Atomic and nuclear properties of materials:
Hafnium (Hf)

Quantity	Value	Units	Value	Units
Atomic number	72
Atomic mass	178.49(2)	g mole-1
Density	13.3	g cm-3
Mean excitation energy	705.0	eV
Minimum ionization	1.152	MeV g-1cm2	15.33	MeV cm-1
Nuclear collision length	109.5	g cm-2	8.226	cm
Nuclear interaction length	190.1	g cm-2	14.28	cm
Pion collision length	133.0	g cm-2	9.995	cm
Pion interaction length	216.9	g cm-2	16.30	cm
Radiation length	6.89	g cm-2	0.5177	cm
Critical energy	8.22	MeV (for e-)	7.93	MeV (for e+)
Molière radius	17.77	g cm-2	1.335	cm
Plasma energy	66.77	eV
Muon critical energy	155.	GeV

For muons, dE/dx = a(E) + b(E) E. Tables of b(E): PS PDF TEXT
Table of muon dE/dx and Range: PS PDF TEXT
Explanation of some entries
Table of isotopes Warning: may not be current
x ray mass attenuation coefficients