Absorber

Density (g/cm³)

Penetration Depth, mm

2.3 MeV

1.1 MeV

0.546 MeV

0.060 MeV

Air

1.2 mg/cm³

8.8 m

3.8 m

1.9 m

0.23 m

Water (soft tissue)

1.10 g/cm³

11 mm

4.6 mm

2.28 mm

0.20 mm

Plastic (Acrylic)

1.2

9.6

4.0

1.99

0.197

Glass (Pyrex)

2.2

5.6

2.2

1.09

0.107

Aluminum

2.7

4.2

2.0

0.99

0.097

Gadolinium

7.9

1.7

0.7

0.35

0.034

Dysprosium

8.54

1.3

0.6

0.30

0.029

Copper

8.9

1.2

0.5

0.25

0.024

Lead

11.3

1.0

0.4

0.20

0.005