Boron-15

Properties and data of the isotope ¹⁵B.

Contents

Boron-15 is a radioisotope of the chemical element boron, which has 10 neutrons in its atomic nucleus in addition to the element-specific 5 protons; the sum of the number of these atomic nucleus building blocks results in a mass number of 15. The very short-lived, only artificially produced, unstable and thus radioactive nuclide has no practical significance; the study of ¹⁵B is exclusively for academic purposes.

Boron-15 was discovered as a fragment that occurred when a uranium foil was irradiated with 5.3 GeV protons [1].

General data

Name of the isotope:Boron-15; B-15Symbol:¹⁵B or 155BMass number A:15 (= number of nucleons)Atomic number Z:5 (= number of protons)Neutrons N:10Isotopic mass:15.031087(23) u (atomic weight of Boron-15)Nuclide mass:15.0283441 u (calculated nuclear mass without electrons)Mass excess:28.95735 MeVMass defect:0.09468732 u (per nucleus)Nuclear binding energy:88.20067046 MeV (per nucleus)
5.8800447 MeV (average binding energy per nucleon)Separation energy:S_N = 2.78(3) MeV (first neutron)
S_P = 18.286(134) MeV (first proton)Half-life:10.18(35) msDecay constant λ:68.089114003924 s^-1Specific activity α:2.733614903732 × 10⁺²⁴ Bq g^-1
73881483884670 Ci g^-1Spin and parity:
(nuclear angular momentum)3/2-Magnetic dipole moment:μ(μ_N) = +2.659(15)Quadrupole moment Q:0.0379(11) barn (100 fm²)Nuclear g-factor:g_l = 1.7726666666667Mirror nucleus:Neon-15Year of discovery:1966

Radioactive Decay

Half-life T_½ = 10.18(35) ms respectively 1.018 × 10^-2 seconds s.

Decay mode	Daughter	Probability	Decay energy
β^-	¹⁵C	< 1.3 %	19.085(21) MeV
β^-, n	¹⁴C	98.7(10) %
β^-, 2n	¹³C	< 1.5 %

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 10) and isobaric (same nucleon number A = 15) with Boron-15. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 10	Isobar A = 15
3	¹³Li
4	¹⁴Be	¹⁵Be
5	¹⁵B	¹⁵B
6	¹⁶C	¹⁵C
7	¹⁷N	¹⁵N
8	¹⁸O	¹⁵O
9	¹⁹F	¹⁵F
10	²⁰Ne	¹⁵Ne
11	²¹Na
12	²²Mg
13	²³Al
14	²⁴Si
15	²⁵P
16	²⁶S

External data and identifiers

Adopted Levels, Gammas:NuDat 15B

Literature and References

[1] - A. M. Poskanzer, S. W. Cosper, Earl K. Hyde, Joseph Cerny:
New Isotopes: ¹¹Li, ¹⁴B, and ¹⁵B.
In: Physical Review Letters, 17, 1271, (1966), DOI 10.1103/PhysRevLett.17.1271.

[2] - R. Kalpakchieva, H.G. Bohlen, W. von Oertzen et al.:
Spectroscopy of ¹³B, ¹⁴B, ¹⁵B and ¹⁶B using multi-nucleon transfer reactions.
In: The European Physical Journal A - Hadrons and Nuclei, 7, (2000), DOI 10.1007/PL00013641.