ORAU TEAM

Dose Reconstruction

Project for NIOSH

Oak Ridge Associated Universities I Dade Moeller I MJW Technical Services

Page 1 of 20

DOE Review Release 05/03/2010

Document Title:

Area IV of the Santa Susana Field Laboratory, the 

Canoga Avenue Facility, the Downey Facility, and 

the De Soto Avenue Facility (sometimes referred 

to as Energy Technology Engineering Center 

[ETEC] or Atomics International) – Occupational 

External Dose

Document Number: ORAUT-TKBS-0038-6

Revision: 02 

Effective Date: 04/26/2010

Type of Document: TBD

Supersedes: Revision 01 

Subject Expert(s): Leo G. Faust and Eugene W. Potter

Site Expert(s): N/A

Approval: Signature on File Approval Date: 04/22/2010

Melton H. Chew, Document Owner

Concurrence: Signature on File Concurrence Date: 04/22/2010

John M. Byrne, Objective 1 Manager

Concurrence: Keith A. McCartney Signature on File for Concurrence Date: 04/23/2010

Edward F. Maher, Objective 3 Manager

Concurrence: Signature on File Concurrence Date: 04/23/2010

Kate Kimpan, Project Director

Approval: Signature on File Approval Date: 04/26/2010

James W. Neton, Associate Director for Science

New Total Rewrite Revision Page Change

FOR DOCUMENTS MARKED AS A TOTAL REWRITE, REVISION, OR PAGE CHANGE, REPLACE THE PRIOR 

REVISION AND DISCARD / DESTROY ALL COPIES OF THE PRIOR REVISION.
Document No. ORAUT-TKBS-0038-6 Revision No. 02 Effective Date: 04/26/2010 Page 2 of 20

PUBLICATION RECORD

EFFECTIVE 

DATE

REVISION

NUMBER DESCRIPTION

02/22/2006 00 New technical basis document for the Energy Technology 

Engineering Center – Occupational External Dose. First approved 

issue. Initiated by Melton H. Chew.

11/16/2006 01 Approved Revision 01 to change the site name to Atomics 

International throughout the document in keeping with DOE site 

naming conventions. Updated required language in Section 6.1. 

Constitutes a total rewrite of document. Incorporates internal formal 

review comments and corrects typographical errors. Adds a 

paragraph to section 6.1.2 and clarification to missed dose and 

magnitude of background dose, Sections 6.2 and 6.8 respectively, as

requested by DOL. This revision results in no change to the 

assigned dose, and no PER is required. Training required: As 

determined by the Task Manager. Initiated by Melton H. Chew.

04/26/2010 02 Revised to incorporate SEC information in Section 6.1.2 and 

corrected an error in Table 6-8 pertaining to NTA film and footnote b. 

Incorporated formal internal and NIOSH review comments. Training 

required: As determined by the Objective Manager. Initiated by 

Melton H. Chew.
Document No. ORAUT-TKBS-0038-6 Revision No. 02 Effective Date: 04/26/2010 Page 3 of 20

TABLE OF CONTENTS

SECTION TITLE PAGE

Acronyms and Abbreviations ...............................................................................................................4

6.1 Introduction ..............................................................................................................................5

 6.1.1 Purpose........................................................................................................................6

 6.1.2 Special Exposure Cohort Petition Information............................................................... 6

 6.1.3 Scope...........................................................................................................................7

6.2 Missed Dose ............................................................................................................................8

6.3 Radiation Energies and Percentages at Selected Facilities......................................................9

6.4 Neutron Radiations and Percentages.....................................................................................10

6.5 Recorded Dose Practices.......................................................................................................12

6.6 Interpretation of Reported Doses ...........................................................................................12

6.7 External Coworker study ........................................................................................................13

6.8 Adjustments to Recorded Dose..............................................................................................13

6.9 Bias and Uncertainty..............................................................................................................14

6.10 Attributions and Annotations ..................................................................................................14

References ........................................................................................................................................15

Glossary ............................................................................................................................................18

LIST OF TABLES

TABLE TITLE

6-1 Estimated annual missed photon, beta, and neutron dose .......................................................

PAGE

9

6-2 Beta and photon energies and percentages at reactors and critical 

facilities ..................................................................................................................................10

6-3 Beta and photon energies and percentages at support facilities............................................. 11

6-4 Facilities, neutron energies, percentages, and correction factors ........................................... 12

6-5 Recorded dose practices........................................................................................................ 12

6-6 Interpretation of reported dose ............................................................................................... 13

6-7 Adjustments to recorded dose................................................................................................ 13

6-8 Uncertainty.............................................................................................................................14
Document No. ORAUT-TKBS-0038-6 Revision No. 02 Effective Date: 04/26/2010 Page 4 of 20

ACRONYMS AND ABBREVIATIONS

AI Atomics International

D deuterium

DOE U.S. Department of Energy

EEOICPA Energy Employees Occupational Illness Compensation Program Act of 2000

hr hour

keV kiloelectron-volt, 1,000 electron-volts

MDL minimum detectable level

MeV megaelectron-volt, 1 million electron volts

mR milliroentgen

mrad millirad

mrem millirem

MWt megawatt (thermal)

NIOSH National Institute for Occupational Safety and Health

NTA nuclear track emulsion, type A

NVLAP National Voluntary Laboratory Accreditation Program

OW open window

PIC pocket ionization chamber

POC probability of causation

QF quality factor

SNAP Systems for Nuclear Auxiliary Power

SRE Sodium Reactor Experiment

T tritium

TBD technical basis document

U.S.C. United States Code

WB whole body

wk week

§ section or sections
Document No. ORAUT-TKBS-0038-6 Revision No. 02 Effective Date: 04/26/2010 Page 5 of 20

6.1 INTRODUCTION

Technical basis documents (TBDs) and site profile documents are not official determinations made by 

the National Institute for Occupational Safety and Health (NIOSH) but are rather general working 

documents that provide historic background information and guidance to assist in 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 NIOSH staff 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 a site. It does not necessarily connote an “atomic weapons 

employer facility” or a “Department of Energy [DOE] facility” as defined in the Energy Employees 

Occupational Illness Compensation Program Act [EEOICPA; 42 U.S.C. § 7384l(5) and (12)]. 

EEOICPA defines a DOE facility as “any building, structure, or premise, including the grounds upon 

which such building, structure, or premise is located ... in which operations are, or have been, 

conducted by, or on behalf of, the Department of Energy (except for buildings, structures, premises, 

grounds, or operations ... pertaining to the Naval Nuclear Propulsion Program)” [42 U.S.C. § 

7384l(12)]. Accordingly, except for the exclusion for the Naval Nuclear Propulsion Program noted 

above, any facility that performs or performed DOE operations of any nature whatsoever is a DOE 

facility encompassed by EEOICPA.

For employees of DOE or its contractors with cancer, the DOE facility definition only determines 

eligibility for a dose reconstruction, which is a prerequisite to a compensation decision (except for 

members of the Special Exposure Cohort). The compensation decision for cancer claimants is based 

on a section of the statute entitled “Exposure in the Performance of Duty.” That provision [42 U.S.C. § 

7384n(b)] says that an individual with cancer “shall be determined to have sustained that cancer in the 

performance of duty for purposes of the compensation program if, and only if, the cancer ... was at 

least as likely as not related to employment at the facility [where the employee worked], as 

determined in accordance with the POC [probability of causation1

The statute also includes a definition of a DOE facility that excludes “buildings, structures, premises, 

grounds, or operations covered by Executive Order No. 12344, dated February 1, 1982 (42 U.S.C. 

7158 note), pertaining to the Naval Nuclear Propulsion Program” [42 U.S.C. § 7384l(12)]. While this 

definition excludes Naval Nuclear Propulsion Facilities from being covered under the Act, the section 

of EEOICPA that deals with the compensation decision for covered employees with cancer [i.e., 42 

U.S.C. § 7384n(b), entitled “Exposure in the Performance of Duty”] does not contain such an 

exclusion. Therefore, the statute requires NIOSH to include all occupationally-derived radiation 

exposures at covered facilities in its dose reconstructions for employees at DOE facilities, including 

radiation exposures related to the Naval Nuclear Propulsion Program. As a result, all internal and 

external occupational radiation exposures are considered valid for inclusion in a dose reconstruction. 

No efforts are made to determine the eligibility of any fraction of total measured exposure for inclusion 

in dose reconstruction. NIOSH, however, does not consider the following exposures to be 

occupationally derived (NIOSH 2007a): 

] guidelines established under 

subsection (c) ...” [42 U.S.C. § 7384n(b)]. Neither the statute nor the probability of causation 

guidelines (nor the dose reconstruction regulation, 42 C.F.R. Pt. 82) define “performance of duty” for 

DOE employees with a covered cancer or restrict the “duty” to nuclear weapons work (NIOSH 2007a).

• Background radiation, including radiation from naturally occurring radon present in 

conventional structures 

• Radiation from X-rays received in the diagnosis of injuries or illnesses or for therapeutic 

reasons 

 

1 The U.S. Department of Labor (DOL) is ultimately responsible under the EEOICPA for determining the POC.
Document No. ORAUT-TKBS-0038-6 Revision No. 02 Effective Date: 04/26/2010 Page 6 of 20

6.1.1

The purpose of this TBD is to describe external dosimetry systems and practices at Area IV of the 

Santa Susana Field Laboratory, Canoga Avenue Facility, Downey Facility, and De Soto Avenue 

Facility (sometimes referred to as Energy Technology Engineering Center [ETEC] or Atomics 

International). This document discusses historical and current practices at the facilities that, unless 

otherwise noted, used the same dosimeters and external dosimetry programs (Rutherford and Barnes

2006) in relation to the evaluation of external exposure data for monitored and unmonitored workers. 

Purpose

6.1.2

Although NIOSH found that it is not possible to completely reconstruct radiation doses for the SEC 

classes below, NIOSH intends to use any internal and external monitoring data that may become 

available for an individual claim (and that can be interpreted using existing NIOSH dose 

reconstruction processes or procedures). Therefore, dose reconstructions for individuals employed at 

the Area IV, Canoga Avenue, De Soto Avenue, or Downey facilities during the SEC periods stated 

below, but who do not qualify for inclusion in the SEC, may be performed using these data as 

appropriate.

Special Exposure Cohort Petition Information

Class Added to the SEC

Area IV of SSFL (1955-1958)

• All employees of the Department of Energy (DOE), its predecessor agencies, and DOE 

contractors and subcontractors who worked in any area of Area IV of the Santa Susana Field 

Laboratory for a number of work days aggregating at least 250 work days from January 1, 

1955 through December 31, 1958, or in combination with work days within the parameters 

established for one or more other classes of employees in the SEC (Sebelius 2009).

NIOSH determined in 2009 (NIOSH 2009) that it cannot estimate internal exposures with sufficient 

accuracy during the period from 1955 through 1958. This includes the time from the beginning of 

Area IV radiological activities in 1955, to late 1958 (selected as December 31, 1958 for SEC 

evaluation purposes). NIOSH intended the end of the SEC period to correspond with the date after 

which a routine bioassay program existed at SSFL and after which sufficient internal monitoring was 

thought to have been identified. Later in 2009 after further data review, NIOSH determined that 

sufficient data are not available for adequate dose reconstruction until January 1, 1965; NIOSH 

subsequently initiated a second SEC class for Area IV for the years 1959-1964, as described below. 

Classes Recommended by NIOSH for addition to the SEC

• All employees of the Department of Energy, its predecessor agencies, and their contractors 

and subcontractors who worked in any area of Area IV of the Santa Susana Field Laboratory 

from January 1, 1959 through December 31, 1964, for a number of work days aggregating at 

least 250 work days, occurring either solely under this employment or in combination with work 

days within the parameters established for one or more other classes of employees included in 

the Special Exposure Cohort (NIOSH 2010a).

Area IV of SSFL (1959-1964)

Through the course of ongoing dose reconstruction, continued data capture efforts, and investigations 

associated with SEC-00093, NIOSH determined in 2010 (NIOSH 2010a) that it cannot estimate with 

sufficient accuracy the potential internal exposures to various radionuclides to which the proposed 
Document No. ORAUT-TKBS-0038-6 Revision No. 02 Effective Date: 04/26/2010 Page 7 of 20

class may have been subjected during the time period from January 1, 1959 through December 31, 

1964. NIOSH found that it is likely feasible to reconstruct external dose, including occupational 

medical dose, for Area IV of the Santa Susana Field Laboratory workers with sufficient accuracy.

• All employees of the Department of Energy, its predecessor agencies, and its contractors and 

subcontractors who worked at the Canoga Avenue Facility, Los Angeles, California, from 

January 1, 1955 through December 31, 1960 for a number of working days aggregating at 

least 250 work days, occurring either solely under this employment or in combination with work 

days within the parameters established for one or more other classes of employees in the SEC 

(NIOSH 2010b).

Canoga Avenue Facility

NIOSH determined in 2010 (NIOSH 2010b) that it cannot estimate internal exposures with sufficient 

accuracy during the period from 1955 through 1960. This includes the entire covered period for the 

Canoga Avenue Facility. NIOSH found that it is likely feasible to reconstruct external dose, including 

occupational medical dose, for Canoga Avenue workers with sufficient accuracy.

• All employees of the Department of Energy, its predecessor agencies, and their contractors 

and subcontractors who worked at the Downey Facility in Los Angeles County, California, from 

January 1, 1948 through December 31, 1955, for a number of work days aggregating at least 

250 work days, occurring either solely under this employment or in combination with work days 

within the parameters established for one or more other classes of employees included in the 

Special Exposure Cohort (NIOSH 2010c).

Downey Facility

NIOSH determined in 2010 (NIOSH 2010c) that it cannot estimate internal exposures with sufficient 

accuracy during the period from 1948 through 1955. This includes the entire covered period for the 

Downey Facility so only partial dose reconstructions will be performed for individuals who do not 

qualify for inclusion in the SEC.

• All employees of the Department of Energy, its predecessor agencies, and their contractors 

and subcontractors who worked at the De Soto Avenue Facility in Los Angeles County, 

California, from January 1, 1959 through December 31, 1964, for a number of work days 

aggregating at least 250 work days, occurring either solely under this employment or in 

combination with work days within the parameters established for one or more other classes of 

employees included in the Special Exposure Cohort (NIOSH 2010d).

De Soto Avenue Facility

NIOSH determined in 2010 (NIOSH 2010d) that it cannot estimate internal exposures with sufficient 

accuracy during the period from 1959 through 1964. The De Soto Avenue Facility has a covered 

period of DOE 1959-1995 and DOE Remediation 1998. Therefore, dose reconstructions will be 

performed for 1965 through 1995 and partial dose reconstructions will be performed for individuals 

who do not qualify for inclusion in the SEC for 1959 through 1964.

6.1.3

This TBD contains supporting documentation to assist in the evaluation of occupational external 

doses from processes that occurred at SSFL. An objective of this document is to provide supporting 

technical data to evaluate, with assumptions favorable to claimants, occupational external doses that 

Scope
Document No. ORAUT-TKBS-0038-6 Revision No. 02 Effective Date: 04/26/2010 Page 8 of 20

can reasonably be associated with worker radiation exposures. This document addresses the 

evaluation of unmonitored and monitored worker exposure, missed dose, and the bias and uncertainty 

associated with the monitoring of external dose.

The SSFL facilities, which include four locations, have been identified in various ways over time. This 

TBD uses SSFL to refer to all locations unless more specific location information is warranted. In that 

context, SSFL includes Area IV of the Santa Susana Field Laboratory (which has also been known as 

the Nuclear Development Field Laboratory, the Liquid Metal Engineering Center, and the Energy 

Technology Engineering Center), portions of the Downey facility, the Canoga facility, and the De Soto 

facility.

North American Aviation (NAA) entered into a contract with AEC to conduct nuclear research 

operations at Area IV and the Downey, Canoga and De Soto sites. At that time, Atomics 

International, an internal division of NAA, was the company’s designated nuclear research and 

development division. In addition to the employees of the AI division, other employees of NAA who 

worked at any of the above sites during the AEC contract period are potentially eligible for EEOICPA 

benefits.

SSFL had its own dosimeter in the beginning that was very similar to the multielement film dosimeters 

used at the Y-12 plant (ORAUT 2009b) and the Hanford Site (ORAUT 2010) based on the design 

developed by Pardue, Goldstein, and Wollan (1944) as well as pocket ionization chambers (PICs or 

pencil dosimeters). Both penetrating and nonpenetrating doses were recorded. SSFL started using 

commercial vendors in the early 1960s and continued that practice throughout the rest of its operating 

life. 

6.2 MISSED DOSE

Missed doses at SSFL facilities generally resulted from dosimeter minimum detectable levels (MDLs) 

and exchange periods. In reviewing an individual dose record from December 31, 1956, to December 

30, 1957, entries were both weekly and biweekly with the former starting in May 1957 (Author 

unknown 1956). This would suggest that exchange periods varied with time, job, and individual. 

SSFL (1960) states, “Normally film badges are to be worn for monthly periods except where the 

possibility of exceeding 100 mrem/wk of exposure is expected. Then the badges are to be analyzed 

more frequently.” Therefore, missed doses before 1963, if not derived by review of individual records, 

would be based on weekly exchanges and would be applicable to both Hp(0.07) and Hp(10). Starting 

in 1963, most dosimeters were processed by their vendor (Landauer or its predecessor) (Garcia and 

Carpenter 1963a). On occasion, workers wore special dosimeters to monitor nonroutine work such as 

“hot jobs or cell entries” and always without their regular dosimeter. These special dosimeters were 

always worn in pairs; the results were averaged, and that average result was sent to the vendor for 

inclusion in the total dose for that period’s regular dosimeter result. It has not been determined if the 

special dosimeter procedure was in effect before 1963. Extremity finger ring film dosimeters were 

worn on both hands, and individual results were recorded for each hand. It has not been determined 

when this practice started, but it was in place in the December 31, 1956, dose record (Author 

unknown 1956) and included what appears to be the same exchange periods.

In cases of lost or destroyed dosimeters, results were derived from past results of similar work, 

coworker results, or the product of instrument measurements and time spent in the radiation zone. 

These practices are typical of sites with similar circumstances.

Neutron doses were measured with neutron track analysis, type A (NTA) film beginning with the start 

of reactor operations and the use of Van de Graaff accelerators. Both fast and thermal neutrons were 

measured and recorded as whole-body (WB) dose in rem. The NTA film is not effective at energies 
Document No. ORAUT-TKBS-0038-6 Revision No. 02 Effective Date: 04/26/2010 Page 9 of 20

<0.5 MeV or at exposures of <50 mrem (ORAUT 2009b). However, cadmium and lead filters over the 

beta-gamma film were included in the film holder. The difference in densities behind these filters 

provides a means of detecting thermal neutrons via a neutron-gamma reaction in the cadmium filter. 

The thermal neutron dose, if any, was included with the dose detected by the NTA film. It has not 

been determined what quality factors (QFs) were used. However, because a Po-Be neutron source 

was used for calibration, a reasonable assumption would be QF = 10 (Garcia 1970).

Missed doses for unmonitored employees could be as much as 500 mrem or 10% of whatever 

standard was in effect at the time of employment as allowed by AEC and its successors (AEC Manual 

Chapter 0524 and DOE Order 5480.11). However, the site policy was that everyone who entered a 

controlled area was issued a dosimeter (AI 1960a). To allow for the possibility that this policy was not 

followed or that records may not be available, an external dose coworker study has been published 

(ORAU 2009a). The unmonitored workers may have been exposed to annual doses, above 

background, ranging from 10 to 40 mrem (ORAUT 2007) if they worked in Area IV. 

Table 6-1 lists the periods of use, types of dosimeters, exchange periods, MDLs, and estimated 

annual missed doses. 

Table 6-1. Estimated annual missed photon, beta, and neutron dose (rem). 

Perioda Dosimeterb 

Exchange 

period MDLc

Estimated annual

missed dosed

1954–1962 Pocket dosimeter (PIC) Daily 0.005 0.625

Weekly 0.04 1.04

Site-specific two-element film Biweekly 0.04 0.52

Monthly 0.04 0.24

1963–1979 Landauer multielement film Monthly 0.04e 0.24

Quarterly 0.04 0.08

1980f–present Landauer multielement film Quarterly 0.01g 0.02

1954–1989 NTA film Bi-weekly <0.05 0.650

Monthly <0.05 0.300

a. Estimated use periods for first entry. Landauer or its predecessor was the vendor in 1963 and maybe 

 earlier (Garcia and Carpenter 1963a). 

b. Neither the actual number of dosimeter elements of the first entry dosimeter nor the period of use of PICs 

has been determined. 

c. Estimated MDLs for each dosimeter in the workplace even though many doses were reported at less than 

the MDL.

d. Estimated annual missed dose calculated using MDL/2 from NIOSH (2002).

e. Based on NAS (1989). 

f. Neutron dosimeters continued monthly exchanges (Tuttle 1979).

g. Yoder (2005). 

6.3 RADIATION ENERGIES AND PERCENTAGES AT SELECTED FACILITIES

As described in ORAUT (2006a), there were many different types of facilities and processes at SSFL 

and other facilities during their periods of operation; these include reactors, critical test facilities, fuel 

preparation and postirradiation examination facilities, accelerator and calibration facilities, and support 

facilities. Most reactors were low power (a few kilowatts), with the maximum being 20 MWt, and all 

had relatively short operating histories. The major accelerator was a Van de Graaff (DeuteriumTritium) machine producing neutrons with a maximum energy of 14 MeV. The fuel examination and 

manufacturing facilities, reactors, and critical facilities handled fissionable fuels with various 

enrichments, mostly compounds of uranium including carbides. They also handled relatively small 

quantities of plutonium and thorium with the exception of Buildings 4023, 4029, 4030, and 4363. 

SSFL did not perform chemical separations of irradiated fuel and, therefore, there were minimal gross 

fission product problems. The Canoga facility performed some nuclear fuel reprocessing 
Document No. ORAUT-TKBS-0038-6 Revision No. 02 Effective Date: 04/26/2010 Page 10 of 20

experiments, but the metallic uranium had not been highly irradiated according to one of the workers 

(Miles 2009). SSFL did declad some fuels in the hot cells, which resulted in considerable quantities of

those fission products with high fission yields (e.g., 90Sr and 137Cs). There was some 152Eu and 154Eu 

along with some 3

H. Tables 6-2 and 6-3 list the facilities and related data.

Table 6-2. Beta and photon energies and percentages at reactors and critical facilities. 

Process/

building Descriptiona

Operations Radiation

type

Energy

Begin End (keV) Percentage

All Reactors 1956 1980 Beta >15 100

Photons 30–250 25

>250 75

4143 SRE reactor 1957 1964 Beta >15 100

Photons 30–250 25

>250 75

4010 SNAP Experimental Reactor and 

SNAP 8 Development ReactorS8ER

1959 1965 Beta >15 100

Photons 30–250 25

>250 75

4024 SNAP 2 Development ReactorS2DR 1961 1962 Beta >15 100

SNAP 10 Flight Simulation 

ReactorS10FS3

1965 1966 Photons 30–250 25

SNAP test facilities 1971 1971 >250 75

4028 Shield Test Reactor and 

Shield Test and Irradiation 

ReactorSTIR

1961 1972 Beta >15 100

Photons 30–250 25

>250 75

4059 SNAP 8 Development ReactorS8DR 1968 1969 Beta >15 100

Photons 30–250 25

>250 75

4009 Organic Moderated ReactorOMR, 

and 

Sodium Graphite ReactorSGR

1958 1967 Beta >15 100

Photons 30–250 25

>250 75

4100 Advanced Epithermal Thorium 

ReactorAETR

1960 1974 Beta >15 100

Photons 

(thorium)

30–250 25

>250 75

a. SNAP = Systems for Nuclear Auxiliary Power; SRE = Sodium Reactor Experiment. 

6.4 NEUTRON RADIATIONS AND PERCENTAGES 

Table 6-4 lists facilities with neutron radiations. They are reactors, accelerators, and fuel storage 

facilities. The table includes the plutonium fuel storage facilities, Buildings 4005 and 4064, which 

were used for Pu storage from 1967 to 1987 and from 1958 to 1993, respectively. However, these 

facilities are assumed to be a negligible contributor to neutron doses due to the limited quantities of 

fuel present at any one time. NTA film was implemented in 1956 to measure personnel exposures to 

the “degraded fission spectrum” that was expected from facilities such as the SRE. A study 

performed at the time showed that SSFL had a good understanding of the shortcomings of NTA film

(AI 1956). Initially, NTA film was incorporated in the film dosimeters if there was a potential of 

exposure >100 mrem/month whole bode dose in those facilities where neutron exposures were 

possible (AI 1960b, AEC 1963). How that was determined has not been found. However, it appears 

that NTA film was added for specific locations where neutrons were a concern (AI 1960b). In the 

dose record, there are entries in the “n” column. The dose recorded was the sum of fast neutron 

exposure and thermal neutron exposure, if any. 

A neutron survey report of the SRE Hot Cell containing a 14-MeV neutron generator (Clow 1966) lists 

dose rates of 75 mrem/hr fast and 11.8 mrem/hr thermal with “the assumption that all fast neutrons 
Document No. ORAUT-TKBS-0038-6 Revision No. 02 Effective Date: 04/26/2010 Page 11 of 20

are 14 MeV.” Clow also states, “As further surveys are taken and the spectrum completely analyzed, 

the dose rates may be reduced.” These surveys were done on the roof of the facility and were higher 

than those taken at “a window” (62.2 mrem/hr fast and 7.1 mrem/hr thermal) or ”at the console” 

(7.1 mrem/hr fast and 2.2 mrem/hr thermal). The Van de Graaff accelerator with its D-T reaction 

generates 14-MeV neutrons that are quite monoenergetic in the 0° and 180° directions (Etherington 

1958), which might support the assumption that all fast neutrons can be treated as 14 MeV. 

Table 6-3. Beta and photon energies and percentages at support facilities.

Building Description

Operations

Radiation

Energy 

Begin End (keV) Percentages

*SRE-4003, 4163, 

4041, 4654, 4689, 

4653, 4606, 4773

Support facilities 1954 1964 Beta >15 100

Photons 30–250 25

>250 75

*4020 Hot Laboratory 1957 1988 Beta >15 100

Photons 30–250 25

>250 75

*4064 Fuel Storage 1958 1993 Beta >15 100

Photons 30–250 25

>250 75

4011 Radiation Instrument 

Calibration Laboratory

1984 1996 Beta >15 100

Photons 30–250 25

>250 75

*4021/4022 Radiation Materials 

Handling Facility

1959 Present Beta >15 100

Photons 30–250 25

>250 75

4100 Calibration Laboratory 1985 Present Beta >15 100

Photons 30–250 25

>250 75

4363 Mechanical Component 1956 1963 Beta >15 100

Photons 30–250 50

>250 50

4029 Radioactive Measurement 

Laboratory

1959 1974 Beta >15 100

Photons 30–250 25

>250 75

4030 Van de Graaff accelerator 1960 1964 Beta >15 100

Photons 30–250 25

>250 75

4023 Liquid Metal Component 

Testing

1962 1986 Beta >15 100

Photons 30–250 50

>250 50

*4005 Union Carbide Fuel Pilot 

Plant

1964 1967 Beta >15 100

Photons 30–250 25

>250 75

*4055 Nuclear Materials 

Development Facility

1967 1979 Beta >15 100

Photons 30–250 25

>250 75

*For operations involving Th-232, 1964 and 1979.
Document No. ORAUT-TKBS-0038-6 Revision No. 02 Effective Date: 04/26/2010 Page 12 of 20

Table 6-4. Facilities, neutron energies, percentages, and correction factors. 

Facility Source

Neutron energy 

(MeV)

Default dose % and 

correction factors

Reactors Reactors 0.1–2.0, WR=20 100%

Pu fuel storage Correction factor = 1.91

Buildings. 4005 & 4064

Spontaneous fission and 

alpha- neutron reactions

4030 Van de Graaff 

accelerator

D-T reaction 2–14 max, WR=20 100%

Correction factor = 1.32

The distribution of energies and International Commission on Radiological Protection Publication 60 

conversion correction factors (ICRP 1991 and ORAUT 2006b) are also listed in Table 6-4. The 

correction factor for the 2- to 14-MeV energy group was calculated from data in the Y-12 TBD 

(ORAUT 2009b).

6.5 RECORDED DOSE PRACTICES

Recorded dose quantities at SSFL are given in Table 6-5 and include those provided by the site, 

Landauer (the site vendor), and special dosimeters (Hart 1979). The special dosimeters were

processed by site personnel using site calibrations, and only the results were sent to the vendor for 

inclusion in the individual’s total dose for that period. This could have resulted in different quantities, 

on occasion, from those listed in Table 6-5. 

Table 6-5. Recorded dose practices.

a

Period Dosimeter measured quantities Compliance dose quantitiesb

1954–1962 + NTA film Beta = OW, mremc

Photon (P), mR

Fast Neutron (FN), mrem

Skin = OW + P

WB = P + FN

1963–1984

Landauer + NTA film

Beta (B) or nonpenetrating, mR

Photon (P), mR

Fast Neutron (FN), mrem

Skin = (B) + P

WB = B + P + FN

WB = 0.15 (B-X-ray) + P + FNd 

1985–present Nonpenetrating (Npen)

Penetrating (Pen)

Fast Neutron (FN)

Skin = Npen + WBe

WB = Pen + neutronse 

a. OW = open window.

b. Before 1985, the Landauer assessment or calibration quantity was the roentgen at the surface of the body. In 1985, 

Landauer switched to International Commission on Radiation Units and Measurements tissue doses to incorporate 

American National Standards Institute Standard N 13.11 (HPS 1983) and DOE Laboratory Accreditation Performance

Program (DOELAP)(DOE 1986) performance testing dose quantities (Yoder 2005).

c. Garcia and Carpenter (1963 b) discusses the use of eye and gonadal shields that, if used, reduced beta values by a 

factor of 2.

d. Garcia and Carpenter (1963 b).

e. Garcia (1970).

Garcia and Carpenter (1963a) provided a formula for correcting beta doses measured by the special 

dosimeters that is different from that in Garcia (1970). The differences are not great and are limited to 

beta dose corrections. The differences could be the result of a change from DuPont to Kodak film, 

which could have occurred in the period between the two procedures. Landauer changed to Kodak 

film in 1968 with the introduction of its Gardray film badge (Yoder 2005).

6.6 INTERPRETATION OF REPORTED DOSES 

Table 6-6 summarizes the guidance on the interpretation of reported doses. Personnel doses from 

Landauer before 1985 were reported in milliroentgen as either penetrating (photon) or nonpenetrating 
Document No. ORAUT-TKBS-0038-6 Revision No. 02 Effective Date: 04/26/2010 Page 13 of 20

(beta) exposure if beta activity was present. The reported total values included any special dosimeter 

results sent by SSFL for that exchange period. Dose reconstructors should obtain organ doses, as 

needed, from External Dose Reconstruction Implementation Guideline (NIOSH 2002). 

In general, reported doses have been corrected for background using site-furnished controls. The 

controls were dosimeters at locations on the site used for storing personnel dosimeters. All personnel 

dosimeters were stored in storage racks when workers left the site at the end of their shifts. No 

workers took their dosimeters home at night; all were kept at the site and, as far as could be 

determined, this practice was in place since startup.

The exception to background correction could occur if individual dosimeters were not exchanged in 

time to be included with the regular exchange because controls were sent only with each exchange 

batch. While this could lead to an incorrect result, that result would be favorable to claimants because

it would include background and, therefore, err on the high side (Rowles 1988). 

Table 6-6. Interpretation of reported dose. 

Period

Reported 

quantity Description

Interpretation 

of zerosa

Interpretation 

of blanks 

(no data)

Rollup of 

individual and 

annual datab Monitored/ unmonitored

1954–

1962 

Skin = rad

WB = mR

Neutrons = rem

mrad, mR, and 

mrem used 

interchangeably

MDL/2 times 

number of 

zeros

If no dosimeter 

for that period, 

treat as 

unmonitored.

If special 

dosimeters were 

used, include 

results.

All personnel expected to 

be exposed to 

>100 mrem in an 

exchange period were 

required to be monitored.

1963–

present

Skin = mrem

WB = mrem

Neutrons = mrem 

mrem used for 

all

MDL/2 times 

number of 

zeros

If no dosimeter 

for that period, 

treat as 

unmonitored.

If special 

dosimeters were 

used, include 

results.

Workers entering 

controlled areas were 

required to wear a 

dosimeter.

a. The missed dose is calculated by assigning a value of MDL/2 to all recorded doses <MDL/2 which includes zero values. 

See guidance in IG-001 (NIOSH 2007b).

b. If special dosimeters were used, the results were forwarded to the vendor for inclusion in the totals for that period. It has 

not been determined if this was always accomplished.

6.7 EXTERNAL COWORKER STUDY

A external coworker study has been published to provide information to allow dose reconstructors to 

assign doses that are based on site coworker data to workers who were employed at Area IV and 

associated sites and for whom there is no or limited monitoring data (ORAUT 2009a).

6.8 ADJUSTMENTS TO RECORDED DOSE

Because most but not all penetrating photons are above 30 keV, it is suggested that an adjustment is 

necessary to account for the contribution to Hp(10) from low-energy photons from uranium and 

thorium. It is estimated that a correction equal to 10% of the <250-keV values should be made. 

Corrections are made for each energy group. Table 6-2 should be consulted for the applicable facility 

specific energy fractions. This adjustment also increases the nonpenetrating Hp(0.07) dose, 

regardless of which dosimeter was used, because that dose was always the sum of the OW and WB 

doses. Table 6-7 lists these corrections. The fading correction for NTA film is about 9%/week (Meyer 

1994), and the angular dependence correction factor is 1-3 (Kathren 1965).

Table 6-7. Adjustments to recorded dose. 

Period Dosimeter Facility

Adjustments to reported dose

Photon Energy Multiply by

1954–1963 Site-specific All facilities 30-250 keV 1.1

> 250 keV 1.0
Document No. ORAUT-TKBS-0038-6 Revision No. 02 Effective Date: 04/26/2010 Page 14 of 20

1963–1985 Landauer All facilities 30-250 keV 1.1

> 250 keV 1.0

1985–present Landauer All facilities 30-250 keV 1.1

> 250 keV 1.0

6.9 BIAS AND UNCERTAINTY

Bias and uncertainty values were not found in any site data. The uncertainty factors in Table 6-8 are

proposed based on judgment of uncertainty of dosimeter performance in the site specific fields.

Table 6-8. Uncertainty.

a

Dosimeter Uncertainty Factora

Two-element Film Dosimeter (1954-63) 1.4

Multi-element Film (1964-present 1.3

NTA Film (1954-present) (2-14 MeV) 1.3

NTA Film (1954-present) (0.1-2 MeV 1.5

a. Estimated variability of measured dose based on dosimeter technology as used in site radiation fields for long term 

workers. 

6.10 ATTRIBUTIONS AND ANNOTATIONS

All information requiring identification was addressed via references integrated into the reference 

section of this document.
Document No. ORAUT-TKBS-0038-6 Revision No. 02 Effective Date: 04/26/2010 Page 15 of 20

REFERENCES

AI (Atomics International), 1956, “Fast Neutron Monitoring with NTA Film Packets,” NAA-SR-1536,

 July 15. [SRDB Ref ID: 73063]

AI (Atomics International), 1960a, “Radiological Safety at Atomics International, A Division of North 

American Aviation, Inc.,” AI-MEMO 5468, July 13. [SRDB Ref ID: 19144]

AI (Atomics International). 1960b, Health and Safety Manual – Historical, Routine Urine Specimen

Collection, July 22. [SRDB Ref ID: 39671]

AEC (U.S. Atomic Energy Commission), 1963, "Standards for Radiation Protection," Chapter 0524, 

AEC Manual, Washington D.C. August 12. [SRDB Ref ID: 13037]

ANSI (American National Standards Institute), 1983, American National Standard, Criteria for Testing 

Personnel Dosimetry Performance, ANSI N13.11, New York.

Author unknown, 1956, “Examples of Data from Old Dosimetry Files.” [SRDB Ref ID: 19706]

Barnes, J. G, 2006, “Background Doses”, e-mail to L. G. Faust (M.H. Chew & Associates, Inc.),The 

Boeing Co., Canoga Park, CA, October 10. [SRDB Ref ID: 32581]

Clow, H. E., 1966, “Neutron Survey of ’SRE Hot Cell’ Containing a 14 MeV Neutron Generator,” 

memorandum to E. T. Bramlitt, Atomics International, February 3. [SRDB Ref ID: 19061]

DOE (U. S. Department of Energy), 1986, Department of Energy Standard for the Performance 

Testing of Personnel Dosimetry Systems, DOE Laboratory Accreditation Program for 

Personnel Dosimetry Systems, DOE/EH-0027, Assistant Secretary for Environment, Safety,

and Health, Washington, D.C., December. [SRDB Ref ID: 12294]

Etherington, H., editor, 1958, Nuclear Engineering Handbook, McGraw-Hill Book Company.

Garcia, R. R., 1970, Dose Interpretation, Reporting, and Controls in the AI Personnel Film Badge 

Program, PM-15, North American Aviation, October 30. [SRDB Ref ID: 19670] 

Garcia, R. R., and G. D. Carpenter, 1963a, Handling of Routine Film Badges, North American 

Aviation, April 5. [SRDB Ref ID: 19182]

Garcia, R. R., and G. D. Carpenter, 1963b, Dose Determination, PM-14, North American Aviation, 

July 15. [SRDB Ref ID: 19687]

Hart, R. S., 1979, Annual Review of Radiological Controls-1975, N001T1990002, Rockwell 

International, July 2. [SRDB Ref ID: 19137]

HPS (Health Physics Society), 1983, An American National Standard, Personnel Dosimetry 

Performance – Criteria for Testing, ANSI/HPS N13.11-1983, McLean, Virginia.

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

International Commission on Radiological Protection, Publication 60, Pergamon Press, Oxford, 

England.
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Kathren R. L., Prevo, C. T., and Block, S., 1965, “Angular Dependence Of Eastman Type A (NTA) 

Personnel Monitoring Film,” Health Physics, volume 11, October, pp. 1067–1069. [SRDB Ref 

ID: 6180]

Meyer, H. E. (compiler), 1994, History of Personnel External Dosimetry Program at the Dayton Project 

and Mound Laboratory 1946-1993, Mound Laboratory, Miamisburg, Ohio. [SRDB Ref ID: 

3276]

Miles, Chris, 2009, “Canoga Park (1955 to 1980); Downey (1948 to 1955); and DeSoto (1959 to 1965) 

Facilities” interview with Jerold Guon, Atomics International, Canoga Park, California, 

December 16. [SRDB Ref ID: 77824] 

NRC (National Research Council), 1989, Film Badge Dosimetry in Atmospheric Nuclear Tests, 

National Academy of Sciences, National Academy Press, Washington, D.C. [SRDB Ref ID:

1905]

ORAUT (Oak Ridge Associated Universities Team), 2006, Technical Basis Document for the Y-12

NIOSH (National Institute for Occupational Safety and Health), 2007a, Radiation Exposures Covered 

for Dose Reconstructions Under Part B of the Energy Employees Occupational Illness 

Compensation Program Act, OCAS-IG-003, Rev. 0, Office of Compensation Analysis and 

Support, Cincinnati, Ohio, November. [SRDB Ref ID: 35987]

NIOSH (National Institute for Occupational Safety and Health), 2007b, External Dose Reconstruction 

Implementation Guidelines, OCAS-IG-001, Rev. 1, Office of Compensation Analysis and 

Support, Cincinnati, Ohio, November. 

NIOSH (National Institute for Occupational Safety and Health), 2009, Special Exposure Cohort, 

Petition Evaluation Report Petition SEC-00093, Office of Compensation Analysis and Support, 

Cincinnati, Ohio

NIOSH (National Institute for Occupational Safety and Health), 2010a, Special Exposure Cohort, 

Petition Evaluation Report Petition SEC-00156, Office of Compensation Analysis and Support, 

Cincinnati, Ohio 

NIOSH (National Institute for Occupational Safety and Health), 2010b, Special Exposure Cohort, 

Petition Evaluation Report Petition SEC-00151, Office of Compensation Analysis and Support, 

Cincinnati, Ohio 

NIOSH (National Institute for Occupational Safety and Health), 2010c, Special Exposure Cohort, 

Petition Evaluation Report Petition SEC-00167, Office of Compensation Analysis and Support, 

Cincinnati, Ohio 

NIOSH (National Institute for Occupational Safety and Health), 2010d, Special Exposure Cohort, 

Petition Evaluation Report Petition SEC-00168, Office of Compensation Analysis and Support, 

Cincinnati, Ohio 

ORAUT (Oak Ridge Associated Universities Team), 2006a, Energy Technology Engineering Center – 

Site Description, ORAUT-TKBS-0038-2, Rev. 00, Oak Ridge, Tennessee, February 2. [Note: 

Rev. 01 of ORAUT-TKBS-0038-2 will use Atomics International rather than Energy 

Technology Engineering Center to refer to this site.] 
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ORAUT (Oak Ridge Associated Universities Team), 2006b, Technical Basis for Conversion from 

NCRP Report 38 Neutron Quality Factors to ICRP Publication 60 Radiation Weighting Factors 

for Respective IREP Input Neutron Energy Ranges, ORAUT-OTIB-0055 Rev 00, Oak Ridge, 

Tennessee, June 5. 

ORAUT (Oak Ridge Associated Universities Team), 2007, AI- Occupational Environmental, ORAUTTKBS-0038-4, Rev-00, Oak Ridge, Tennessee, March 8.

ORAUT (Oak Ridge Associated Universities Team), 2009a, External Coworker Dosimetry Data for 

Area IV of Santa Susana Field Laboratory, the Canoga Avenue Facility (Vanowen Building), 

and the De Soto Avenue Facility (sometimes referred to as Energy Technology Engineering 

Center [ETEC] or Atomics International), ORAUT-OTIB-0077, Rev. 00, Oak Ridge, 

Tennessee, August 3. 

ORAUT (Oak Ridge Associated Universities Team), 2009b, Y-12 National Security Complex – 

Occupational External Dosimetry, ORAUT-TKBS-0014-6, Rev. 02, Oak Ridge, Tennessee, 

December 18.

ORAUT (Oak Ridge Associated Universities Team), 2010, Hanford Site – Occupational External 

Dose, ORAUT-TKBS-0006-6, Rev. 04, Oak Ridge, Tennessee, January 7.

Pardue, L. A., N. Goldstein, and E. O. Wollan, 1944, Photographic Film As a Pocket Radiation 

Dosimeter, CH-1553-A-2223, University of Chicago, Metallurgical Laboratory, Chicago, Illinois, 

April. [SRDB Ref ID: 8599] 

Rowles, J. A., 1988, External Radiation Dosimetry Program, N0010P00005, Rockwell Aviation, March 

29. [SRDB Ref ID: 19143]

Rutherford, P. D., and J. G. Barnes, 2006, “Dosimeter Questions,” e-mail to L. G. Faust (M.H.Chew &

Assc.), The Boeing Company, Canoga Park, California, April 20. [SRDB Ref ID: 32582]

Sebelius, K., 2009, HHS Designation of Additional Members of the Special Exposure Cohort under 

the Energy Employees Occupational Illness Compensation Program Act of 2000, Designating 

a Class of Employees from Santa Susana Field Laboratory – Area IV, Santa Susana, 

California, U.S. Department of Health and Human Services, Office of the Secretary, 

Washington, D.C., June 18.

Tuttle, R. J., 1979, “Modification of Film Badge Program,” letter to Those Listed, Rockwell 

International, August 2. [SRDB Ref ID: 19671]

United States Atomic Energy Commission (AEC), Permissible Levels of Radiation Exposure, AECMC-0524. [SRDB Ref ID: 10678]

United States Department of Energy (US-DOE), Radiation Protection For Occupational Workers, DOE 

Order 5480.11, Dec. 1988. [SRDB Ref ID: 8073]

Yoder, R. C., 2005, “Landauer film info,” e-mail to L. Faust (M.H.Chew &Assc.), Landauer Inc, 

Glenwood, Illinois, December 7. [SRDB Ref ID: 19707]
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GLOSSARY

accreditation

Recognition that a dosimeter system has passed the performance criteria of the DOE 

Laboratory Accreditation Program (DOELAP), (DOE 1986), in specified irradiation categories 

or the National Voluntary Laboratory Accreditation Program (NVLAP).

accuracy

If a series of measurements has small systematic errors, they are said to have high accuracy. 

The accuracy is represented by the bias.

beta particle

A charged particle of very small mass emitted spontaneously from the nuclei of certain 

radioactive elements. Most (if not all) of the direct fission products emit (negative) beta 

particles. Physically, the beta particle is identical with an electron moving at high velocity.

favorable to claimants

Using a process of estimation based on technical considerations such that the estimated dose 

is not underestimated.

deep dose equivalent [Hp(10)]

The dose equivalent at the respective depth to 10 millimeters in tissue.

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 gray, H is in seiverts (1 sievert = 

100 rem.)

dosimeter

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

elements (filters) and an insert with radiation-sensitive elements packaged to provide a record 

of absorbed dose or dose equivalent received by an individual.

dosimetry system

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

extremities. This includes the fabrication, assignment, and processing of the dosimeters as 

well as interpretation of the results.

exchange period (frequency)

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

exposure

A measure expressed in roentgens of the ionization produced by gamma (or X) rays in air.

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.

film dosimeter

A small packet of film within a holder that attaches to a worker.
Document No. ORAUT-TKBS-0038-6 Revision No. 02 Effective Date: 04/26/2010 Page 19 of 20

filter

Material used to adjust radiation response of a dosimeter to provide an improved tissue 

equivalent or dose response.

gamma rays

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 of high energy, the only essential difference being that X-rays do 

not originate in the nucleus.

ionizing radiation

Electromagnetic radiation (consisting of photons or particulate radiation consisting of 

electrons, neutrons, protons, etc.) capable of producing charged particles through interactions 

with matter.

neutron

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

nonpenetrating dose [Hp(0.07)]

Designation (i.e., NP or NPen) on film dosimeter reports that implies a radiation dose, typically 

to the skin of the whole body, from beta and lower energy photon radiation.

open window (OW)

Designation on a dosimeter that implies the use of little or no shielding. It commonly is used to 

label the film response corresponding to the open window area.

penetrating dose [Hp(10)]

Designation (i.e. P, Pen, or Neutrons and Gamma) on a dosimeter of the dose recorded at 

depth of 10 millimeters.

personal dose equivalent [Hp(d)]

Radiation quantity recommended for use as the operational quantity to be recorded for 

radiological protection purposes by the International Commission on Radiological Units and 

Measurements. The personal dose equivalent is represented by Hp(d), where d identifies the 

depth in millimeters and represents the point of reference for dose in tissue. For weakly 

penetrating radiation of significance to skin dose, d = 0.07 millimeter and is noted as Hp(0.07). 

For penetrating radiation of significance to whole-body dose, d = 10 millimeters and is noted 

as Hp(10).

photon

A unit of electromagnetic radiation consisting of X- and/or gamma rays.

PM

A procedure detailing specific actions or directions and usually limited to one service or 

activity.

rad

A unit of absorbed dose equal to the absorption of 100 ergs per gram of absorbing material 

such as body tissue.
Document No. ORAUT-TKBS-0038-6 Revision No. 02 Effective Date: 04/26/2010 Page 20 of 20

radioactivity

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

neutrons from unstable nuclei.

rem

A unit of dose equivalent in human tissue equal to the product of the number of rads and the 

quality factor and any other modifying factors. The word derives from roentgen equivalent in 

man.

rep

Historically, used extensively for the specification of permissible doses of ionizing radiations 

other than X-rays or gamma rays. Several definitions have appeared in the literature but the 

most widely adopted is a unit of absorbed dose with a magnitude equal to 93 ergs per gram. 

The word derives from roentgen equivalent physical.

roentgen

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

rays that will produce a total charge of 2.58 × 10-4 coulomb in 1 kilogram of dry air. An 

exposure of 1 roentgen is approximately equivalent to an absorbed dose of 1 rad in soft tissue.

sievert

The International System unit for dose equivalent (1 sievert = 100 rem).

skin dose

Absorbed dose at a tissue depth of 0.07 millimeters (7 milligrams per square centimeter).

tissue equivalent

Term used to imply that the radiation response of the material being irradiated is equivalent to 

tissue.

whole-body dose

Commonly defined as the absorbed dose at a tissue depth of 10 millimeters (1,000 milligrams

per square centimeter); also used to refer to the “dose of record.”

X-ray

Ionizing electromagnetic radiation of extra-nuclear origin.