC2cA quoted value is deduced by the evaluators from Q-value; an upper limit
220AC3cA of the intensity is from 1996Li05
220AC cG E,RI$From 1996Li05, unless otherwise noted. Original I|g values from
220AC2cG 1996Li05 are for per 1000 |a decays and the evaluators have converted
220AC3cG them to values for per 100 |a decays.
220AC cG M$Deduced by 1996Li05 based on their measured |a(K)exp, |a(L)exp and
220AC2cG K/L ratios. But the ce data are not explicitly given by the authors
220AC cG E(X),RI(X)$Possible doublet, assigned by the evaluators based on |a
220AC2cG data in 1996Li05 and 1987FuZT. 1996Li05 place 28|g only from 68.7-keV
220AC3cG level with I|g=8.1 {I6}, while a 28-keV level is suggested by an
220AC4cG observed E|a=7529 group in 1987FuZT, which could also decay by a 28-keV
220AC5cG transition to ground state. The total I|g of this possible doublet is
220AC6cG divided based on the intensity balance of |g+ce and |a intensity
220AC7cG balance at E=69 level.
220AC cL $Evaluators of previous evaluations (1997Ar04, 2011Br05) have
220AC2cL significantly modified the decay scheme by introducing a 28-keV level
220AC3cL from energy conservation calculations, as suggested in 1987FuZT. The
220AC4cL 7258 kev |a was assigned to the ground state originally. Thus, the
220AC5cL 28-keV |g ray reported in 1996Li05 is probably a doublet. The
220AC6cL individual intensities have been adjusted to produce a more consistent
220AC7cL transition-intensity balance in the decay scheme, and to reproduce the
220AC8cL experimental alpha-particle intensities. The multipolarity of the
220AC9cL 40.7-keV |g ray has been reported as M1 in 1996Li05. Evaluators,
220ACAcL however, have assigned an M1+3%E2 multipolarity to the |g ray for
220ACBcL consistency in the decay-scheme transition intensity balance, since its
220ACCcL conversion coefficient is very sensitive to an E2 admixture. Using this
220ACDcL interpretation, the sum of the |g-ray transition intensities to the
220ACEcL ground state and 13-keV level is 116% {I13}
220AC cL E$From a least-squares fit to |g-ray energies.
220AC cL J$Proposed by 1996Li05, based on |g-ray multipolarities, |a hindrance
220AC2cL factors, and shell-model expectations, unless otherwise noted. The same
220AC3cL assignments are adopted in Adopted Levels
220AC cL J(M)$Configuration=|ph{-9/2}~#|ni{-11/2} (1996Li05)
220AC cL J(N)$Configuration=|ph{-9/2}~#|ng{-9/2} (1996Li05)
224PA P 0 (5-) 0.846 S 20 7694 4
224PA cP J,T$From Adopted Levels of {+224}Pa in ENSDF database (2022 update)
224PA cP QP$From 2021Wa16
220AC N 1.0 1.0
220AC PN 2
220AC L 0.0 (3-) 26.4 MS 2 M
220AC cL T$from |a(t) of {+220}Ac |a decay in correlation with 7460 and 7555 |a
220AC2cL from {+224}Pa decay (1990An19)
220AC A 7556 0.5 LT 1234 GT A ?
220AC L 13.78 13 (2-) M
220AC A 7543 0.5 LT 1112 GT A ?
220AC G 13.8 S
220AC cG E$from level energy difference; this |g transition is only shown in the
220AC2cG decay scheme in 1996Li05 but is probably not observed
220AC L 28.00 10 ?
220AC cL $This level is suggested by E|a=7529 group in 1987FuZT and
220AC2cL Q-value=7694, which gives E(level)=29 keV. Note that 1987FuZT assign
220AC3cL this |a group to the ground state, which however is inconsistent with
220AC4cL the adopted Q-value.
220AC A 7528 1.30 18 420 75
220AC cA E$from 1987FuZT only, |a group not seen in 1996Li05. Note that 1987FuZT
220AC2cA assign this |a group to ground state, but Q-value=7694 and this E|a
220AC3cA give E(level)=29
220AC cA IA$others: 2.9 {I6} (1987FuZT)
220AC G 28.0 1 0.30 4 [E1] 3.34 6 X ?
220ACS G LC=2.50 4$MC=0.634 11
220ACS G NC=0.1631 28$OC=0.0340 6$PC=0.00487 8$QC=0.0001637 26
220AC cG M$E1 is assumed by the evaluators based on intensity balance,
220AC2cG considering that either M1 or E2 would give a very large |a(total)
220AC3cG value and thus a large I(|g+ce)(28|g) indicating a strong decay to
220AC4cG 28-keV level which is inconsistent with observation in 1996Li05
220AC L 40.69 10 (4-) M
220AC A 7516 0.5 LT 905 GT A ?
220AC cA IA$other: negative feeding from |g+ce intensity balance indicates no |a
220AC2cA decay to this level
220AC G 40.7 1 1.34 8 M1 47.5 8
220ACS G LC=36.0 6$MC=8.64 14
220ACS G NC=2.29 4$OC=0.533 8$PC=0.0987 16$QC=0.00878 14
220AC L 68.71 13 (5-) N
220AC A 7488 71 7 5.6 7
220AC cA E$other: 7489 in 1987FuZT assigned to a level at E=40 keV, however,
220AC2cA Q-value=7694 and this E|a is consistent with E(level)=69 keV
220AC cA IA$others: 66 {I3} (1987FuZT), 70 (1996Li05).
220AC G 28.0 1 0.51 5 M1 143.4 25 X
220ACS G LC=108.4 19$MC=26.1 5
220ACS G NC=6.93 12$OC=1.611 28$PC=0.298 5$QC=0.0266 5
220AC L 71.56 20 (1-)
220AC A 7486 0.7 LT 510 GT A ?
220AC cA E$this very weak group if existing is completely obscured by the
220AC2cA strongest E|a=7488 group to 69-keV level
220AC cA IA$other: 3.3 {I20} from |g+ce intensity balance.
220AC G 57.8 2 0.26 9 [M1] 16.96 29
220ACS G LC=12.83 22$MC=3.08 5
220ACS G NC=0.817 14$OC=0.1901 33$PC=0.0352 6$QC=0.00313 5
220AC cG M$[M1,E2] from level scheme, but E2 would give a large |a(total) and
220AC2cG thus a very large I(|g+ce)(57.8|g) which would require a strong |a
220AC3cG decay to 72 level, inconsistent with the weak |a group assigned to that
220AC4cG level in 1996Li05
220AC L 108.51 18 (3-) N
220AC A 7449 3.8 12 77 30
220AC cA IA$other: 4.0 (1996Li05).
220AC G 67.8 2 0.38 10 M1 10.63 18
220ACS G LC=8.05 13$MC=1.931 32
220ACS G NC=0.512 8$OC=0.1191 20$PC=0.0220 4$QC=0.001959 32
220AC L 113.33 19 (1-) N
220AC A 7444 1.13 21 251 57
220AC cA IA$other: 2.5 (1996Li05).
220AC G 113.3 2 0.16 3 (E2) 6.07 10
220ACS G KC=0.266 4$LC=4.25 7$MC=1.163 19
220ACS G NC=0.309 5$OC=0.0675 11$PC=0.01059 17$QC=5.02E-5 8
220AC L 145.56 28 ?
220AC cL $I(|a)=0.34 {I11} from |g+ce intensity balance. No |a decay to this
220AC2cL level has been observed
220AC G 74.0 2 0.27 9 [E1] 0.253 4 ?
220ACS G LC=0.1912 30$MC=0.0465 7
220ACS G NC=0.01212 19$OC=0.00267 4$PC=0.000436 7$QC=2.165E-5 33
220AC cG $This transition is marked as tentative by the evaluators since the
220AC2cG decaying level is tentative in 1996Li05
220AC cG M$assumed by the evaluators based on |g+ce intensity balance and no
220AC2cG observation of |a decay to 146 level, considering that either M1 or E2
220AC3cG would give a large |a(total) value and thus a large I(|g+ce)(74.0|g)
220AC4cG which would require a strong |a decay to to 146 level
220AC L 150.18 14 (4-) N
220AC A 7408 3.5 4 61 10
220AC cA E$other: 7408 in 1987FuZT probably a doublet of 7408+7405 groups in
220AC2cA 1996Li05, considering I|a=17 {I2} for this group in 1987FuZT. Note that
220AC3cA 1987FuZT assign this |a group to a 122 level, which is not confirmed by
220AC4cA other studies and thus is not adopted by the evaluators; Q-value=7694
220AC5cA and E|a=7408 give E(level)=151
220AC cA IA$other: 4.0 (1996Li05).
220AC G 109.5 1 0.30 3 M1 13.07 19
220ACS G KC=10.43 15$LC=2.000 28$MC=0.480 7
220ACS G NC=0.1272 18$OC=0.0296 4$PC=0.00547 8$QC=0.000486 7
220AC L 153.00 10 (2-) N
220AC A 7405 11.0 16 19 4
220AC cA E$see comments for E|a=7408 at 150 level
220AC cA IA$others: 12 (1996Li05); 1987FuZT reported 17 {I2} for E|a=7408, which
220AC2cA is probably a doublet
220AC G 39.5 ?
220AC cG E$only shown in Fig.4 of 1996Li05 as a tentative transition
220AC G 81.5 3 0.30 LE M1 6.22 11
220ACS G LC=4.71 8$MC=1.129 20
220ACS G NC=0.300 5$OC=0.0697 12$PC=0.01288 23$QC=0.001145 20
220AC G 139.2 1 0.48 4 M1 6.65 9
220ACS G KC=5.32 8$LC=1.003 14$MC=0.2406 34
220ACS G NC=0.0638 9$OC=0.01484 21$PC=0.00275 4$QC=0.0002434 34
220AC G 153.0 1 1.07 7 M1 5.08 7
220ACS G KC=4.07 6$LC=0.766 11$MC=0.1836 26
220ACS G NC=0.0487 7$OC=0.01133 16$PC=0.002095 30$QC=0.0001857 26
220AC L 184.21 16 (3-)
220AC A 7375 2.8 6 58 15
220AC cA E$other: 7388 from 1987FuZT is probably the same |a group. 1987FuZT
220AC2cA assign this |a to a 143 level, however, Q-value=7694 and E|a=7375 give
220AC3cA E(level)=171, which is close to the adopted E(level)=184. Note that
220AC4cA E|a=7388 group is obscured by the tail of the stronger E|a=7408 group
220AC5cA as seen in the |a spectrum in Fig.2 of 1987FuZT
220AC cA IA$others: 2.5 (1996Li05); 4.4 {I5} (1987FuZT).
220AC G 170.5 3 0.19 3 M1 3.74 6
220ACS G KC=3.00 4$LC=0.563 8$MC=0.1349 20
220ACS G NC=0.0358 5$OC=0.00832 12$PC=0.001539 23$QC=0.0001364 20
220AC G 184.2 2 0.63 5 M1 3.01 4
220ACS G KC=2.412 35$LC=0.452 6$MC=0.1083 16
220ACS G NC=0.0287 4$OC=0.00668 10$PC=0.001236 18$QC=0.0001095 16
220AC L 233.81 17 (5+)
220AC A 7326 0.96 17 114 25
220AC cA E$others: two |a groups with E|a=7337, I|a=1.4 {I3} and E|a=7316,
220AC2cA I|a=1.9 {I3} reported in 1987FuZT and assigned to a level at E=195 and
220AC3cA 216, respectively, neither of which is confirmed by 1996Li05.
220AC4cA Q-value=7694 and E|a in 1987FuZT gives E(level)=223 and 245,
220AC5cA respectively.
220AC cA IA$other: 1.5 (1996Li05).
220AC G 165.1 1 0.84 15 E1 0.1458 21
220ACS G KC=0.1150 16$LC=0.02338 33$MC=0.00563 8
220ACS G NC=0.001476 21$OC=0.000333 5$PC=5.76E-5 8$QC=3.64E-6 5
220AC L 263.22 15 (4+)
220AC A 7297 2.75 15 32 3
220AC cA E$other: 7292 assigned to a 240 level in 1987FuZT, but Q-value=7694
220AC2cA give E(level)=269.
220AC cA IA$others: 2.0 (1996Li05), 3.6 {I5} (1987FuZT)
220AC G 113.1 2 0.51 5 E1 0.360 5
220ACS G KC=0.278 4$LC=0.0623 9$MC=0.01506 22
220ACS G NC=0.00394 6$OC=0.000880 13$PC=0.0001488 22$QC=8.47E-6 12
220AC G 154.7 2 0.28 6 [E1] 0.1705 24
220ACS G KC=0.1340 19$LC=0.0276 4$MC=0.00665 10
220ACS G NC=0.001744 25$OC=0.000393 6$PC=6.77E-5 10$QC=4.21E-6 6
220AC G 194.5 1 1.57 10 E1 0.0986 14
220ACS G KC=0.0782 11$LC=0.01544 22$MC=0.00371 5
220ACS G NC=0.000974 14$OC=0.0002204 31$PC=3.84E-5 5$QC=2.53E-6 4
220AC L 312.0 7
220AC A 7249 0.03 AP 1954 AP
220AC cA IA$other: 0.1 (1996Li05).
220AC G 298.2 7 0.03 AP
220AC L 335.18 20
220AC A 7226 1.1 5 44 27
220AC cA E$other: 7221 assigned to a 313 level in 1987FuZT, but Q-value=7694
220AC2cA give E(level)=341.
220AC cA IA$others: 0.1 (1996Li05), 1.3 {I4} (1987FuZT)
220AC G 151.0 2 0.17 5 [D,E2] 2.7 26
220AC dG CC$mean of max and min values of CC(E1)=0.1810 {I30}, CC(M1)=5.28 {I8}
220AC2dG and CC(E2)=1.820 {I30} by BrIcc
220AC G 182.0 4 0.10 AP [D,E2] 1.6 15
220AC dG CC$mean of max and min values of CC(E1)=0.1155 {I18}, CC(M1)=3.11 {I5}
220AC2dG and CC(E2)=0.880 {I15} by BrIcc
220AC G 294.7 5 0.080 AP [D,E2] 0.4 4
220AC dG CC$mean of max and min values of CC(E1)=0.0376 {I6}, CC(M1)=0.812 {I12}
220AC2dG and CC(E2)=0.1690 {I30} by BrIcc
220AC G 335.0 7 0.040 AP [D,E2] 0.30 27
220AC dG CC$mean of max and min values of CC(E1)=0.0283 {I5}, CC(M1)=0.571 {I9}
220AC2dG and CC(E2)=0.1155 {I18} by BrIcc
220AC L 356.14 24
220AC A 7205 0.68 18 60 19
220AC cA E$other: 7191 assigned to a 343 level in 1987FuZT is probably the same
220AC2cA |a group, and Q-value=7694 and this E|a give E(level)=372
220AC cA IA$others: 0.2 (1996Li05), 0.7 {I2} (1987FuZT)
220AC G 247.6 3 0.18 5 [D,E2] 0.7 6
220AC dG CC$mean of max and min values of CC(E1)=0.0560 {I8}, CC(M1)=1.315 {I19}
220AC2dG and CC(E2)=0.295 {I5} by BrIcc
220AC G 287.4 3 0.21 5 [D,E2] 0.5 4
220AC dG CC$mean of max and min values of CC(E1)=0.0398 {I6}, CC(M1)=0.870 {I13}
220AC2dG and CC(E2)=0.1830 {I30} by BrIcc
220AC G 315.8 7 0.040 AP [D,E2] 0.35 32
220AC dG CC$mean of max and min values of CC(E1)=0.0323 {I5}, CC(M1)=0.671 {I11}
220AC2dG and CC(E2)=0.1372 {I22} by BrIcc
220AC L 411.9 7
220AC A 7151 0.05 AP 517 AP
220AC cA IA$other: <0.05 (1996Li05).
220AC G 398.0 10 0.020 AP [D,E2] 0.19 17
220AC dG CC$mean of max and min values of CC(E1)=0.01950 {I30}, CC(M1)=0.357
220AC2dG {I6} and CC(E2)=0.0718 {I12} by BrIcc
220AC G 412.0 10 0.020 AP [D,E2] 0.17 15
220AC dG CC$mean of max and min values of CC(E1)=0.01820 {I30}, CC(M1)=0.325
220AC2dG {I5} and CC(E2)=0.0656 {I10} by BrIcc