List of levels for 231RA

Authors: Balraj Singh, Jagdish K. Tuli, and Edgardo Browne | Citation: Nucl. Data Sheets 185, 560 (2022) | Cutoff date: 31-Aug-2022

1985Hi02: ²³¹Fr produced in spallation reaction of ²³⁸U induced by 600 MeV protons from the CERN synchrocyclotron, followed by mass-separation using the ISOLDE II online separator. Measured Eγ and half-life of the decay of ²³¹Ra.

2001Fr05: ²³¹Fr was produced by spallation of 1 GeV proton beam on uranium targets. The activity was mass-separated at CERN ISOLDE on-line separator, deposited on a magnetic tape, and then radiations were counted at two stations.

2018Ly01: radioactive beams of Radium isotopes (α=222-233) produced by impinging 1.4-GeV protons onto a thick uranium carbide (UC_x) target at the ISOLDE-CERN facility. Radium atoms diffusing out of the target were ionized by a combination of surface ionization and multistep laser resonance ionization, using the resonance ionization laser ion source (RILIS), then accelerated to 30 keV and mass separated using the high resolution separator (HRS). Finally, the ions were cooled and bunched using the ISOLDE linear Paul trap ISOLDE cooler (ISCOOL), re-accelerated to 30 keV and directed to the Collinear Resonance Ionization Spectroscopy (CRIS) beam line. Measured high-resolution hyperfine-structure spectra of the 7s²¹S{+0|)7s7p³P₁ atomic transition in the neutron-rich radium isotopes from α=222 to 232, changes in rms charge radii, isotope shifts, static magnetic dipole and electric quadrupole moments.

Atomic mass measurements: 2012Ch19 (also 2008ChZI), 2010Li02, 2005He26

2013Fr09 cite 1983Ah03 for discovery of the ²³¹Ra isotope, but there is no mention of this isotope in 1983Ah03. Evaluators consider 1985Hi02 as the first article reporting discovery of this isotope.

1938Ha01 listed ²³¹Ra with half-life of 25 min followed by decay of ²³¹Ac with a half-life of 40 min. But with presently known half-lives, these activities must belong to other activities.

Theoretical nuclear structure calculations: consult the NSR database (www.nndc.bnl.gov/nsr/) for five primary references, also listed in this dataset under ’document’ records, which can be accessed through on-line ENSDF database at www.nndc.bnl.gov/ensdf/

Q-value: S(2n)=10488 19, S(2p)=15724 17 (2021Wa16)

E(level) (keV)	J^π(level)	T_1/2(level)	E(γ) (keV)	Multipolarity	Mixing Ratio	Conversion Coefficient	Additional Data
46.23	(7/2+)		46.3 2	[M1]		29.5	α=29.5 6
66.21	(1/2+)	≈ 53 µs % IT ≈ 100	66.2 1	E2		67.4	B(E2)(W.u.)≈0.0015, α=67.4 10
87.64	(3/2+)		21.4	[M1]		286	α=286 4
95.50	(5/2-)	4.72 ns 6	49.3 1	E1		0.727	B(E1)(W.u.)=1.34E-5 13, α=0.727 10
95.50	(5/2-)	4.72 ns 6	95.5 1	E1		0.1247	B(E1)(W.u.)=3.60E-5 6, α=0.1247 18
285.62	(5/2+)		239.4 3	(M1)		1.324	α=1.324 19
285.62	(5/2+)		285.7 2	M1		0.811	α=0.811 12
397.33	(3/2+)		309.9 2	M1		0.648	α=0.648 9
	(3/2+)		331.2 2	M1		0.540	α=0.540 8
	(3/2+)		397.3 3	(E2(+M1))	0.7 GT	0.24	α=0.24 18
458.95	(1/2-,3/2-)	≤ 15 ps	363.4 2	M1(+E2)	0.7 7	0.31	α=0.31 11
511.36	(1/2+,3/2+)		445.1 2	M1+E2	0.45 30	0.21	α=0.21 4
520.29	(1/2-)	92 ps 5	123.1 2	E1		0.291	B(E1)(W.u.)=4.1E-6 6, α=0.291 4
	(1/2-)	92 ps 5	432.6 2	E1		0.01588	B(E1)(W.u.)=1.33E-5 9, α=0.01588 22
	(1/2-)	92 ps 5	454.0 2	E1		0.01437	B(E1)(W.u.)=9.0E-6 6, α=0.01437 20

Q(β-)=2454 keV 17	S(n)= 4371 keV 15	S(p)= 8559 keV 13	Q(α)= 2906 keV 18
Reference: 2021WA16

E(level) (keV)	XREF	J^π(level)	T_1/2(level)	E(γ) (keV)	I(γ)	M(γ)	Final Levels
0.0	A	(5/2+)	103.9 s 14 % β^- = 100
46.23 11	A	(7/2+)		46.3 2 ?	100	[M1]	0.0	(5/2+)
66.21 9	A	(1/2+)	≈ 53 µs % IT ≈ 100	66.2 1	100	E2	0.0	(5/2+)
87.64 13	A	(3/2+)		21.4S		[M1]	66.21	(1/2+)
95.50 9	A	(5/2-)	4.72 ns 6	49.3 1 95.5 1	5.1 3 100 7	E1 E1	46.23 0.0	(7/2+) (5/2+)
285.62 16	A	(5/2+)		239.4 3 285.7 2 ?	<19 100 9	(M1) M1	46.23 0.0	(7/2+) (5/2+)
397.33 13	A	(3/2+)		309.9 2 331.2 2 397.3 3	100 10 88 12 37 4	M1 M1 (E2(+M1))	87.64 66.21 0.0	(3/2+) (1/2+) (5/2+)
455.0 4	A	(1/2-:9/2-)		359.5 3	100		95.50	(5/2-)
458.95 16	A	(1/2-,3/2-)	≤ 15 ps	363.4 2 392.8 3 ?	100 10 26 10	M1(+E2)	95.50 66.21	(5/2-) (1/2+)
503.33 21	A	(1/2,3/2,5/2+)		415.6 3 437.4 3	100 12 <43		87.64 66.21	(3/2+) (1/2+)
511.36 15	A	(1/2+,3/2+)		423.8 2 ? 445.1 2	18 5 100 10	M1+E2	87.64 66.21	(3/2+) (1/2+)
520.29 14	A	(1/2-)	92 ps 5	123.1 2 432.6 2 454.0 2	0.70 10 100 5 78 5	E1 E1 E1	397.33 87.64 66.21	(3/2+) (3/2+) (1/2+)
605.4 3	A	(1/2-,3/2,5/2+)		510.3 5 539.1 3	33 7 100 21		95.50 66.21	(5/2-) (1/2+)
620.59 24	A	(3/2,5/2,7/2)	≤ 12.5 ps	525.2 3 620.2 5 ?	100 10 16.5 22		95.50 0.0	(5/2-) (5/2+)
646.6 4	A	(1/2-:7/2)		551.3 4	100		95.50	(5/2-)
740.72 18	A	(3/2+,5/2+)		645.2 3 653.2 3 674.6 5 694.4 4 740.5 5	33 17 37 10 100 10 <43 17 5		95.50 87.64 66.21 46.23 0.0	(5/2-) (3/2+) (1/2+) (7/2+) (5/2+)
E(level) (keV)	XREF	J^π(level)	T_1/2(level)	E(γ) (keV)	I(γ)	M(γ)	Final Levels
750.86 18	A	(1/2,3/2,5/2+)		239.4 3 ? 353.6 3 663.1 3 684.6 5	<18 13 5 100 10 <45	(M1)	511.36 397.33 87.64 66.21	(1/2+,3/2+) (3/2+) (3/2+) (1/2+)
760.5 4	A	(1/2,3/2,5/2+)		672.8 5 694.4 4	100 24 <164		87.64 66.21	(3/2+) (1/2+)
772.80 15	A	(1/2+,3/2)		252.5 2 261.6 3 375.7 3 684.6 5 706.5 5 772.8 3	38 8 29 6 <40 <135 100 10 90 10		520.29 511.36 397.33 87.64 66.21 0.0	(1/2-) (1/2+,3/2+) (3/2+) (3/2+) (1/2+) (5/2+)
796.2 3	A	(1/2,3/2,5/2+)		708.6 5 730.0 3	42 6 100 19		87.64 66.21	(3/2+) (1/2+)
834.63 18	A	(1/2+,3/2,5/2-)		314.4 3 375.7 3 437.4 3 746.9 4 834.5 6	24 8 <40 <56 100 20 65 10		520.29 458.95 397.33 87.64 0.0	(1/2-) (1/2-,3/2-) (3/2+) (3/2+) (5/2+)
929.2 4	A	(1/2,3/2,5/2+)		841.4 6 862.9 6	<64 100 14		87.64 66.21	(3/2+) (1/2+)
931.9 3	A	(1/2,3/2,5/2)		428.8 3 ? 472.8 5 843.5 5	42 17 100 25 67 17		503.33 458.95 87.64	(1/2,3/2,5/2+) (1/2-,3/2-) (3/2+)
944.31 22	A	(1/2+,3/2,5/2+)		659.0 5 ? 877.9 4 944.3 3	53 11 37 16 100 16		285.62 66.21 0.0	(5/2+) (1/2+) (5/2+)
971.1 6	A	(1/2,3/2,5/2+)		883.6 6 904.6 10	<102 100 25		87.64 66.21	(3/2+) (1/2+)
1138.79 24	A	(1/2,3/2,5/2+)		387.7 3 1051.4 3 1072.5 6	42 9 100 23 <77		750.86 87.64 66.21	(1/2,3/2,5/2+) (3/2+) (1/2+)
E(level) (keV)	XREF	J^π(level)	T_1/2(level)	E(γ) (keV)	I(γ)	M(γ)	Final Levels
1634.1 4	A	(1/2,3/2,5/2+)		704.8 5 883.6 6 1546.4 6 1567.8 6	100 13 <37 73 27 53 20		929.2 750.86 87.64 66.21	(1/2,3/2,5/2+) (1/2,3/2,5/2+) (3/2+) (1/2+)
1693.3 3	A	(1/2+,3/2,5/2+)		1072.5 6 1408.0 6 ? 1605.5 4 1627.2 6 1693.7 8	<30 30 6 100 12 33 9 52 15		620.59 285.62 87.64 66.21 0.0	(3/2,5/2,7/2) (5/2+) (3/2+) (1/2+) (5/2+)
1718.2 3	A	(1/2,3/2,5/2+)		883.6 6 1097.8 6 1630.6 5 1651.9 6	<29 37 11 100 16 26 11		834.63 620.59 87.64 66.21	(1/2+,3/2,5/2-) (3/2,5/2,7/2) (3/2+) (1/2+)
1730.1 4	A	(1/2,3/2,5/2+)		1642.5 5 1663.8 5	100 10 41 8		87.64 66.21	(3/2+) (1/2+)
1773.90 25	A	(1/2,3/2,5/2+)		841.4 6 939.8 7 1001.7 6 1127.5 5 1376.1 6 1686.1 5 1707.6 7	<24 19 4 32 26 24 5 24 5 100 13 26 11		931.9 834.63 772.80 646.6 397.33 87.64 66.21	(1/2,3/2,5/2) (1/2+,3/2,5/2-) (1/2+,3/2) (1/2-:7/2) (3/2+) (3/2+) (1/2+)

E(level)	E(gamma)	Comments
87.64	21.4	E(γ): γ ray was not observed. Iγ given in ²³¹Fr β^- decay is an upper limit.
285.62	239.4	E(γ): Multiply placed with undivided intensity I(γ): Multiply placed with undivided intensity
458.95	392.8	E(γ): Possible doublet.
503.33	437.4	E(γ): Multiply placed with undivided intensity I(γ): Multiply placed with undivided intensity
511.36	423.8	E(γ): Tentatively assigned to ²³¹Ra.
740.72	674.6	E(γ): Possible doublet.
740.72	694.4	E(γ): Multiply placed with undivided intensity I(γ): Multiply placed with undivided intensity
750.86	239.4	E(γ): Multiply placed with undivided intensity I(γ): Multiply placed with undivided intensity
750.86	684.6	E(γ): Multiply placed with undivided intensity I(γ): Multiply placed with undivided intensity
760.5	672.8	E(γ): Possible doublet.
760.5	694.4	E(γ): Multiply placed with undivided intensity I(γ): Multiply placed with undivided intensity
772.80	375.7	E(γ): Multiply placed with undivided intensity I(γ): Multiply placed with undivided intensity
	684.6	E(γ): Multiply placed with undivided intensity I(γ): Multiply placed with undivided intensity
	706.5	E(γ): Possible multiplet.
	772.8	E(γ): Possible doublet.
796.2	708.6	E(γ): Possible multiplet.
796.2	730.0	E(γ): Possible doublet.
834.63	375.7	E(γ): Multiply placed with undivided intensity I(γ): Multiply placed with undivided intensity
834.63	437.4	E(γ): Multiply placed with undivided intensity I(γ): Multiply placed with undivided intensity
929.2	841.4	E(γ): Multiply placed with undivided intensity I(γ): Multiply placed with undivided intensity
931.9	428.8	E(γ): Tentatively assigned to ²³¹Ra.
931.9	843.5	E(γ): Possible doublet.
971.1	883.6	E(γ): Multiply placed with undivided intensity I(γ): Multiply placed with undivided intensity
1138.79	1072.5	E(γ): Multiply placed with undivided intensity I(γ): Multiply placed with undivided intensity
1634.1	704.8	E(γ): Possible multiplet.
1634.1	883.6	E(γ): Multiply placed with undivided intensity I(γ): Multiply placed with undivided intensity
E(level)	E(gamma)	Comments
1693.3	1072.5	E(γ): Multiply placed with undivided intensity I(γ): Multiply placed with undivided intensity
1693.3	1408.0	E(γ): Possible doublet.
1718.2	883.6	E(γ): Multiply placed with undivided intensity I(γ): Multiply placed with undivided intensity
1718.2	1651.9	E(γ): Possible doublet.
1773.90	841.4	E(γ): Multiply placed with undivided intensity I(γ): Multiply placed with undivided intensity
	1127.5	E(γ): Possible doublet.
	1686.1	E(γ): Possible doublet.

E(level)	J^π(level)	T_1/2(level)	Comments
0.0	(5/2+)	103.9 s 14 % β^- = 100	μ=-0.3554 11 (2018Ly01,2019StZV), Q=+3.282 170 (2018Ly01) Measured isotope shifts: δν(²¹⁴Ra,²³¹Ra)=-56534 MHz 4; δν(²²⁶Ra,²³¹Ra)=-14790 MHz 3 (2018Ly01).