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 emitter
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 emitter
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 emitter
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 emitter
This equation tends to underestimate the half-value
thickness for low energy betas and overestimate the
half-value thickness for high energy betas.