DTRA / NTPR - Standard Operating Procedures Manual 

ED05 – Lens of the Eye Dose 

Revision No.: 2.0 

Date: April 30, 2021 

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DEFENSE THREAT REDUCTION AGENCY

NUCLEAR TEST PERSONNEL REVIEW PROGRAM

RADIATION DOSE ASSESSMENT

STANDARD METHOD

ED05 – Lens of the Eye Dose

Revision 2.0 

Cleared for Release 

Key to SOP ID Codes 

RA (Radiation Assessment - SOP) 

ED (External Dose - Standard Methods) 

ID (Internal Dose - Standard Methods) 

UA (Uncertainty Analysis - Standard Methods)
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Date: April 30, 2021

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Revision Control

Revision Revision Description Revision 

Date

Authorization 

Official

1.0 Original 10/31/2007 Paul K. Blake

1.3 No Revisions 1.1 or 1.2 of this SM were prepared

-Minor editorial changes

01/31/2010 Paul K. Blake

2.0 References updated, and minor editorial changes throughout 

document.

04/30/2021 James D. Franks
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Table of Contents

Table of Contents............................................................................................................................ 3

List of Tables .................................................................................................................................. 4

1. Purpose/Summary............................................................................................................... 5

2. Scope................................................................................................................................... 5

3. Responsibilities................................................................................................................... 5

4. Definitions........................................................................................................................... 5

5. Method Description ............................................................................................................ 6

5.1 Introduction............................................................................................................. 6

5.2 Gamma Dose to Lens of Eye from Fallout ............................................................. 6

5.3 Beta Dose to Lens of Eye from Fallout .................................................................. 7

5.3.1 Infinite Plane Source................................................................................... 7

5.3.2 Finite Plane Source ..................................................................................... 8

5.3.3 Point Source.............................................................................................. 15

5.3.4 Dermal Contamination on Eyelid ............................................................. 16

5.4 Beta Dose to Lens from Activation Products ....................................................... 17

6. Data and Input................................................................................................................... 18

7. Referenced SOPs and Standard Methods from this Manual............................................. 18

8. References......................................................................................................................... 19
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List of Tables

Table 1. Lens Beta-to-Gamma Dose Ratios as Function of Time and Height (cm) at PPG.......... 8

Table 2. Lens Beta-to-Gamma Dose Ratios as Function of Time and Height (cm) at NTS ......... 8

Table 3. Index to Tables of Typical Finite Applications and Associated Beta-to-Gamma Lens 

Dose Ratios................................................................................................................... 9

Table 4. Al at Distance H = 0.1 m (PPG) .................................................................................... 10

Table 5. Al at Distance H = 0.5 m (NTS).................................................................................... 10

Table 6. Al at Distance H = 1 m (NTS)....................................................................................... 11

Table 7. Al at Distance H = 1 m (PPG) ....................................................................................... 11

Table 8. Al at Distance H = 2.0 m (NTS).................................................................................... 12

Table 9. Al at Distance H = 2.0 m (NTS).................................................................................... 12

Table 10. Fe at Distance H = 0.3 m (1 ft) (PPG) ......................................................................... 13

Table 11. Fe at Distance H = 0.5 m (NTS).................................................................................. 13

Table 12. Fe at Distance H = 1.0 m (NTS).................................................................................. 14

Table 13. Fe at Distance H = 1.0 m (PPG) .................................................................................. 14

Table 14. Fe at Distance H = 2.0 m (NTS).................................................................................. 15

Table 15. Ratio of Lens Dose to Eyelid Dose.............................................................................. 16

Table 16. Beta-to-Gamma Lens Dose Ratio for Induced Radioactivity in Soil as a Function of 

Time and Height at NTS Area 7 ................................................................................. 17

Table 17. Beta-to-Gamma Lens Dose Ratio for Induced Radioactivity in Soil as a Function of 

Time and Height at NTS Frenchman Flat................................................................... 18
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Standard Method

ED05 – Lens of the Eye Dose

1. Purpose/Summary

Standard Method (SM) ED05, Lens of the Eye Dose, provides general technical methods 

for assessing dose to the lens of the human eye from surface deposited fallout, activated 

sources, and dermal contamination to individuals in the Nuclear Test Personnel Review 

(NTPR) Program according to the procedures specified in SOP RA01.

2. Scope

This standard method provides technical guidance for reconstructing dose to the lens of 

the eye due to beta and gamma ionizing radiation as a result of source exposure. This 

standard method should not be used to determine skin doses due to alpha radiation, 

internally deposited radioactive material exposures, or as the sole method for determining 

external radiation exposures (including skin contamination). This standard method is 

used in conjunction with SMs ED03, Skin Dose from External Sources, and ED04, Skin 

Dose from Dermal Contamination, for assessing whole body external radiation exposures 

in accordance with the requirements of Title 32, Code of Federal Regulations, Part 218 

“Guidance for the Determination and Reporting of Nuclear Radiation Dose for DoD 

Participants in the Atmospheric Nuclear Test Program” (DoD, 2020).

3. Responsibilities

Qualified radiation dose analysis staff members use these methods and associated tools 

for assessing the radiation doses for exposed individuals. If situations arise where these 

methods and techniques are inadequate to address a specific exposure scenario, it is the 

responsibility of the analyst encountering this deficiency to bring it to the attention of the 

RDA Manager so that the methodology can be extended as required to provide adequate 

estimates of lens of the eye doses. It is the responsibility of the analyst executing and 

implementing this extension to document such extension in a revision to this standard 

method.

4. Definitions

Individual: Any person who participated in the nuclear weapons testing program as a 

member of the US armed forces.

Infinite Plane Gamma Source: Fallout deposited over a large surface is considered to be 

an infinite geometric plane with uniform, isotropic emission from each point source in the 

plane (Barss and Weitz, 2006). Such a surface is generally represented by land (Pacific 

Islands and the Nevada Test Site [NTS]) where the gamma radiation can originate up to 

200 meters (m) or more from an individual standing on the ground. 
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Finite Plane Gamma Source: Fallout deposited over a very small area with respect to the 

infinite source with localized contamination and isotropic emission from each point 

source. Shrinking a finite gamma source down to its lowest diameter constitutes point 

source geometry.

5. Method Description

5.1 Introduction

Individuals present during the nuclear weapons testing at the Pacific Proving Ground 

(PPG) or the NTS were potentially exposed to initial gamma and neutron emissions from 

a detonation, mixed fission products and actinides in fallout, and neutron activation 

products in the soil and surrounding environment. The initial gamma emissions for the 

nuclear detonation, along with mixed fission products in fallout and activation products, 

present an external gamma exposure source to the lens of the eye.

In close proximity to the body, beta radiation can have sufficient energy to penetrate to

the lens of the eye; thus it can also be considered an external radiation source 

contributing to lens dose along with gamma radiation (Turner, 1995). 

Film badges were worn by many individuals, or groups of individuals, during weapon 

testing activities. These monitoring devices measured the amount of gamma radiation 

individuals received during testing activities. If a specific individual did not wear a film 

badge, it is possible to reconstruct the individual’s exposure, based upon film badges 

worn by other individuals in the nearby vicinity or using radiological intensity data. 

Utilizing film badge data or gamma dose reconstruction, it is also possible to estimate the 

dose the individual received to the lens of the eye due to beta radiation from the 

surrounding radiological environment.

5.2 Gamma Dose to Lens of Eye from Fallout

Film badge readings or reconstructed gamma doses form the basis to estimate the whole 

body gamma dose. 

Gamma radiation has sufficient energy to penetrate the lens tissue of the eye as well as 

the epidermal skin layer, along with the body organs and skeleton structure. For the 

purposes of dose reconstruction, dose to the lens due to gamma radiation is assumed to be 

the same as the whole body external dose based on a film badge or reconstruction, not 

taking into consideration attenuation characteristics of distance, geometry, and tissue

depth. This method establishes conservative worst-case gamma doses to the lens of the 

eye, which are subsequently used to estimate a beta dose from a beta-to-gamma dose 

ratio. The whole body dose is based on the film badge reading or on a film badge 

equivalent dose calculated by reconstruction according to SM ED02 - Whole Body 

External Dose - Reconstruction, and must be characterized first in order to use the 

following standard methods.
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5.3 Beta Dose to Lens of Eye from Fallout

Beta dose to the lens from external sources is accrued simultaneously with the gamma 

dose from mixed fission products and actinides in fallout or neutron induced 

radionuclides (activated sources). As a result, the beta dose is proportional to the gamma 

dose, and its relative magnitude can be expressed by a beta-to-gamma dose ratio. This 

beta-to-gamma dose ratio is dependent on the spectrum of the emitted radiation and on 

the geometrical relationship between an individual and the source (e.g., distance from or 

height above the source, or finite or infinite plane geometry). Gamma and beta energy 

spectra are interdependent functions of time, and consequently, the beta-to-gamma dose 

ratio depends on time after a detonation (Barss and Weitz, 2006).

Due to beta particle range and attenuation characteristics, beta dose assessments depend 

more critically than gamma dose assessments on geometry and the shielding material 

between the radioactive source and the individual. Thus, the nature of specific jobs or 

task-related activities and their associated protective measures must be considered when

reconstructing beta dose to the lens (Barss and Weitz, 2006).

Beta doses to the eye are evaluated at the lens of the eye. The depth for the evaluation is

3 mm (300 mg cm−2) from the anterior surface of the eye where the lenticular tissue at 

risk for posterior subcapsular cataract development is located. This depth is consistent 

with ICRP (2002) as the reference density thickness. 

Beta doses from external origin generally involve three exposure pathways based on

infinite, finite, and point source geometries. Fallout deposited over a large surface (such 

as a residence island in the Pacific) is considered to be an infinite plane with uniform, 

contamination and isotropic emission from each point source in the plane (Barss and 

Weitz, 2006). Fallout deposited over a small area or surface is considered to be a finite 

source with localized contamination and isotropic emission (Weitz, 2011). Finite 

radiation sources include the contaminated topside of a ship, contaminated equipment, 

and material such as aircraft engines. Fallout deposited as a “hot-spot” is considered to be 

point-source geometry. 

Beta doses to the lens of the eye do not consider the attenuation effects of the eyelid or 

glasses.

5.3.1 Infinite Plane Source 

For a person exposed to an infinite-sized fallout-contaminated area while wearing a film 

badge or from a reconstructed gamma dose, the dose to the lens can be estimated using 

the same methods and general equations number 1, 3, 4, and 5 as specified in Section 

5.2.1 of ED03, replacing the beta-to-gamma ratios for skin with the beta-to-gamma ratios 

for the lens of the eye as specified in Table 1 and Table 2 below and after adjustment for 

the height of the head from a ground surface based on the individual’s height while 

standing or sitting (Stiver, 2006). 
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Table 1. Lens Beta-to-Gamma Dose Ratios as Function of Time and Height (cm) at PPG

Table 2. Lens Beta-to-Gamma Dose Ratios as Function of Time and Height (cm) at NTS

The computational method used to calculate the above ratios was the same as that used to 

calculate the skin beta-to-gamma ratios (SM ED03) with the skin being replaced by a 

3 mm over-layer and a 1 cm backing layer of water (Barss and Weitz, 2006).

5.3.2 Finite Plane Source

Similar to the finite plane source dose ratios for skin, calculations were performed to 

derive finite source beta-to-gamma dose ratios for the lens. Examples of some scenarios 

involving eye exposures to finite-sized sources of beta and gamma radiation include 

decontaminating an aircraft engine and other surfaces, operating a small shuttle boat, 

performing post-decontamination maintenance activities, and performing maintenance on 

evaporators in the engine room of a contaminated ship.

The results shown in this standard method are analogous in concept to those provided for 

the basal skin layer. The computational method employing the radiation transport code 

ITS CYLTRAN (Halbleib et al., 1992) is identical to that described in (Barss and Weitz,

2006), except that the skin model is replaced with an eye model consisting of a 

3-millimeter (mm) over-layer, a 1-micrometer (μm) sensitive layer (for the lens), and a 

1-centimeter (cm) backing layer, all composed of standard-density water. The timeTime [days] at H = 1 cm at H = 10 cm at H = 20 cm at H = 40 cm at H = 60 cm at H = 80 cm at H = 100 cm at H = 120 cm at H = 160 cm at H = 200 cm

0.5 hour 0.0208 3.61 3.45 3.28 2.97 2.69 2.44 2.22 2.02 1.67 1.39

1 hour 0.0417 2.87 2.74 2.60 2.33 2.09 1.88 1.69 1.53 1.24 1.01

2 hours 0.0833 2.64 2.51 2.38 2.12 1.90 1.70 1.52 1.37 1.10 0.89

4 hours 0.1667 3.21 3.05 2.89 2.59 2.33 2.09 1.88 1.69 1.38 1.13

6 hours 0.25 3.96 3.77 3.58 3.22 2.89 2.61 2.35 2.13 1.74 1.43

12 hours 0.5 4.23 4.02 3.80 3.40 3.04 2.73 2.45 2.21 1.79 1.46

1 day 1 2.56 2.40 2.24 1.96 1.72 1.51 1.33 1.17 0.91 0.71

2 days 2 1.30 1.20 1.10 0.92 0.78 0.66 0.57 0.48 0.36 0.26

3 days 3 0.86 0.78 0.71 0.57 0.47 0.39 0.32 0.27 0.19 0.13

1 week 7 0.53 0.48 0.43 0.34 0.27 0.22 0.18 0.15 0.10 0.07

2 weeks 14 0.61 0.56 0.50 0.40 0.32 0.26 0.22 0.18 0.12 0.09

1 month 30 0.93 0.85 0.77 0.63 0.52 0.43 0.36 0.30 0.22 0.16

2 months 60 1.59 1.47 1.35 1.14 0.96 0.82 0.70 0.60 0.45 0.34

4 months 120 2.44 2.29 2.13 1.85 1.61 1.40 1.23 1.07 0.83 0.65

6 months 180 3.32 3.14 2.95 2.60 2.30 2.04 1.80 1.60 1.27 1.00

9 months 270 5.74 5.47 5.18 4.64 4.15 3.72 3.33 2.99 2.40 1.92

1 year 365 10.42 9.96 9.46 8.52 7.68 6.91 6.22 5.59 4.51 3.62

2 years 730 36.55 34.97 33.27 30.08 27.17 24.52 22.10 19.90 16.07 12.90

Time [days] at H = 1 cm at H = 10 cm at H = 20 cm at H = 40 cm at H = 60 cm at H = 80 cm at H = 100 cm at H = 120 cm at H = 160 cm at H = 200 cm

0.5 hour 0.0208 3.56 3.41 3.26 2.98 2.72 2.49 2.28 2.09 1.76 1.48

1 hour 0.0417 2.84 2.72 2.59 2.34 2.13 1.93 1.75 1.59 1.32 1.09

2 hours 0.0833 2.61 2.49 2.37 2.14 1.93 1.74 1.58 1.43 1.17 0.96

4 hours 0.1667 3.18 3.04 2.89 2.62 2.37 2.15 1.95 1.77 1.47 1.22

6 hours 0.25 3.91 3.74 3.56 3.23 2.94 2.67 2.43 2.21 1.84 1.54

12 hours 0.5 4.16 3.97 3.77 3.40 3.08 2.79 2.53 2.29 1.89 1.57

1 day 1 2.51 2.38 2.23 1.97 1.75 1.55 1.38 1.23 0.98 0.78

2 days 2 1.28 1.19 1.10 0.94 0.80 0.69 0.59 0.52 0.39 0.29

3 days 3 0.85 0.78 0.71 0.59 0.49 0.41 0.34 0.29 0.21 0.15

1 week 7 0.52 0.47 0.43 0.35 0.28 0.23 0.19 0.16 0.11 0.08

2 weeks 14 0.60 0.55 0.50 0.41 0.34 0.28 0.23 0.20 0.14 0.10

1 month 30 0.92 0.85 0.77 0.65 0.54 0.46 0.39 0.33 0.24 0.18

2 months 60 1.57 1.46 1.35 1.15 0.99 0.85 0.74 0.64 0.48 0.37

4 months 120 2.40 2.26 2.12 1.86 1.64 1.44 1.27 1.13 0.89 0.71

6 months 180 3.26 3.10 2.93 2.61 2.33 2.09 1.87 1.67 1.35 1.09

9 months 270 5.63 5.38 5.12 4.63 4.19 3.79 3.43 3.10 2.53 2.07

1 year 365 10.25 9.83 9.38 8.53 7.76 7.05 6.40 5.81 4.78 3.92

2 years 730 35.95 34.53 33.00 30.10 27.44 24.99 22.74 20.67 17.03 13.97
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dependent beta and gamma fallout spectral data are taken from (Finn et al., 1979). The 

beta-to-gamma dose ratios presented in this section apply to an individual looking 

directly at the radiation source, i.e., no shielding factors are included. It is also assumed 

that the beta dose in the numerator of the ratio and gamma dose in the denominator were 

accrued at the same distance from the source, as would generally be the case if the 

gamma dose is a film badge or film badge equivalent dose (i.e., a reconstruction).

Beta and gamma dose to the lens of the eye based on finite geometry is calculated in an 

identical manner as for external skin dose based on finite geometry (as specified in 

SM ED03), replacing the beta-to-gamma finite dose ratios for skin with those specified 

for the lens of the eye. 

The eye lens beta-to-gamma dose ratios are presented in this section as functions of 

source radius, source distance (H), substrate material, and time after detonation (Weitz,

2012). 

Typical radii for aircraft decontamination range from 3 (F-84) to 5 m (B-29) based on 

size of aircraft.

Table 3 provides an index for the finite applications and associated beta-to-gamma dose 

ratios listed in Tables 4 through 14 for the specified substrate (Aluminum or Iron), 

distance from source (H), and job activity. 

NOTE: The only difference between PPG and NTS beta-to-gamma dose ratio 

calculations is an air density of 1.15 and 1.05 mg cm−3, respectively (Barss and Weitz,

2006). The beta-to-gamma dose ratio for the lens is slightly greater at NTS due to the less 

dense air; see Table 6 and Table 7, ratios for 4 hours. 

Table 3. Index to Tables of Typical Finite Applications and

Associated Beta-to-Gamma Lens Dose Ratios

Substrate Distance (m) Activity Location

Al 0.1 Aircraft inspection & maintenance (PPG) Table 4

Al 0.5 Decon equipment (NTS) Table 5

Al 1.0 Decon aircraft (NTS) Table 6

Al 1.0 Decon aircraft (PPG) Table 7

Al 2.0 Decon aircraft (NTS) Table 8

Al 3.66 (12 ft) Decon aircraft with high pressure hose (PPG) Table 9

Fe 0.3 (1 ft) Hand scrub decon aboard ship (PPG) Table 10

Fe 0.5 Decon (NTS) Table 11

Fe 1.0 Decon (NTS) Table 12

Fe 1.0 Decon (PPG) Table 13

Fe 2.0 Decon (NTS) Table 14
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Table 4. Al at Distance H = 0.1 m (PPG)

Table 5. Al at Distance H = 0.5 m (NTS)

Source Time after Detonation:

 Radius (m) 1 hour 4 hours 1 day 1 week 6 months

0.10 18.3 21.0 14.6 3.9 19.2

0.25 13.2 15.2 10.3 2.5 13.4

0.50 10.3 11.9 7.9 1.8 10.3

1 8.3 9.6 6.4 1.4 8.3

2 6.9 8.0 5.3 1.2 6.9

3 6.3 7.3 4.8 1.1 6.3

4 5.9 6.8 4.5 1.0 5.9

5 5.6 6.5 4.3 1.0 5.7

7 5.2 6.0 4.0 0.89 5.3

10 4.9 5.6 3.8 0.83 5.0

15 4.5 5.2 3.6 0.78 4.7

20 4.3 5.0 3.4 0.74 4.5

50 3.8 4.4 3.0 0.66 4.0

100 3.5 4.1 2.8 0.61 3.7

200 3.3 3.8 2.7 0.58 3.5

500 3.2 3.7 2.6 0.56 3.4

Source Time after Detonation:

 Radius (m) 2 hours 4 hours 6 hours 12 hours

0.10 17.7 21.2 26.6 28.8

0.25 17.3 20.5 25.4 26.8

0.50 15.0 18.1 22.4 23.5

1 11.6 14.1 17.4 18.3

2 8.6 10.6 13.0 13.4

3 7.3 8.9 11.0 11.3

4 6.5 8.0 9.8 10.1

5 6.0 7.3 9.0 9.3

7 5.3 6.5 8.1 8.2

10 4.8 5.9 7.2 7.4

15 4.3 5.2 6.5 6.6

20 4.0 4.9 6.0 6.2

50 3.3 4.1 5.0 5.1

100 3.0 3.7 4.5 4.6

200 2.8 3.4 4.2 4.3

500 2.6 3.3 4.0 4.1
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Table 6. Al at Distance H = 1 m (NTS)

Table 7. Al at Distance H = 1 m (PPG)

Source Time after Detonation:

 Radius (m) 2 hours 4 hours 6 hours 12 hours

0.10 16.2 21.0 25.6 24.3

0.25 16.8 19.2 25.3 26.3

0.50 15.9 19.2 23.7 25.2

1 13.5 16.7 20.7 21.4

2 10.0 12.3 15.4 15.8

3 8.1 10.0 12.5 12.7

4 7.0 8.6 10.7 10.9

5 6.2 7.7 9.6 9.8

7 5.3 6.6 8.2 8.3

10 4.5 5.7 7.0 7.1

15 3.9 4.9 6.1 6.2

20 3.6 4.5 5.5 5.6

50 2.8 3.6 4.4 4.5

100 2.5 3.1 3.9 4.0

200 2.3 2.9 3.6 3.7

500 2.2 2.7 3.4 3.5

Source Time after Detonation:

 Radius (m) 1 hour 4 hours 1 day 1 week 6 months

0.10 18.0 20.9 17.2 3.1 25.9

0.25 18.3 20.0 16.6 3.1 21.3

0.50 17.3 18.8 15.3 2.8 20.0

1 15.0 16.1 12.5 2.1 17.2

2 10.9 11.9 8.7 1.3 11.9

3 8.7 9.7 6.8 1.0 9.3

4 7.5 8.3 5.7 0.81 7.8

5 6.6 7.4 5.1 0.71 6.9

7 5.6 6.3 4.3 0.60 5.8

10 4.8 5.4 3.7 0.51 5.0

15 4.2 4.7 3.2 0.44 4.3

20 3.8 4.3 2.9 0.40 3.9

50 3.0 3.4 2.3 0.32 3.1

100 2.7 3.0 2.1 0.28 2.7

200 2.5 2.8 1.9 0.26 2.5

500 2.4 2.6 1.8 0.25 2.4
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Table 8. Al at Distance H = 2.0 m (NTS)

Table 9. Al at Distance H = 2.0 m (NTS)

Source Time after Detonation:

 Radius (m) 2 hours 4 hours 6 hours 12 hours

0.10 12.5 14.9 22.7 28.0

0.25 13.1 17.4 19.8 21.7

0.50 13.1 16.7 20.3 22.2

1 12.5 15.2 18.7 20.8

2 10.1 12.7 15.4 16.6

3 8.2 10.2 12.6 13.4

4 6.8 8.6 10.7 11.2

5 5.8 7.5 9.3 9.6

7 4.7 6.1 7.5 7.7

10 3.8 4.9 6.1 6.2

15 3.1 4.0 5.0 5.0

20 2.7 3.5 4.4 4.4

50 2.0 2.6 3.2 3.3

100 1.7 2.2 2.8 2.8

200 1.6 2.0 2.5 2.6

500 1.5 1.9 2.4 2.4

Source Time after Detonation:

 Radius (m) 6 hours 12 hours 1 day

0.5 9.2 11.0 5.0

1 9.8 10.4 5.2

2 8.9 8.9 4.4

3 7.7 7.9 3.6

4 6.6 6.6 2.9

5 5.8 5.7 2.5

7 4.5 4.4 1.8

10 3.4 3.3 1.3

15 2.6 2.5 1.0

20 2.2 2.1 0.8
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Table 10. Fe at Distance H = 0.3 m (1 ft) (PPG)

Table 11. Fe at Distance H = 0.5 m (NTS)

Source Time after Detonation:

 Radius (m) 1 week 1 month 6 months

0.10 4.0 6.3 19.5

0.25 3.2 5.3 17.3

0.50 2.4 4.1 14.2

1 1.7 3.0 10.9

2 1.3 2.3 8.5

3 1.1 2.0 7.4

4 1.0 1.8 6.7

5 0.93 1.7 6.3

7 0.85 1.5 5.8

10 0.78 1.4 5.3

15 0.71 1.3 4.8

20 0.67 1.2 4.6

50 0.57 1.0 3.9

100 0.53 0.95 3.6

200 0.50 0.89 3.4

500 0.48 0.86 3.3

Source Time after Detonation:

 Radius (m) 2 hours 4 hours 6 hours 12 hours

0.1 16.2 19.6 24.6 26.9

0.25 15.7 18.9 23.3 24.8

0.5 14.1 17.0 21.1 22.1

1 11.3 13.8 17.1 17.7

2 8.5 10.5 13.0 13.3

3 7.3 8.9 11.1 11.4

4 6.5 8.0 10.0 10.2

5 6.0 7.4 9.2 9.4

7 5.4 6.6 8.3 8.4

10 4.9 5.9 7.4 7.6

15 4.4 5.4 6.7 6.8

20 4.1 5.0 6.2 6.4

50 3.4 4.2 5.2 5.3

100 3.1 3.8 4.7 4.8

200 2.9 3.5 4.4 4.5

500 2.7 3.4 4.2 4.3
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Table 12. Fe at Distance H = 1.0 m (NTS)

Table 13. Fe at Distance H = 1.0 m (PPG)

Source Time after Detonation:

 Radius (m) 2 hours 4 hours 6 hours 12 hours

0.1 15.9 16.3 23.0 24.2

0.25 15.7 18.5 23.6 25.4

0.5 15.0 17.7 22.4 23.9

1 12.8 15.6 19.4 20.6

2 9.8 12.0 14.9 15.6

3 8.0 9.9 12.3 12.8

4 7.0 8.6 10.7 11.1

5 6.3 7.7 9.6 9.9

7 5.4 6.7 8.3 8.5

10 4.7 5.8 7.2 7.4

15 4.1 5.0 6.2 6.4

20 3.7 4.6 5.7 5.9

50 3.0 3.7 4.6 4.7

100 2.6 3.3 4.0 4.2

200 2.4 3.0 3.7 3.9

500 2.3 2.8 3.5 3.7

Source Time after Detonation:

 Radius (m) 1 week 2 weeks

0.10 2.9 2.3

0.25 2.7 3.0

0.50 2.5 2.8

1 1.9 2.2

2 1.2 1.5

3 0.95 1.2

4 0.80 1.0

5 0.71 0.87

7 0.61 0.74

10 0.52 0.64

15 0.46 0.55

20 0.42 0.51

50 0.33 0.41

100 0.29 0.36

200 0.27 0.33

500 0.26 0.32
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Table 14. Fe at Distance H = 2.0 m (NTS)

Due to the complexities of beta dose calculations, tables for applications not listed above 

are generated on a case-by-case basis.

5.3.3 Point Source

Similar to the method for point source dose to skin, calculations were performed for the 

lens of the eye. Examples of some scenarios involving eye exposures to point sources of 

beta and gamma radiation include inspecting the external surface of an aircraft that 

contains isolated “hot spots”, removing contaminated air filters collected during cloud 

sampling, and viewing small objects removed from contaminated target ships as 

specimens or souvenirs. 

Beta dose rates to the lens of the eye from point sources of fallout beta radiation have 

been calculated using the aforementioned eye model with the CEPXS radiation transport 

code (Lorence et al., 1989). The source is modeled as a point from which beta radiation, 

having Finn spectral characteristics (Finn et al., 1979) is emitted isotropically. The point 

source is surrounded by a spherically symmetrical layer of air with radius R, which in 

turn is surrounded by the layers that comprise the eye. The energy deposited in the lens of 

the eye, as determined in this manner, is converted to a dose rate per unit activity (i.e., 

rad h

−1 Ci−1

) in the point source by assuming 1 beta/decay.

The dose to the lens of the eye from a point source at 1 foot and 1 m as a function of time 

after a detonation and to skin at 1 foot and 1 m are presented in tandem in Tables II-2 and 

II-3 of Weitz, 2012.

Source Time after Detonation:

 Radius (m) 2 hours 4 hours 6 hours 12 hours

0.1 15.9 15.5 20.2 23.4

0.25 13.5 15.2 20.3 21.1

0.5 12.1 15.4 19.2 21.0

1 11.6 14.5 18.7 18.9

2 9.6 12.0 15.4 16.2

3 8.0 10.0 12.7 13.3

4 6.7 8.5 10.8 11.1

5 5.8 7.5 9.4 9.7

7 4.8 6.1 7.7 7.8

10 3.9 4.9 6.3 6.3

15 3.2 4.1 5.1 5.2

20 2.8 3.6 4.5 4.6

50 2.1 2.7 3.4 3.4

100 1.8 2.3 2.9 2.9

200 1.6 2.1 2.6 2.7

500 1.5 2.0 2.5 2.5
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5.3.4 Dermal Contamination on Eyelid 

This section addresses dose to the lens of the eye caused by possible contamination 

deposited on the outer surface of the eyelid. It is therefore necessary to calculate the 

contamination dose to the eyelid as though a skin cancer was manifest, using the standard 

methods given in SM ED04. 

Once the dermal contamination dose to the eyelid has been calculated, the dose to the 

lens of the eye from eyelid contamination can be calculated using the data in Table 15

(Weitz, 2012). Table 15 provides the ratio of the beta dose to the lens with respect to the 

beta dose in the basal cell layer of the eyelid as a function of time. The eyelid is assumed 

to have a thickness of 600 m with the basal layer at a depth of 30 μm. The sensitive 

layer for the lens is assumed to be at a tissue depth of 3 mm. The radiation transport was 

performed with the CEPXS transport code (Lorence et al., 1989) and using the Finn beta 

spectral data (Finn et al., 1979; Weitz, 2012).

The corresponding beta dose to the lens is simply the beta dose to the eyelid multiplied 

by the Dose Ratio given in the last column of Table 15. As can be observed from

Table 15, the dose to the lens of the eye if contamination of the eyelid occurred at H+12

hour is approximately 3.33 percent of the contamination dose to the eyelid and generally 

less during an Operation. The lens dose rises back to 3 percent at about 9 months to 1 

year after a detonation (e.g., for possible post-operational decontamination activities). 

Because it is likely that no eyelid contamination occurred to most personnel within 

several hours after the detonation (with the possible exception of cloud sampling aircraft 

crews or recovery personnel), most personnel did not accrue a lens dose from dermal 

contamination on the eyelid greater than 4.5 percent at any time after a detonation. Thus, 

the 4.5 percent is used as a default.

Table 15. Ratio of Lens Dose to Eyelid Dose

Time after Avg beta energy Dose at 30 um in eyelid: Dose at 3 mm in eye (lens): Dose Ratio

Detonation (MeV) MeV-cm2/g rad/hr/beta/cm2-s MeV-cm2/g rad/hr/beta/cm2-s Lens:Eyelid

1 hr 0.824 5.01 2.89E-04 0.2388 1.38E-05 4.76E-02

2 hr 0.789 4.99 2.88E-04 0.2182 1.26E-05 4.37E-02

4 hr 0.767 4.98 2.87E-04 0.2092 1.21E-05 4.20E-02

6 hr 0.753 4.97 2.87E-04 0.2046 1.18E-05 4.11E-02

12 hr 0.679 4.95 2.85E-04 0.1647 9.49E-06 3.33E-02

1 d 0.539 4.88 2.81E-04 0.0896 5.16E-06 1.84E-02

2 d 0.425 4.80 2.77E-04 0.0393 2.27E-06 8.19E-03

3 d 0.370 4.76 2.74E-04 0.0232 1.34E-06 4.88E-03

1 wk 0.315 4.70 2.71E-04 0.0132 7.63E-07 2.82E-03

2 wk 0.317 4.70 2.71E-04 0.0150 8.66E-07 3.20E-03

1 mo 0.338 4.72 2.72E-04 0.0216 1.24E-06 4.58E-03

2 mo 0.347 4.70 2.71E-04 0.0335 1.93E-06 7.13E-03

4 mo 0.360 4.69 2.70E-04 0.0526 3.03E-06 1.12E-02

6 mo 0.388 4.70 2.71E-04 0.0728 4.19E-06 1.55E-02

9 mo 0.445 4.73 2.73E-04 0.1086 6.26E-06 2.29E-02

1 yr 0.504 4.77 2.75E-04 0.1436 8.27E-06 3.01E-02

2 yr 0.559 4.80 2.77E-04 0.1740 1.00E-05 3.62E-02
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5.4 Beta Dose to Lens from Activation Products

Activation products are produced by neutron absorption in soil and other materials. The 

radioisotopes Na-24, Mn-56, Si-31, Ca-45, and K-42 are the primary contributors to the 

gamma and beta radiation in the vicinity of activated soil for the first few weeks after 

detonation, with Sc-46 and Co-60 at later times (e.g., months to years after the 

detonation.). Aluminum activation products decayed to immeasurable levels within 

minutes after a test detonation and, therefore, did not contribute to an eye dose by the 

time test participants approached the contaminated area. 

External beta-to-gamma ratios for neutron activated products in soil are calculated using 

their respective parent elemental compositions and typical depths in soil with a density of 

1.7 g cm−3. Table 16 and Table 17 provide the resultant beta-to-gamma dose ratios.

Table 16. Beta-to-Gamma Lens Dose Ratio for Induced Radioactivity in Soil as a Function 

of Time and Height at NTS Area 7

Results for NTS Area 7:

Time after

detonation Beta/gamma eye dose ratio at eye height:

(hours) 20 cm 40 cm 80 cm 100 cm 120 cm 160 cm 200 cm

0.5 0.0550 0.0496 0.0402 0.0362 0.0325 0.0263 0.0211

1 0.0537 0.0484 0.0393 0.0354 0.0318 0.0257 0.0207

2 0.0511 0.0461 0.0375 0.0337 0.0304 0.0246 0.0198

3 0.0483 0.0436 0.0355 0.0320 0.0289 0.0234 0.0189

4 0.0455 0.0411 0.0335 0.0303 0.0273 0.0222 0.0180

5 0.0427 0.0386 0.0316 0.0285 0.0258 0.0210 0.0171

6 0.0400 0.0362 0.0296 0.0268 0.0243 0.0199 0.0162

7 0.0374 0.0339 0.0278 0.0252 0.0228 0.0187 0.0154

8 0.0350 0.0318 0.0261 0.0237 0.0215 0.0177 0.0146

9 0.0329 0.0298 0.0246 0.0223 0.0203 0.0168 0.0138

10 0.0309 0.0280 0.0232 0.0211 0.0192 0.0159 0.0132

12 0.0276 0.0251 0.0208 0.0190 0.0173 0.0145 0.0121

15 0.0241 0.0220 0.0183 0.0168 0.0154 0.0129 0.0108

20 0.0209 0.0191 0.0160 0.0147 0.0135 0.0114 0.0097

24 0.0195 0.0178 0.0149 0.0137 0.0126 0.0107 0.0091

36 0.0172 0.0157 0.0131 0.0121 0.0111 0.0094 0.0080

48 0.0155 0.0141 0.0118 0.0109 0.0100 0.0085 0.0072

72 0.0128 0.0116 0.0096 0.0088 0.0081 0.0069 0.0058

120 0.0087 0.0078 0.0064 0.0058 0.0053 0.0045 0.0038

168 0.0061 0.0054 0.0043 0.0039 0.0035 0.0030 0.0025
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Date: April 30, 2021

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Table 17. Beta-to-Gamma Lens Dose Ratio for Induced Radioactivity in Soil as a Function 

of Time and Height at NTS Frenchman Flat

Beta and gamma doses to the lens of the eye are calculated in an identical manner as for 

external skin dose from activation products by replacing the beta-to-gamma dose ratios 

for skin with those specified for the lens of the eye given above. 

6. Data and Input

Operation and shot-specific data are compiled in SOP Appendices A–C.

7. Referenced SOPs and Standard Methods from this Manual

(1) SOP RA01 - Radiation Dose Assessments for Cases Requiring Detailed Analysis

(2) SM ED02 - Whole Body External Dose Assessment

(3) SM ED03 - Skin Dose from External Sources

(4) SM ED04 - Skin Dose from Dermal Contamination

Results for NTS Frenchman Flat:

Time after

detonation Beta/gamma eye dose ratio at eye height:

(hours) 20 cm 40 cm 80 cm 100 cm 120 cm 160 cm 200 cm

0.5 0.0509 0.0457 0.0369 0.0331 0.0297 0.0238 0.0191

1 0.0493 0.0443 0.0358 0.0321 0.0288 0.0231 0.0185

2 0.0461 0.0414 0.0334 0.0300 0.0270 0.0217 0.0174

3 0.0427 0.0384 0.0310 0.0279 0.0251 0.0202 0.0162

4 0.0394 0.0354 0.0286 0.0257 0.0231 0.0187 0.0150

5 0.0360 0.0324 0.0262 0.0236 0.0212 0.0172 0.0138

6 0.0329 0.0296 0.0240 0.0216 0.0194 0.0157 0.0127

7 0.0299 0.0269 0.0218 0.0196 0.0177 0.0144 0.0117

8 0.0271 0.0244 0.0198 0.0179 0.0161 0.0131 0.0107

9 0.0246 0.0222 0.0180 0.0163 0.0147 0.0120 0.0098

10 0.0224 0.0202 0.0164 0.0148 0.0134 0.0110 0.0090

12 0.0188 0.0169 0.0138 0.0125 0.0113 0.0094 0.0077

15 0.0151 0.0136 0.0111 0.0101 0.0092 0.0077 0.0064

20 0.0119 0.0107 0.0088 0.0080 0.0073 0.0062 0.0052

24 0.0107 0.0096 0.0079 0.0072 0.0066 0.0056 0.0047

36 0.0092 0.0083 0.0068 0.0062 0.0057 0.0048 0.0041

48 0.0084 0.0075 0.0061 0.0056 0.0051 0.0043 0.0037

72 0.0070 0.0062 0.0050 0.0045 0.0041 0.0035 0.0030

120 0.0050 0.0043 0.0034 0.0031 0.0028 0.0023 0.0020

168 0.0037 0.0032 0.0024 0.0021 0.0019 0.0016 0.0014
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Date: April 30, 2021

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8. References

Barss, N.M. and Weitz, R.L., 2006. “Reconstruction of External Dose From Beta Radiation 

Sources of Nuclear Weapon Origin.” Health Physics 91(4):379-389.

DoD (U.S. Department of Defense), 2020. “Guidance for the Determination and Reporting of 

Nuclear Radiation Dose for DoD Participants in the Atmospheric Nuclear Test Program

(1945-1962).” Title 32, Code of Federal Regulations, Part 218. Washington, DC. July 1.

Finn, S.P., Simmons, G.L., and Spencer, L.V., 1979. Calculation of Fission Product Gamma Ray 

and Beta Spectra at Selected Times after Fast Fission of U238 and U235 and Thermal 

Fission of U235. SAI Report SAI-78-782-LJ/F. February 23.

Halbleib, J.A., Kensek, R.P., Mehlhorn, T.A., Valdez, G.D., 1992. ITS version 3.0: the 

integrated TIGER series of coupled-electron Monte Carlo transport codes. Report SAND 

91-1634, Sandia National Laboratories.

ICRP (International Commission on Radiological Protection), 2002. Basic Anatomical and 

Physiological Data for Use in Radiological Protection: Reference Values. ICRP 

Publication 89, Ann. ICRP 32 (3-4), International Commission on Radiological 

Protection. 

Lorence, L.J., Morel, J.E., Valdez, G.D., 1989. User’s Guide to CEPXS/ONEDANT: A onedimensional coupled electron-photon discrete ordinates code package, Version 1.0, 

Report SAND 89-1661, Sandia National Laboratories.

Stiver, J., 2006. “Excel Spreadsheet for Calculation of Anatomical Locations Based on an 

Individual’s Height and Reference Man, Revision 3,” Science Applications International 

Corporation, McLean, VA. November 21.

Turner, James E., 1995. Atoms, Radiation, and Radiation Protection. John Wiley and Sons, Inc., 

2

nd Edition.

Weitz, R.L., 2011. Analysis of Skin Dose from Circular Sources of Fallout. NTPR-TM-11-03, 

Defense Threat Reduction Agency, Ft Belvoir, VA. July 1.

Weitz, R.L., 2012. Compendium of Eye Dose Calculations for Fallout Sources of Finite Size.

NTPR-TM-11-05, Defense Threat Reduction Agency, Ft Belvoir, VA. May 1.