231PA 231U EC DECAY (4.2 D) 1994BR36,1996LE01 22NDS 202210
231PA H TYP=FUL$AUT=Balraj Singh, Jagdish K. Tuli, and Edgardo Browne$
231PA2 H CIT=NDS 185, 560 (2022)$CUT=31-Aug-2022$
231PA c 1994Br36: {+231}U activity was produced via the electron capture decay
231PA2c of {+231}Np, which was formed in the {+233}U(p,3n) reaction with 49-MeV
231PA3c protons. The recoiling reaction products of {+231}Np were chemically
231PA4c separated from their {+231}U daughter nuclei. Measured E|g, I|g, E(ce),
231PA5c I(ce), |g|g-coin using HPGe detector for |g rays, pin diode for
231PA7c conversion electrons. Main contaminants were {+237}U and {+117m}Sn.
231PA8c Deduced conversion coefficients, |g-ray multipolarities.
231PA c 1996Le01: {+231}U activity produced by {+232}Th(|a,5n), E=52 MeV and
231PA2c mass separated. Measured E|g, I|g using HPGe detector. Main
231PA3c contaminant was {+231}Th, produced in {+232}Th(|a,|a'n) reaction
231PA c 1961Ho29, 1957Ho07: data from private communications from
231PA2c J.M. Hollander listed in 1978LeZA (Table of Isotopes)
231PA c Evaluators' note: the decay scheme seems fairly complete, except for
231PA2c lack of spectral information for 9.18 and 77.69-keV |g transitions.
231PA cG $Measured energies and intensities of Pa x-rays relative to 100 for
231PA2cG the 84.21-keV |g ray from {+231}U |e decay (1994Br36):
231PA cG $Pa K{-|a2}: 92.3 keV {I1}, relative intensity=238 {I14} (1994Br36).
231PA cG $Pa K{-|a1}: 95.8 keV {I1}, relative intensity=382 {I22} (1994Br36).
231PA cG $Pa K{-|b3}: 107.5 keV {I2}, relative intensity=34.6 {I28} (1994Br36).
231PA cG $Pa K{-|b1}: 108.3 keV {I2}, relative intensity=78 {I6} (1994Br36).
231PA cG $Pa K{-|b2}: 111.4 keV {I2}, relative intensity=37.6 {I26} (1994Br36).
231PA cG $Pa O{-23}: 112.2 keV {I2}, relative intensity=9.2 {I12} (1994Br36).
231PA cG E$From the Adopted Gammas, which are mostly from {+231}Th |b{+-} decay,
231PA2cG unless otherwise indicated
231PA cG RI$Relative intensities listed in 1994Br36 and 1996Le01 are normalized
231PA2cG to 100 for the 84.21-keV |g ray from a level of this energy
231PA cG E(d),RI(e)$From 1996Le01
231PA cG RI(a)$From 1994Br36
231PA cG RI(g)$Deduced from the |g-branching ratios in Adopted Gammas, which
231PA2cG are mostly from {+231}Th |b{+-} decay
231PA cG M,MR$From the Adopted Gammas, unless otherwise stated
231PA cG $Experimental Pa K| x ray intensities: 17.5% {I10} (K|a{-2}| x ray),
231PA2cG 28.1% 16 (K|a{-1}| x ray), and 11.8% {I6} (K|b| x ray) compare with
231PA3cG 17.85% {I8} (K|a{-2}| x ray), 28.73% {I12} (K|b| x ray), respectively,
231PA4cG calculated by evaluators (using the computer program RADLST) from
231PA5cG |g-ray intensities, K-conversion coefficients and K-electron capture
231PA6cG probabilities presented here, using a K-fluorescence yield of 0.970
231PA7cG {I4} (1996Sc06). This agreement shows that most |g rays with energies
231PA8cG greater than 112.6 keV (the K-binding in Pa) have accurate intensities
231PA9cG and correct multipolarities, and that K-electron capture probabilities
231PAacG are also correct.
231PA cG $Q(|b{+-})=381.6 keV {I20} (2021Wa16) compares with a
231PA2cG total average radiation energy of 350 keV, calculated by evaluators
231PA3cG using the computer program RADLST. The small discrepancy between these
231PA4cG values is probably due to low-energy |g rays (i.e., 9.2-, 17.2-, and
231PA5cG 19.1-keV transitions) not included in the calculation because their
231PA6cG intensities are unknown. These results support the consistency and
231PA7cG completeness of the decay scheme.
231PA cL E$Deduced from least-squares fit to E|g values
231PA cL J,T$From the Adopted Levels
231U P 0.0 (5/2-) 4.2 D 1 381.6 20
231U cP J,T$From {+231}U Adopted Levels
231U cP QP$From 2021Wa16
231PA N 0.073 4 0.073 4 1.0 1.0
231PA PN 4
231PA cN NR$From a relative K| x ray intensity of 780 {I28} (1994Br36), a
231PA2cN theoretical |eK/|e=0.59 (1977Ba48), and a K-fluorescence yield of
231PA3cN 0.970 {I4} (1996Sc06) the total number of atomic vacancies produced by
231PA4cN the electron capture process and the I|g normalization factor become
231PA5cN 1362 {I66} and 0.073 {I4}, respectively. The total
231PA6cN number of atomic vacancies also agrees with the total relative |g-ray
231PA7cN transition intensity (photons plus electrons) of 1350 {I70} to the
231PA8cN ground and 9.2-keV levels. This result is consistent with the absence
231PA9cN of any appreciable electron-capture decays to these levels.
231PA cN BR$%|e|?100 for {+231}U |e decay
231PA L 0.0 3/2- 32570 Y 130
231PA L 9.186 20 1/2-
231PA G 9.183 8.8 3 S
231PA cG E$from the Adopted Gammas
231PA cG TI$from transition intensity balance at 9.19 level, assuming no direct
231PA2cG |e feeding to the 9.19 level, as expected from |DJ|p=(2), |D|p=(no)
231PA L 58.570 3 7/2- 274 PS 10
231PA G 58.5700 24 6.8 4 E2 155.5 22 a
231PA2 G %IG=0.50 4
231PA cG E$other: 58.55 {I4} (1994Br36)
231PA cG RI$6.4 {I4} in 1994Br36 is adjusted by evaluators to 6.8 {I4} to
231PA2cG obtain transition intensity balance at 58.57 level, with no direct
231PA3cG |e feeding to this level
231PA cG $Ice(L1+L2)=205 {I21}, Ice(L3)=156 {I16}, Ice(M)=116 {I12},
231PA2cG Ice(N)=31 {I3} (1994Br36). Other: 1961Ho29
231PA dG $Ice(L1)=5.7, Ice(L2)=189, Ice(L3)=170 (1961Ho29, cited by 1994Br36)
231PA2 G EL1C+EL2C=64 8 $ EL3C=49 6 $ EMC=36 5$ ENC=10 2 (1994Br36)
231PAS G LC=113.6 16$MC=31.3 5
231PAS G NC=8.43 12$OC=1.90 3$PC=0.306 5$QC=0.000818 12
231PA L 77.69 4 5/2-
231PA E 0.52 8 8.4 1
231PAS E CK=0.6300 17$CL=0.2681 12$CM+=0.1019 5
231PA G 68.5 1 0.079 E2 73.3 10
231PA2 G %IG=0.00577
231PA dG $Ice(L2)=2.2, Ice(L3)=1.5 (1961Ho29, cited by 1994Br36)
231PAS G LC=53.5 8$MC=14.76 21$
231PAS G NC=3.98 6$OC=0.898 13$PC=0.1448 21$QC=0.000423 6
231PA cG RI$from 1961Ho29, cited by 1994Br36, where I|g is deduced from
231PA2cG relative conversion electron intensity and |a(theory) for E2
231PA G 77.69 0.057 [M1+E2] 24 16 S
231PA2 G %IG=0.00416
231PA cG E$from level-energy difference
231PAS G LC=18 12$MC=5 4$
231PAS G NC=1.3 9$OC=0.30 20$PC=0.05 3$QC=0.0009 7
231PA L 84.2150 20 5/2+ 45.1 NS 13
231PA E 44 23 6.4 2
231PAS E CK=0.6245 18$CL=0.2719 12$CM+=0.1036 6
231PA G 25.65 2 200 12 E1 4.37 6 a
231PA2 G %IG=14.6 12$
231PA cG E$other: 25.65 {I4} (1994Br36)
231PA2 G M1/M3=0.38$ M2/M3=0.61$ M4/M3=0.38$ M5/M3=0.38 (1961Ho29)
231PAS G LC=3.25 5$MC=0.842 13$
231PAS G NC=0.219 4$OC=0.0471 7$PC=0.00673 10$QC=0.000196 3
231PA G 84.2140 22 100 6 E1 2.17 21 a
231PA2 G %IG=7.3 6$
231PA cG E$other: 84.23 {I7} (1994Br36)
231PA cG $Ice(L1+L2)=83 {I1}, Ice(M)=24 {I1}, Ice(N)=17 {I1} (1994Br36).
231PA2cG Other: 1961Ho29
231PA dG $Ice(L1)=71, Ice(L2)=37, Ice(L3)=4.1 (1961Ho29, cited by 1994Br36)
231PA cG $Total conversion coefficient from ce data in {+231}Th |b{+-} decay.
231PA2cG Other: 2.6 {I1} from summed conversion coefficients in 1994Br36
231PA cG $Transition is anomalously converted (1960As02). See also 2008Go10.
231PA2 G EL1C+EL2C=1.7 1 $ EMC=0.48 4$ ENC=0.34 3 (1994Br36)
231PA2 G EM1C=0.34$ EM2C=0.21$ EM3C=0.009$ EN1C=0.17 (1961Ho29)
231PA cG $|a(O1)exp=0.031 (1961Ho29)
231PA L 101.409 4 7/2+ 0.7 NS 2
231PA cL T$combined for 101.4+102.3 levels (1975Ho14, {+231}Th |b{+-} decay)
231PA G 17.195 21 0.014 LE (M1) 166 3 2.3 LE S
231PA2 G %IG LE 0.0010
231PA cG TI$from I(|g+ce)|<2.3 for 82.087|g from 183.4 level
231PA cG RI$from I(|g+ce) and |a(theory)
231PAS G LC=1.4$ MC=122.6 18$ NC=32.7 5$OC=7.75 12$PC=1.505 22$QC=0.144 2
231PA L 102.2687 22 3/2+ 0.7 NS 2
231PA cL T$combined for 101.4+102.3 levels (1975Ho14, {+231}Th |b{+-} decay)
231PA E 59 23 6.2 2
231PAS E CK=0.6073 21$CL=0.2837 15$CM+=0.1089 7
231PA G 18.055 18 3.6 13 M1+E2 0.040 +18-0 218 28 g S
231PA2 G %IG=0.26 10$
231PAS G LC=45 15$MC=128 8
231PAS G NC=34 2$OC=8.1 4 $PC=1.55 5 $QC=0.124 1
231PA G 93.02 4 1.8 2 (E1) 0.1463 21 g S
231PA2 G %IG=0.131 16$
231PAS G LC=0.1103 16$MC=0.0269 4$
231PAS G NC=0.00711 10$OC=0.001633 23$PC=0.000279 4$QC=1.363E-5 20
231PA G 102.2700 24 17.2 10 (E1) 0.1141 16 a
231PA2 G %IG=1.26 10$
231PA cG E$other: 102.3 {I1} (1994Br36)
231PAS G LC=0.0860 13$MC=0.0209 3$
231PAS G NC=0.00554 8$OC=0.001275 19$PC=0.000220 4$QC=1.106E-5 16
231PA L 174.160 5 (5/2-)
231PA E 0.06 3 8.8 2
231PAS E CK=0.487 6$CL=0.366 4$CM+=0.1469 18
231PA G 72.7510 29 0.15 8 [E1] 0.280 4 g S
231PA2 G %IG=0.011 6$
231PAF G FL=101.409
231PAS G LC=0.211 3$MC=0.0517 8$
231PAS G NC=0.01363 20$OC=0.00310 5$PC=0.000519 8$QC=2.33E-5 4
231PA G 89.95 2 0.58 32 (E1) 0.1598 23 e
231PA2 G %IG=0.042 23$
231PAS G LC=0.1205 17$MC=0.0294 5$
231PAS G NC=0.00777 11$OC=0.001782 25$PC=0.000304 5$QC=1.467E-5 21
231PA L 183.496 3 5/2+ 0.19 NS LE
231PA E 0.14 7 8.4 2
231PAS E CK=0.460 7$CL=0.384 5$CM+=0.1554 20
231PA G 81.2280 21 0.32 LE M1(+E2) 0.00 8 7.66 20
231PA2 G %IG LE 0.0234
231PAF G FL=102.2687
231PA cG RI$from 1996Le01. Other: I|g=0.19, Ice(L1)=0.51 (1961Ho29,
231PA2cG cited by 1994Br36).
231PAS G LC=5.78 14$MC=1.40 4
231PAS G NC=0.374 11$OC=0.0898 24$PC=0.0172 4$QC=0.001422 22
231PA G 82.0870 22 0.26 LE M1(+E2) 0.04 6 7.47 23
231PA2 G %IG LE 0.019
231PAF G FL=101.409
231PA cG RI$from 1996Le01. Other: I|g=0.26, Ice(L1)=0.73 (1961Ho29,
231PA2cG cited by 1994Br36).
231PAS G LC=5.63 17$MC=1.36 5
231PAS G NC=0.365 12$OC=0.088 3$PC=0.0167 5$QC=0.001377 22
231PA G 99.2780 36 0.050 LE M1+E2 0.35 7 5.2 4 g S
231PA2 G %IG LE 0.00365
231PAS G LC=3.9 3$MC=0.97 8
231PAS G NC=0.261 20$OC=0.062 5$PC=0.0113 7$QC=0.00072 3
231PA L 273.719 16 (1/2+)
231PA E 0.13 3 7.5 1 1U
231PAS E CL=0.6777 16$CM+=0.3223 16
231PA G 171.43 3 0.200 16[M1+E2] 2.8 16 d
231PA2 G %IG=0.0146 14$
231PAF G FLAG=e
231PAF G FL=102.2687
231PAS G KC=1.8 17$LC=0.72 6$MC=0.19 3$
231PAS G NC=0.051 7$OC=0.0118 14$PC=0.00207 8$QC=9.E-5 8
231PA G 189.5 0.0053 LE e S
231PA2 G %IG LE 0.00039
231PA cG E$from level-energy difference.
231PA G 196.0 0.0053 LE e S
231PA cG $|g to 5/2- is unlikely
231PA2 G %IG LE 0.00039
231PA cG E$from level-energy difference.
231PA G 264.55 2 0.279 26[E1] 0.0506 7 d
231PA2 G %IG=0.0204 22$
231PAF G FLAG=e
231PAS G KC=0.0403 6$LC=0.00781 11$MC=0.00188 3$
231PAS G NC=0.000500 7$OC=0.0001176 17$PC=2.14E-5 3$QC=1.389E-6 20
231PA G 273.71 2 0.621 32[E1] 0.0469 7 d
231PA2 G %IG=0.0453 34$
231PAF G FLAG=e
231PAS G KC=0.0373 6$LC=0.00721 10$MC=0.001735 25$
231PAS G NC=0.000461 7$OC=0.0001085 16$PC=1.98E-5 3$QC=1.292E-6 18
231PA L 317.94 5 (3/2+) 0.07 NS +11-3
231PA E 0.0028 3 8.6 1
231PAS E CL=0.610 7$CM+=0.390 7
231PA G 240.27 5 0.0132 16[E1] 0.0630 9 e
231PA2 G %IG=0.00096 13$
231PA cG E$other: 240.3 {I2} (1996Le01)
231PAS G KC=0.0500 7$LC=0.00984 14$MC=0.00237 4$
231PAS G NC=0.000631 9$OC=0.0001480 21$PC=2.68E-5 4$QC=1.703E-6 24
231PA G 308.78 7 0.0195 21[E1] 0.0358 5 e
231PA2 G %IG=0.00142 17$
231PA cG E$other: 308.7 {I2} (1996Le01)
231PAS G KC=0.0287 4$LC=0.00544 8$MC=0.001307 19$
231PAS G NC=0.000348 5$OC=8.19E-5 12$PC=1.501E-5 22$QC=1.006E-6 15
231PA G 317.87 8 0.0042 16[E1] 0.0336 5 e
231PA2 G %IG=0.00031 12$
231PA cG E$other: 317.7 {I3} (1996Le01)
231PAS G KC=0.0269 4$LC=0.00509 8$MC=0.001223 18$
231PAS G NC=0.000325 5$OC=7.67E-5 11$PC=1.406E-5 20$QC=9.48E-7 14
231PA L 320.207 22 3/2-
231PA E 0.53 10 6.3 1
231PAS E CL=0.603 7$CM+=0.397 7
231PA G 136.75 7 0.57 5 [E1] 0.237 3 e
231PA2 G %IG=0.042 4$
231PAS G KC=0.184 3$LC=0.0404 6$MC=0.00981 14$
231PAS G NC=0.00260 4$OC=0.000603 9$PC=0.0001061 15$QC=5.83E-6 9
231PA G 217.94 3 4.1 11[E1] 0.0789 11
231PA2 G %IG=0.30 8$
231PAS G KC=0.0624 9$LC=0.01249 18$MC=0.00301 5$
231PAS G NC=0.000801 12$OC=0.000188 3$PC=3.39E-5 5$QC=2.10E-6 3
231PA cG E$other: 217.9 {I2} (1994Br36)
231PA cG $Energy is from 1994Br36. I|g is a unweighted average of discrepant
231PA2cG values: 5.26 {I3} (1996Le01) and 3.0 {I4} (1994Br36).
231PA G 236.04 6 1.22 6 [E1] 0.0657 9 e
231PA2 G %IG=0.089 7$
231PAS G KC=0.0521 8$LC=0.01028 15$MC=0.00248 4$
231PAS G NC=0.000659 10$OC=0.0001545 22$PC=2.80E-5 4$QC=1.770E-6 25
231PA G 242.51 4 0.111 11[M1+E2] 1.01 66 e
231PA2 G %IG=0.0081 9$
231PAS G KC=0.72 61$LC=0.22 4$MC=0.055 7
231PAS G NC=0.0147 17$OC=0.0035 5$PC=0.00062 13$QC=3.5E-5 28
231PA G 311.00 5 0.37 5 M1(+E2) 0.7 9 0.61 27 e
231PA2 G %IG=0.027 4$
231PAS G KC=0.47 24$LC=0.107 24$MC=0.026 5
231PAS G NC=0.0071 14$OC=0.0017 4$PC=0.00031 8$QC=2.2E-5 11
231PA G 320.15 8 0.0158 16 [M1+E2] 0.46 32
231PA2 G %IG=0.00115 13$
231PAS G KC=0.34 28$LC=0.088 29$MC=0.0221 61
231PAS G NC=0.0059 17$OC=0.00140 41$PC=2.57E-4 89$QC=1.6E-5 13