Silicon-38

Properties and data of the isotope ³⁸Si.

Contents

Silicon-38 is a radioisotope of the chemical element silicon, which has 24 neutrons in its atomic nucleus in addition to the element-specific 14 protons; the sum of the number of these atomic nucleus building blocks results in a mass number of 38. The very short-lived, only artificially produced, unstable and thus radioactive nuclide has no practical significance; the study of ³⁸Si is exclusively for academic purposes.

According to a report from 1979, the neutron-rich isotope ³⁸Si was discovered during the fragmentation of calcium-48 ions - accelerated to 212 MeV per nucleon - on a Be target [1].

See also: List of individual Silicon isotopes (and general data sources).

General data

Name of the isotope:Silicon-38; Si-38Symbol:³⁸Si or 3814SiMass number A:38 (= number of nucleons)Atomic number Z:14 (= number of protons)Neutrons N:24Nucleon pairing (Z - N):even - evenNuclear ratio (N/Z ratio):1.7142857142857 (= neutron-proton ratio)Neutron excess (N-Z):10Isotopic mass:37.99552(11) u (atomic weight of Silicon-38)Nuclide mass:37.98784 u (calculated nuclear mass without electrons)Mass excess:-4.17309 MeVMass defect:0.321988432 u (per nucleus)Nuclear binding energy:299.93029248 MeV (per nucleus)
7.89290243 MeV (average binding energy per nucleon)Separation energy:S_N = 5.670(155) MeV (first neutron)
S_P = 21.269(208) MeV (first proton)Half-life:63(8) msDecay constant λ:11.002336199364 s^-1Specific activity α:1.790746442728 × 10⁺²³ Bq g^-1
4839855250617.3 Ci g^-1Spin and parity:
(nuclear angular momentum)0+Year of discovery:1979

Radioactive Decay

Half-life T_½ = 63(8) ms respectively 6.3 × 10^-2 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β^-	³⁸P	75(10) %	10.45(13) MeV
β^-, n	³⁷P	25(10) %	6.754(111) MeV

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 24) and isobaric (same nucleon number A = 38) with Silicon-38. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 24	Isobar A = 38
10	³⁴Ne
11	³⁵Na	³⁸Na
12	³⁶Mg	³⁸Mg
13	³⁷Al	³⁸Al
14	³⁸Si	³⁸Si
15	³⁹P	³⁸P
16	⁴⁰S	³⁸S
17	⁴¹Cl	³⁸Cl
18	⁴²Ar	³⁸Ar
19	⁴³K	³⁸K
20	⁴⁴Ca	³⁸Ca
21	⁴⁵Sc	³⁸Sc
22	⁴⁶Ti	³⁸Ti
23	⁴⁷V
24	⁴⁸Cr
25	⁴⁹Mn
26	⁵⁰Fe
27	⁵¹Co
28	⁵²Ni
29	⁵³Cu
30	⁵⁴Zn

External data and identifiers

Adopted Levels, Gammas:NuDat 38Si

Literature and References

[1] - G. D. Westfall, T. J. M. Symons, D. E. Greiner et al.:
Production of Neutron-Rich Nuclides by Fragmentation of 212-MeV/amu ⁴⁸Ca.
In: Physical Review Letters,43, 1859, (1979), DOI 10.1103/PhysRevLett.43.1859.