Rad Data Handbook 20.. - Voss Associates

SHIELDING MATERIALS
α
a single sheet of paper
β -
low Z, such as plastic or aluminum
γ
high Z, such as tungsten
mixed β - /γ low Z, then high Z
neutron hydrogenous material to thermalize (such as
polyethylene) then neutron absorber (such as Cd, B, Li, Hf),
then high Z to absorb "capture gammas"
Photon Half-Value Layers in CM
100 KeV 600 KeV 1 MeV 2 MeV
U 0.005 0.25 0.48 0.78
W 0.008 0.35 0.58 0.82
Pb 0.012 0.52 0.90 1.35
Sn 0.06 1.20 1.38 1.80
Cu 0.18 1.01 1.70 1.65
Fe 0.25 1.15 1.32 1.55
Al 1.12 3.30 4.45 5.90
Concrete 1.8 3.8 4.6 6.2
Water 4.2 7.8 9.6 14.2
This table applies to a thin shield and no provision is made for
buildup factor. Always perform a radiation measurement to
confirm adequacy of shield.
Tenth-Value Thickness
Simply multiply the half-value thickness by the square root of
10 (3.162) to get the tenth-value thickness.
Example: A half-value thickness of concrete for Cs-137
gamma radiation is 3.8 cm.
The tenth-value thickness is 3.8 cm x 3.162 = 12 cm.
53
SHIELDING MATERIALS
α
a single sheet of paper
β -
low Z, such as plastic or aluminum
γ
high Z, such as tungsten
mixed β - /γ low Z, then high Z
neutron hydrogenous material to thermalize (such as
polyethylene) then neutron absorber (such as Cd, B, Li, Hf),
then high Z to absorb "capture gammas"
Photon Half-Value Layers in CM
100 KeV 600 KeV 1 MeV 2 MeV
U 0.005 0.25 0.48 0.78
W 0.008 0.35 0.58 0.82
Pb 0.012 0.52 0.90 1.35
Sn 0.06 1.20 1.38 1.80
Cu 0.18 1.01 1.70 1.65
Fe 0.25 1.15 1.32 1.55
Al 1.12 3.30 4.45 5.90
Concrete 1.8 3.8 4.6 6.2
Water 4.2 7.8 9.6 14.2
This table applies to a thin shield and no provision is made for
buildup factor. Always perform a radiation measurement to
confirm adequacy of shield.
Tenth-Value Thickness
Simply multiply the half-value thickness by the square root of
10 (3.162) to get the tenth-value thickness.
Example: A half-value thickness of concrete for Cs-137
gamma radiation is 3.8 cm.
The tenth-value thickness is 3.8 cm x 3.162 = 12 cm.
53
SHIELDING MATERIALS
α
a single sheet of paper
β -
low Z, such as plastic or aluminum
γ
high Z, such as tungsten
mixed β - /γ low Z, then high Z
neutron hydrogenous material to thermalize (such as
polyethylene) then neutron absorber (such as Cd, B, Li, Hf),
then high Z to absorb "capture gammas"
Photon Half-Value Layers in CM
100 KeV 600 KeV 1 MeV 2 MeV
U 0.005 0.25 0.48 0.78
W 0.008 0.35 0.58 0.82
Pb 0.012 0.52 0.90 1.35
Sn 0.06 1.20 1.38 1.80
Cu 0.18 1.01 1.70 1.65
Fe 0.25 1.15 1.32 1.55
Al 1.12 3.30 4.45 5.90
Concrete 1.8 3.8 4.6 6.2
Water 4.2 7.8 9.6 14.2
This table applies to a thin shield and no provision is made for
buildup factor. Always perform a radiation measurement to
confirm adequacy of shield.
Tenth-Value Thickness
Simply multiply the half-value thickness by the square root of
10 (3.162) to get the tenth-value thickness.
Example: A half-value thickness of concrete for Cs-137
gamma radiation is 3.8 cm.
The tenth-value thickness is 3.8 cm x 3.162 = 12 cm.
53
SHIELDING MATERIALS
α
a single sheet of paper
β -
low Z, such as plastic or aluminum
γ
high Z, such as tungsten
mixed β - /γ low Z, then high Z
neutron hydrogenous material to thermalize (such as
polyethylene) then neutron absorber (such as Cd, B, Li, Hf),
then high Z to absorb "capture gammas"
Photon Half-Value Layers in CM
100 KeV 600 KeV 1 MeV 2 MeV
U 0.005 0.25 0.48 0.78
W 0.008 0.35 0.58 0.82
Pb 0.012 0.52 0.90 1.35
Sn 0.06 1.20 1.38 1.80
Cu 0.18 1.01 1.70 1.65
Fe 0.25 1.15 1.32 1.55
Al 1.12 3.30 4.45 5.90
Concrete 1.8 3.8 4.6 6.2
Water 4.2 7.8 9.6 14.2
This table applies to a thin shield and no provision is made for
buildup factor. Always perform a radiation measurement to
confirm adequacy of shield.
Tenth-Value Thickness
Simply multiply the half-value thickness by the square root of
10 (3.162) to get the tenth-value thickness.
Example: A half-value thickness of concrete for Cs-137
gamma radiation is 3.8 cm.
The tenth-value thickness is 3.8 cm x 3.162 = 12 cm.
53