Information about Helium-4:

		(no NIST x-ray data)	(no NIST attenuation data)
Wikipedia	Neutron Cross Sections	X-Ray Transitions	X-Ray Attenuation

Mass-Energy Data:

Atomic Mass:	4.002603	±	0.000000	amu
Excess Mass (Δ):	2.424911	±	0.000001	MeV
Binding Energy:	28.295673	±	0.000005	MeV
β^- Decay Energy:	-22.895261	±	0.212132	MeV

"The 1995 update to the atomic mass evaluation" by G.Audi and A.H.Wapstra, Nuclear Physics A595 vol. 4 p.409-480, December 25, 1995.

Radioactive Decay Data:

Atomic Percent Abundance: 99.999863%(3
Spin: 0+
Stable Isotope
Possible parent nuclides:
1
0
n emission from
5
2
He

1
1
p⁺ emission from
5
3
Li

2
1
1
p⁺ from
6
4
Be

R.R.Kinsey, et al.,The NUDAT/PCNUDAT Program for Nuclear Data,paper submitted to the 9 th International Symposium of Capture-Gamma_raySpectroscopy and Related Topics, Budapest, Hungary, Octover 1996.Data extracted from NUDAT database (Jan. 14/1999)