Beta Dose Rates in rad/hr per mCi
MeV 1 cm 10 cm 30 cm 60 cm 90 cm 1.0 m
0.15 1,200 1.7 0 0 0 0
0.25 1,000 2.2 0.1 0 0 0
0.30 900 3.6 0.1 0 0 0
0.50 750 5.2 0.4 0.05 0.01 0
0.75 650 5.0 0.5 0.05 0.01 0
1.0 550 4.6 0.4 0.1 0 0
1.25 450 4.3 0.4 0.1 0.04 0.02
1.50 400 4.0 0.4 0.1 0.04 0.02
1.75 350 3.4 0.4 0.1 0.04 0.02
2.00 340 3.6 0.4 0.1 0.04 0.02
2.25 320 3.3 0.4 0.1 0.04 0.02
Beta dose should be treated as a “shallow” dose and should
not be summed with “deep” doses. This chart should also be
used to determine beta+ doses from positron emitters.
Half-value Thickness vs Beta Energy
Isotope Emax (MeV) Half-Value Thickness mg / cm
2
C-14 0.156 2
Tc-99 0.292 7.5
Cl-36 0.714 15
Sr/Y-90 0.546 / 2.284 150
U-238 Betas from short lived progeny
0.191 / 2.281 130
P-32 1.710 150
Estimate the half-value thickness for a beta emitter.
mg/cm
2
= 50 x E
2
where E is Emax in MeV for the beta emitte
This equation tends to underestimate the half-value
thickness for low energy betas and overestimate the
half-value thickness for high energy betas.
Beta Dose Rates in rad/hr per mCi
MeV 1 cm 10 cm 30 cm 60 cm 90 cm 1.0 m
0.15 1,200 1.7 0 0 0 0
0.25 1,000 2.2 0.1 0 0 0
0.30 900 3.6 0.1 0 0 0
0.50 750 5.2 0.4 0.05 0.01 0
0.75 650 5.0 0.5 0.05 0.01 0
1.0 550 4.6 0.4 0.1 0 0
1.25 450 4.3 0.4 0.1 0.04 0.02
1.50 400 4.0 0.4 0.1 0.04 0.02
1.75 350 3.4 0.4 0.1 0.04 0.02
2.00 340 3.6 0.4 0.1 0.04 0.02
2.25 320 3.3 0.4 0.1 0.04 0.02
Beta dose should be treated as a “shallow” dose and should
not be summed with “deep” doses. This chart should also be
used to determine beta+ doses from positron emitters.
Half-value Thickness vs Beta Energy
Isotope Emax (MeV) Half-Value Thickness mg / cm
2
C-14 0.156 2
Tc-99 0.292 7.5
Cl-36 0.714 15
Sr/Y-90 0.546 / 2.284 150
U-238 Betas from short lived progeny
0.191 / 2.281 130
P-32 1.710 150
Estimate the half-value thickness for a beta emitter.
mg/cm
2
= 50 x E
2
where E is Emax in MeV for the beta emitte
This equation tends to underestimate the half-value
thickness for low energy betas and overestimate the
half-value thickness for high energy betas.
Beta Dose Rates in rad/hr per mCi
MeV 1 cm 10 cm 30 cm 60 cm 90 cm 1.0 m
0.15 1,200 1.7 0 0 0 0
0.25 1,000 2.2 0.1 0 0 0
0.30 900 3.6 0.1 0 0 0
0.50 750 5.2 0.4 0.05 0.01 0
0.75 650 5.0 0.5 0.05 0.01 0
1.0 550 4.6 0.4 0.1 0 0
1.25 450 4.3 0.4 0.1 0.04 0.02
1.50 400 4.0 0.4 0.1 0.04 0.02
1.75 350 3.4 0.4 0.1 0.04 0.02
2.00 340 3.6 0.4 0.1 0.04 0.02
2.25 320 3.3 0.4 0.1 0.04 0.02
Beta dose should be treated as a “shallow” dose and should
not be summed with “deep” doses. This chart should also be
used to determine beta+ doses from positron emitters.
Half-value Thickness vs Beta Energy
Isotope Emax (MeV) Half-Value Thickness mg / cm
2
C-14 0.156 2
Tc-99 0.292 7.5
Cl-36 0.714 15
Sr/Y-90 0.546 / 2.284 150
U-238 Betas from short lived progeny
0.191 / 2.281 130
P-32 1.710 150
Estimate the half-value thickness for a beta emitter.
mg/cm
2
= 50 x E
2
where E is Emax in MeV for the beta emitte
This equation tends to underestimate the half-value
thickness for low energy betas and overestimate the
half-value thickness for high energy betas.
Beta Dose Rates in rad/hr per mCi
MeV 1 cm 10 cm 30 cm 60 cm 90 cm 1.0 m
0.15 1,200 1.7 0 0 0 0
0.25 1,000 2.2 0.1 0 0 0
0.30 900 3.6 0.1 0 0 0
0.50 750 5.2 0.4 0.05 0.01 0
0.75 650 5.0 0.5 0.05 0.01 0
1.0 550 4.6 0.4 0.1 0 0
1.25 450 4.3 0.4 0.1 0.04 0.02
1.50 400 4.0 0.4 0.1 0.04 0.02
1.75 350 3.4 0.4 0.1 0.04 0.02
2.00 340 3.6 0.4 0.1 0.04 0.02
2.25 320 3.3 0.4 0.1 0.04 0.02
Beta dose should be treated as a “shallow” dose and should
not be summed with “deep” doses. This chart should also be
used to determine beta+ doses from positron emitters.
Half-value Thickness vs Beta Energy
Isotope Emax (MeV) Half-Value Thickness mg / cm
2
C-14 0.156 2
Tc-99 0.292 7.5
Cl-36 0.714 15
Sr/Y-90 0.546 / 2.284 150
U-238 Betas from short lived progeny
0.191 / 2.281 130
P-32 1.710 150
Estimate the half-value thickness for a beta emitter.
mg/cm
2
= 50 x E
2
where E is Emax in MeV for the beta emitte
This equation tends to underestimate the half-value
thickness for low energy betas and overestimate the
half-value thickness for high energy betas.