Division of Compensation Analysis and 

Support

Technical Basis Document for Atomic Energy Operations at 

the Iowa Army Ammunition Plant (IAAP)

Document Number:

DCAS-TKBS-0001

Effective Date: 10/20/2011

Revision No.:01

Controlled Copy No.:

________

Page 1 of 18

Subject Experts: Mark Rolfes/Tim Taulbee

Approval: Signature on file Date: 10/20/2011

 James W. Neton, Associate Director for Science

Supersedes:

OCAS-TKBS-0001 Rev 0

RECORD OF ISSUE / REVISIONS .............................................................................. 2

ACRONYMS AND ABBREVIATIONS .......................................................................... 3

1.0 INTRODUCTION ..................................................................................................... 4

2.0 SITE DESCRIPTION, OPERATIONAL HISTORY, AND PROCESS ............. 4

3.0 OCCUPATIONAL MEDICAL RADIATION EXPOSURE ................................... 6

4.0 ESTIMATION OF INTERNAL RADIATION EXPOSURE ................................. 7

5.0 ESTIMATION OF EXTERNAL RADIATION EXPOSURE ................................ 8

5.1 Photon Radiation ............................................................................................... 8

5.2 Neutron Radiation .............................................................................................. 8

5.3 Electron Radiation ............................................................................................. 9

5.4 Extremities Exposures ...................................................................................... 9

5.5 Uncertainty .......................................................................................................... 9

REFERENCES ............................................................................................................... 10

GLOSSARY .................................................................................................................... 11

Appendix A—U.S. Department of Labor Correspondence ...................................... 16

LIST OF TABLES

Table 2.1 Significant Radiation Safety Program Events..................................6 

Table 3.1 Hospital Exposure Settings.........................................................7 

Table 5.1 Summary of Photon Dosimetry Data.............................................9 
Effective Date: 10/20/2011 Revision No. 01 DCAS-TKBS-0001 Page 2 of 18

RECORD OF ISSUE / REVISIONS 

ISSUE 

AUTHORIZATION 

DATE

EFFECTIVE 

DATE

REV. 

NO. DESCRIPTION

Draft 11/29/2005 00

Significant changes to ORAUT-TKBS-0018 

Rev 01 based upon the feasibility 

determination by the Secretary of Health and 

Human Services.

Incorporated comments received from OGC 

pertaining to reconstruction of medical X-ray 

procedures.

10/17/2011 10/20/2011 01

Changes to the lumbar spine medical X-ray 

dose assignment guidance. Initiated by Mark 

Rolfes.
Effective Date: 10/20/2011 Revision No. 01 DCAS-TKBS-0001 Page 3 of 18

ACRONYMS AND ABBREVIATIONS 

AEC US Atomic Energy Commission 

AP Anterior-posterior (or front-to-back) irradiation of the body 

BAECP Burlington Atomic Energy Commission Plant 

DCF dose conversion factor 

DOE U. S. Department of Energy 

DU depleted uranium

EDA Explosives Disposal Area 

FS Firing Site 

GSD geometric standard deviation 

Hp(d) personnel dose equivalent at depth d in tissue 

IAAP Iowa Army Ammunition Plant (also sometimes IAAAP) 

ICRP International Commission on Radiological Protection

ICRU International Commission on Radiation Units and Measurements

IREP Interactive RadioEpidemiological Program 

keV kilo (thousand) electron volts, a unit of energy 

MED Manhattan Engineer District 

MeV million electron volts, a unit of energy 

MDL minimum detectable level 

mrem millirem one-thousandth of a rem 

NCRP National Commission on Radiological Protection and Measurements 

NIOSH National Institute for Occupational Safety and Health 

NTA Eastman Kodak Nuclear Track Emulsion type A 

OCAS Office of Compensation Analysis and Support 

ORAU Oak Ridge Associated Universities 

R roentgen, unit of exposure to ionizing photons in air 

SRS Savannah River Site 

TBD technical basis document 

TLD thermoluminescent dosimeter 
Effective Date: 10/20/2011 Revision No. 01 DCAS-TKBS-0001 Page 4 of 18

1.0 INTRODUCTION 

Technical basis documents are general working documents that provide guidance concerning 

the preparation of dose reconstructions at particular sites or categories of sites. They will be 

revised in the event additional relevant information is obtained about the affected site(s). These 

documents may be used to assist the National Institute for Occupational Safety and Health 

(NIOSH) in the completion of the individual work required for each dose reconstruction. 

In this document the word ―facility‖ is used as a general term for an area, building or group of 

buildings that served a specific purpose at IAAP. It does not necessarily connote an ―atomic 

weapons employer facility‖ or a ―Department of Energy facility‖ as defined in the Energy 

Employee Occupational Illness Compensation Program Act of 2000 (42 U.S.C. § 7384I (5) and 

(12)). 

This document provides information on interpretation of dosimetry records to estimate external 

doses for workers at the Iowa Army Ammunition Plant in Burlington, Iowa. The Iowa Army 

Ammunition Plant was responsible for high explosive (HE) fabrication, assembly of non-nuclear 

and nuclear components, retrofits, modifications, surveillance, and disassembly of nuclear 

weapons. 

The Secretary of Health and Human Services determined that it is not feasible for NIOSH to 

estimate with sufficient accuracy, the radiation exposures for Line 1 Iowa Army Ammunition 

Plant workers, from March 1949 through December 1974. As a result of this determination, 

NIOSH is only able to conduct dose reconstructions using actual measured radiation exposure 

data for an individual whose dose is being reconstructed (USDOL 2005). Correspondence 

received by NIOSH from the U.S. Department of Labor concerning dose reconstruction for 

members of the designated Special Exposure Cohort can be found in Appendix A of this 

document. 

2.0 SITE DESCRIPTION, OPERATIONAL HISTORY, AND PROCESS 

The Iowa Army Ammunition Plant (IAAP) is a load, assemble, and pack munitions facility that 

began production in 1941 and continues to operate as a Government-owned, contractoroperated installation. IAAP is in the southeastern part of Iowa, near the town of Middletown in 

Des Moines County. It is about 10 miles west of the Mississippi River and the town of 

Burlington (U. S. Army 1988). Less than a third of the IAAP’s 19,015-acre (30-square-mile) 

property is occupied by active or formerly active production or storage facilities. The remaining 

land is evenly divided between leased agricultural acreage and woodlands (JAYCOR 1996). 

Since operations began in 1941, IAAP has used explosives and lead-based initiating 

compounds to produce a wide variety of ordnance items. The Line 1 area, portions of the Firing 

Site (FS) area, the Explosive Disposal Area (EDA) sites, and Yards C, G, and L came under the 

jurisdiction of the Atomic Energy Commission [AEC; now the U. S. Department of Energy 

(DOE)]. In addition, the Security Command Center, the Emergency Response Command Post, 

the Deactivation furnace, Line 3 Warehouse 301, and the North Burn Pads Landfill might have 

been utilized. This area, totaling around 1,630 acres, became known as the Burlington Atomic 

Energy Commission Plant (BAECP). The site was officially renamed the Iowa Army 
Effective Date: 10/20/2011 Revision No. 01 DCAS-TKBS-0001 Page 5 of 18

Ammunition Plant in 1965. The site has also been referred to as the Iowa Ordnance Plant. 

Specific buildings and the functions of various radiological buildings can be found in Appendix B 

of this report. 

During the summer of 1947, Silas Mason Company entered into a contract with the Ordnance 

Department to assist in the design and engineering to perform the construction and to operate a 

facility for the purpose of supplying the Atomic Energy Commission (AEC) with explosive 

components for nuclear weapons. In May 1948, Silas and Mason Company supervisor 

personnel entered a training program at the Naval Ordnance Test Station (China Lake, 

California). Upon returning from training, these supervisors trained other IAAP personnel. By 

the spring of 1949, IAAP was at full production for HE fabrication (Mitchell 2003). In March 

1949, it was decided that certain weapon assembly operations (non-nuclear components) would 

also be conducted at IAAP (Poole and Harrison, 1954, Mitchell, 2003). Until March 1949, all of 

the initial work at IAAP focused solely on high explosive manufacturing. Based on a review of 

IAAP Project History reports (Poole and Harrison, 1954), NIOSH has concluded that the first 

nuclear weapon assembly operations began in 1949 with the Mark IV. 

Based on the review conducted during the development of the initial site profile, NIOSH felt 

certain that fissile materials were onsite from at least 1958 forward. The concern for these 

materials is that they are generally the most radioactive component of a nuclear weapon and 

result in the largest external dose. NIOSH has uncovered considerable evidence that indicated 

fissile materials were not onsite at IAAP until 1955. This evidence considers IAAP’s mission, 

early weapon design and the development of a Rad-Safe (Radiation Safety) program. 

According to the IAAP History of Line 1 Operations (Ahlstrand, 1956a, 1956b, 1957b), with the 

planned assembly of new sealed pit weapon designs, IAAP instituted a radiological monitoring 

program which included the routine external dose monitoring for some workers using film 

badges. A chronology of significant events can be found in Table 2.1. 
Effective Date: 10/20/2011 Revision No. 01 DCAS-TKBS-0001 Page 6 of 18

 Table 2.1 Significant Radiation Safety Program Events 

 Time Event Reference

November

 1955

Selected workers issued film dosimetry on an intermittent basis. Badge exchange

frequency was weekly.

 TracerLab 

Reports (1955)

March 1956 Safety Manager attends Rad-Safe training at LASL. Ahlstrand

 (1956a)

July 1956

Formal establishment of a Rad-Safe program

Training of all Division B Personnel

Acquirement of Rad-Safe Equipment

Continuous Air Monitoring

 Ahlstrand

 (1956b)

 

July 1957

The following excerpt is from the IAAP Project History Report in 1957.

Continued emphasis on Rad-Safe Training for the safe handling of radioactive materials in order to

prepare all workers for the new phases of work in division “B”. Even though this material is 

received at this installation in sealed containers and is low energy radiation, employees are 

trained in all phases of safe handling of these materials.

 Ahlstrand

 (1957b)

September

 1957

Establishment of a team for Off-site Emergency Radiological Monitoring Ahlstrand

 (1957b)

January –

June 1958

Extensive Rad-Safe training conducted including training on urinalysis.

72 Employees attended Primer Course 2T

7 employees spent a week in April at the Nevada Test Site for special Rad-

 safe training

The Plant’s Registered nurses and certain members of the Safety, Mechanical

and Chemical Laboratory departments spent approximately 200 hours special

training on urinalysis procedures and the operation and maintenance of

monitoring equipment.

 Ahlstrand

 (1958a)

July 1959 Radiation Safety inspector visits Pantex and LASL to discuss radiological and health

problems.

 Ahlstrand

 (1959b)

 1962 First instance of AEC Form 191 documenting no internal exposures at IAAP during the

year.

AEC Report 191

 (1962-1974)

September

 1962

Routine issuance of film dosimeter badges to personnel. Badge exchange frequency

was weekly. First routine area dosimeters in buildings 1-11 and 1-77.

 Landauer

Reports (1962)

 January

 1963

Badge exchange frequency changed to bi-weekly. Landauer

Reports (1963)

 January

 1964

Badge exchange frequency changed to 4 weeks. A total of 13 cycles per year. Some

highly exposed workers continued on bi-weekly basis.

 1968 Significant increase (doubling) in the issuance of dosimeters to personnel. Landauer

Reports (1968)

October

 1969

IAAP establishes hand monitoring program following an AEC recommendation in 1969:

Hand exposure studies have been made in the past, with results that indicate only nominal 

exposure. However, no hand monitoring has been done within the past year. With new items that

are coming into production, and the strong possibility of a reduced exposure guide for extremities,

a program of hand monitoring should be provided for those employees who work directly with the

radioactive units that have significant surface dose rates.

 Davis (1969)

3.0 OCCUPATIONAL MEDICAL RADIATION EXPOSURE 

 

Medical examinations at the IAAP were required as a condition of employment. Generally a 

chest X-ray was given to each IAAP employee annually. During the worker outreach meeting in 

July 2004, some workers indicated that they received chest X-rays on a semi-annual basis, 

while others indicated that it was more frequent on a quarterly basis. Assuming medical 
Effective Date: 10/20/2011 Revision No. 01 DCAS-TKBS-0001 Page 7 of 18

monitoring practices were similar between IAAP and Pantex, there is evidence that male 

employees in certain job categories (heavy lifters, perhaps) received lumbar spine 

examinations, the frequency of which was not available. At Pantex, lumbar spine examinations 

were given to men when they were hired to check for pre-existing back conditions. Even though 

measured X-ray exposure data does not exist for every IAAP employee, some records of X-ray 

machine exposures do exist as described below. Therefore, the claimant favorable assumption 

was made to include this source of occupational radiation exposure, consistent with NIOSH 

guidance (2002, 2005 communication via email). 

Background information on X-ray doses can be found in Dose Reconstruction from 

Occupationally Related Diagnostic X-ray Procedures (ORAUT 2011). Only limited data were 

found concerning X-ray exposures at IAAP. The exposure information was located within the 

dosimetry records indicating chest exposures at the plant hospital. During a study, several 

Landauer film badges were exposed to select X-ray machine settings. Table 3.1 below 

summarizes the X-ray settings and measured film badge dose for the special study. 

Table 3.1 Hospital Exposure Settings 

 

 #

 Amperage

 (mA) Voltage (kVp) Duration (sec)

 Dosimeter

 Reading (mR)

 1 200 mA 85 kVp 0.1 s 20

 2 100 mA 95 kVp 0.6 s 690

 3 100 mA 70 kVp 0.4 s 300

 4 100 mA 45 kVp 0.05 s 0

A chest exposure of 20 mAs (200mA x 0.1s) is fairly common for typical chest exposures as 

indicated in exposure #1. Since this exposure was first in the series, it is expected that these 

were the default values for the common chest X-ray. As indicated in ORAUT-OTIB-0006, X-ray 

measurements with films results in large uncertainty, and great care is needed to properly 

evaluate the dose. This study likely did not consider the calibration of the commercial film 

badge nor the effects that filtration has on the resulting spectral energy. As a result, the 20 mR 

could be either an underestimate or an overestimate depending on a multitude of variables. As 

a result, the claimant favorable default values provided in ORAUT-OTIB-0006 should be used 

for chest X-rays (Tables A-1, A-5, A-7, A-8, and A-9).

The dose reconstructor should by default assume an annual posterior-anterior (PA) chest X-ray 

for all employees applicable from 1947 through 1975. Semiannual chest X-rays should be 

assumed for all assembly workers, and quarterly chest X-rays should be assumed for workers 

involved in radiography. Do not apply X-ray dose for years other than 1947 through 1975, 

regardless if the worker was employed at IAAP during other years. 

A PA view lumbar spine X-ray dose should be assigned to males in the year of hire from 1947 

through July 1975 unless person-specific information is found indicating otherwise. Default 

organ dose values for lumbar spine X-ray examination are provided in ORAUT-OTIB-0006 

(Tables A-2, A-6, A-10, and A-11). 

4.0 ESTIMATION OF INTERNAL RADIATION EXPOSURE 

Internal radiation exposures result from the inhalation, ingestion, and transdermal absorption of 

radioactive materials. Intakes of radioactive materials could have occurred and probably did 
Effective Date: 10/20/2011 Revision No. 01 DCAS-TKBS-0001 Page 8 of 18

occur to a certain extent during weapons assembly and disassembly procedures. No actual 

internal exposure data could be located for any given individual worker involved in Line 1 

operations. Based upon the recommendations of the Secretary of Health and Human Services, 

it was determined that internal exposures cannot be estimated with sufficient accuracy to 

complete dose reconstructions (USDOL 2005); thus, no internal dose should be assigned for 

Iowa Army Ammunition Plant employment. 

 

5.0 ESTIMATION OF EXTERNAL RADIATION EXPOSURE 

External radiation exposures are received from sources of ionizing radiation and radioactive 

materials located outside of the body. The radiation dose received from working with 

radioactive materials can be measured using a radiation sensitive film badge, ionization 

chamber, or thermoluminescent dosimeter. 

5.1 Photon Radiation 

The external dose contribution for photon exposures at the IAAP was predominately from 30-

250 keV photons. For the purposes of dose reconstruction, a claimant-favorable photon energy 

distribution of 100% 30 – 250 keV photons should be assumed, with an anterior to posterior 

radiation exposure geometry. Exposure dose conversion factors should be used to translate 

recorded whole body photon dose to target organ dose (NIOSH 2002). A missed photon dose 

value may be assigned (NIOSH 2002) for each reported non-positive dosimetry result 

(represented by ―0‖ or ―M‖) recorded in an employee’s exposure history. Information on the 

detection sensitivity of the dosimetry used at the IAAP can be found in Table 5.1 below. A 

claimant-favorable limit of detection value equal to 20 mrem should be used for missed dose 

calculations from the years 1955 through 1960, and 10 mrem from 1962 through 1974, if there 

are records of monitoring with reported zeroes in an individual’s exposure records. Missed 

dose should not be assigned unless a reported ―0‖ or ―M‖ exists in the individual’s exposure 

history records. 

 

5.2 Neutron Radiation 

Recorded neutron dose as reported in an individual’s dosimetry records must be adjusted with 

an ICRP Publication 60 neutron weighting factor of 1.91 for dose input into the Interactive 

RadioEpidemiological Program (IREP) (ICRP 1994). A neutron energy spectrum of 100% 100 

keV to 2 MeV (Fission Spectrum) should be assumed. Recorded neutron dose should be 

converted to organ dose using deep dose equivalent to organ dose equivalent dose conversion 

factors (NIOSH 2002). Missed dose may be assigned for neutron badge cycles when a ―zero‖

reported dose is documented in an individual’s exposure records provided to NIOSH. Nonpositive neutron dosimetry results may have been reported as either ―0‖ or as ―M‖.

Based on a review of the neutron dosimetry information for Line 1 workers, the lowest reported 

detectable neutron dose observed for an employee was 20 mrem, during a monitoring cycle in 

1974. Neutron dose reported during weekly cycles in 1962 was as low as 24 mrem. These 

reported values are likely below the actual limit of detection for the NTA film employed; 

therefore, a claimant-favorable limit of detection value of 50 mrem should be assumed for 

missed dose calculations based on known detection sensitivities for similar NTA films (ORAUT 

2005). 
Effective Date: 10/20/2011 Revision No. 01 DCAS-TKBS-0001 Page 9 of 18

5.3 Electron Radiation 

The primary source of electron exposures at the IAAP on Line 1 was from depleted uranium 

metal. Electron exposures as recorded by an employee’s film badge should be assigned using 

a dose conversion factor of unity and an energy distribution of 100% greater than 15 keV 

electrons. A review of the dosimetry exposure data at the IAAP indicates a limit of detection for 

electron exposures of 40 mrem. A missed dose of 40 mrem may be assigned for each reported 

―zero‖ dose result documented in an energy employee’s exposure history record.

5.4 Extremities Exposures 

Recorded positive extremity dose results should be assigned only for target organs of the 

extremities, and missed dose for each reported non-positive dosimetry result may be assigned 

using the limit of detection values documented above for the whole body badge. Extremity 

exposures should be assigned using a photon energy distribution of 100% 30 – 250 keV or 

electrons with energies greater than 15 keV, whichever is more claimant favorable for 

calculating dose to the target organ. 

5.5 Uncertainty 

Recorded positive external photon, neutron, and electron exposures should be assigned as 

point estimates (constant values) in the Interactive RadioEpidemiological Program. Missed 

doses calculated using the nLOD / 2 method (NIOSH 2002) should be assigned using a 

lognormal distribution where nLOD / 2 is the median value of the distribution, and nLOD is the 

95th percentile. 

Table 5.1 Summary of Photon Dosimetry Data 

Year

Exchange

Frequency First Badge Date

 End Date for last

 cycle

 Minimum

Reported Dose

1955 Weekly November 14, 1955 January 1, 1956 20

1956 Weekly January 2, 1956 February 13, 1956 20

1957 Weekly May 6, 1957 August 4, 1957 10a

1958 Weekly July 28, 1958 November 2, 1958 5

a

1959 Weekly June 29, 1958 October 4 1958 5

a

1960 Weekly March 7, 1960 June 19, 1960 5

a

1961b

1962 Weekly September 3, 1962 December 3, 1962 10

1963 Bi-Weekly January 7, 1963 January 5, 1964 10

1964 4 Week January 6, 1964 January 3, 1965 10

1965 4 Week January 4, 1965 January 2, 1966 10

1966 4 Week January 3, 1966 January 1, 1967 10

1967 4 Week January 2, 1967 December 31, 1967 10

1968 4 Week January 1, 1968 December 29, 1968 10

1969 4 Week December 30, 1968 December 28, 1969 10

1970 4 Week December 29, 1969 December 27, 1970 10

1971 4 Week December 28, 1970 January 23, 1972 10

1972 4 Week January 24, 1972 January 21, 1973 10

1973 4 Week January 22, 1973 January 20, 1974 10

1974 4 Week January 21, 1974 January 19, 1975 10

aGiven the dosimeter designs of this time period, it is highly unlikely that the film dosimeter could measure 

this level. For this early time period, a detection level of 20 mR is more credible. 

bNote that no film badge exposure data for IAAP workers could be located prior to 1955 or for the year of 1961. 
Effective Date: 10/20/2011 Revision No. 01 DCAS-TKBS-0001 Page 10 of 18

REFERENCES 

AEC (US Atomic Energy Commission), 1962-1973a, Summary of Radiation Exposures 

 Resulting in the Internal Body Deposition of Radioactive Material For The Year, AEC 

 Form 191 submitted by Mason & Hanger-Silas Mason Co. Inc., Burlington, Iowa. 

AEC (US Atomic Energy Commission), 1962-1973b, Summary of Radiation Exposures To 

 External Penetrating Radiation Accumulated During The Year, AEC Form 190 submitted 

 by Mason & Hanger-Silas Mason Co. Inc., Burlington, Iowa. 

Davis, C. E., 1969, Health Protection Survey Report, Burlington AEC Plant, report on annual 

 health protection survey by the AEC Albuquerque Office of Burlington operations held 

 September 17-19, 1969 (ORAU file locator 000923).

Decisioneering Inc., 2000, Crystal Ball 2000 User Manual, Denver, Colorado. 

Email communication, 2005, Medical X-ray Exposures for SEC-Designated Class Members. 

ICRP (International Commission on Radiation Protection), 1982, Protection of the Patient in 

 Diagnostic Radiology, Publication 34, Pergamon Press, Oxford, England. 

ICRP (International Commission on Radiological Protection), 1991, ―1990 Recommendations of 

 the International Commission on Radiological Protection,‖ Annals of the ICRP, 

Publication 60, Pergamon Press, Oxford, England. 

JAYCOR (JAYCOR and ICAIR Life Systems, Inc.), 1996, Remedial Investigation/Risk 

 Assessment Iowa Army Ammunitions Plant Revised Draft Final, 11 Volumes, May 21. 

Landauer (R. S. Landauer, Jr. and Company), Reports of film badge exposure for selected 

 periods during 1955 – 1975, Matteson, Illinois (ORAU file locators 000935-000955). 

NIOSH (National Institute for Occupational Safety and Health), 2002, External Dose 

 Reconstruction Implementation Guidelines, OCAS-IG-001, Revision 1, Office of 

 Compensation Analysis and Support, Cincinnati, Ohio. 

ORAUT-TKBS-0003. 2005. Savannah River Site Profile. Rev 03, April 5, 2005, Oak Ridge 

 Associated Universities (ORAU), Oak Ridge, TN. 

ORAUT-OTIB-0006, 2011. Dose Reconstruction from Occupationally Related Diagnostic X-ray 

Procedures. Rev. 04, June 20, 2011. Oak Ridge Associated Universities (ORAU), Oak Ridge, 

TN. 

Poole, C. R. and K. C. Harrison, 1954. ―Project History of Line 1 Operations at Iowa Ordnance 

 Plant, January 1, 1947 through July 1, 1954,‖ Silas Mason Company, Inc., Burlington, 

 Iowa, ORAU file locator 001487. 

U.S. Army, 1988, Review of Draft Endangerment Assessment Iowa Army Ammunitions Plant 

(IAAP), Toxic and Hazardous Materials Agency, November 28. 

U.S. Department of Labor correspondence, 2005, Return of Iowa Army Ammunition Plant Cases 

 for New SEC Class for 1949 – 1974. 
Effective Date: 10/20/2011 Revision No. 01 DCAS-TKBS-0001 Page 11 of 18

GLOSSARY 

Atomic Energy Commission

 Original agency established for nuclear weapons and power production; a predecessor 

to the U. S. Department of Energy.

beta radiation 

Radiation consisting of charged particles of very small mass (i.e. the electron) emitted 

 spontaneously from the nuclei of certain radioactive elements. Physically, the beta 

 particle is identical to an electron moving at high velocity. 

curie

 A special unit of activity. One curie (1 Ci) exactly equals 3.7 x 1010 nuclear transitions 

 per second. 

deep absorbed dose (Dd) 

The absorbed dose at the depth of 1.0 cm in a material of specified geometry and 

 composition. 

deep dose equivalent (Hd) 

 The dose equivalent at the respective depth of 1.0 cm in tissue. 

detection limit (lower)

The minimum quantifiable exposure or neutron flux that can be detected. 

dose equivalent (H)

 The product of the absorbed dose (D), the quality factor (Q), and any other modifying 

 factors. 

 The special unit is the rem. When D is expressed in Gy, H is in sieverts (Sv). 

 (1 Sv = 100 rem). 

dose of record

 The dose files provided by DOE to NIOSH as part of the individual worker files. 

dosimeter

A device used to measure the quantity of radiation received. A holder with radiation-

 absorbing element (filters) and an insert with radiation-sensitive elements packaged to 

 provide a record of absorbed dose or dose equivalent received by an individual. (See 

film dosimeter, neutron film dosimeter, thermoluminescent dosimeter). 

dosimetry 

The science of assessing absorbed dose, dose equivalent, effective dose equivalent, 

 etc., from external or internal sources of radiation. 

dosimetry system

A system used to assess dose equivalent from external radiation to the whole body, 

 skin, and extremities. This includes the fabrication, assignment, and processing of 

 dosimeters as well as interpretation and documentation of the results. 
Effective Date: 10/20/2011 Revision No. 01 DCAS-TKBS-0001 Page 12 of 18

DU

 Depleted uranium; uranium having less than the natural mass of 235U; used as 

 components in nuclear weapons or as a surrogate for enriched uranium or plutonium in 

 testing. 

exchange period (frequency)

 Period (weekly, biweekly, monthly, quarterly, etc.) for routine exchange of dosimeters. 

exposure 

 As used in the technical sense, a measure expressed in roentgens (R) of the ionization 

 produced by photons (i.e., gamma and X-rays) in air. 

extremity 

 That portion of the arm extending from and including the elbow through the fingertips, 

 and that portion of the leg extending from and including the knee and patella through the 

 tips of the toes. 

field calibration

 Dosimeter calibration based on radiation types, intensity and energies present in the 

 work environment. 

film

 Generally means a ―film packet‖ that contains one or more pieces of film in a light-tight 

 wrapping. The film when developed has an image caused by radiation that can be 

 measured using an optical densitometer. (See Dupont 552, Dupont 558, Eastman 

 Kodak, Nuclear Emulsions). 

film density 

 See optical density. 

film dosimeter 

 A small packet of film in a holder that attaches to a wearer. 

gamma rays (γ) 

 Electromagnetic radiation (photons) originating in atomic nuclei and accompanying many 

 nuclear reactions (e.g. fission, radioactive decay, and neutron capture). Physically, 

 gamma rays are identical to X-rays but with higher energy; the only essential differences 

 is that X-rays do not originate in the nucleus. 

Gertie 

 A facility covered with crushed gravel used to suppress the potential radioactive 

 contamination from the accidental explosion of a nuclear weapon during assembly. Also 

 referred to as a Gravel Gertie. 

Gray 

 SI unit of absorbed dose. Unit symbol, Gy. 1 Gy = 100 rad. 

hydroshot 

Detonation of explosives used as a quality control technique for measuring the 

performance of plastic-bonded explosives.
Effective Date: 10/20/2011 Revision No. 01 DCAS-TKBS-0001 Page 13 of 18

ionizing radiation 

 Electromagnetic or particulate radiation capable of producing charged particles through 

 interactions with matter. 

Line 1

 Facilities and operations taken over by the AEC in 1947 for casting of baratols and 

processes related to the assembly of nuclear weapons. 

Minimum Detectable Level (MDL) 

A term used in this document and other NIOSH documents to refer to a statistically 

 determined minimum detection level, Lower Limit of Detectability (LD), and related 

quantities. 

Minimum Reportable Dose (MRD) 

 A general term used to identify the minimum dose recorded and reported, normally 

 based on site-specific policy. 

neutron 

 A basic particle that is electrically neutral weighing nearly the same as the hydrogen 

atom. 

neutron, fast 

 Neutrons with energy equal or greater than 10 keV. 

neutron, intermediate

 Neutrons with energy between 0.5 eV and 10 keV. 

neutron, thermal 

 Strictly, neutrons in thermal equilibrium with surroundings. Generally, neutrons with 

 energy less than about 0.5 eV. 

neutron film dosimeter 

 A film dosimeter that contains a Neutron Track Emulsion, type A, film packet. 

nuclear emulsion 

 Often referred to as ―NTA‖ film and used to measure personnel dose from neutron 

 radiation. 

nuclear track emulsion, type A (NTA) 

 A film that is sensitive to fast neutrons. The developed image has tracks caused by 

 neutrons that can be seen by using an appropriate imaging capability such as oil 

 immersion and a 1000X power microscope or a projection capability. 

open window 

 Designation on film dosimeter reports that implies the use of little shielding. It commonly 

 is used to label the film response corresponding to the open window area. 
Effective Date: 10/20/2011 Revision No. 01 DCAS-TKBS-0001 Page 14 of 18

optical density

 The quantitative measurement of photographic blackening with the density defined as D 

= Log10 (Io/I). 

personal dose equivalent Hp(d)

 Represents the dose equivalent in soft tissue below a specified point on the body at an 

 appropriate depth d. The depths selected for personnel dosimetry are 0.07 mm and 10 

 mm, respectively, for the skin and body. These are noted as Hp(0.07) and Hp(10), 

 respectively. 

photon

 A unit or ―particle‖ of electromagnetic radiation consisting of X- or gamma rays. 

photon – X-ray 

 Electromagnetic radiation of energies between 10 keV and 100 keV whose source can 

be an X-ray machine or radioisotope. 

quality factor, Q 

 A modifying factor used to derive dose equivalent from absorbed dose. 

radiation 

 Alpha, beta, neutron, and photon radiation with sufficient energy to ionize atoms. See 

 also ionizing radiation. 

radioactivity 

 The spontaneous emission of radiation, generally alpha or beta particles, gamma rays, 

and neutrons from unstable nuclei.

rem

 A special unit of dose equivalent, which is equal to the product of the number of rad 

 absorbed and the ―quality factor.‖

roentgen (R)

 A unit of exposure to gamma (or X-ray) radiation. It is defined precisely as the quantity 

 of gamma (or x) rays that will produce a total charge of 2.58 x 10-4 coulomb in 1 kg of dry 

 air. An exposure of 1 R is approximately equivalent to an absorbed dose of 1 rad in soft 

 tissue for higher (>100 keV) energy photons. 

shallow absorbed dose (Ds) 

 The absorbed dose at a depth of 0.007 cm in a material of specified geometry and 

 composition. 

shallow dose equivalent (Hs) 

Dose equivalent at a depth of 0.007 cm in tissue. 

shielding

 Any material or obstruction that absorbs (or attenuates) radiation and thus tends to 

 protect personnel or materials from radiation. 
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skin dose

Absorbed dose at a tissue depth of 7 mg/cm2. 

thermoluminescent 

 Property of a material that causes it to emit light as a result of being excited by heat. 

thermoluminescent dosimeter (TLD) 

 A holder containing solid chips of material that when heated will release the stored 

 energy as light. The measurement of this light provides a measurement of absorbed 

 dose. 

whole-body dose 

 Commonly defined as the absorbed dose at a tissue depth of 1.0 cm (1000 mg/cm2); 

 however, this term is also used to refer to the recorded dose. 

X-ray 

Ionizing electromagnetic radiation that originates external to the nucleus of an atom. 

 
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Appendix A—U.S. Department of Labor Correspondence 
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