ORAU TEAM

Dose Reconstruction

Project for NIOSH

Oak Ridge Associated Universities I Dade Moeller I MJW Technical Services

Page 1 of 81

DOE Review Release 03/12/2010

Document Title:

Lawrence Livermore National Laboratory –

Occupational External Dose

Document Number: ORAUT-TKBS-0035-6

Revision: 02

Effective Date: 02/26/2010

Type of Document: TBD

Supersedes: Revision 01

Subject Expert(s): John J. Fix and Stephen Spanos

Site Expert(s): N/A

Approval: Signature on File Approval Date: 02/25/2010

Ralph W. Kenning, Document Owner

Concurrence: Signature on File Concurrence Date: 02/25/2010

John M. Byrne, Objective 1 Manager

Concurrence: Signature on File Concurrence Date: 02/25/2010

Edward F. Maher, Objective 3 Manager

Concurrence: Signature on File Concurrence Date: 02/25/2010

Kate Kimpan, Project Director

Approval: Signature on File Approval Date: 02/26/2010

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-0035-6 Revision No. 02 Effective Date: 02/26/2010 Page 2 of 81

PUBLICATION RECORD

EFFECTIVE 

DATE

REVISION

NUMBER DESCRIPTION

10/07/2005 00 New technical basis document for the Lawrence Livermore National 

Laboratory – Occupational External Dose. First approved issue. 

Initiated by Jay J. Maisler.

04/26/2007 01 Approved revision to respond to comments by ORAU and Task 5. 

This revision specifically does not respond to Worker Outreach 

comments received; which will be addressed in a future revision. 

Constitutes a total rewrite of the document. Incorporates formal 

internal and NIOSH review comments. Adds Attributions and 

Annotations section. 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 Paul A. Szalinski.

02/26/2010 02 Revision to incorporate LLNL measured personnel doses, LLNL 

document collections and to respond to comments. Incorporates 

formal internal and NIOSH review comments. Constitutes a total 

rewrite of the document. Training required: As determined by the 

Objective Manager. Initiated by Stephen Spanos and Ralph W. 

Kenning.
Document No. ORAUT-TKBS-0035-6 Revision No. 02 Effective Date: 02/26/2010 Page 3 of 81

TABLE OF CONTENTS

SECTION TITLE

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

PAGE

6

6.1 Introduction ..............................................................................................................................8

6.1.1 Purpose........................................................................................................................9

6.1.2 Special Exposure Cohort Petition Information for LLNL ................................................9

6.1.3 Scope...........................................................................................................................9

6.2 LLNL Operations....................................................................................................................10

6.2.1 Radiation Safety Practices..........................................................................................10

6.2.2 Radiological Records..................................................................................................12

6.3 Dose Reconstruction Parameters........................................................................................... 13

6.3.1 Historical Administrative Practices..............................................................................16

6.3.2 LLNL Personnel Dosimetry Technology......................................................................16

6.3.2.1 Beta/Photon Radiation Personnel Dosimeters.............................................. 17

6.3.2.2 Neutron Radiation Personnel Dosimeters .................................................... 18

6.3.3 Calibration and Dosimeter Response Characteristics .................................................19

6.3.3.1 LLNL Beta/Photon Dosimeters..................................................................... 19

6.3.3.2 LLNL Neutron Dosimeters............................................................................ 19

6.3.4 Workplace Radiation Fields ........................................................................................19

6.3.4.1 Beta/Photon Radiation ................................................................................. 19

6.3.4.2 Neutron Radiation ........................................................................................ 20

6.4 Monitored LLNL Workers – Measured Dose........................................................................... 22

6.4.1 Photon Dose Adjustments ..........................................................................................22

6.4.2 Photon Organ Dose Conversion Factors ....................................................................22

6.4.3 Neutron Dose Adjustments.........................................................................................22

6.4.4 Neutron Weighting Factor...........................................................................................22

6.5 Monitored LLNL Workers – Missed Dose ............................................................................... 23

6.6 Unmonitored LLNL Workers................................................................................................... 24

6.6.1 Ambient Neutron Dose ...............................................................................................24

6.6.2 Coworker Assigned Photon Dose ...............................................................................25

6.6.3 Neutron-to-Photon Dose Ratio....................................................................................25

6.6.3.1 NP Ratio Application .................................................................................... 27

6.6.3.2 Construction Workers................................................................................... 28

6.6.3.3 Specific Locations ........................................................................................ 28

6.7 Uncertainty.............................................................................................................................28

6.7.1 Measured Photon Dose..............................................................................................29

6.7.2 Measured Neutron Dose.............................................................................................31

6.7.3 Measured Beta Dose..................................................................................................31

6.8 Shallow Dose.........................................................................................................................32

6.8.1 Assigned Shallow Dose..............................................................................................32

6.8.2 Assigned Extremity Skin Dose....................................................................................32

6.9 Non-Site-Specific Factors....................................................................................................... 33
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6.9.1 Adjustment for Glovebox Workers ..............................................................................33

6.9.2 Lead Vests Worn By Vault Operations Technicians....................................................33

6.10 Attributions and Annotations .................................................................................................. 34

References ........................................................................................................................................36

Glossary ............................................................................................................................................45

ATTACHMENT A, HISTORICAL TIMELINE OF RADIATION EXPOSURE ASSOCIATED 

EVENTS AT LLNL................................................................................................50

LIST OF TABLES

TABLE TITLE

6-1 LLNL radiation protection guidance........................................................................................

PAGE

11

6-2 Determination of LLNL recorded dose.................................................................................... 13

6-3 Interpretation of LLNL reported dose data.............................................................................. 14

6-4 LLNL beta/photon dosimeter type, period of use, exchange frequency, LOD, 

and potential annual missed dose.......................................................................................... 17

6-5 LLNL neutron dosimeter type, period of use, exchange frequency, LOD, and 

potential annual missed dose................................................................................................. 18

6-6 Selection of workplace beta/photon radiation energies and dose fractions............................. 20

6-7 Selection of workplace neutron radiation energies and dose fractions ................................... 21

6-8 Photon dose conversion factors ............................................................................................. 22

6-9 Conversion from NCRP 38 neutron quality factors to ICRP 60 weighting 

factors....................................................................................................................................23

6-10 Perimeter fence neutron doses from Building 212.................................................................. 24

6-11 LLNL NP ratio from TLD measurements ................................................................................ 26

6-12 Collective TLD measured photon and neutron dose (person-rem) ......................................... 27

6-13 Statistical parameters for facility-specific TLD neutron and photon dose data, 

1994-2006..............................................................................................................................27

6-14 Statistical parameters for facility-specific measured neutron and photon dose 

data, 1982..............................................................................................................................28

6-15 Recommended NP ratio for Dose Reconstruction .................................................................. 28

6-16 Summary of neutron calibration factors for LLNL buildings..................................................... 29

6-17 Summary of LLNL measured TLD and film doses .................................................................. 30

6-18 LLNL participation in DOE dosimeter performance testing ..................................................... 30

6-19 Examples of extremity skin dose assignments ....................................................................... 33

6-20 Correction factors for application to photon dose received while wearing a 

lead vest ................................................................................................................................33

A-1 Chronology of radiation standards: occupational external WB dose 

equivalent limits .....................................................................................................................51
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LIST OF FIGURES

FIGURE TITLE

6-1 Trend in the number of LLNL monitored workers, the number of workers with 

recorded photon doses >0, and the number of workers with recorded neutron 

doses >0, 1952–2006.............................................................................................................

PAGE

12

6-2 Box plot of historical measured LLNL worker whole-body photon doses 

showing median, whiskers at 25th and 75th percentiles, respectively, and 

bullets at 95th percentile compared to official dose limits ....................................................... 15

6-3 Trend of TLD measured LLNL worker neutron to photon dose ratio with 

respective neutron ≥40 mrem and photon ≥20 mrem dose components ................................ 26

6-4 LLNL paired TLD neutron ≥40 mrem and photon ≥20 mrem dose 

measurements .......................................................................................................................26
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ACRONYMS AND ABBREVIATIONS

AEC U.S. Atomic Energy Commission

ALARA as low as reasonably achievable

amp ampere

AVLIS Atomic Vapor Laser Isotope Separation

CFR Code of Federal Regulations

Ci curie

cm centimeter

CR-39 allyl diglycol carbonate or Columbia Resin

CTW construction trade worker

d day

DCF dose conversion factor

DOE U.S. Department of Energy

DOELAP DOE Laboratory Accreditation Program

DOL U.S. Department of Labor

DOT U.S. Department of Transportation

EEOICPA Energy Employees Occupational Illness Compensation Program Act of 2000

ERDA U.S. Energy Research and Development Administration

eV electron-volt

FN fast neutron

g gram

GM geometric mean

GSD geometric standard deviation

Hp(d) personal dose equivalent at depth d (deep dose, d = 10 mm; shallow dose, d = 0.07 

mm) in tissue

HE high-explosive

hr hour

ICRP International Commission on Radiological Protection

ICT Insulated Core Transformer

in. inch

IREP Interactive RadioEpidemiological Program

keV kiloelectron-volt, 1,000 electron-volts

LANL Los Alamos National Laboratory

LBNL Lawrence Berkeley National Laboratory

LINAC linear accelerator

LLL Lawrence Livermore Laboratory

LLNL Lawrence Livermore National Laboratory

LOD limit of detection

LPTR Livermore Pool Type Reactor

LRL Lawrence Radiation Laboratory

m meter

MeV megaelectron-volt, 1 million electron-volts
Document No. ORAUT-TKBS-0035-6 Revision No. 02 Effective Date: 02/26/2010 Page 7 of 81

mm millimeter

mR milliroentgen

mrem millirem

mSv millisievert

MW megawatt

n neutron

NCRP National Council on Radiation Protection and Measurements

NIST National Institute of Standards and Technology

NIOSH National Institute for Occupational Safety and Health

NP neutron-to-photon

ns nanosecond

NTA nuclear track emulsion, type A

NTS Nevada Test Site

ORAU Oak Ridge Associated Universities

ORNL Oak Ridge National Laboratory

OSP Operational Safety Procedure

OW open window

PIC pocket ionization chamber

PNL Pacific Northwest Laboratory

POC probability of causation

R roentgen

RBE relative biological effectiveness

RTNS Rotating Target Neutron Source

S radiation response in the shielded region of film

s second

SEC Special Exposure Cohort

SN slow neutron

SRDB Ref ID Site Research Database Reference Identification (number)

TBD technical basis document

TED track-etch dosimetry 

TLD thermoluminescent dosimeter

TRIGA Training, Research, Isotopes, General Atomics

UCRL University of California Radiation Laboratory

U.S.C. United States Code

WB whole-body

wk week

yr year

μrem microrem

γ gamma

§ section or sections
Document No. ORAUT-TKBS-0035-6 Revision No. 02 Effective Date: 02/26/2010 Page 8 of 81

6.1 INTRODUCTION

Technical basis documents 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-0035-6 Revision No. 02 Effective Date: 02/26/2010 Page 9 of 81

6.1.1

The Lawrence Livermore National Laboratory (LLNL) was established in 1952 as a major 

government-owned scientific and nuclear weapons research site. Later operations included 

nonmilitary applications of nuclear energy. The purpose of this TBD is to describe the external 

radiation dosimetry systems and protection practices at LLNL. This document discusses historical 

and current practices in relation to the evaluation of external radiation exposure of monitored and 

unmonitored workers. It documents historical practices at LLNL and provides information for the 

evaluation of external radiation exposed workers. It can serve as a supplement to, or substitute for, 

individual monitoring data.

Purpose

6.1.2

Classes Added to the SEC

Special Exposure Cohort Petition Information for LLNL

NIOSH has determined, with concurrence from the Secretary of Health and Human Services (HHS), 

that MFP doses at LLNL cannot be reconstructed with sufficient accuracy between 1950 and 1973, 

inclusive. For this reason, the following class of LLNL employees has been added to the SEC (Leavitt 

2008). 

Employees of the DOE, its predecessor agencies, and DOE contractors or subcontractors who were 

monitored for radiation exposure while working at the Lawrence Livermore National Laboratory from 

January 1, 1950, through December 31, 1973, for a number of workdays aggregating at least 250 

workdays or in combination with workdays within the parameters established for one or more other

classes of employees in the Special Exposure Cohort.

Class Recommended by NIOSH for addition to the SEC

NIOSH has subsequently determined that MFP doses for workers not monitored for radiation 

exposure at LLNL also cannot be reconstructed with sufficient accuracy between 1950 and 1973, 

inclusive. For this reason, NIOSH has recommended that the following class of LLNL employees be 

added to the SEC (NIOSH 2009). 

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

subcontractors who worked at the Lawrence Livermore National Laboratory in Livermore, California 

from January 1, 1950 through December 31, 1973, 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 in the Special Exposure 

Cohort.

The NIOSH-recommended SEC class includes all workers during the SEC period. Because of the 

identified dose reconstruction infeasibility, all dose reconstructions for all workers having employment 

during the SEC period are considered partial dose reconstructions. If monitoring data are available 

for workers included in the SEC, dose is to be assigned as appropriate based on such data; however, 

such dose reconstructions are still considered partial dose reconstructions because the HHS has 

determined that exposure to mixed fission and activation products during the SEC period cannot be 

bounded.

6.1.3

Workers at LLNL were exposed to radiation from a variety of radioactive materials and radiationproducing machines. LLNL workers were assigned beta/photon dosimeters apparently from the 

beginning of operations. LLNL workers also worked at the Nevada Test Site (NTS) or were involved 

Scope
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with other weapons tests where they could have received radiation exposures. Personnel dosimeter 

records are generally available for all periods at LLNL for workers who had any potential for significant 

occupational radiation exposure. As illustrated in Attachment A, Section A.2, the operations and 

radiation safety staff routinely reviewed LLNL workplace hazards and dosimeter results for 

compliance with radiation control limits and investigated doses approaching weekly, quarterly, or 

annual radiation dose limits. LLNL radiation dosimetry practices were based on experience at other 

DOE laboratories such as Lawrence Berkeley National Laboratory (LBNL), Oak Ridge National 

Laboratory (ORNL) and Los Alamos National Laboratory (LANL). The collective DOE radiation 

protection experience also included several decades of radium and X-ray medical diagnostic and 

therapy applications.

Attributions and annotations, indicated by bracketed callouts and used to identify the source, 

justification, or clarification of the associated information, are presented in Section 6.10.

6.2 LLNL OPERATIONS

LLNL in Livermore, California, is a DOE scientific laboratory. The University of California managed 

and operated LLNL until October 1, 2007, when a partnership of the University of California, Bechtel 

Corporation, Babcock and Wilcox, the URS Corporation, and Battelle Memorial Institute assumed this 

role. LLNL was established in 1952 as the Lawrence Radiation Laboratory (LRL) at Livermore as an 

associated operation of the University of California Radiation Laboratory (UCRL) at Berkeley (now 

LBNL). The University of California-administered LBNL and LLNL had close working relationships. In 

historical official planning documents and records, LBNL is designated as Site 100, LLNL as Site 200, 

and LLNL's remote test location as Site 300. This TBD addresses LLNL operations at the historical 

Site 200 and Site 300 operations. LBNL radiation protection practices are expected to have been 

adopted at LLNL during the earliest years of LLNL operation. Personnel dosimetry at LLNL was 

provided by the LBNL dosimetry laboratory initially until LLNL developed capabilities to process staff 

and visitor assigned dosimeters. There is ongoing collaboration between these two laboratories. 

6.2.1

Information regarding routine LLNL radiation safety practices historically is available from the various 

references and policies noted in Attachment A. Table A-1 contains a detailed summary of radiation 

protection whole-body (WB), skin, and extremity (hand) dose limits applicable to DOE and 

predecessor agencies historically along with LLNL site-specific guidance. Section A.2 contains a

historical timeline of radiation associated reports and events that illustrate LLNL practices and 

policies. LLNL workers were assigned personnel dosimeters provided by LBNL in 1952 based on the 

LLNL dose records, and according to policy (Thompson 1953; Block 1954) all workers were issued 

personnel film and pocket dosimeters by LLNL beginning in March 1953. Available LLNL radiation 

protection guidance to monitor and control worker exposure to radiation is summarized in Table 6-1. 

Radiation Safety Practices
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Table 6-1. LLNL radiation protection guidance.

Reference Description

Block 1954;

LRL ca. 1954

Block, S., 1954, “Personnel Monitoring Procedure for UCRL, Livermore,” memorandum to 

All Department Heads, University of California, Lawrence Radiation Laboratory, 

Livermore, California, July 19. [SRDB Ref ID: 16949]

LRL (Lawrence Radiation Laboratory), ca. 1954, Personnel Monitoring Procedure for 

UCRL, Livermore, University of California, Livermore, California. [SRDB Ref ID: 

23478]

These references described features and requirements of LLNL personnel monitoring as 

follows:

• Film badges were provided for all personnel employed at UCRL, Livermore site. Each 

film badge was identified with a number assigned to an individual.

• PICs would be provided at the Film Badge Office for those who did not have access to 

them. The PICs would be read and a record kept of the individual’s exposure. 

Because one of the chambers was a self-reading type, the exposure could be read by 

the individual concerned.

• For those who worked in radiation areas, the film badges were exchanged once a 

week.

• For personnel who did not work in a radiation area, film badges were exchanged 

monthly.

• Persons who routinely visited radiation areas would have film badges exchanged 

weekly. This group included laboratory guards and custodians and some installation 

and maintenance personnel.

• Any person who suspected a significant exposure had to have their dosimeter 

processed as soon as possible on delivery to Health Physics.

• Measured exposures exceeding 0.3 rem/wk required an investigation. 

LLL 1977 LLL (Lawrence Livermore Laboratory), 1977, Health and Safety Manual, M-010, Change 

10, University of California, Livermore, California, November 1. [SRDB Ref ID: 

15756]

This manual described the radiation safety regulations and LLNL practices to monitor, 

measure, and control worker exposure to comply with Chapter 0524 of the ERDA Manual

(ERDA 1977).

Straume 1980 Straume, T., 1980, Radiation Safety Program for Site 300, University of California, 

Lawrence Livermore Laboratory, Livermore, California, September. [SRDB Ref ID: 

72845]

Personnel film beta/photon dosimeters and pocket ionization chambers (PICs) were made available 

beginning at least as early as 1953, and records were maintained of only the measured positive doses 

(Block 1954). Recorded doses began in 1952. Trends in the number of monitored workers are 

shown in Figure 6-1, which is based on analysis of a copy of LLNL radiological records (Shingleton 

2007). The analysis was of dose records with beginning and ending wear dates less than 18 months 

apart (i.e., multiyear transfer doses from previous employers for new employees are often recorded in 

subsequent employer records with a single dose entry covering a multiyear period) to minimize the 

impact from transfer doses from other facilities on the analysis. Figure 6-1 illustrates the number of 

monitored workers and the number of workers with positive recorded WB dose from photon and 

neutron radiation, respectively. The trend in the number of monitored workers and the number of 

workers with positive recorded photon dose is nearly identical before the early 1980s, which confirms 

the LLNL stated practice to record positive measured doses only. The trend in the number of workers 

with a measured positive neutron dose illustrates a gradual increase beginning in the 1980s. The 
Document No. ORAUT-TKBS-0035-6 Revision No. 02 Effective Date: 02/26/2010 Page 12 of 81

situation concerning technical limitations to measure neutron radiation dose in many workplaces is 

discussed below in this TBD. Basically, LLNL workers were monitored and the positive dose results 

recorded before the mid-1980s approximately, and thereafter all doses (including zero doses) were 

recorded. 

Figure 6-1. Trend in the number of LLNL monitored workers, the number of workers with recorded 

photon doses >0 and the number of workers with recorded neutron doses >0, 1952–2006.

6.2.2

LLNL maintains a computerized radiological record system. There are many thousands of images of 

hard-copy dosimetry cards containing worker name, identification number, date, dosimeter badge 

assigned, and film processing result shown as the ratio of the dose for the film open-window (OW) to 

shielded (S) film regions (LRL 1952–1959). Practices to calculate the LLNL recorded WB, skin (SK) 

and extremity hand (HN) doses from the measured dosimeter dose components are summarized in 

Table 6-2. The measured neutron dose has been included in the WB dose for all years. Dose 

reconstructors can use the information in Table 6-2 and the additional information in Table 6-3 to

assist in the interpretation of LLNL external dosimetry summary reports. 

Radiological Records 
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Table 6-2. Determination of LLNL recorded dose [1].

Period

Dosimeter measured 

quantities Compliance dose quantities*

Beta/photon film dosimeter + NTA neutron film dosimeter

1952–1963 Beta (B)

Gamma (G)

Neutron (N)

WB = gamma + neutron

SK = WB + beta

HN = hand extremity dose (HN = hands) 

1963–1969 Beta (B)

Gamma (G)

Neutron (N)

WB = gamma + neutron

SK = shallow (SK = skin) = gamma + neutron + beta

HN = hand extremity dose (HN = hands) 

Beta/photon/neutron–LLNL TLD

1969–1985 Beta (B)

Gamma (G)

Neutron (N)

WB = gamma + neutron

SK = shallow (SK = skin) = gamma + neutron + beta

HN = hand extremity dose (HN = hands) 

Beta/photon/neutron–Panasonic TLD + CR-39 neutron dosimeter

1985–present B/G/N SK = NPEN + WB

WB = PEN + SN + FN

1995–2003 Shallow (SH or SK)

Deep photon (PH DP)

Deep neutron (NU DP)

SK = beta + photon + neutron (B/G/N)

WB = photon deep + neutron deep

* WB = Whole Body, SK = Skin, HN = extremity (Hand), NPEN = nonpenetrating, PEN = 

penetrating, SN = Slow Neutron, FN = Fast Neutron.

During the early 1950s, the National Council on Radiation Protection and Measurements (NCRP)

introduced the concept of permissible dose to replace the tolerance dose concept. As noted in 

Attachment A, the NCRP recommended that the maximum permissible dose to the gonads and bloodforming organs be 0.3 rem (3 mSv) per week in 1954, which corresponds to an annual WB dose limit 

of 15 rem (150 mSv). In the later 1950s, the potential significance of cumulative radiation exposure to 

genetic and cancer risks became a concern leading to implementation of the WB dose limit of 5 × 

(N-18) rem, where N is measured in years. In the later 1980s, changes in the WB dose limit were 

associated with an NCRP recommendation to limit WB dose to a maximum of 10 rem averaged over 5 

years (i.e., average of 2 rem/yr). The historical trend in LLNL WB photon dose, dose limits, and in 

comparison with the median and 95th-percentile LLNL recorded WB annual photon doses are 

presented in Figure 6-2. The recommended annual dose limits by applicable scientific and regulatory 

agencies are shown in Figure 6-2. Attachment A provides a more detailed history of official and LLNL 

radiation dose control limits. The reasons for the dramatic improvement in the variability of the 

measured doses in 1985 are likely associated with the implementation of the Panasonic dosimetry 

system, capabilities to utilize individual element radiation calibration factors, preparations for DOE 

Laboratory Accreditation Program (DOELAP) dosimeter performance testing that became mandatory 

in 1985 (DOE 1986), and the assignment of dosimeters to a much larger number of workers.

6.3 DOSE RECONSTRUCTION PARAMETERS

Examinations of the beta, photon (X-ray and gamma ray), and neutron radiation type, energy, and 

geometry of exposure in the workplace, and the characteristics of the LLNL dosimeter responses are
Table 6-3. Interpretation of LLNL reported dose data [2].

Period

Reported 

quantity Description

Interpretation 

of zeroes

Interpretation 

of blanks 

(no data)

Rollup of individual 

and annual data

Monitored/ 

unmonitored

1952–1968 rem Reported WB doses 

qualified with “G” for 

gamma and “N” for 

neutron. Skin and 

extremity (hand) doses 

are also reported

Zeroes were generally 

not recorded. Reported 

zero should be 

interpreted as meaning 

less than LOD.

Blanks should be 

interpreted as individual 

was monitored with 

zero result.

Photon WB dose.

Neutron WB dose.

Shallow skin dose.

Total deep WB dose.

All employees were 

monitored for 

beta/gamma 

radiation. Selected 

employees were 

monitored for 

neutron radiation. 

1969–1985 rem Reported WB doses 

qualified as either “G” 

for gamma or “N” for 

neutron. Beta reported 

with “S” and/or “SK” for 

skin. 

Zeroes were generally 

not recorded before 

1980. However, for any 

year, a blank or reported 

zero result should be 

interpreted as meaning 

less than LOD.

Blanks should be 

interpreted as individual 

was monitored with 

zero result.

Photon WB dose.

Neutron WB dose.

Shallow skin dose.

Total deep WB dose.

All employees with 

significant 

measurable 

exposure potential 

were monitored for 

beta/gamma and 

neutron exposure.

1985–

present

rem Photon deep, neutron 

deep, and shallow dose 

reported. 

Zeroes were typically 

reported. Reported zero 

should be interpreted as 

meaning less than LOD.

Blanks should be 

interpreted as individual 

was monitored with 

zero result.

Photon WB dose.

Neutron WB dose.

Shallow skin dose.

Total deep WB dose.

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2

6/2010 Page 13 of 81
Document No. ORAUT-TKBS-0035-6 Revision No. 02 Effective Date: 02/26/2010 Page 15 of 81

Figure 6-2. Box plot of historical measured LLNL worker whole-body photon doses showing median, 

whiskers at 25th and 75th percentiles, respectively, and bullets at 95th percentile compared to official

dose limits. 

important to the assessment of the original recorded dose in relation to the radiation dose equivalent 

quantity Hp(d), where d = 10 mm or d = 0.07 mm for WB deep and shallow dose, respectively. Dose 

reconstructors can compare earlier dosimetry systems to current systems to evaluate their 

performance based on the premise that current systems have more stringent criteria, as indicated in 

DOELAP dosimeter performance testing.

Accuracy and precision of the recorded individual worker doses depend on (Fix et al. 1997a):

• Administrative practices

•

that facilities adopted to calculate and record personnel dose based 

on technical, administrative, and statutory compliance considerations.

Dosimetry technology

•

, which includes the physical capabilities of the dosimetry system, such 

as the response to different types and energies of radiation, in particular in mixed radiation 

fields.

Calibration and dosimeter response characteristics

•

of the respective monitoring systems and 

similarity of the methods of calibration to sources of exposure in the workplace.

Workplace radiation fields, which can include mixed types of radiation, variations in exposure 

geometries, and environmental conditions.
Document No. ORAUT-TKBS-0035-6 Revision No. 02 Effective Date: 02/26/2010 Page 16 of 81

An evaluation of the original recorded doses, as available, combined with detailed examinations of 

workplace radiation fields and dosimeter responses to those fields is the recommended option to 

provide the best estimate of Hp(d) for individual workers.

6.3.1

As noted in Attachment A, Section A.2, references of historical LLNL radiation associated events, 

LLNL used personnel dosimeters to measure and record doses from external radiation to workers 

throughout the history of its operations. These dosimeters include one or more of the following:

Historical Administrative Practices

• Personnel WB film and thermoluminescent beta/photon dosimeters 

• PIC (electrometers, etc.) dosimeters for photon and thermal neutron detection

• Personnel extremity (particularly hand) dosimeters

• Personnel neutron nuclear track emulsion, type A (NTA) film, thermoluminescent and tracketch dosimeters

Dose reconstruction parameters concerning LLNL administrative practices significant to dose 

reconstruction involve policies to:

• Assign dosimeters to workers.

• Exchange dosimeters.

• Estimate dose for missing or damaged dosimeters.

• Replace destroyed or missing records.

• Evaluate and record dose for incidents.

• Obtain and record occupational dose to workers for other employer exposure.

LLNL policies were apparently in place for all these parameters. From its inception, LLNL had policies 

to monitor individuals with significant potential for radiation exposure. The practice of providing film 

and pocket ionization dosimeters to all workers has been in effect since March 1953 (Thompson 

1953) and in 1958 film badges became part of the security badge (Nolan 1958), which effectively 

mandated that all workers wear their film dosimeters at all times. Dosimeter exchange frequencies 

varied over the years depending on the dosimeter type in use at the time and on the exposure 

potential of the individual being monitored. Individuals with lower exposure potential tended to have 

less frequent exchange frequencies than those with higher exposure potential. Neutron dose results 

are observed in the early 1950s, as noted in Attachment A, Section A.2. Individual worker dose 

histories typically include recorded dose at LLNL from the early 1950s. As noted above, LLNL 

recorded only positive doses until the early 1980s. As evident in Figure 6-1, there was comparably 

little recorded dose in the earlier years and comparatively very little recorded neutron dose. Certainly 

this trend in recorded dose is in part an indication of the establishment of a new laboratory with 

personnel dosimetry originally provided by LBNL with little potential for significant worker exposures. 

Doses increased with time as new facilities were constructed and became operational and, at least for 

neutron radiation, as improved dosimetry methods became available. 

6.3.2

LLNL began operations in 1952 using dosimeter and processing technical support provided by LBNL. 

LLNL developed its own capabilities to process dosimeters in 1953 and proceeded to improve 

capabilities adopting multielement film, thermoluminescent, and track-etch dosimetry technology.

LLNL Personnel Dosimetry Technology
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6.3.2.1 Beta/Photon Radiation Personnel Dosimeters

Initially, LBNL provided LLNL with beta/photon film dosimeters and processing, and PICs (Thompson 

1953). These film dosimeters were similar in design to those developed at the Metallurgical 

Laboratory at the University of Chicago (Pardue, Goldstein, and Wollan 1944) and widely adopted at 

many other DOE sites (ORNL, Hanford, etc.). LLNL had developed its own fully functional personnel 

dosimetry film and PIC program with in-house processing by March 1953 (Thompson 1953). Early 

exposure records, likely from LBNL, provided “electrometer” results (designated by “E” in selected 

claimant files), which supplemented the film dosimeter results. For purposes of dose reconstruction, 

the electrometer or E results should be used in a qualitative manner in the same manner as PIC data. 

The film dosimeter recorded dose results should be used to estimate the actual dose to workers until 

the thermoluminescent dosimeter (TLD) was implemented in 1969 (Rich 1969).

Table 6-4 summarizes the personnel beta/photon dosimeters used at LLNL over the years, along with 

their periods of use, exchange frequencies, limits of detection (LODs), and estimated annual missed 

doses. The LLNL dosimetry methods evolved during the years as improved technology was 

developed and the complex radiation fields encountered in the workplace were better understood. 

The adequacy of the respective dosimetry methods to measure radiation dose accurately depends on 

radiation type, energy, and exposure geometry. The exchange frequency of the dosimeters was 

gradually lengthened and corresponded generally to downward reductions in the radiation protection 

guidelines (Attachment A; Morgan 1961; Taylor 1971). The dosimeter designs accommodated the 

numerous beta/photon radiation field types that workers might encounter throughout the LLNL 

complex. In 1969, TLDs, which had been under development for many years, fully replaced film 

dosimeters. LLNL constructed the TLDs used from 1969 through 1984, using Harshaw TLD-100,

TLD-200, TLD-600, and TLD-700 elements. The use of Panasonic 802 and 810 dosimeters began in 

1985 and has continued to the present. 

Table 6-4. LLNL beta/photon dosimeter type, period of use, exchange frequency, LOD, and potential 

annual missed dose [3].

Period of use Dosimeter

LODa

(rem)

Exchange

frequencyb

Annual 

missed 

dosec (rem)

LLNL film dosimeters

1952–1968d Beta/Photon–DuPont 558 film

0.030

Weekly (n = 50) 0.75

Biweekly (n = 25) 0.38

Monthly (n = 12) 0.18

LLNL thermoluminescent dosimeters

1969–1984 Beta/Photon/Neutron–Harshaw TLD-100, 

TLD-200, TLD-600, and TLD-700 phosphors 0.020

Monthly (n = 12) 0.12

Quarterly (n = 4) 0.04

Semiannual (n = 2)e 0.02

1985–present Beta/Photon–Panasonic 810AS and 802AS 

TLD 0.010

Monthly (n = 12) 0.06

Quarterly (n = 4) 0.02

Semiannual (n = 2) 0.01

a. Estimated LODs for each dosimeter technology in the workplace. LLNL radiological records include dose values 

recorded at levels less than the LOD.

b. Exchange frequencies were dependent on work assignment. If the exchange frequency is not evident based on trends 

in an individual’s personnel records, assume a monthly exchange frequency.

c. Annual missed dose calculated using the LOD/2 method from NIOSH (2007b).

d. Initially LBNL provided and processed LLNL beta/photon film dosimeters. 

e. From January 1974 to June 1978, the site began a test semiannual badge exchange monitoring program for about 

2,000 employees. The semiannual badge exchange program was implemented after this for certain buildings (Hoots 

1978). 
Document No. ORAUT-TKBS-0035-6 Revision No. 02 Effective Date: 02/26/2010 Page 18 of 81

6.3.2.2 Neutron Radiation Personnel Dosimeters 

Table 6-5 summarizes the personnel neutron dosimeters used at LLNL over the years, along with 

their periods of use, exchange frequencies, LODs, and estimated annual missed doses. Initially, 

LBNL supplied and processed NTA film dosimeters and thermal neutron-sensitive pencil dosimeters. 

LLNL had implemented capabilities for the thermal neutron-sensitive pencil dosimeters by March 1953 

(Thompson 1953) but it is not certain when LLNL had fully implemented in-house NTA processing 

capabilities. Neutron dosimeters were assigned to LLNL workers according to need as noted in 

several Attachment A historical record notes. It appears clear from the record that workers should be 

assigned neutron dosimeters for any significant exposure; for example, in Personnel Monitoring 

Procedure for UCRL, Livermore (LRL ca. 1954), it is stated that: “A film badge containing fast neutron 

sensitive film shall also be provided for persons who will be working within areas where significant 

neutron exposures are possible.” However, as illustrated in Figure 6-1, there is relatively little 

recorded neutron dose for LLNL workers until the latter 1980s when TLDs were being used. Rich 

(1969) noted the inability of NTA dosimeters to measure known neutron doses during workplace 

comparisons with TLDs (see Section 6.6.4). 

Table 6-5. LLNL neutron dosimeter type, period of use, exchange frequency, LOD, and potential 

annual missed dose [4].

Period of use Dosimeter

LODa

(rem)

Exchange

frequencyb

Annual 

missed 

dosec (rem)

LLNL NTA Film Dosimeters

1952–1968 Kodak NTA film (b)

Weekly (n = 50) 1.25

Biweekly (n = 25) 0.625

Monthly (n = 12) 0.30

LLNL TLD

1969–1984 Beta/Photon/Neutron - Harshaw TLD-100, 

TLD-200, TLD-600, and TLD-700 phosphors 0.020 Monthly (n = 12) 0.12

Quarterly (n = 4) 0.04

LLNL Track-Etch Dosimeter

1985–present Neutron–CR-39 0.010 Monthly (n = 12) 0.06

Quarterly (n = 4) 0.02

a. Estimated LODs for each dosimeter technology in the workplace. LLNL radiological records include dose values 

recorded at levels less than the LOD.

b. The estimated LOD for NTA based on laboratory studies is 50 mrem. However, as noted in Rich (1969) often no 

positive neutron dose was measured in workplaces with known neutron dose. As such, it is recommended that the 

missed neutron dose be determined by multiplying the missed photon dose by a NP ratio.

c. Annual missed dose calculated using the LOD/2 method from NIOSH (2007b).

TLDs fully replaced NTA film dosimeters by 1969 (Rich 1969). LLNL constructed the TLDs used from 

1969 through 1985, which contained Harshaw TLD-100, TLD-200, TLD-600, and TLD-700 elements. 

From 1969 through 1975, the neutron dosimeter included the thermal neutron response of TLD-100 

phosphors and, as such, the percent of thermal radiation was incorporated into the neutron dose 

evaluation (Hankins 1982a). Later dosimeter modifications introduced a design with cadmiumshielded TLD-600 and TLD-700 components on all sides except the side facing the wearer’s body.

This design effectively shielded incident thermal neutrons from the TLD-600 and TLD-700 elements 

and detected only thermal neutrons reflected from the wearer’s body. A further design change 

incorporated shielding on all sides of the TLD-600 and TLD-700 elements, which minimized the overresponse of the earlier designs and was in use until 1985 when LLNL implemented CR-39 track-etch 

neutron dosimeters. The combination of the Panasonic System and CR-39 is currently in use.
Document No. ORAUT-TKBS-0035-6 Revision No. 02 Effective Date: 02/26/2010 Page 19 of 81

6.3.3

Potential error in measured radiation dose is dependent on the dosimetry technology response 

characteristics to each radiation type, energy, and geometry; the methodology used to calibrate the 

dosimetry system; and the similarity between the radiation fields used for calibration and in the 

workplace.

Calibration and Dosimeter Response Characteristics

6.3.3.1 LLNL Beta/Photon Dosimeters

Dosimeters were calibrated using a variety of beta radiation sources and photon beams as noted in 

the studies in Attachment A. LLNL dosimetrists appear to have been well aware of technical 

considerations to match calibration and workplace spectra, and processing quality assurance (Hoots 

and Landrum 1981), to achieve accurate measured doses. Hankins (1982a) reported a retrospective 

study of LLNL dosimeter response characteristics to reconstruct an exposure to beta and gamma 

radiation that occurred in 1963. Typical higher energy photon-emitting nuclides such as 226Ra, 137Cs, 

or 60Co were used to irradiate dosimeters in air (i.e., no phantom) until the early 1980s when DOELAP 

personnel dosimeter performance testing (Roberson et al. 1983) was imminent with on-phantom 

exposures. Since 1986, photon calibrations have been to 137Cs with dosimeters placed on a phantom. 

Beta calibrations were routinely to 90Sr.

6.3.3.2 LLNL Neutron Dosimeters

Neutron dosimeters were calibrated using selected neutron sources such as polonium-beryllium or 

plutonium-beryllium sources before about 1970. In later years, unmoderated and moderated 252Cf has 

been used. LLNL staff members (Hankins 1967, 1975a,b; Griffith et al. 1977, 1978a,b; Hankins 

1978a,b; Griffith and Hankins 1980; Hankins 1982b, 1984a, Hankins, Homann and Buddemeier 1989) 

provide substantial information on considerations of calibration of albedo neutron dosimeters for 

various workplace neutron spectra. LLNL archive records provide a history of neutron calibration 

sources and tolerance limits from 1953 through 1955 as well as monitoring results (LRL 1953–1955). 

Kathren, Prevo, and Block (1965) described LLNL studies of NTA response characteristics. NTA 

response was found to be a function of the angle of incidence of a neutron with the plane of the film 

and the energy. A factor of 1.3 was recommended to correct the recorded dose from NTA film for the 

effects of angular dependence and fast-neutron energy. A documented conversation (Fix 2010) with 

a subject and site expert recommended that the factor of 1.3 also be used to correct the recorded 

neutron dose from TLDs. 

6.3.4

The radiation fields at LLNL are highly variable. They include radiation from a variety of radiationproducing machines such as electron accelerators, X-ray machines, cyclotrons, neutron generators, 

and a research nuclear reactor. In addition, many different radioactive materials have been used at 

LLNL. As noted in Attachment A, reviews of potential workplace hazards in LLNL facilities, including 

radiological, were often done. These reviews provided a summary listing of potential radiation 

hazards in the respective facilities.

Workplace Radiation Fields

6.3.4.1 Beta/Photon Radiation

Evaluations of potential beta and photon (gamma and X-ray) radiation hazards in LLNL workplaces 

have been done on numerous occasions as noted in Attachment A, Section A.2. Table 6-6 lists 

several of the beta/photon radiation sources potentially encountered at LLNL over the years, the 

approximate energy category, and the associated dose fraction. All workplace beta radiation energies 

of potential external radiation exposure significance to workers are greater than 15 keV. 
Document No. ORAUT-TKBS-0035-6 Revision No. 02 Effective Date: 02/26/2010 Page 20 of 81

Table 6-6. Selection of workplace beta/photon radiation energies and dose fraction [5].

Buildings–

old 

numbersa

Buildings–

new 

numbersa Description

Radiation 

type

Energy 

selection (keV)

Dose 

fraction

101, 102, 

106, 117, 

118, 147, 

176, 192

222, 221, 

223, 224, 

234, 232,

233, 167, 

168, 169

Chemistry: radioactive materials 

including Co-60, fission products, 

enriched uranium, depleted 

uranium, natural uranium, U-233, 

Cm-244, Pu-239, Am-241, others

Beta >15 100

Photon 30–250 

>250

50

50

153, 154, 

157, 173, 

180, 194

210, 212; 

171, 173-

177; 241, 

243; 435, 

442, 443; 

194

Physics: accelerators, activation 

products, H-3, others

Beta >15 100

Photon 30–250 

>250

25

75

103, 114, 

125, 127, 

174, 175

215, 321, 

419, 514, 

243, 253

Laboratory Services: radioactive 

materials

Beta >15 100

Photon 30–250 

>250

75

25

110 261 Criticality Test Facility Beta >15 100

Photon 30–250 

>250

50

50

115 327 Radiography Beta >15 100

Photon 30–250 

250

25

75

121 412 Hot cells: high beta waste, Sr-90 Beta >15 100

Photon 30–250 

>250

75

25

170 131 Weapons Beta >15 100

Photon <30

30–250 

50

50

171 332 Metallurgical Chemistry 

(Plutonium Facility)

Beta >15 100

Photon <30

30–250 

50

50

172 331 Gaseous Chemistry 

(Tritium Facility)

Beta >15 100

Photon <30b 100

182 162, 165, 

166

Laboratory Services: 

55-Ci Co-60 (1958)

Beta >15 100

Photon 30–250 

>250

25

75

190 251 Chemistry Heavy Elements 

Facility: Cm-244, Am-241, U-233, 

Pu-239, others

Beta >15 100

Photon <30

30–250 

>250

25

50

25

193 281 Reactor Beta >15 100

Photon 30–250 

>250

25

75

Site 300 Site 300 Explosives Testing: linear 

accelerators, depleted uranium, 

H-3, radiography

Beta >15 100

Photon 30–250 

>250

25

75

a. Trost (2005).

b. Bremsstrahlung X-ray radiation from tritium beta radiation.

6.3.4.2 Neutron Radiation

Evaluations of potential neutron radiation hazards in LLNL workplaces have also been done on 

numerous occasions, as noted in Attachment A, Section A.2. Table 6-7 lists neutron radiation 

sources potentially encountered at LLNL over the years, the approximate energy category, and the 

associated dose fraction. Workplace neutron radiation energies of potential external radiation 
Document No. ORAUT-TKBS-0035-6 Revision No. 02 Effective Date: 02/26/2010 Page 21 of 81

exposure significance to workers are between 10 keV and 20 MeV. The default neutron energy 

selection of 0.1 – 2.0 MeV in Table 6-7 was chosen because sources of neutron radiation were 

normally shielded. This energy range also typically has the highest organ dose conversion factor 

(DCF; see NIOSH 2007b, Appendix C) that is favorable to claimants.

Table 6-7. Selection of workplace neutron radiation energies and dose fractions [6].

Buildings–

old 

numbersa

Buildings–

new 

numbersa Descriptionb

Radiation 

type

Energy 

selection 

(MeV) Percentage

101, 102, 

106, 117, 

118, 147, 

176, 192

222, 221, 

223, 224, 

234, 235,

232, 233, 

167, 168, 

169

Chemistry: radioactive materials including 

Co-60, fission products, enriched uranium, 

depleted uranium, natural uranium, U-233, 

Cm-244, Pu-239, Am-241, others

Neutron 0.1–2.0 100

153, 154, 

157, 173, 

180, 194

210, 212; 

171, 173-

177; 241, 

243; 435, 

442, 443; 

194

Physics: accelerators, activation products, 

H-3, others

Neutron 0.1–2.0 100

103, 114, 

125, 127, 

174, 175

215, 321, 

419, 514, 

243, 253

Laboratory Services: radioactive 

materials

Neutron 0.1–2.0 100

110 261 Criticality Test Facility Neutron 0.1–2.0 100

115 327 Radiography Neutron 0.1–2.0 100

121 412 Hot cells: high beta waste, Sr-90 Neutron 0.1–2.0 100

170 131 Weapons Neutron 0.1–2.0 100

171 332 Metallurgical Chemistry: AKA Plutonium 

Facility

Neutron 0.1–2.0 100

172 331 Gaseous Chemistry: (Tritium Facility) Neutron 0.1–2.0 100

182 162, 165, 

166

Laboratory Services: 55 Ci Co-60 (1958) Neutron 0.1–2.0 100

190 251 Chemistry Heavy Elements Facility: Cm244, Am-241, U-233, Pu-239, othersNeutron 0.1–2.0 100

255 Radiological Calibration and Instrument 

Repair Facility

Neutron 0.1–2.0 100

193 281 Reactor Neutron 0.1–2.0 100

Site 300 Site 300 Explosives Testing: linear accelerators, 

depleted uranium, H-3, radiography

Neutron 0.1–2.0 100

a. Trost (2005).

b. The facilities listed in this table represent the buildings where there was a potential for exposure to neutron radiation.

The NTA dosimeter (1952–1968) exhibited a lower neutron energy threshold of approximately 500 

keV and consequently underestimated the neutron exposure (Rich 1969; Griffith and Hankins 1980;

NCRP 2007). The photon dose was measured adequately and all LLNL neutron dose was 

accompanied by a significant photon dose. For neutron dose received before 1969, the dose should 

be adjusted by using a neutron-to-photon (NP) ratio. The ratio varies by operation and task (Hankins 

1982b). Neutron spectral and dose measurements in LLNL facilities were done in later years, as 

noted in Attachment A, Section A.2.
Document No. ORAUT-TKBS-0035-6 Revision No. 02 Effective Date: 02/26/2010 Page 22 of 81

6.4 MONITORED LLNL WORKERS – MEASURED DOSE

6.4.1

No adjustment to recorded photon doses is recommended. LLNL film and thermoluminescent 

dosimeters provided reasonably accurate measurement of photon radiation exposure in the facilities 

and for all years of operation. In the early years, the ratio of the OW film dosimeter response and the 

shielded film response was used to evaluate the energy of the incident photon radiation and to 

distinguish if significant beta radiation was present. Multielement film dosimeters were used later 

consistent with practices at other DOE sites. PIC and radiation detection instruments were also used,

which provided another source of reference for the measured photon exposure. Kathren (1965) 

reported results of a workplace comparison of film and thermoluminescent dosimeters. Approximately 

60% of the compared results showed good agreement defined as dose results differing by the greater 

of 20 mR or ≤20% of the higher dose interpretation. 

Photon Dose Adjustments

6.4.2

The measured photon dose is used with the DCFs to calculate organ doses of interest using the 

external dose reconstruction implementation guidelines (NIOSH 2007b). For LLNL measured photon 

dose before 1986 (film badge and TLD), the DCFs from exposure to organ dose should be used [7]. 

After 1985, the DCFs from deep dose equivalent to organ dose should be used. This is summarized 

in Table 6-8. It is recommended that the 100% anterior-posterior (i.e., front-to-back) geometry should 

be assumed for the irradiation geometry and for conversion to organ dose [8]. 

Photon Organ Dose Conversion Factors

Table 6-8. Photon dose conversion factors.

Period Dosimeter Facility Adjustment to reported dose

1952–1985 Photon dosimeters All facilities Use roentgen-to-organ dose conversion factors. 

1986–present Photon dosimeters All facilities Use Hp(10)-to-organ dose conversion factors.

6.4.3

There is very little recorded neutron dose before the mid-1980s according to Figure 6-1. Based on 

evaluations by Rich (1969) and by the U.S. Atomic Energy Commission (AEC) at other DOE 

plutonium facilities (Vallario, Hankins, and Unruh 1969; Biles 1972; Fix, Wilson, and Baumgartner 

1997b), the NTA-measured neutron dose underestimated the actual neutron dose. As such,

adjustments to the LLNL recorded neutron dose are necessary to arrive at a favorable to claimant 

dose considering the uncertainty associated with the recorded dose as follows [9]:

Neutron Dose Adjustments

• Neutron doses determined before January 1, 1969, with the NTA film dosimeter are likely too 

low and an NP ratio should be multiplied by the measured photon dose to assign a favorable 

neutron dose to the claimant. It should be noted that if the Energy Employee has recorded 

neutron dose, the assigned neutron dose should be compared with the recorded neutron dose 

and the assigned dose used only if it is higher [10].

• Neutron dose measurements with the workplace performance-validated TLD implemented in 

1969 should be multiplied times an angular correction factor of 1.3.

6.4.4

The neutron dose must be adjusted to account for the change in neutron quality factors between 

historical and current scientific guidance as described in NIOSH (2007b). LLNL neutron calibration 

factors were determined historically from National Institute of Standards and Technology (NIST)

calibrated sources. The quality factor is incorporated in the NIST calibration methodology, which used 

Neutron Weighting Factor
Document No. ORAUT-TKBS-0035-6 Revision No. 02 Effective Date: 02/26/2010 Page 23 of 81

flux-to-dose-rate conversion factors for varying neutron energies for each calibration source. Flux-todose-rate conversion factors were typically based on NCRP Report 38 (NCRP 1971). The NCRP 

report lists both flux-to-dose-rate conversion factors and associated quality factors. Table 6-9

summarizes historical changes in the quality factors, the average NCRP Report 38 quality factor for 

the neutron energy groups used as input to the Interactive RadioEpidemiological Program (IREP), the 

associated International Commission on Radiological Protection (ICRP) Publication 60 (ICRP 1991) 

weighting factor, and the ratio to convert from NCRP Report 38 to ICRP Publication 60 (see ORAUTOTIB-0055, ORAUT 2006b).

Table 6-9. Conversion from NCRP Report 38 (NCRP 1971) neutron quality factors to ICRP 

Publication 60 (ICRP 1991) weighting factors.

Neutron energy

Historical dosimetry 

guidelinesa

NCRP Report 38 group 

averaged quality factor

ICRP Publication 60 

neutron weighting factor Ratiob

Thermal 3 2.35 5 2.13

0.5 eV–10 keV 10

10 keV–100 keV 5.38 10 1.86

100 keV–2 MeV 10.49 20 1.91

2 MeV–20 MeV 7.56 10 1.32

20 MeV–60 MeV 6.96c 5 1.00d

a. First Tripartite Conference at Chalk River in 1949 (Warren et al. 1949; Fix, Gilbert, and Baumgartner 1994); National 

Bureau of Standards Handbook 59 (NBS 1954; also known as NCRP Report 17); and Taylor (1971).

b. Ratio of the ICRP Publication 60 weighting factor to the group averaged NCRP 38 quality factor each neutron energy 

group (ICRP 1991; NCRP 1971). 

c. “Not applicable” is usually inserted here rather than the NCRP group averaged value of 6.96, which is larger than the 

ICRP Publication 60 weighting factor of 5 for 20-to-60-MeV neutrons and results in a non favorable to claimant reduction 

in the corrected dose for this neutron energy group (ICRP 1991; NCRP 1971).

d. Ratio for adjusting neutron dose from NCRP Report 38 quality factor to ICRP Publication 60 weighting factor is arbitrarily 

set equal to unity to avoid a non favorable to claimant reduction in the corrected dose for this neutron energy group

(ICRP 1991; NCRP 1971).

DOE is in the process of implementing ICRP Publication 60 (ICRP 1991) neutron weighting factors 

into the routine determination of the recorded neutron dose. For LLNL, the date this is scheduled to 

begin will need to be determined. Once this change is made, no adjustment in the recorded neutron 

dose will be necessary thereafter [11]. 

6.5 MONITORED LLNL WORKERS – MISSED DOSE 

Missed doses to LLNL workers are assigned for monitored workers (NIOSH 2007b). Thompson 

(1953) documented that all workers at LLNL were monitored for radiation exposure however as noted 

in Block (1954) only positive measured doses were recorded. The potential for missed dose exists 

when workers are exposed to radiation at levels below the detection limit of their personnel 

dosimeters or if dosimeters were not worn for all work involving radiation exposure. Nolan (1958) 

documented the experience that new or additional low-level exposure was observed for some workers 

when the LLNL security and dosimeter badge were combined in 1958. LLNL policy was to monitor 

any significant radiation exposure. Generally in the early years of radiation monitoring, when 

relatively high detection limits were combined with short monitoring durations, missed doses could be 

significant. Watson et al (1964) describes a method to reconstruct doses for any exchange periods 

without a recorded dose. The assignment of a missed dose is based on a determination of (1) the 

number of dosimeter results with a recorded dose less than the LOD divided by 2, and (2) 

multiplication of the LOD/2 value by the number of dosimeter results < LOD/2 to include potential 

unrecorded dose according to the scheduled dosimeter exchange period (NIOSH 2007b). Rich 

(1969) stated that often no positive neutron dose was measured with NTA film in workplaces with 

known neutron dose. As such, the missed dose from neutron radiation before 1969 should not be 

based on the NTA dosimeter results but rather the missed neutron dose should be determined by 

multiplying the missed photon dose by an NP ratio. For neutron dose measured with the TLD, the 
Document No. ORAUT-TKBS-0035-6 Revision No. 02 Effective Date: 02/26/2010 Page 24 of 81

assignment of a missed neutron dose is based on a determination of (1) the number of dosimeter 

results with a recorded neutron dose less than the LOD divided by 2, and (2) multiplication of the 

LOD/2 value times the number of dosimeter results < LOD/2 to include potential unrecorded neutron 

dose according to the scheduled dosimeter exchange period (NIOSH 2007b). 

6.6 UNMONITORED LLNL WORKERS

There should generally not be any occupationally exposed unmonitored LLNL workers because 

workers were assigned a dosimeter. However, there might be some situations regarding unrecorded 

dose for work activities that involved comparatively low-level exposure, considering only positive 

doses were recorded before about 1980. LLNL workers who were apparently unmonitored for 

external radiation are assigned either external onsite ambient doses, if they were nonradiological 

workers and would not have been exposed to workplace radiation sources, or unmonitored doses 

using coworker studies or some other evaluation if a potential for exposure was evident. As noted in 

the historical timeline of dosimeter assignment practices in Attachment A, LLNL policy was to assign 

dosimeters to all workers. This policy was clearly stated in 1954 (Block 1954) and might have existed 

earlier because there are records of earlier measured photon and neutron dose (see Attachment A, 

Section A.2). As such, the potential for a significant unmonitored beta/photon radiation exposure 

appears minimal. 

6.6.1

There does appear to be a potential for ambient neutron radiation exposure associated with ICT 

Building 212 operations beginning in about 1966 extending over a period of many years. As noted in 

Attachment A, Section A.2, elevated neutron exposures at the fence and at a nearby bus stop were 

evaluated on many occasions. LLNL-measured annual neutron dose at the perimeter fence from this 

facility is presented in Table 6-10. Documentation by Myers (1984) and various references noted in 

Attachment A indicate that elevated neutron exposure from this facility existed at least through 1986. 

Ambient Neutron Dose

Table 6-10. Perimeter fence neutron doses from Building 212.

Year

Maximum annual 

dose (mrem) SRDB reference Year

Maximum annual 

dose (mrem) SRDB reference

1972 250 Gudiksen et al. 1973 1983 113 Griggs, Meyers, and 

Buddemeier 1984

1973 250 Silver et al. 1974 1984 45 Griggs, Meyers, and 

Buddemeier 1985

1974 370 Silver et al. 1975 1985 7 Griggs and 

Buddemeier 1986

1975 700 Silver et al. 1976 1986 30 Holland, Buddemeier, 

and Brekke 1987

1976 600 Silver et al. 1977 1987 9 Holland and Brekke 

1988

1977 550 Silver et al. 1978 1988 5 Kamelgarn 1989

1978 137 Silver et al. 1979 1989 6 Sims et al. 1990

1979 80 Silver et al. 1980 1990 6 Sims et al. 1991

1980 85 Toy et al. 1981 1991 7 Gallegos et al. 1992

1981 33 Auyong, Griggs, and 

Buddemeier 1982

1992 7 Gallegos et al. 1993

1982 36 Griggs, Gonzales, and 

Buddemeier 1983

1993 7 Gallegos et al. 1994

The annual doses in Table 6-10 would generally relate to a comparably low dose rate per hour. 

Considering that all LLNL workers were assigned neutron-sensitive TLDs beginning at least in 1969 

(Rich 1969), any occupationally significant ambient neutron dose would have been detected and 

measured by these dosimeters. However, it is possible that low-level neutron exposures were not 
Document No. ORAUT-TKBS-0035-6 Revision No. 02 Effective Date: 02/26/2010 Page 25 of 81

measured. As such, the dose reconstructor can consider whether to assign a comparatively low 

ambient neutron dose to a worker in comparison with typically much greater measured and assigned 

occupational dose components. 

6.6.2

As noted above, there generally should be no unmonitored LLNL workers. 

Coworker Assigned Photon Dose

6.6.3

The inability of the NTA film dosimeter to measure the neutron dose (Rich 1969) can be considered 

an example of an unmonitored exposure. The photon dose was reliably measured with LLNL film and 

thermoluminescent dosimeters, and essentially any significant neutron dose would be accompanied 

by significant photon dose. The LLNL TLDs provide paired neutron and photon dose measurements. 

A total of 554 LLNL TLD personnel dose measurements were obtained with measured photon and 

neutron doses equal to or greater than 20 and 40 mrem, respectively, to minimize effects in the 

analysis of measured doses near the LOD. The development of the NP ratio enables the use of the 

recorded photon radiation dose from an individual’s personnel dosimeter to be used to estimate the 

unmonitored neutron dose. Figure 6-3 illustrates the NP ratio for each of the 554 measured neutron 

and photon dose measurements. The range in NP values appears similar for all years without a 

distinctive trend. The neutron and photon doses are not, however, well correlated, as shown in Figure

6-4 with a Pearson Correlation of 0.38, likely because photon radiation exposure of workers occurred 

in many workplaces whereas neutron exposure occurred primarily in plutonium facilities with variable 

NP dose ratios.

Neutron-to-Photon Dose Ratio 

The 554 NP values of paired measured photon and neutron doses are well represented by a 

lognormal distribution (i.e., Kolmogorov–Smirnov test = 0.076). The statistical parameters are 

summarized in Table 6-11.

Beginning in 1994, the LLNL Radiation Exposure (REX) database records often included the facility to 

which each worker was assigned and presumably, in the case of measured neutron dose, the facility 

where the neutron exposure occurred. Analyses of the collective dose for this subset of the 554 TLD

paired neutron and photon doses according to year and building are summarized in Table 6-12. Four 

LLNL buildings (i.e., 235, 332, 335 and 3340) respectively had a collective neutron dose exceeding 1 

rem during this 12-year period. The majority of the collective neutron dose is associated with work in 

the LLNL Plutonium Facility Building 332 (i.e., Buildings 335 and 3340 are office buildings used by 

personnel working at Building 332). 

Analyses of statistical parameters for each of these buildings are presented in Table 6-13. These 

facilities would be expected to comprise all of the facilities with significant potential for neutron 

exposure during the period of 1994 to 2006. Statistical parameters for the subset of the 554 paired 

measurement data shown in Table 6-13 with an identified facility (i.e., 215 values) are very similar to 

the parameters shown in Table 6-11 for the analysis of all 554 paired measurements. 
Document No. ORAUT-TKBS-0035-6 Revision No. 02 Effective Date: 02/26/2010 Page 26 of 81

 

1.E-03

1.E-02

1.E-01

1.E+00

1.E+01

1.E+02

1982 1984 1987 1990 1993 1995 1998 2001 2004 2006 2009

Year

N:P Ratio

Figure 6-3. Trend of TLD measured LLNL worker NP dose ratio with respective neutron ≥40 

mrem and photon ≥20 mrem dose components.

Figure 6-4. LLNL paired TLD neutron ≥40 mrem and photon ≥20 mrem dose measurements.

Table 6-11. LLNL NP ratio from TLD measurements.

Description Values GM GSD 95th percentile Fita

TLD personnel dose data 554 0.78 1.91 2.27 0.076

a. Kolmogorov–Smirnov test is used as a measure of goodness of fit to a lognormal distribution.
Document No. ORAUT-TKBS-0035-6 Revision No. 02 Effective Date: 02/26/2010 Page 27 of 81

Table 6-12. Collective TLD measured photon and neutron dose (person-rem).

Year

Collective dosea

Building 332 Building 3340 Building 335 Building 235 Totals

Neut. Phot. Neut. Phot. Neut. Phot. Neut. Phot. Neut. Phot.

1994 0.105 0.294 0.090 0.118 0.000 0.000 0.195 0.412

1995 0.294 0.608 0.182 0.299 0.023 0.000 0.499 0.907

1996 0.222 0.777 0.049 0.396 0.000 0.064 0.271 1.237

1997 0.182 1.132 0.050 0.456 0.000 0.017 0.232 1.605

1998 0.242 0.493 0.000 0.180 0.000 0.000 0.242 0.673

1999 0.346 0.825 0.224 0.353 0.053 0.042 0.623 1.220

2000 0.303 0.900 0.121 0.490 0.000 0.100 0.424 1.490

2001 0.395 0.807 0.292 1.128 0.025 0.193 0.712 2.128

2002 0.217 0.551 0.328 0.791 0.482 1.211 0.505 0.298 1.532 2.851

2003 0.187 0.430 0.646 1.220 0.567 1.420 0.321 0.290 1.721 3.360

2004 0.149 0.222 0.467 0.913 0.432 1.615 0.090 0.596 1.138 3.346

2005 0.072 0.115 0.247 0.524 0.037 0.256 0.000 0.033 0.356 0.928

2006 0.167 0.153 0.769 1.045 0.073 1.638 0.035 0.469 1.044 3.305

Totals 2.881 7.307 2.457 4.493 2.599 9.560 1.052 2.102 8.989 23.462

a. Neut. = neutron; Phot. = photon.

 Table 6-13. Statistical parameters for facility-specific TLD neutron and 

 photon dose data, 1994–2006.

Statistical 

parameters

LLNL facility

231 235 332 335 3340 Overall

Points 1 9 52 53 99 214

Fita 0.23 0.22 0.13 0.09 0.07

GM 1.86 0.55 1.07 0.74 0.79

GSD 1.44 1.42 1.92 1.68 1.86

95th 

percentile

3.38 0.97 3.14 1.73 2.18

Maximum 1.22 2.97 1.31 2.67 2.52 2.97

average 1.97 0.58 1.27 0.85 0.96

Minimum 1.22 1.03 0.39 0.15 0.25 0.15

 a. Kolmogorov–Smirnov test is used as a measure of goodness of fit to a lognormal

 distribution.

Hankins (1982b) provides 236 paired neutron and photon measurements for numerous LLNL 

facilities. The statistical analysis results are summarized in Table 6-14. Again, for 1982, these 

buildings are apparently the only facilities with a potential for significant neutron exposure. These 

data illustrate a slightly higher NP geometric mean (GM) and geometric standard deviation (GSD)

compared to the statistical parameters determined from the personnel TLD measurements in Tables 

6-11 through 6-13.

6.6.3.1 NP Ratio Application

The combination of the 554 personnel TLD data during the period from 1982 to 2004 and the 236 

points from the 1982 measurements provides a reasonable sample to evaluate statistical parameters 

of the NP ratio for the majority of workers. The 1982 workplace measured data however in Table 6-14 

better represent the variability in workplace (Fix 2010) and the recommended lognormal distribution 

parameters for use in dose reconstruction are summarized in Table 6-15 [12]. This distribution is 

combined with measured and missed dose distributions using Monte Carlo methods described in 

ORAUT-OTIB-0012, Monte Carlo Methods for Dose Uncertainty Calculations (ORAUT 2005c). The 

resulting total neutron dose should be partitioned for input to IREP assuming that 100% is from 

neutrons from 0.1 to 2 MeV.
Document No. ORAUT-TKBS-0035-6 Revision No. 02 Effective Date: 02/26/2010 Page 28 of 81

Table 6-14. Statistical parameters for facility-specific measured neutron and photon dose data, 1982 

(Hankins 1982b).

Statistical

parameter

LLNL facility

131 212(ICT) 231 233 251 281 332 Site 300 Overall

No. of values 3 9 31 24 20 34 81 34 236

Fit 0.29 0.26 0.22 0.13 0.15 0.14 0.08 0.16 0.09

GM 5.28 3.08 0.87 0.52 2.43 0.63 1.58 1.21 1.19

GSD 5.02 1.94 1.91 2.99 2.56 4.38 2.91 2.22 3.18

95th 

percentile

75.15 9.17 2.51 3.16 11.42 7.13 9.12 4.52 7.96

Maximum 19.33 7.50 5.91 5.00 25.00 7.50 20.29 3.33 25.00

Average 9.67 3.59 1.09 0.92 4.06 1.40 2.73 1.53 2.20

Minimum 0.87 0.67 0.09 0.09 0.75 0.03 0.03 0.10 0.03

a. Kolmogorov–Smirnov test is used as a measure of goodness of fit to a lognormal distribution.

 Table 6-15. Recommended NP ratio for Dose Reconstruction.

Description GM GSD 95th percentile

LLNL Dose Reconstruction 1.19 3.18 7.96

6.6.3.2 Construction Workers

If a construction worker received a TLD and worked in a facility with significant neutron exposure, this 

will be detected by the TLD. The NTA film dosimeter assigned to some workers before 1969 might 

not detect significant neutron exposure (Rich 1969) and, therefore, a favorable to claimant option 

must be selected to reconstruct potential neutron exposure. As such, the dose reconstructor should 

assume neutron exposure occurred unless there is other information indicating the construction work 

was conducted only in areas with little or no neutron radiation.

6.6.3.3 Specific Locations

Generally the standard NP ratio with a GM of 1.19 and a GSD of 3.18 (Table 6-15) should be used for 

workers unless the individual’s records indicate that they worked in a specific facility and time where 

measurements are available in Tables 6-13 (1994–2004) and 6-14 (1982), respectively, or the facility 

has only photon exposure. An examination of LLNL recorded dose records shows only a few 

buildings with positive TLD-measured neutron dose as shown in Tables 6-13 and 6-14. Hankins 

(1982b) provided a summary of calibration factors for each of the facilities according to workplace 

measurements of the neutron radiation dose fraction. The neutron dose from the TLD results is 

divided

6.7 UNCERTAINTY

by the calibration factor shown in Table 6-16 to obtain the neutron dose for the various 

workplaces. The calibration factor is indicative of the effective neutron energy (i.e., the lower the 

value of the calibration factor, the higher the effective energy of the neutron spectrum).

A number of factors contribute to uncertainty in measured doses. Systematic errors can occur from 

calibration and processing as well as from extraneous conditions such as moisture, heat, and fading. 

Random errors arise from variations among workers, the workplace energy spectra, and geometries 

of their exposures. NIOSH data collections of LLNL documentation have identified studies of 

uncertainty assessments for LLNL dosimeter systems. Many of these are illustrated in the historical 

timeline in Attachment A, Section A.2. The LLNL systems have much in common with dosimetry 

systems used at other DOE facilities. 
Document No. ORAUT-TKBS-0035-6 Revision No. 02 Effective Date: 02/26/2010 Page 29 of 81

6.7.1

NIOSH (2007b) provides guidance for estimating uncertainty in external dose reconstruction. Under 

good laboratory conditions, film-badge uncertainty can be at the level of 10% to 15%. The absolute 

Measured Photon Dose

Table 6-16. Summary of neutron calibration factors for LLNL buildings (Hankins 1982a).

Facility Building Rooms/sources

Calibration 

factor

LLNL Plutonium Facility 332

Room 1378 0.4

Other rooms 0.3

Vaults 0.4

Room 1378 during PuBe work 0.2

Shielded PuBe work 0.2

Vault 231 Inside vault 0.45

Chemistry 233 Building 233 0.45

Rotating target neutron 

source

212 ICT – Building 212 0.9

Top of ICT Shielding 0.5

Chemistry Heavy 

Elements Facility 251

Shielded boxes 0.8

Unshielded work: Cm-244 tracers 0.3

Cf-252 tracers 0.2

Boxes (top-bottom-no shield) 0.3

Reactor 281 Reactor 1.6a

Weapons Engineering

Calibration Laboratory

Site 300

131

255

Site 300

Shielded sources: Cf-252

PuBe

0.4

0.2

Unshielded sources: Cf-252

PuBe

0.14

0.1

Berm shielded accelerator 0.8

255 Control Room 1.0

a. An additional correction for over-response of the 9-in. sphere must also be applied.

uncertainty at 95% confidence should not be less than the LOD, which for LLNL was about 0.03 rem 

for beta/gamma film dosimetry in the 1950s. LLNL researchers have published several articles on 

evaluations of personnel photon dose measurements and evaluations as follows:

• Wilcox (1956) reported on test exposures of DuPont 555 film from 5 mR to 1,000 mR with 

some testing in excess of 1,000 mR (Wilcox 1956). The ranges of this film for mixed photon 

energies at LLNL were stated to be: 

60Co 0.010 – 2,000 R

30 keV 0.001 – 200 R

• Table 6-17 presents a summary of intercomparison results described in a memorandum by 

Kathren (1965) between film- and TLD-measured doses in LLNL workplaces. Film badge 

interpretations and TLD-100 dose evaluations were compared over the April-to-August 1965 

interval. During this period, there were 176 pairs of dosimeters that could be compared. 

Table 6-17 gives the results of the comparison. Good agreement was defined as 

interpretations differing by the greater of 20 mR or ≤20% of the higher interpretation. The 

June-to-August period was separated because special precautions were taken to ensure that 

the two dosimeters were changed at the same time and that no overlapping intervals occurred. 

Of the 40 cases in which the film readings were higher that the LiF, at least 32 were with 

persons known to have been exposed to low-energy X-rays; an additional 3 had possible lowenergy X-ray exposure. In these cases, the developed film generally showed a typical lowenergy X-ray pattern. Thus, the higher film badge results can be attributed to the lack of 

response by the TLD-100; the film badge data are more indicative of actual exposure. By 
Document No. ORAUT-TKBS-0035-6 Revision No. 02 Effective Date: 02/26/2010 Page 30 of 81

contrast, there is no obvious explanation in which the TLD interpretations are higher than 

those for the film. 

Table 6-17. Summary of LLNL measured TLD and film 

doses (Kathren 1965).

Condition

April–August June–August

Number Percent Number Percent

Good agreement 105 60 58 57

Film higher 40 23 22 22

TLD-100 higher 31 18 22 22

Total 176 100 102 100

• LRL and PNL (1966–1967) prepared documentation of LLNL dosimeter performance in the 

DOE-sponsored study in 1967 to evaluate a complex-wide dosimeter performance standard,

which is described in BNWL-542, The Establishment and Utilization of Film Dosimeter 

Performance Criteria (Unruh et al. 1967). The criteria in this document were used to develop 

performance testing criteria used in a study of 35 government, military, and commercial 

dosimeter processors at that time. LLNL-reported doses in comparison with the given doses 

are summarized in Table 6-18.

Table 6-18. LLNL participation in DOE dosimeter performance 

testing (LRL and PNL 1966–1967).

Dosimeter No.

Given 

dose

LLNL 

dose

Dose 

difference Percent

Gamma radiation

1 1.000 1.050 0.050 5.0

2 1.000 1.050 0.050 5.0

3 1.000 1.050 0.050 5.0

4 1.000 1.050 0.050 5.0

5 1.000 1.010 0.010 1.0

6 1.000 1.100 0.100 10.0

7 0.240 0.245 0.005 2.1

8 0.240 0.280 0.040 16.7

Beta radiation 

1 0.500 0.530 0.030 6.0

2 0.500 0.520 0.020 4.0

3 0.500 0.500 0.000 0.0

4 0.500 0.530 0.030 6.0

5 0.500 0.520 0.020 4.0

6 0.500 0.510 0.010 2.0

7 0.500 0.510 0.010 2.0

Neutron radiation

1 0.262 0.291 0.029 11.1

2 0.787 0.862 0.075 9.5

3 0.262 0.280 0.018 6.9

• Hankins (1982a) reported results of a retrospective study of LLNL dosimeter response 

characteristics in a study to reconstruct an LLNL worker 1963 exposure at the Nevada Test 

Site (NTS) using beta and gamma irradiations from the LANL Godiva IV Critical Assembly. 

This study concluded that for the evaluated beta irradiations the film dosimeter without the 

security badge is reasonably accurate and about a factor of 2 too low when the security 

credential is in place. The gamma irradiations were accurate within about ±20%. The LLNL 

TLDs used at the time of this study (i.e., 1982) showed a similar accuracy (±20%) for gamma 

radiation and a factor of 2 too low for beta irradiations.
Document No. ORAUT-TKBS-0035-6 Revision No. 02 Effective Date: 02/26/2010 Page 31 of 81

6.7.2

LLNL researchers (Hankins 1967; Hankins and Nealy 1971; Hankins 1976; Griffith et al. 1977; 

Hankins 1977a; Griffith et al. 1978a,b; Hankins et al. 1978a,b; Slaughter et al. 1978; Griffith and 

Hankins 1980; Hankins 1982a,b, 1984b; Hankins, Homann, and Buddemeier 1989) have prepared 

numerous documents regarding neutron dose evaluation. A few selected documents follow:

Measured Neutron Dose

• LRL and PNL (1966–1967) documentation of LLNL dosimeter performance in the DOEsponsored study in 1967 included neutron radiation, as shown in Table 6-18. 

• Hankins (1978b) described studies of albedo neutron dosimeter performance. As described in 

this report, a neutron survey inside containment of the Farley Nuclear Plant was made to 

determine the spectra of leakage neutrons and to evaluate the accuracy of a 9-in.-diameter 

sphere remmeter (PNR-4) and of albedo-neutron dosimeters. Variations in the neutron 

spectra, the ratio of gamma-to-neutron dose rates, and the thermal neutron component of the 

neutron dose were also studied. The results indicated the neutron spectra were constant 

throughout the reactor with a 25-keV component on a 1/E spectrum. The albedo-neutron 

dosimeter performed within about ±25% of the measured dose. A neutron survey was also 

made at a neutron radiography facility with an accuracy of the albedo-neutron dosimeter within 

approximately ±33% of the measured dose.

• Hankins (1982a) described techniques to evaluate the neutron exposures received by 

personnel at the LLNL. Two types of evaluations are discussed covering the use of the routine 

personnel dosimeter and of the albedo-neutron dosimeter. Included in the report are field 

survey results that were used to determine the calibration factors to be applied to the 

dosimeter readings. Calibration procedures were discussed and recommendations were made 

on calibration and evaluation procedures. The document described methods used to develop 

workplace-specific dose calibration factors. The techniques used were stated to typically 

agree within ±30%. For the lower calibration factors, low readings of up to 50% were 

observed. At these points, the neutrons were known to be approximately isotropic and a low 

calibration factor was expected from the badge results. The calibration factor obtained by 

using the 9/3-in. sphere ratio is accurate to within ±30%.

6.7.3

LLNL researchers have prepared documents regarding beta dose evaluation as noted in Attachment 

A, Section A.2. A few selected documents follow:

Measured Beta Dose

• LRL and PNL (1966–1967) documentation of LLNL dosimeter performance in the DOEsponsored study in 1967 included beta radiation as shown in Table 6-18. 

• Hankins (1984a) reported results of a retrospective study of LLNL dosimeter response 

characteristics to reconstruct a LLNL worker 1963 exposure at the NTS using beta and 

gamma irradiations from the LANL Godiva IV Critical Assembly. This study concluded that for 

the evaluated beta irradiations the film dosimeter without the security badge is reasonably 

accurate and about a factor of 2 too low when the security credential is in place. The gamma 

irradiations were accurate within about ±20%. The LLNL TLDs used at the time of this study 

(i.e., 1984) showed a similar accuracy (±20%) for gamma radiation and a factor of 2 too low for 

the beta irradiations used in this study. 
Document No. ORAUT-TKBS-0035-6 Revision No. 02 Effective Date: 02/26/2010 Page 32 of 81

6.8 SHALLOW DOSE

6.8.1

LLNL dosimeters measured nonpenetrating and penetrating beta/photon radiation exposure. The 

assignment of shallow dose according to beta, photon, or neutron radiation components can be 

complex because of mixed radiation fields and site-specific practices to calculate the compliance WB

penetrating, WB skin, and extremity skin dose quantities. LLNL historical records are typically 

identified as beta, gamma, or neutron doses. The dose reconstructor can validate the 

reasonableness of the assigned shallow photon dose to the skin of the whole body because it should 

be equal to or greater than the assigned photon deep dose in essentially all cases. If it is not, the 

shallow photon dose component should be calculated as equal to the sum of the shallow and deep 

photon doses. In cases of assigning a shallow dose to the extremities, such as the hand, which was 

often evaluated at LLNL, the assigned shallow dose to the extremities should be equal to or greater 

than the WB shallow photon dose in essentially all cases. 

Assigned Shallow Dose

6.8.2

There is uncertainty with respect to reconstructed extremity skin dose because of geometry, shielding,

and dosimeter response parameters. According to LLNL dose records, extremity dosimeters were 

assigned to LLNL radiation workers. A standard monitoring practice is to establish a factor between 

WB and extremity exposures to determine when the extremity dose would be limiting and, thus, 

extremity dosimeters should be assigned. The factor is typically based on radiation guidelines for the 

extremity, skin, and whole body, which have varied over the years as described in Attachment A, 

Table A-1. At the 1949 meeting in Chalk River, Canada, among U.S., United Kingdom, and Canadian 

nuclear weapon development organizations, several aspects of operational health physics were 

defined (Taylor 1971). The identified limits were:

Assigned Extremity Skin Dose

Whole body–0.3 rem/wk;

Skin–0.5 rem/wk; and 

Extremity–1.5 R/wk.

Based on comparison of the dose limits, it would not be necessary to monitor the extremity dose 

unless it was greater than a factor of about 5 multiplied by the WB dose; otherwise, the WB dose 

would be limiting. Therefore, it is recommended that the measured WB photon dose be increased by 

a factor of 5 to assign a dose to the extremities based on the premise that extremity dosimeters would 

have been assigned and the dose reported for higher exposures [13]. The extremity dose is always 

equal to or greater than the measured WB skin dose (i.e., an estimated extremity dose is equal to the 

sum of the WB gamma, neutron, and beta doses). Unless it is clear that the extremity dosimeter is 

always worn, the measured extremity dose should also be included in the total assigned dose. The 

dose reconstructor can use guidance in ORAUT-OTIB-0017, Interpretation of Dosimetry Data for 

Assignment of Shallow Dose (ORAUT 2005d). An example is shown in Table 6-19.

Determination of assigned Extremity Dose

Assigned Whole Body (WB).Dose = Gamma + Neutron

Assigned WB Skin = WB Penetrating + Beta

Assigned Extremity Dose = WB Skin + extremity dose

Assign greater of: 1) 5 x Gamma dose

 2) Assigned Extremity dose
Document No. ORAUT-TKBS-0035-6 Revision No. 02 Effective Date: 02/26/2010 Page 33 of 81

Table 6-19. Examples of extremity skin dose assignments (assuming no clothing 

correction) (mrem).

LLNL reported dose Assigned extremity 

Beta Gamma Neutron Extremity skin dose

50 0 0 0 = (0 + 0) + 50 + 0 = 50 

0 50 25 0 = 5 × (50) = 250

100 20 0 60 = (20 + 0) + 100 + 60 = 180

100 50 0 100 = 5 × 50 = 250

= (50 + 0) + 100 + 100 = 250

6.9 NON-SITE-SPECIFIC FACTORS

6.9.1

There is uncertainty with respect to the reconstructed organ dose in the lower abdomen for workers 

working substantially in a chemical benchtop environment such as the LLNL plutonium facility 

glovebox operations. Guidance in OCAS-TIB-0010, Best Estimate External Dose Reconstruction for 

Glovebox Workers (NIOSH 2005), should be used to adjust the measured photon dose to workers in 

identified LLNL plutonium facilities where extensive and long-term glovebox work was conducted. In 

general, this correction should be considered for any worker with a glovebox checked on the 

Computer Assisted Telephone Claim form and whether the identified places of work included

glovebox or other benchtop work environments.

Adjustment for Glovebox Workers

6.9.2

During 1990, LLNL Vault Operations technicians wore lead vests when conducting some of their tasks

in the vault (Shingleton 1991). The technicians wore two dosimeters, one on the inside and the other 

on the outside of the vest. The lead vest resulted in a significant reduction of the recorded photon 

dose ranging from 9 to 44%. Dose reconstruction must consider the site of the cancer to ensure a 

favorable to claimant reconstructed dose. LLNL practices for wearing lead vests appear to vary from 

facility to facility and, even for the vault operations described in Shingleton (1991), the wearing of a 

lead vest was for only some tasks. The fraction of the measured photon dose for the dosimeter worn 

under the vest is dependent on the radiation field and the lead vest specifications. Passmore (1992, 

1995a,b) has reported similar measurements of the effect of lead vests on recorded photon doses at 

Pantex and Rocky Flats Plant plutonium facilities. Until the specific details of LLNL practices to 

require workers to wear lead vests and to ensure integrity of the vests, the recommended option is to 

incorporate a correction factor depending on the cancer site, as shown in Table 6-20. If the dosimeter 

location is not known, the most clamant-favorable dosimeter locations should be assumed. Table 6-

20 values were derived from the LLNL measurements (Shingleton 1991) to represent a maximizing 

best estimate of the correction factor based on the available measurement results and are applied as 

a constant. The lead vest did not affect the neutron dose component.

Lead Vests Worn By Vault Operations Technicians

Table 6-20. Correction factors for application to photon dose received while 

wearing a lead vest [14].

Dosimeter 

location

Cancer 

location

Neutron 

dose

Deep photon 

dose

Shallow 

photon dosea

Under apron Protected area 1 1 1

Outside vest 1 2 1

Outside apron Protected area 1 (b) 1

Outside vest 1 1 1

a. Shallow dose would be based on dosimeter worn outside the vest.

b. In this case, the measured dose will be too high and will be favorable to the claimant.
Document No. ORAUT-TKBS-0035-6 Revision No. 02 Effective Date: 02/26/2010 Page 34 of 81

Adjustment to dose for use of protective lead vests depends on the location of the cancer site in 

relation to the lead vest. The vests covered the torso of the body but did not cover the head, neck, 

arms, or lower portion of the legs. If the cancer site is under the vest, there is no adjustment (i.e., the 

factor is 1.0), because a dosimeter under the vest will reasonably measure a dose to the cancer site. 

If the cancer site is in an area not protected by the lead vest, and for which the dosimeter-measured 

dose might be too low, the recommended adjustment factor as listed in Table 6-19 should be applied.

6.10 ATTRIBUTIONS AND ANNOTATIONS

Where appropriate in this document, bracketed callouts have been inserted to indicate information, 

conclusions, and recommendations provided to assist in the process of worker dose reconstruction.

These callouts are listed here in the Attributions and Annotations section, with information to identify 

the source and justification for each associated item. Conventional References, which are provided in 

the next section of this document, link data, quotations, and other information to documents available 

for review on the Project’s Site Research Database (SRDB).

[1] Fix, Jack J. Dade Moeller & Associates. Senior Health Physicist. October 2009. 

Mr. Fix reviewed the historical LLNL claimant dose reports to evaluate methods used to 

determine the WB penetrating, WB skin, and extremity (hand) skin doses from the dosimeter 

results.

[2] Thomas, Bill R. Integrated Environmental Management. Health Physicist. April 2006.

Mr. Thomas reviewed DOE dose reports for Energy Employee claims to evaluate trends in the 

types of dose data.

[3] Fix, Jack J. Dade Moeller & Associates. Senior Health Physicist. October 2009. 

Mr. Fix reviewed the historical documentation to estimate the types of beta/photon dosimeters, 

exchange frequencies, and associated LODs used to monitor LLNL workers. The LODs were 

estimated according the type of dosimeter technology and typical capabilities. Kathren (1964) 

provides LLNL beta/photon film LOD estimates for 1963. The annual potential missed dose 

was calculated using the method in OCAS-IG-001 (NIOSH 2007b). 

[4] Fix, Jack J. Dade Moeller & Associates. Senior Health Physicist. October 2009. 

Mr. Fix reviewed the historical documentation to estimate the types of neutron dosimeters, 

exchange frequencies, and associated LODs used to monitor LLNL workers. The LODs were 

estimated according the type of dosimeter technology and typical capabilities. Kathren (1964) 

provides LLNL NTA LOD estimates for 1963. The annual potential missed dose was 

calculated using the method in OCAS-IG-001 (NIOSH 2007b). 

[5] Thomas, Bill R. Integrated Environmental Management. Health Physicist. April 2006.

Mr. Thomas reviewed the types of activities described in ORAUT (2005e). Given the type of 

operations and the types of radioactive isotopes reported for each building, the energy 

fractions were selected in a manner similar to those for the LANL facilities.

[6] Thomas, Bill R. Integrated Environmental Management. Health Physicist. April 2006. 

Mr. Thomas reviewed the types of activities that involved isotopes and tasks in which neutron 

radiation could be encountered as described in ORAUT (2005e). Given the type of operations 

and the types of radioactive isotopes reported for each building, the neutron energy selection 

of 0.1 – 2.0 MeV was chosen because the DCF is typically favorable to claimants.

[7] Thomas, Bill R. Integrated Environmental Management. Health Physicist. April 2006. 

The precise date LLNL implemented on-phantom photon radiation calibrations is not known. It 

is expected that this was done for beta/photon dosimeters certainly no later than 1986 when 
Document No. ORAUT-TKBS-0035-6 Revision No. 02 Effective Date: 02/26/2010 Page 35 of 81

DOELAP dosimeter performance testing was required. This is a favorable to claimant

judgment pending information regarding the precise date this was done. 

[8] Fix, Jack J. Dade Moeller & Associates. Senior Health Physicist. October 2009. 

The selection of the geometry is described in OCAS-IG-001 (NIOSH 2007b).

[9] Fix, Jack J. Dade Moeller & Associates. Senior Health Physicist. October 2009. 

This represents the judgment of Mr. Fix and is consistent with statements in Rich (1969). This 

position is also substantially based on information in Fix, Wilson, and Baumgartner (1997b) 

and the similarity between LLNL and Hanford workplace radiation in plutonium facilities. 

[10] Fix, Jack J. Dade Moeller & Associates. Senior Health Physicist. March 2007. 

The recommendation to use the claim-specific NP dose ratio if higher than the recommended 

default values is to ensure that the neutron dose of record for the claimant is not reduced.

[11] Fix, Jack J. Dade Moeller & Associates. Senior Health Physicist. October 2009. 

DOE has informed NIOSH by letter that DOE contractors have a 3-year window to implement 

the ICRP Publication 60 weighting factors (ICRP 1991). Therefore, it will be necessary for the 

NIOSH Office of Compensation Analysis and Support points of contact with each site to obtain 

the planned implementation date. This information will need to be requested from LLNL.

[12] Fix, Jack J. Dade Moeller & Associates. Senior Health Physicist. February 2010. 

The information in this section is based on the judgment of a LLNL Subject and Site expert 

(Fix 2010) regarding options to assure favorable to claimant neutron dose reconstruction as 

documented by Mr. Fix.

[13] Fix, Jack J. Dade Moeller & Associates. Senior Health Physicist. October 2009.

The information in this section is based on the judgment of Mr. Fix recommending to the dose 

reconstructor, depending on the target tissue, consideration to assign an extremity dose in the 

event that monitoring for extremity dose is not performed or is incomplete or the extremity 

dose is not reported by DOE.

[14] Fix, Jack J. Dade Moeller & Associates. Senior Health Physicist. November 2009.

The tabled values of the recorded photon dose correction factor for wearing a lead vest was 

based on the dose response measurements in the Shingleton (1991) reference. The 

maximum value in this reference stated a 44% reduction in the gamma dose. A favorable to 

claimant value of 50% was assumed, resulting in the tabled correction factor of 2 for a cancer 

site on the whole body such as the head or upper arm, not under the lead vest, but for which 

the dosimeter is located under the vest.
Document No. ORAUT-TKBS-0035-6 Revision No. 02 Effective Date: 02/26/2010 Page 36 of 81

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Report for 1990, Lawrence Livermore National Laboratory, UCRL-50027-90, D. R. 

Schwoegler, editor, University of California, Lawrence Livermore National Laboratory, 

Livermore, California. [SRDB Ref ID: 26725]

Slaughter, D. R., D. W. Rueppel, and D. A. Fuess, 1978, Neutron Spectrum Measurements for 

Radiation Protection Purposes, UCRL-52415, University of California, Lawrence Livermore

Laboratory, Livermore, California, February 21. [SRDB Ref ID: 76958]

Straume, T., 1980, Radiation Safety Program for Site 300, University of California, Lawrence 

Livermore Laboratory, Livermore, California, September. [SRDB Ref ID: 72845]

Taylor, L. S., 1971, Radiation Protection Standards, CRC Press, Cleveland, Ohio.

Thompson, D. R., 1953, “Film Badge and Pocket Dosimeter Information,” memorandum to All 

Livermore Employees, University of California Radiation Laboratory, Livermore, California, 

March 9. [SRDB Ref ID: 15709]

Toy, A. J., C. L. Lindeken, K. S. Griggs, and R. W. Buddemeier, 1981, Environmental Monitoring at 

the Lawrence Livermore National Laboratory: 1980 Annual Report, UCRL-50027-80, 

University of California, Lawrence Livermore National Laboratory, Livermore, California, April 

15. [SRDB Ref ID: 14835]

Trost, M., 2005, "LLNL Building Index: Pre 1966 and Post 1966," facsimile to J. J. Maisler (Integrated 

Environmental Management), University of California, Lawrence Livermore National 

Laboratory, Livermore, California, February 15. [SRDB Ref ID: 16948]

Unruh, C. M, H. V. Larson, T. M. Beetle, and A. R. Keene, 1967, The Establishment and Utilization of 

Film Dosimeter Performance Criteria, BNWL-542, Battelle Memorial Institute, Pacific 

Northwest Laboratory, Richland, Washington, September. [SRDB Ref ID: 14914]

Vallario, E. J, D. E. Hankins, and C. M. Unruh, 1969, AEC Workshop on Personnel Neutron 

Dosimetry, September 23 to 24, 1969, BNWL-1340, Battelle Memorial Institute, Pacific 

Northwest Laboratory, Richland, Washington. [SRDB Ref ID: 11096]

Warren, S., J. S. Mitchell, A. C. Chamberlain, G. J. Neary, E. F. Edson, G. O. Failla, J. G. Hamilton, L. 

Hempelman, H. M. Parker, K. Z. Morgan, B. S. Wolf, A. Brues, L. S. Taylor, W. Langham, D. 

Hoffman, W. B. Lewis, A. J. Cipriani, G. C. Laurence, H. Carmichael, G. H. Guest, E. Renton, 
Document No. ORAUT-TKBS-0035-6 Revision No. 02 Effective Date: 02/26/2010 Page 44 of 81

G. E. McMurtrie, and A. O. Braaten, 1949, Minutes of the Permissible Doses Conference Held 

at Chalk River, Canada, September 29th-30th, 1949, R.M.-10, Tri-Partite Conference, Chalk 

River, Canada. [SRDB Ref ID: 16640]

Watson, J. E. Jr., J. L. Wood, W. G. Tankersley, and C. M. West, 1994, "Estimation of Radiation 

Doses for Workers without Monitoring Data for Retrospective Epidemiologic Studies," Health 

Physics, volume 67, number 4, pp. 402–405. [SRDB Ref ID: 8601]

Wilcox, G. E., 1956, “New Film - 555 for 1956 - 1957,” memorandum to W. E. Nolan and S. Block, 

University of California, Lawrence Livermore National Laboratory, Livermore, California, March 

19. [SRDB Ref ID: 15705]
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GLOSSARY

albedo dosimeter 

Thermoluminescent dosimeter that measures the thermal, intermediate, and fast neutrons 

scattered and moderated by the body or a phantom from an incident fast neutron flux.

ampere (A) 

International System unit of electrical current equal to 1 coulomb per second.

beta radiation

Charged particle emitted from some radioactive elements with a mass equal to 1/1,837 that of 

a proton. A negatively charged beta particle is identical to an electron. A positively charged 

beta particle is a positron.

claimant 

Individual who has filed for compensation under the Energy Employees Occupational Illness 

Compensation Program. This individual can be the energy employee (worker), a survivor, or 

the legal representative of the energy employee.

class 

A "class of employees" is defined in the EEOICPA rule as a group of employees who work or 

worked at the same DOE facility or AWE facility, and for whom the availability of information 

and recorded data on radiation exposures is comparable with respect to the informational 

needs required to complete a radiation dose reconstruction.

Columbia Resin Number 39 (CR-39)

Radiosensitive material used in track-etch neutron dosimeters.

curie (Ci)

A special unit of activity. One curie exactly equals 3.7 × 1010 nuclear transitions per second.

deep dose equivalent (Hd)

Dose equivalent in units of rem or sievert for a 1-centimeter depth in tissue (1,000 milligrams 

per square centimeter). See dose.

DOE Laboratory Accreditation Program (DOELAP) 

Program for accreditation by DOE of DOE site personnel dosimetry and radiobioassay 

programs based on performance testing and the evaluation of associated quality assurance, 

records, and calibration programs. 

dose 

In general, the specific amount of energy from ionizing radiation that is absorbed per unit of 

mass. Effective and equivalent doses are in units of rem or sievert; other types of dose are in 

units of roentgens, rads, reps, or grays

dose equivalent (H)

In units of rem or sievert, product of absorbed dose in tissue multiplied by a weighting factor 

and sometimes by other modifying factors to account for the potential for a biological effect 

from the absorbed dose. See dose.

dosimeter

Device that measures the quantity of received radiation, usually a holder with radiationabsorbing filters and radiation-sensitive inserts packaged to provide a record of absorbed dose 
Document No. ORAUT-TKBS-0035-6 Revision No. 02 Effective Date: 02/26/2010 Page 46 of 81

received by an individual. See albedo dosimeter, film dosimeter, neutron film dosimeter, 

pocket ionization chamber, thermoluminescent dosimeter, and track-etch dosimeter.

dosimetry 

Measurement and calculation of internal and external radiation doses.

dosimetry system 

System for assessment of received radiation dose. This includes the fabrication, assignment, 

and processing of external dosimeters, and/or the collection and analysis of bioassay samples, 

and the interpretation and documentation of the results. 

Energy Employees Occupational Illness Compensation Program Act of 2000, as 

amended (EEOICPA; 42 U.S.C. § 7384 et seq.) 

Law that provides for evaluation of cause and potential compensation for energy employees 

who have certain types of cancer.

exchange period 

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

exchange frequency.

external dose 

Dose received from radiation emitted by sources outside the body.

film

In the context of external dosimetry, radiation-sensitive photographic film in a light-tight 

wrapping. See film dosimeter.

film dosimeter

Package of film for measurement of ionizing radiation exposure for personnel monitoring 

purposes. A film dosimeter can contain two or three films of different sensitivities, and it can 

contain one or more filters that shield parts of the film from certain types of radiation. When

developed, the film has an image caused by radiation measurable with an optical 

densitometer. Also called film badge.

gamma radiation 

Electromagnetic radiation (photons) of short wavelength and high energy (10 kiloelectron-volts 

to 9 megaelectron-volts) that originates in atomic nuclei and accompanies many nuclear 

reactions (e.g., fission, radioactive decay, and neutron capture). Gamma photons are 

identical to X-ray photons of high energy; the difference is that X-rays do not originate in the 

nucleus. 

glovebox 

Enclosure with special rubber gloves through which an operator can handle radioactive or 

toxic material without risk of injury or contamination normally operated at a slightly reduced 

pressure so that air leakage, if any, is inward.

limit of detection (LOD)

Minimum level at which a particular device can detect and quantify exposure or radiation. Also 

called lower limit of detection and detection limit or level. 

linear accelerator (LINAC) 

Straight single-pass particle accelerator in which radio frequencies accelerate the beam over 

the length of the accelerator.
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missed dose

In relation to external dose, dose to monitored workers that was not measured or recorded due 

to such factors as a missing or damaged dosimeter or a result below the detection limits of the 

dosimeter. Missed dose is especially important in the early years of radiation monitoring, 

when relatively high detection limits were combined with short exchange periods.

neutron

Basic nucleic particle that is electrically neutral with mass slightly greater than that of a proton. 

There are neutrons in the nuclei of every atom heavier than normal hydrogen.

neutron film dosimeter

Film dosimeter with a nuclear track emulsion, type A, film packet.

nuclear track emulsion, Type A (NTA)

Film sensitive to fast neutrons made by Eastman Kodak. The developed image has tracks 

caused by neutrons that are visible under oil immersion with about 1,000-power magnification.

occupational dose

Internal and external ionizing radiation dose from exposure during employment. Occupational 

dose does not include that from background radiation or medical diagnostics, research, or 

treatment, but does include dose from occupationally required radiographic examinations that 

were part of medical screening.

on-phantom

Exposure of a dosimeter on a phantom to simulate the dosimeter’s response when worn on a 

person.

open window (OW) 

Area of a film dosimeter that has little to no radiation shielding (e.g., only a holder and visible 

light protection). See film dosimeter.

personal dose equivalent Hp(d)

Dose equivalent in units of rem or sievert in soft tissue below a specified point on the body at 

an appropriate depth d. The depths selected for personal dosimetry are 0.07 millimeters 

(7 milligrams per square centimeter) and 10 millimeters (1,000 milligrams per square 

centimeter), respectively, for the skin (shallow) and whole-body (deep) doses. These are 

noted as Hp(0.07) and Hp(10), respectively. The International Commission on Radiological 

Measurement and Units recommended Hp(d) in 1993 as dose quantity for radiological 

protection. 

photon

Quantum of electromagnetic energy generally regarded as a discrete particle having zero rest 

mass, no electric charge, and an indefinitely long lifetime. The entire range of electromagnetic 

radiation that extends in frequency from 1023 cycles per second (hertz) to 0 hertz. 

pocket ionization chamber (PIC) 

Cylindrical monitoring device commonly clipped to the outer clothing of an individual to 

measure ionizing radiation. A PIC may be self-reading or require the use of a outside device 

to be able to read the dosimeter. Also called pencil, pocket pencil, pencil dosimeter, and 

pocket dosimeter.
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rad

Traditional unit for expressing absorbed radiation dose, which is the amount of energy from 

any type of ionizing radiation deposited in any medium. A dose of 1 rad is equivalent to the 

absorption of 100 ergs per gram (0.01 joules per kilogram) of absorbing tissue. The rad has

been replaced by the gray in the International System of Units (100 rads = 1 gray). The word 

derives from radiation absorbed dose. 

radiation

Subatomic particles and electromagnetic rays (photons) with kinetic energy that interact with 

matter through various mechanisms that involve energy transfer.

radioactivity

Property possessed by some elements (e.g., uranium) or isotopes (e.g., 14C) of spontaneously 

emitting energetic particles (electrons or alpha particles) by the disintegration of their atomic 

nuclei. See radionuclide. 

rem

Traditional unit of radiation dose equivalent that indicates the biological damage caused by 

radiation equivalent to that caused by 1 rad of high-penetration X-rays multiplied by a quality 

factor. The sievert is the International System unit; 1 rem equals 0.01 sievert. The word 

derives from roentgen equivalent in man; rem is also the plural.

roentgen

Unit of photon (gamma or X-ray) exposure for which the resultant ionization liberates a positive 

or negative charge equal to 2.58 × 10-4 coulombs per kilogram (or 1 electrostatic unit of 

electricity per cubic centimeter) of dry air at 0°C and standard atmospheric pressure. An 

exposure of 1 R is approximately equivalent to an absorbed dose of 1 rad in soft tissue for 

higher energy photons (generally greater than 100 kiloelectron-volts). 

shallow absorbed dose (Ds)

Absorbed dose at a depth of 0.07 millimeters (7 milligrams per square centimeter) in a material 

of specified geometry and composition.

shallow dose equivalent (Hs)

Dose equivalent in units of rem or sievert at a depth of 0.07 millimeters (7 milligrams per 

square centimeter) in tissue equal to the sum of the penetrating and nonpenetrating doses.

sievert (Sv)

International System unit for dose equivalent, which indicates the biological damage caused 

by radiation. The unit is the radiation value in gray (equal to 1 joule per kilogram) multiplied by 

a weighting factor for the type of radiation and a weighting factor for the tissue; 1 Sv equals 

100 rem.

thermoluminescence

Property that causes a material to emit light as a result of heat.

thermoluminescent dosimeter (TLD)

Device for measuring radiation dose that consists of a holder containing solid chips of material 

that, when heated by radiation, release the stored energy as light. The measurement of this 

light provides a measurement of absorbed dose. 
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track-etch dosimeter 

Device for evaluation of fast neutron dose through examination of traces left by the neutrons 

on the Columbia Resin Number 39 emulsion.

unmonitored dose

Potential unrecorded dose that could have resulted because a worker was not monitored. See 

missed dose.

whole-body (WB) dose

Dose to the entire body excluding the contents of the gastrointestinal tract, urinary bladder, 

and gall bladder and commonly defined as the absorbed dose at a tissue depth of 

10 millimeters (1,000 milligrams per square centimeter). Also called penetrating dose. 

See dose.

X-ray radiation 

Electromagnetic radiation (photons) produced by bombardment of atoms by accelerated 

particles. X-rays are produced by various mechanisms including bremsstrahlung and electron 

shell transitions within atoms (characteristic X-rays). Once formed, there is no difference 

between X-rays and gamma rays, but gamma photons originate inside the nucleus of an atom. 
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TABLE OF CONTENTS

SECTION TITLE

A1. Radiation Protection...............................................................................................................

PAGE

50

A2. Historical Timeline..................................................................................................................53

LIST OF TABLES

A-1 Chronology of radiation standards: occupational external WB dose 

equivalent limits .....................................................................................................................51

This attachment contains a summary of LLNL Radiation Protection practices and an abbreviated 

historical timeline used in the preparation of the LLNL radiation protection practices and workplace 

measurements and controls. 

A1. RADIATION PROTECTION

The basic elements of DOE and predecessor radiation protection policies were generally well defined 

at the beginning of LLNL operations. 

Radiation Protection Standards

The basic elements of LLNL radiation protection practices were defined in the earliest years of 

operating LLNL facilities. In the earliest years of LLNL operations, the AEC used radiation protection 

guidance provided by national and international organizations. The limits and chronology are shown 

in Table A-1. To demonstrate compliances of workplace beta, photon, and neutron radiation 

exposure to workers, doses have been monitored by health physics personnel using personnel 

dosimeters, PICs, and portable radiation detection instruments. Personnel dosimeters represent the 

primary method to measure and record the official dose for a worker. However, personnel dosimeters 

are assigned to workers typically for a specified period (i.e., weekly, monthly, quarterly, or 

semiannually at LLNL beginning in 1974 depending on potential for radiation exposure), and 

exchanged for new dosimeters according to an established monthly or quarterly schedule. 

Dosimeters on return are typically processed and doses assigned. Typically, the official dose based 

on the dosimeter was not received by the worker or their supervision until many days after a 

dosimeter has been routinely exchanged and certainly well after radiation exposure to the worker has 

occurred. Administrative control of worker exposures is based on workplace controls or the results of 

dose measurements using PICs or portable instruments and timekeeping. These instrument 

measurements represent the real methods used day-to-day to limit worker radiation exposures. 

Basically, a cumulative administrative radiation exposure record is maintained for each worker for use 

in tracking and, as necessary, limiting exposures. Dose results from the personnel dosimeters for 

each exchange cycle are used to update the administrative exposure record. The dosimeter 

exchange cycle is selected based on the exposure potential for each worker and, in case of an 

incident, personnel dosimeters can be special-processed at any time. This process requires close 

attention by supervision and radiation safety personnel to the total exposure accumulated by each 

worker.

ATTACHMENT A

HISTORICAL TIMELINE OF RADIATION EXPOSURE ASSOCIATED EVENTS AT LLNL

Page 1 of 32
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ATTACHMENT A

HISTORICAL TIMELINE OF RADIATION EXPOSURE ASSOCIATED EVENTS AT LLNL

Page 2 of 32

Table A-1. Chronology of radiation standards: occupational external WB dose equivalent limits.

Year

ICRP NCRP AEC/ERDA/DOE

LLNL radiation 

protection guidance

Criteria Ref. Criteria Ref. Criteria Ref. Criteria Ref.

1950 0.3 rad/wk 0.3 rad/wk 0.3 rad/wk

3.9 rad/13 wk

NBS Handbook 

47 (NBS 1950)

1954 0.3 rad/wk 3.0 rad/13 wk

0.3 rad/wk 

15 rem/yr

NBS Handbook 

59 (NBS 1954)

3.0 rad/13 wk

0.3 rad/wk max, 

15 rem/yr

NBS Handbook 

59 (NBS 1954)

0.3 rem/wk LRL ca. 1954

1955 Neutron weekly 

allowable 

exposure is 1.3 

tracks per field 

based on 30 

n/cm2

/s for 40 

hr

LRL 1955

1957 0.3 rad/wk 5 rem/yr avg

12 rem/yr max

Addendum to 

NBS Handbook 

59 (NBS 1958)

3.0 rad/13 wk 

0.3 rad/wk max

15 rem/yr

1958 0.1 rem/wk, 

3.0 rem/13 wk, 

5 (N-18) rem*

ICRP 

Publication 1 

(ICRP 1959)

0.3 rem/wk 

3 rem/13 wk, 

12 rem/yr max, 

5 (N-18) rem*

Addendum to 

NBS Handbook 

59 (NBS 1958)

0.3 rem/wk, 3.0 

rem/13 wk

12 rem/yr 

5 (N-18) rem*

NBS Handbook 

59 (NBS 1954)

1960 0.1 rem/wk, 

3.0 rem/13 wk, 

5 (N-18) rem*

0.3 rem/wk 

3 rem/13 wk, 12 

rem/yr

5 (N-18) rem*

3 rem/13 wk, 5 

rem/yr avg 

5 (N-18) rem*

Federal 

Radiation 

Council Report 

1 (FRC 1960)
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ATTACHMENT A

HISTORICAL TIMELINE OF RADIATION EXPOSURE ASSOCIATED EVENTS AT LLNL

Page 3 of 32

1963 Prospective:

Qtr–3 rem

Year–5 rem

Retrospective 

Accumulated 

Dose: 5(N-18)

AEC Manual, 

Chapter 0524 

(AEC 1963)

1965 3 rem/13 wk

5 rem/yr

ICRP 

Publication 9 

(ICRP 1966)

0.3 rem/wk 

3 rem/13 wk

12 rem/yr 

5 (N-18) rem*

3 rem/13 wk

5 rem/yr avg

5 (N-18) rem*

1971 3 rem/13 wk

5 rem/yr 

3 rem/13 wk

5 rem/yr

NCRP 

Report 38 

(NCRP 1971)

3 rem/13 wk

5 rem/yr avg

5 (N-18) rem*

1974 3 rem/13 wk

5 rem/yr 

3 rem/13 wk

5 rem/yr

3 rem/13 wk

5 rem/yr

NCRP Report 

38 (NCRP 

1971)

1977 5 rem/yr 

acceptable risk

ICRP 

Publication 26 

(ICRP 1977)

3 rem/13 wk

5 rem/yr

3 rem/13 wk

5 rem/yr

* N refers to age of the worker in years.
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A2. HISTORICAL TIMELINE

Because of the number of relevant references, this section contains a timeline of historical radiationassociated events at LLNL. This was prepared as an aid in examining the issues and practices. As 

feasible, pertinent information has been transcribed from the references in the NIOSH Project SRDB. 

The reference listing and SRDB reference identification (SRDB Ref ID) number are also provided. 

These references do not necessarily appear in the main reference list for this document.

Powell, F., 1952, untitled letter to E. O. Lawrence (University of California Radiation Laboratory), 

California Research and Development Company, San Francisco, California, June 24. [SRDB 

Ref ID: 15231]

1952

Provided film dosimeter dose results for all film badge readings recorded in the permanent files for 

Radiation Laboratory personnel at Livermore. Unless exposures are noted by date, it is understood 

that the film indicated no exposure. There are slightly more than two pages of dose results for 

identified personnel.

Block, S. 1952, “Personnel Monitoring for Thermal Neutrons by the Cd (n, γ) reaction,” memorandum 

to F. P. Cowan, University of California Radiation Laboratory, Livermore, California, 

September 17. [SRDB Ref ID: 15717]

Described a sensitive method for detecting low-level integrated doses of slow neutrons in the 

presence of gamma radiation using Cd(n,γ) reaction and film. This reaction showed good promise to 

provide a method for personnel monitoring of slow neutrons.

Thompson, D. R., 1953, “Film Badge and Pocket Dosimeter Information,” memorandum to All 

Livermore Employees, University of California Radiation Laboratory, Livermore, California, 

March 9. [SRDB Ref ID: 15709]

1953

Stated the film badge and PIC dosimeter program was in place at Livermore. All personnel whose 

daily work might expose them to ionizing radiation of any kind were requested to start wearing their 

film badges. With few exceptions, there was a film badge for each employee at Livermore. 

Supervisors were asked to insist that each employee under his supervision wear his or her film badge 

if and when it was required. PICs of the gamma or slow neutron type were available to scientific 

personnel on request.

LRL (Lawrence Radiation Laboratory), 1954, collection of memoranda from B. Lagiss and S. Block, 

March through December, University of California, Livermore, California. [SRDB Ref ID: 

36304]

These memoranda reported measured film badge doses for LLNL groups and film dosimeter 

exchange weeks. The weekly tolerance was 0.3 R.

LLNL (Lawrence Livermore National Laboratory), 1953–1985, collection of external radiation dose 

records, University of California, Livermore, California. [SRDB Ref ID: 23463]

Contained external radiation dose records from 1953 through 1985 for selected personnel.

ATTACHMENT A

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Page 4 of 32
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LRL (Lawrence Radiation Laboratory), 1953–1955, collection of film badge reports, University of 

California, Livermore, California. [SRDB Ref ID: 36349]

These reports provided a history of neutron calibration sources and tolerance limits.

Block, S., 1954, “Personnel Monitoring Procedure for UCRL, Livermore,” memorandum to All 

Department Heads, University of California, Lawrence Radiation Laboratory, Livermore, 

California, July 19. [SRDB Ref ID: 16949]

1954

Described features and requirements of personnel monitoring as follows:

• Film badges were provided for all personnel employed at UCRL, Livermore site. Each film 

badge was identified with a number assigned to an individual.

• PICs were also provided at the Film Badge Office for those who did not have access to them. 

The PICs were read and a record kept of the individual’s exposure. Because one of the 

chambers was a self-reading type, the exposure could be read by the individual concerned.

• For those who worked in radiation areas, the film badges were exchanged once a week.

• For personnel who did not work in a radiation area, film badges were exchanged monthly.

• Persons who routinely visited radiation areas had film badges exchanged weekly. This group 

included laboratory guards and custodians and some installation and maintenance personnel.

• Any person who suspected a significant exposure had his dosimeter processed as soon as 

possible on delivery to Health Physics. 

LRL (Lawrence Radiation Laboratory), 1954, Livermore Film Badge Report, NTA Films, Week of Nov. 

3-10, 1954, University of California, Livermore, California. [SRDB Ref ID: 36087]

Indicated tolerances as follows:

• One weekly tolerance (PoBe) = 1.38 tracks per field

• Ten week tolerances (PoBe) = 13.6 tracks per field

• Background = 0.05 tracks per field

LRL (Lawrence Radiation Laboratory), ca. 1954, Personnel Monitoring Procedure for UCRL, 

Livermore, University of California, Livermore, California. [SRDB Ref ID: 23478]

Described radiation protection limits and the requirement for all persons entering a radiation area to 

wear a film badge. Film badges were provided for all personnel at the UCRL Livermore Site. The 

badges were for the most part hung on a rack in the Film Badge Office in Building 162. A radiation 

area was defined as an area in which precautions against radiation exposures were required, usually 

designated by a sign bearing the standard radiation symbol. PICs could also be assigned for areas 

with higher exposure levels. Film badges with neutron-sensitive film and boron-lined PICs could also 

be assigned to persons working in areas with the potential for significant neutron radiation exposure. 

The radiation areas were described as general areas with a film badge board to further designate the 

ATTACHMENT A

HISTORICAL TIMELINE OF RADIATION EXPOSURE ASSOCIATED EVENTS AT LLNL

Page 5 of 32
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area and for use to obtain and leave monitoring instruments on entering or exiting a radiation area. 

Measured exposures exceeding 0.3 mrem/wk required an investigation.

LRL (Lawrence Radiation Laboratory), 1955, collection of memoranda from Health Physics and Film 

Badge Office on neutron exposures, University of California, Livermore, California, January 26, 

October 10, and October 28. [SRDB Ref ID: 15693]

1955

These memoranda discussed assignment of positive neutron dose based on neutron tracks recorded 

on neutron film. Memoranda stated the neutron dose was based on a PoBe calibration and the 

percent of the allowable tolerance dose (i.e., weekly allowable exposure is considered to be 1.3 tracks 

per field based on 30 n/cm2

/s for 40 hours. The January 26 memorandum states that all significant 

neutron exposures would be brought to the attention of supervision. Two workers were apparently 

exposed to 14-MeV neutrons. 

Wilcox, G. E., 1956, “New Film - 555 for 1956 - 1957,” memorandum to W. E. Nolan and S. Block, 

University of California, Lawrence Livermore National Laboratory, Livermore, California, March 

19. [SRDB Ref ID: 15705]

1956

Reported test exposures of DuPont film 555 from 5 mR to 1,000 mR with some results in excess of 

1,000 mR. The range of this film for mixed photon energies extent at LLNL was stated to be:

Co-60 0.010 – 2,000 R

30 keV 0.001 – 200 R

Author unknown, ca. 1957, untitled analysis of film badges during 33-week period beginning January 

1, 1956. [SRDB Ref ID: 15230]

Analysis of recorded positive doses identified several patterns as follows:

Considering all workers with a film badge since 1/1/1956

Total number of workers receiving exposures 251

Total number of positive film exposures 1,316

Average positive exposures/worker 5.2

Considering workers with repeated positive exposure only

Total number of workers receiving exposures 183

Total number of positive film exposures 1,248

Average positive exposures/worker 6.8

The percentages of positive exposures by work group were:

• Chemists–42%

• Health Chemists–35%

• Tuballoy Shop–11%

• Pratt & Whitney–11%

• Miscellaneous–2%

Ten workers were identified with 20 or more positive weekly doses, and the curium operation 

appeared to contribute the highest measured doses.

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Lindeken, C. L., 1956, “Film Badge Coverage at Site 300,” memorandum to G. E. Wilcox, University of 

California, Lawrence Radiation Laboratory, Livermore, California, March 14. [SRDB Ref ID: 

15703]

Stated that UCRL personnel assigned to Site 300 were issued film badges. Health Chemistry staff 

members were involved in all operations at Site 300 involving radioisotopes and toxic materials; it was 

proposed in this memorandum that Health Chemistry staff members take responsibility for routine 

exchange of Site 300 dosimeters. 

LRL (Lawrence Radiation Laboratory), 1957, “Radiation Exposures,” memorandum from Health 

Physics to R. Jopson, University of California, Livermore, California, April 9. [SRDB Ref ID: 

15667]

1957

Reported exposure results of Building 157 personnel for April 2 to April 8, 1957. The maximum 

permissible exposure was 0.3 R/wk.

Nolan, W. E., 1958, “Progress Report on Film Badge Program,” memorandum to D. C. Sewell, 

University of California, Lawrence Radiation Laboratory, Livermore, California, November 13. 

[SRDB Ref ID: 23005]

1958

Stated that the film-and-security badge had been in use for 6 months. The philosophy of having every 

person wear a film badge identified a number of workers handling uranium with low-level exposures 

that were not being measured. There were also some recorded doses from badges for workers in 

nonradiological areas, but the badges recorded positive doses because the badge board was 

receiving low-level radiation.

In general, the data received had improved in quality and quantity. LLNL now changed badges for 

approximately 90% of the personnel every month, 99% within 2 months, and only three to five people 

had gone 3 months without an exchange. The readings indicated personnel rather than board 

exposures. The quality seemed better because LLNL could differentiate beta and gamma types more 

easily by the density ratios with less intuition involved. 

Wilcox, F. W., 1958, “Personnel Exposures,” letter to W. E. Nolan (Lawrence Radiation Laboratory), 

Reynolds Electrical & Engineering Company, Las Vegas, Nevada, December 22. [SRDB Ref 

ID: 15235]

Reported measured doses to several LLNL workers participating in nuclear tests at NTS.

LRL (Lawrence Radiation Laboratory), 1960–1962, “Site 300,” University of California, Livermore, 

California. [SRDB Ref ID: 35162]

Listed Site 300 staff members from 1960 to 1962.

Wilcox, F. W., 1959, “Personnel Exposures,” letter to W. E. Nolan (Lawrence Radiation Laboratory), 

Reynolds Electrical & Engineering Company, Las Vegas, Nevada, January 6. [SRDB Ref ID: 

15234]

1959

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Reported measured doses to several LLNL workers participating in nuclear tests at NTS.

LRL (Lawrence Radiation Laboratory), 1962, Hazards Control Quarterly Report No. 7 (October 

through December, 1961), UCRL-6818, University of California, Livermore, California. [SRDB 

Ref ID: 33001]

1961

States that the distribution and use of portable survey meters was restricted to persons familiar with 

the limitations of the instruments. In most instances if a meter was required a Monitor was also 

needed. The Hazards Control Field Representative was responsible for the radiation instruments 

issued in his area. Three survey instruments of each type required were generally issued to each 

Monitor. Additional instruments were issued in the event that more were necessary for adequate dayto-day monitoring. 

LRL (Lawrence Radiation Laboratory), 1961, “Portable Radiation Survey Instruments,” H.C. Manual, 

Part I, Procedure 1106, University of California, Livermore, California, October 16. [SRDB Ref 

ID: 15711]

Described each instrument and limitations. For example, the portable instrument used at LRL to 

detect and measure thermal and fast neutron fluxes was called the Nemo. This instrument was made 

by Nuclear-Chicago Corporation as its Portable Neutron Survey Meter Model 2715. It detected fast, 

slow, or mixed fluxes from 10 to 104 n/cm2

/s. 

Montgomery, D., 1962, “Neutron Film List,” memorandum to B. Smales, Lawrence Radiation 

Laboratory, University of California, Livermore, California, February 6. [SRDB Ref ID: 15731]

1962

Reported several personnel were placed on the Neutron Film List for Building 171 because of work 

with neutron-emitting radioactive materials apparently in Room 1232. The list was to be reviewed 

monthly and changes made accordingly. 

Kathren, R. L., 1962, “Evaluation of Personnel Dosimetry Program,” memorandum to J. J. Balanda, 

Lawrence Radiation Laboratory, University of California, Livermore, California, October 31. 

[SRDB Ref ID: 16145]

Discussed several areas of the LLNL film dosimetry program including badge design and calibration. 

The LOD with the LLNL badge was typically assumed to be 20 mrem for 60Co gamma radiation but 

could be a low as 10 mrem.

Kathren, R. L., W. C. Day, and D. E. Denham, 1963, “Preliminary Health Physics Analysis, Building 

110 Criticality Incident,” memorandum to J. J. Balanda, University of California, Lawrence

Livermore Laboratory, Livermore, California, April 4. [SRDB Ref ID: 15228]

1963

Personnel dosimeters showed gamma doses of 70, 100, and 120 mrem, respectively, for three 

workers and no recorded neutron dose. The lower limits of detectability were about 10 mrem for 

gamma and 50 mrem for fast neutrons.

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Block, S., and K. F. Petrock, 1964, “Evaluation of a Neutron Rem Dosimeter,” p. 17, Hazards Control 

Quarterly Report No. 18 (July–December 1964), UCRL-12167, University of California, 

Lawrence Livermore Laboratory, Livermore, California, February. [SRDB Ref ID: 72280]

1964

Described evaluation of an LLNL-modified neutron rem counter capable of reading RBE dose rate to 

±10% in the intermediate neutron energy region.

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

Personnel Monitoring Film,” Health Physics, volume 11, number 10, pp. 1067–1069. [SRDB 

Ref ID: 6180]

1965

Described NTA response as a function of the angle of incidence of neutron radiation with the plane of 

the film. The angle of maximum response was a function of the energy of the incident neutrons. A 

factor was found that corrected for the effects of angular dependence and fast-neutron energy on the 

track-per-field dose. A factor of 1.3 was recommended to multiply the measured neutron dose to 

compensate for angular response.

Block, S., and C. T. Prevo, 1965, “A Source of Intermediate Energy Neutrons for Dosimeter 

Calibration,” p. 8, Hazards Control Quarterly Report No. 22 (July–September 1965), UCRL14534, University of California, Lawrence Radiation Laboratory, Livermore, California. [SRDB 

Ref ID: 13888]

An Sb-Be neutron source moderated with D2O was used to provide intermediate-energy neutrons for 

dosimetry calibrations.

Kathren, R., 1965, “Preliminary Evaluation of TLD-100-Film Badge Field Comparison,” memorandum 

to D. Jones, Lawrence Radiation Laboratory, Livermore, California, November 2. [SRDB Ref 

ID: 15227]

Film badge interpretations and TLD-100 dose evaluations were compared over the April to August 

1965 interval. During this period, there were 176 pairs of dosimeters that could be compared. The 

following table gives the results of the comparison. Good agreement was defined as interpretations 

differing by the greater of 20 mR or ≤20% of the higher interpretation. The period from June to August 

was separated out because special precautions were taken to ensure that the two dosimeters were 

changed at the same time, and that no overlapping leaving intervals occurred.

Condition

April–August June–August

Number Percent Number Percent

Good agreement 105 60 58 57

Film higher 40 23 22 22

TLD-100 higher 31 18 22 22

Total 176 100 102 100

Of the 40 cases in which the film readings were higher than the LiF readings, at least 32 were for

persons known to have been exposed to low-energy X-rays; an additional 3 had possible low-energy 

X-ray exposure. In these cases, the developed film generally showed a typical low-energy X-ray 

pattern. Therefore, the higher film badge results could be attributed to the lack of response by the 

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TLD-100; the film badge data were more indicative of actual exposure. By contrast, there was no 

obvious explanation in which the TLD interpretations were higher than the film interpretations. 

Bolstad, J. W., G. E. Cummings, J. L. Eagan, and H. F. Finn, 1966, Safety Analysis Report for the 

Livermore Pool Type Reactor, UCRL-50147, University of California, Lawrence Radiation 

Laboratory, Livermore, California, November 20. [SRDB Ref ID: 13890]

1966

Much of the shielding around the reactor was portable and was arranged so continuous work areas 

received no more than 100 mrem/wk. Radiation surveys were made weekly and high-radiation areas 

noted with signs and in some cases with flashing lights. The movement of portable shielding was 

strictly controlled and normally done only with the reactor shut down. Shielding effectiveness was 

carefully checked during the subsequent reactor startup.

Radcliffe, J. B. Jr., E. E. Hill, and G. E. Cummings, 1967, The Livermore Pool Type Reactor (LPTR), 

UCRL-4919, Rev II, University of California, Lawrence Radiation Laboratory, Livermore, 

California, January. [SRDB Ref ID: 13889]

1967

Contained general information for an eventual 3-MW reactor that first achieved criticality during 

December 1957. 

LRL (Lawrence Radiation Laboratory), 1968, Hazards Control Progress Report No. 29 (SeptemberDecember 1967), and Index to Hazards Control Progress Reports, Nos. 27 through 29, UCRL50007-67-3, University of California, Livermore, California. [SRDB Ref ID: 33012]

Myers, D. S., and C. T. Prevo, 1969, “Personnel Dosimetry Associated with the Handling of a Large 

Numbers of 3-Kg 239Pu Billets,” unknown journal, pp. 505–517. [SRDB Ref ID: 53745]

1969

Described the process for measuring WB neutron doses using a neutron-to-gamma dose rate ratio. 

Because the neutron-to-gamma ratio was dependent on the size, spacing, and moderation of the 

array, a new ratio was determined for each array. A neutron-to-gamma dose ratio was also 

established for billet surface radiation using computer techniques. The neutron dose was then 

established by applying the measured neutron-to-gamma ratio to the WB gamma dose as measured 

by film badges, and to the gamma hand dose as measured by TLDs. The monthly neutron-to-gamma 

dose ratio ranged from 2 to 5 and the hand dose was about a factor of 2 greater than the WB dose. 

Rich, B., 1969, “Lawrence Radiation Laboratory (Livermore),” AEC Workshop on Personnel Neutron 

Dosimetry, September 23 to 24, 1969, BNWL-1340, Battelle Memorial Institute, Pacific 

Northwest Laboratory, Richland, Washington, p. 56. [SRDB Ref ID: 11096]

Stated that all of the approximately 6,200 employees and other permanently badged personnel at LRL 

were monitored by TLDs in an automated system. In addition, approximately 1,700 visitors and other 

temporary TLD personnel dosimeters were processed each month. Approximately 85% of monitored 

personnel received no measurable exposure and these were placed on a quarterly exchange with 

plans to go to a longer exchange cycle. The overview stated that TLD-100 was used to provide 

thermal neutron response for personnel potentially exposed to neutrons. The studies showed that 

any significant neutron dose was detected and then investigated, evaluated, and reported by a 

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professional health physicist. In specific applications, the neutron-to-gamma dose ratio approach had 

proven effective. The Anderson-Braun neutron meter was used for neutron dose equivalent rate 

measurements, and the Victoreen Model 400 survey meter was used for gamma rate measurements. 

Ratios in the range of 0.46 to 3.0 were observed for most work locations. Measurements of neutron 

dose equivalent with NTA film were ineffective (i.e., no dose indicated in fields calculated to give 

easily detectable doses.). 

LLL (Lawrence Livermore Laboratory), 1968–1971, Site 300 Radiation Safety Program, University of 

California, Livermore, California. [SRDB Ref ID: 16188]

1971

Described radiation safety practices for several Site 300 facilities with an emphasis on the monitoring 

program. The principal radiation safety hazards at Site 300 were summarized in general terms as 

follows:

• X- or gamma-ray exposures to personnel at Buildings 809, 823, 851 and 874.

• Chronic internal deposition of natural uranium, thorium, depleted uranium, and their alloys 

from firing table high-explosive (HE) tests.

• Occasional exposure to other nuclides in HE tests, and

• Massive contamination and possible internal deposition from plutonium, uranium, and tritium in 

static and dynamic tests in the 832, 834, 836, 854, and 857 test facilities.

Activities with hazardous materials at Site 300 were covered by guidelines in the LRL Health and 

Safety Manual and the Site 300 Safety and Operational Manual. Operations beyond the scope of 

these manuals were supplemented by special OSPs.

Crites, T. R., 1972, collection of three memoranda to D. Jones, “Interpretation of the Special 

Dosimeter in Use in Building 281,” University of California, Lawrence Livermore Laboratory, 

Livermore, California, July 19, August 11, and October 12. [SRDB Ref ID: 14080]

1972

These memoranda described the use of a special dosimeter for LPTR Operations and Experiment 

personnel at B-281. Bonner sphere neutron spectra from two calibration sources and several 

workplace locations showed similarity to 252Cf with various thicknesses of D2O. Neutron-to-gamma 

dose ratios in the general reactor areas varied from 0.1 to 1.0. The TLD-100 neutron response to 

1 rem 252Cf in 30-cm D2O was an indicated 1.1 rem if no reflecting phantom was used and 2.4 rem if in 

contact with a phantom. The TLD neutron response to 1 rem 252Cf in 50-cm D2O was an indicated 7 

rem if no reflecting phantom was used and 10.3 rem if in contact with a phantom. Runs with TLD-100, 

unbacked, in two of the reactor beams yielded an indicated 520- to 850-mrem dose compared to a 

remmeter measured dose of 1 rem.

Singh, M., and C. Slater, 1972, untitled memorandum to P. Hoff, University of California, Lawrence 

Livermore Laboratory, Livermore, California, October 5. [SRDB Ref ID: 15037]

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Reported additional measurements for the Febetron electron beam in Building 166. The operational 

mode of the Febetron was (1) peak energies of 2.5 MeV, (2) pulse duration of 40 ns, (3) 10,000 amps,

and (4) operated with and without the magnets on. 

The following table lists the measured integrated doses for the positions in the figure.

Position Dose (mrem) per pulse

1 19,500

2 330

3 <2

4 8

5 0.29

6 0.004

7 0.83

8 <2

Singh, M. S., 1972, “Febetron Calculations,” memorandum to E. P. Sims and P. Hoff, University of 

California, Lawrence Livermore Laboratory, Livermore, California, October 20. [SRDB Ref ID: 

15035]

LLL (Lawrence Livermore Laboratory), ca. 1973, “Table 1. Radiation Dosimetry Measurements at the 

100 MeV LINAC,” and handwritten notes, University of California, Livermore, California. 

[SRDB Ref ID: 15062]

1973

Hankins, D. E., 1975, “The Energy Response of TLD Badges Located on Personnel,” Health Physics, 

volume 28, number 1, pp. 80–81.

1974

Described studies of various filter combinations to achieve a tissue-equivalent energy response with 

LiF dosimeter as would be worn by personnel. 

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Crites, T. R., 1974, untitled letter to H. W. Dicksen (Oak Ridge, Tennessee), Lawrence Livermore 

Laboratory, Livermore, California, June 14. [SRDB Ref ID: 72712]

Discusses LLNL participation in an intercomparison study of the performance of personnel 

dosimeters.

Hankins, D. E., 1975a, “Evaluation of Personnel TLD Badges Exposed to Neutrons in the Vault of 

Building 231,” memorandum to Distribution, Lawrence Livermore Laboratory, Livermore, 

California, March 12. [SRDB Ref ID: 15111]

1975

Hankins, D. E., 1975b, “Evaluation of Personnel TLD Badges Exposed to Neutrons in Building 332,” 

memorandum to Distribution, Lawrence Livermore Laboratory, Livermore, California, February 

4. [SRDB Ref ID: 15520]

Hankins, D. E., 1975c, Studies of Neutron Dosimetry at the Lawrence Livermore Laboratory, UCRL76808, University of California, Lawrence Livermore Laboratory, Livermore, California, 

November. [SRDB Ref ID: 72225]

These reports described workplace evaluations of the LLNL albedo dosimeter system that employed a 

Harshaw TLD-100 thermal neutron-sensitive phosphor and methods to provide workplace-dependent 

calibration.

Odell, B. N., and A. J. Toy, Jr., 1975, Safety Analysis Report for Building 331 at Lawrence Livermore 

Laboratory, UCRL-51816 Draft, University of California, Lawrence Livermore Laboratory, 

Livermore, California, October 15. [SRDB Ref ID: 13891]

States the primary nuclide handled was tritium. There could have been small quantities of 239Pu, 233U, 

and 235U.

Leahy, E. J,, and G. E. Williams, 1975, “Radiation Survey of Building 239 with 4 MeV Linatron in 

Operation,” memorandum to K. C. MacMillan, University of California, Lawrence Livermore 

Laboratory, Livermore, California, December 15. [SRDB Ref ID: 15080]

A survey was conducted with the Linatron operating at its rated output of 400 R/hr at 1 m. Exterior 

measurements were made using portable radiation instruments. Interior spaces were monitored 

using TLDs over a 6-hour period.

The exterior of Building 239 was found to have radiation exposure rates less than 0.1 mR/hr, with the 

exception of the exterior ramp door. The dose rate at the exterior ramp door would have to be 

determined for operations where the Linatron was positioned in the western portion of the B 9 cell. 

The observed doses for 6 hours of exposure were:

Location Unshielded (mR) Shielded (mR)

Reduction

factor

North 494 16 30

Center 545 21 25

South 438 33 13

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The reduction factors indicated that a lead shield about 0.25-in. thick was all the shielding necessary 

to isolate scattered radiation originating in cell B 9. Scattered radiation into cell B 11 and up the ramp 

area were the only exposure problems that would require continued vigilance.

LRL (Lawrence Livermore Laboratory), undated, “Building 239 Principal Radiation Hazards and Their 

Safety Control,” University of California, Livermore, California. [SRDB Ref ID: 15078]

Contained radiation safety procedures for external and internal radiation monitoring. The primary 

external radiation hazards included several X-ray units and a large (108 n/s) neutron source.

Held, B. J., and M. S. Singh, 1976, “UF6 Operation, Building 177, Room 130,” memorandum to B. 

Roth, University of California, Lawrence Livermore Laboratory, Livermore, California, March 2. 

[SRDB Ref ID: 15051]

1976

Described a review of an experiment using a laser and a maximum of 10 g of enriched (perhaps 93%) 

UF6. The primary potential hazard identified concerned the potential for inhalation.

Hankins, D. E., 1976, “Survey Results in Buildings 231 and 233,” memorandum to Distribution, 

University of California, Lawrence Livermore Laboratory, Livermore, California, February 2. 

[SRDB Ref ID: 15100]

Described results of instrument surveys made in the 231 vault, outside the vault, and in the Building 

233 source storage area using the PNR-4 neutron remmeter. The instrument was used with the 

9- and 3-in. spheres and with the bare probe. The survey was made to confirm that calibration factors 

to TLD readings, determined earlier, were still applicable. The following table provides measurement 

results.

Location

9- to 3-in.

ratio % Thermal

Calibration 

factor

1. In vault 0.63 0.69 0.55

2. In vault 0.72 0.62 0.5

3. In vault 0.84 0.37 0.4

4. In vault 0.59 0.48 0.45

5. In vault 0.64 0.88 0.6

6. In vault 0.67 0.64 0.55

7. In vault 0.63 0.59 0.5

8. In vault 0.59 0.59 0.5

9. In vault 0.67 0.67 0.55

10. Outside vault 0.41 2.7 1.2

11. Outside vault 0.47 2.7 1.2

12. Outside vault 0.33 2.7 1.2

13. Bldg. 233 0.71 2.0 1.0

14. Bldg. 233 0.58 2.0 1.0

15. Bldg. 233 0.54 2.1 1.0

16. Bldg. 233 0.63 1.7 0.9

17. Bldg. 233 0.84 1.8 1.0

18. Bldg. 233 0.43 3.2 1.5

19. Bldg. 233 0.84 1.7 0.9

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Hankins, D. E., 1976, “Planted TLD Badge Results,” memorandum to Distribution, University of 

California, Lawrence Livermore Laboratory, Livermore, California, February 2. [SRDB Ref ID: 

15519]

Described results of TLD badges taped to gallon jugs placed in various locations in Buildings 332, 

233, and 255. The results were used to confirm that TLD calibration factors determined previously 

were correct for current conditions. Measurement results were: 

Location % Thermal

Calibration factor

From curve Experimental

1. Bldg. 233 1.7 0.95 1.35

2. Bldg. 332 Shannon Office 2.1 1.0 1.32

3. Bldg. 332 Walden Office 5.3 2.25 2.57

4. Bldg. 332 Room 1378 0.46 0.43 0.28

5. Bldg. 332 Room 1378 0.31 0.33 0.40

6. Bldg. 255 PuBe storage 0.53 0.48 0.53

Stated that a calibration factor of 2.5 would continue to be used for the office area outside the Building 

332 source storage vault per a February 4, 1975, memorandum. For an unknown workplace, a 

calibration factor of 0.5 was used.

Graham, C. L., 1976, “Off-Site Radiation Dose from B-212 for 1975,” memorandum to D. S. Myers, 

University of California, Lawrence Livermore Laboratory, Livermore, California, March 24. 

[SRDB Ref ID: 15081]

The results of the neutron and gamma doses for 1975 at the fence south of the ICT target room are 

shown below. The results represented the maximum radiation levels at the fence. Gamma dose 

measurements and two neutron measurements were begun on May 15, 1975.

Annual fenceline dose (mrem)

Dates Neutron 1 Neutron 2 Gamma

01/07/75–02/14/75 130

02/14/75–03/31/75 75

03/31/75–05/15/75 70

05/15/75–06/30/75 30 43 21

06/30/75–08/12/75 100 109 49

08/12/75–10/01/75 120 142 51

10/01/75–10/16/75 40 25 21

10/16/75–11/04/75 40 59 24

11/04/75–12/31/75 30 25 22

Totals 685 403 188

From these data, it was estimated that the neutron-to-gamma ratio was 2. Therefore, the gamma 

measurements from January 7 to May 15 could be estimated to be 162 mrem. The total gamma dose 

was then 162 + 188 mrem = 380 mrem. The total neutron and gamma dose above natural 

background for 1975 was 1,035 mrem. Natural background was estimated to be 60 mrem.

Sundbeck, C. W., 1976, “TLD Results,” memorandum to T. Madden, University of California, 

Lawrence Livermore Laboratory, Livermore, California, June 8. [SRDB Ref ID: 15077]

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On March 30, 1976, TLDs were prepared for gamma and neutron measurements at the Building 212 

fenceline. TLDs were read on June 2, 1976. The results were:

Neutron exposure 0.068 rem

Gamma exposure 0.029 R

Fisher, J., 1976, “Periodic Area Rem Meter Readings,” memorandum to J. Powell, University of 

California, Lawrence Livermore Laboratory, Livermore, California, October 14. [SRDB Ref ID: 

15072]

Quarterly reported neutron doses at the fenceline south of Building 212 were as follows:

06/01/76–08/02/76 82 mrem

08/02/76–10/07/76 81 mrem

These neutron doses were measured by recording neutron fission tracks in LexanTM.

Myers, D. S., 1976, “Personnel Dosimetry Requirements for Visitors and Contractors,” memorandum 

to Support Team Leaders, University of California, Lawrence Livermore Laboratory, Livermore, 

California, June 3. [SRDB Ref ID: 16189]

Described the implementation effective July 1, 1976, of a revised TLD badging program for visitors 

and contractors. Under this new program, only the facilities in the following table required TLD 

badges for access by visitors and contractors. 

Livermore Site Site 300

194

212

231 (Vault)

233

239

251

281

321

327

332

431

809

823

851

812E

The list of facilities would be reviewed quarterly. The logistics of issuing the TLD badges for visitors 

and contractors would remain the same; namely, the Personnel Dosimetry Laboratory would provide 

the visitor TLD badges to the Security Department, which would issue them at the Pass Office. LLNL 

would supplement the revised TLD badging requirements with an increased number of area TLDs in 

various facilities as appropriate. In general, if it was likely that visitors or contractors would receive 

measurable radiation doses (>10 mrem), they should have been issued a TLD badge. 

Powell, T. J., 1977, “Personal Radiation Dosimetry Requirements for LLL Visitors,” memorandum to J 

Dixson, University of California, Lawrence Livermore Laboratory, Livermore, California, 

January 27. [SRDB Ref ID: 16078]

1977

Stated that Building 431 should be deleted from the list of buildings requiring the issue of personal 

dosimeters to LLNL visitors.

Hankins, D. E., 1977, “A Modified A-B Remmeter with Improved Directional Dependence and Thermal 

Neutron Sensitivity,” Health Physics, volume 34, pp. 249–254.

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Fisher, J., 1977, “Site Perimeter Neutron Monitoring,” memorandum to T. J. Powell, University of 

California, Lawrence Livermore Laboratory, Livermore, California, January 25. [SRDB Ref ID: 

15071]

The following neutron doses were recorded on the site perimeter remmeters during the indicated 

periods: 

Location Period

Dose (mrem)

Total Monthly average

1 07/15/76–01/07/77 2.4 <1

2 07/15/76–01/07/77 2.8 <1

3 10/07/76–01/07/77 136 45.4

4 07/15/76–01/07/77 3.2 <1

5 07/15/76–01/07/77 2.4 <1

6 07/15/76–01/07/77 2.9 <1

7 07/15/76–01/07/77 2.5 <1

8 07/15/76–01/07/77 2.8 <1

Graham, C. L., 1977, “Off-Site Radiation Dose From Building 212 for 1976,” memorandum to T. J. 

Powell, University of California, Lawrence Livermore Laboratory, Livermore, California, March 

3. [SRDB Ref ID: 15070]

The results of the neutron and gamma doses for 1976 at the fence south of the ICT target room are 

shown below. The results represented the maximum radiation levels at the fence. Neutron No. 1 and 

No. 2 measurements were made with 235U fission foils in an Anderson-Braun remmeter and with TLDs 

in a 10-in. polyethylene sphere, respectively.

Annual fenceline dose (mrem)

Dates Neutron 1 Neutron 2 Gamma

12/29/75–02/02/76 Unavailable 125 62

02/02/76–04/02/76 Unavailable 35 25

04/02/76–06/02/76 54 68 29

06/02/76–08/04/76 82 136 58

08/04/76–10/18/76 81 112 52

10/18/76–01/06/77 136 163 58

Totals 353 639 284

The annual neutron dose was determined by averaging Neutron No. 1 and No. 2 measurements 

where applicable, and by using the No. 2 measurements when the No. 1 measurements were 

unavailable. The annual neutron dose result was 576 mrem. The total neutron and gamma dose 

above natural background for 1976 was 860 mrem. Natural background was estimated to be 

60 mrem.

Slaughter, D. R., and D. W. Rueppel, 1977, Environmental Neutron Spectrum Outside the LLL HighIntensity 14-MeV Neutron Facility,” UCRL-78946, University of California, Lawrence Livermore 

Laboratory, Livermore, California, June 9. [SRDB Ref ID: 15065]

Results of field spectra measurements showed that the transmitted neutron energy spectrum was 

concentrated in two rather strong peaks. Dose equivalent conversion with these spectra could be 

difficult. A standard polyethylene-moderated remmeter or 22.8-cm (9-in.) spherical remmeter would 

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seriously underestimate the 14-MeV transmission peak. However, due to the small contribution from 

energetic neutrons, the measured total dose rate would be only 10% to 15% low.

Hankins, D. E., 1977, “Radiation Survey in Office Areas of Building 233,” memorandum to D. S. 

Myers, University of California, Lawrence Livermore Laboratory, Livermore, California, March 

24. [SRDB Ref ID: 15099]

Described photon radiation survey using a Reuter Stokes high-pressure ion chamber and an SPA-3

scintillation probe assembly. The ion chamber results were considered to be more accurate. The 

highest readings obtained were 350 μR/hr in the hallway and 430 μR/hr at the source storage cabinet.

Madden, T. W., 1977, “Total Man-Rem at Major Facilities,” memorandum to T. J. Powell, University of 

California, Lawrence Livermore Laboratory, Livermore, California, October 11. [SRDB Ref ID: 

16928]

Estimates of person-rem were taken from personnel dosimetry files, and they did not include any dose 

less than 100 mrem/yr. The following table lists collective doses in person-rem and totals for each 

major facility and year in the report.

Bldg. 1973 1974 1975 1976 Total

194 17.60 5.80 7.4 5.82 36.62

212 6.50 7.06 8.0 7.35 28.91

332 3.30 5.18 4.74 6.29 19.51

331 4.20 3.54 0.74 2.38 10.86

251 4.20 6.95 6.13 1.83 19.16

281 3.90 6.24 4.11 1.80 16.05

231 5.50 3.47 1.98 2.62 13.57

233 0.78 2.35 5.73 2.12 10.98

Total 45.98 40.59 38.83 30.26 155.66

The recommendation was made that Buildings 231 and 233 be considered one facility because most 

of the exposures were to Materials Management personnel who worked in both buildings.

Graham, C. L., and S. G. Homann, 1977, Gamma-Ray Dosimetry Errors with TLDs, UCRL-80183, 

University of California, Lawrence Livermore Laboratory, Livermore, California, October 13. 

[SRDB Ref ID: 6184]

Described studies of dosimeter response for selected sources of photon radiation and the potential to 

overestimate the dose based on issues about lack of electronic equilibrium and nonuniform energy 

deposition throughout the TLD phosphor.

Griffith, R. V., D. R. Slaughter, H. W. Patterson, J. L. Beach, E. G. Frank, D. W. Rueppel, and J. C. 

Fisher, 1977, Multi-Technique Characterization of Neutron Fields From Moderated 252Cf and 

238PuBe Sources, UCRL-79483, University of California, Lawrence Livermore Laboratory, 

Livermore, California, November 7. [SRDB Ref ID: 55790]

Bare and moderated neutron sources were used to calibrate survey instruments and personnel 

neutron dosimeters in the Hazards Control Department radiation calibration facility at LLNL. 

Specifically, 252Cf and 238PuBe sources were used in spheres of water, polyethylene, deuterium oxide, 

and aluminum. 

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Griffith, R. V, D. E. Hankins, R. B. Gammage, L. Tommasino, and R. V. Wheeler, 1978, Recent 

Developments in Personnel Neutron Dosimeters – A Review, UCRL-80928, University of 

California, Lawrence Livermore National Laboratory, Livermore, California, March 17. [SRDB 

Ref ID: 72237]

1978

Described primary methods of neutron personnel dosimetry. 

Griffith, R. V., J. C. Fisher, D. E. Hankins, and D. E. Miller, 1978, Personnel Neutron Monitoring 

Developments at LLL, UCRL-81897, University of California, Lawrence Livermore Laboratory, 

Livermore, California, November 14. [SRDB Ref ID: 72238]

Stated that approximately 40 employees at LLNL worked in areas where personnel neutron 

monitoring was necessary. The dose rate in these areas was low, rarely exceeding 0.5 rem/yr. There 

was a wide variety of neutron environments (i.e., DT neutron generators, 3-MW pool type reactor, 

100-MeV LINAC, and a number of vaults and glovebox work areas where alpha, neutron, and 

spontaneous fission sources were stored) that made neutron monitoring difficult. The following table 

reproduces a comparison of instrument and dosimeter measured doses.

Facilityb

NP Ratio

Method of measurementa

AB 9–in. SP TLD NTA FT-Np FT-Th

Pu-238/Be (unmoderated) 0.9 0.9 0.7 1.2 1.2 1.6

High flux neutron generator 1.0 1.3 8.0 0.9 1.1 1.1

Cm-244 handling facility

Location 1 1.1 1.3 5.0 0.8 0.9 0.7

Location 2 1.0 1.5 11.0 0.8 1.0 0.8

Location 3 1.0 1.5 11.0 0.7 1.0 0.5

Cf-252 calibration cell 

Source unmoderated 1.1 1.4 7.0 0.6 0.8 0.4

Source in 25 cm H2O 1.0 1.3 7.0 0.7 0.9 0.5

Source in 25 cm D2O 1.0 1.6 14.0 0.5 0.9 0.4

Source in 25 cm Al 1.1 1.7 11.0 0.4 0.8 0.2

3-MW pool type reactor

Location 1 0.9 2.0 28.0 0.5 1.2 0.6

Location 2 1.0 1.4 13.0 0.7 1.0 0.6

850-MW pressurized power reactor

Location 1 1.2 2.5 23.0 0.2 0.7 0.1

Location 2 1.2 2.8 31.0 0.2 0.8 0.1

250-keV TRIGA reactor

Location 1 1.1 1.6 12.0 0.5 0.8 0.3

Location 2 1.1 1.7 10.0 0.5 0.8 0.3

Location 3 1.1 1.8 13.0 0.5 0.8 0.4

Location 4 1.1 1.8 15.0 0.3 0.7 0.1

a. AB = Anderson Braun remmeter, 9–in. Sp = 9–in. spherical remmeter, TLD = Hankins albedo dosimeter, NTA = 

nuclear track emulsion, type A; FT-Np = fission track Np-237, FT-Th = fission track Th-232.

b. Typically shielded such as in the workplace unless noted as unshielded.

Hankins, D. E., 1978a, “Calibration Factors for Albedo Neutron Dosimeters,” memorandum to 

Distribution, University of California, Lawrence Livermore Laboratory, Livermore, California, 

February 28. [SRDB Ref ID: 72437]

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This memorandum described the results of measurements to develop calibration factors for LLNL 

workplaces as shown in the following table.

Facility Building Rooms/sources

Calibration 

factor

LLNL Plutonium Facility 332 Room 1378 0.4

Other rooms 0.3

Vaults 0.4

Room 1378 during PuBe work 0.2

Shielded PuBe work 0.2

Vault 231 Inside vault 0.45

Chemistry 233 Building 233 0.45

Rotating target neutron source 212 ICT–Building 212 0.9

Top of ICT shielding 0.5

Chemistry Heavy Elements 

Facility

251 Shielded boxes 0.8

Unshielded work: Cm-244 tracers 0.3

Cf-252 tracers 0.2

Boxes (top-bottom-no shield) 0.3

Reactor 281 Reactor 1.6a

Weapons Engineering 131 Shielded sources: Cf-252 0.4

PuBe 0.2

Calibration Laboratory 255 Unshielded sources: Cf-252 0.14

PuBe 0.1

Site 300 Site 300 Berm-shielded accelerator 0.8

255 control room 1.0

a. Additional correction for over-response of 9-in. sphere needs to be applied.

Gibson, T. A., 1978, “Off-Site Radiation Dose from Building 212 for 1977,” memorandum to T. J. 

Powell and W. J. Silver, University of California, Lawrence Livermore Laboratory, Livermore, 

California, March 20. [SRDB Ref ID: 15067]

The results of the neutron and gamma doses for 1976 at the fence south of the ICT target room are 

shown below.

Annual fenceline dose (mrem)

Quarter Neutron 1a Neutron 2b Gamma

1 198 134 79

2 111 111 56

3 72 67 32

4 170 138 72

Totals 551 450 239

a. Neutron No.1 measurements with TLDs in a 10-in. poly sphere, 

b. Neutron No.2 measurements from fission tracks in polycarbonate. 

The annual neutron dose was taken to be the average of the two measurements, which was

500 mrem. The total neutron plus gamma dose (above natural background taken to be 60 mrem) for 

1977 was, therefore, about 680 mrem (i.e., 500 + 239 – 60 = 679 mrem). 

Hankins, D. E., 1978b, Albedo-Neutron Dosimetry Studies at Lawrence Livermore Laboratory, UCRL81889, University of California, Lawrence Livermore Laboratory, Livermore, California, 

November. [SRDB Ref ID: 6186]

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Described various studies of albedo neutron dosimeter performance. A neutron survey inside 

containment of the Farley Nuclear Plant was made to determine the spectra of leakage neutrons and 

to evaluate the accuracy of a 9-in.-diameter sphere remmeter (PNR-4) and of albedo-neutron 

dosimeters. Variations in the neutron spectra, the ratio of gamma-to-neutron dose rates, and the 

thermal neutron component of the neutron dose were also studied. The results indicated the neutron 

spectra were constant throughout the reactor with a 25-keV component on a 1/E spectrum. The 

albedo-neutron dosimeter performed within about ±25% of the measured dose. A neutron survey was 

also made at a neutron radiography facility with an accuracy of the albedo-neutron dosimeter within 

approximately ±33% of the measured dose.

Hoots, S. S., 1978, “Semiannual Dosimeter Exchange Program,” memorandum to D. S. Myers, 

University of California, Lawrence Livermore Laboratory, Livermore, California, December 7. 

[SRDB Ref ID: 14089]

Described results of testing of semiannually exchanged dosimeters to selected personnel that began

in 1974 with the following results.

Period

Total no. 

assigned

No. of positive doses (mrem)

0–50 51–100 >100

Jun 1974 1,582 84 9 10

Dec 1974 1,683 67 14 10

Jun 1975 1,686 69 6 2

Dec 1975 1,678 94 10 7

Jun 1976 1,824 134 15 6

Dec 1976 1,824 33 11 6

Jun 1977 1,899 86 6 5

Dec 1977 1,977 45 8 3

Jun 1978 1,959 81 5 1

Totals 15,982 693 84 50

As a result of this testing, LLNL implemented a routine semiannual dosimeter exchange for personnel 

without potential for significant exposure in routine work activities. Based on this analysis, it was 

concluded that all workers in the following buildings could be placed on a semiannual dosimeter 

exchange:

111 123 219 523

113 125 310 592-594

115 141 311 616

116 215 312-319 618

117 216 322-328 622

119 217 401-411 651

122 218 515-519

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Personnel in the following buildings or areas could be placed on a semiannual dosimeter exchange on 

the basis of work assignment:

121 231 complex 361 complex 615

131 241 complex 381 661

151 253 412 Site 300

160 complex 255 418

170 complex 261 431-435 complex

222 complex 271 511

Personnel in the following buildings should not be on the semiannual exchange:

194 281 331 419

212 complex 292 332 514

251 321 341 complex 612

Hankins, D. E., 1979, untitled letter to R. Medioni (Centre de’ Etudes Nuclearies), University of 

California, Lawrence Livermore Laboratory, Livermore, California, February 26. [SRDB Ref 

ID: 72746]

1979

While I was at LASL we performed a study with about 30 personnel at the Pu facility over a 

period of 6 months. In addition to gamma and NTA film each worker was given bare Li 6 and 

Li 7 TLDs and one of the Hankins-type albedo dosimeters was taped to the bottom of his film 

badge. We were using a calibration factor of 24 mrem/track for the NTA film.

The results of this study indicated that if the person’s neutron exposure exceeded about 

70 mrem/month, we had reasonably good agreement between the NTA and albedo results. If 

the exposure was less than 70 mrem, the NTA only occasionally would record any exposure. 

This is obviously a reader problem. If there were a fairly large number of tracks they were 

evaluated accurately but when few tracks were present, the [track counters] would not see any 

tracks. Occasionally a zero albedo result would be obtained when the NTA badge was positive 

(up to 70 mrem) but this was infrequent.

The 24 mrem/track was based on field calibrations in the facility and was considerably higher 

than the 8 mrem/track usually used. Background was about 3 tracks/film. The total time from 

removal from the refrigerator until developed was about 6 weeks.

For neutron exposures above 70 mrem/months the agreement became better as the exposure 

increased and at ~400 mrem was reasonably good. No effort was made to reevaluate an NTA 

film if poor agreement was obtained since this was a study of routine evaluation techniques.

The gamma component of the dose was being overestimated by the film badge by a factor of 

two. This resulted in the total exposure as determined by TLDs and film being about equal even 

though the NTA film saw nothing at the lower neutron exposures.

Hoots, S., 1979, “Investigation Requirements and Analysis of TLD Readings,” memorandum to 

Procedure File, University of California, Lawrence Livermore Laboratory, Livermore, California, 

October 12. [SRDB Ref ID: 13884]

Describes criteria to be effective as of October 1, 1979, for assigning skin and deep dosimeter doses.

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Leahy, E. J., D. E. Hankins, and T. Straume, 1979, “Radiation Survey, Bldg. 851,” memorandum to W. 

M. Halladay, University of California, Lawrence Livermore Laboratory, Livermore, California, 

November 15. [SRDB Ref ID: 72588]

Describes neutron and gamma ray dose rate measurements made on October 25 and 26 and 

November 7, 1979, in the areas in and around Building 851 that might normally be occupied while the 

LINAC was in operation. Thirty measurement locations were surveyed using PNR-4 neutron and 

Victoreen 440 photon dose meters. NP dose ratios for the 30 locations were determined to range 

from 0.6 to 3.3. NP dose ratios were also determined for three health physicists wearing the standard 

LLNL dosimeter and one person who wore an albedo dosimeter, as shown in the following table.

Person

Dose (mrem)

Gamma Neutron NP ratio

1 15 19 1.3

2 15 22 1.5

3 14 14 1.0

3 (albedo) 13 10 0.8

Roberts, R. S., 1979, “Radiation Safety Practices in the Bldg. 823 Area,” memorandum to D. Dufek, 

University of California, Lawrence Livermore Laboratory, Livermore, California, September 5. 

[SRDB Ref ID: 72599]

Described recommendation to place administrative controls on occupancy of office trailer T-48 and 

outside areas during operation of the LINAC, or to place shielding in the trailer to reduce personnel 

exposure to measured radiation fields between 5 and 8 mR/hr gamma and 1 and 2.5 mrem/hr 

neutron. The control trailer had adequate shielding but the office trailer did not. It was considered 

that exposure of personnel in the office trailer was not necessary and should be eliminated.

Singh, M. S., 1979, Laser Program Radiation Safety Program, University of California, Lawrence 

Livermore Laboratory, Livermore, California, December. [SRDB Ref ID: 15049]

Provided an assessment of potential sources of radiation exposure associated with the LLNL Laser 

Program.

Willhoite, S. B., 1979, Determination of Gamma and Neutron Yearly Doses at the Building 212 Bus 

Stop, University of California, Lawrence Livermore Laboratory, Livermore, California, 

December 12. [SRDB Ref ID: 15066]

Described an assessment of the yearly dose at the bus stop 91 m west of the environmental 

monitoring station south of the Building 212 RTNS. Based on this study, the gamma dose at the bus 

stop in 1978 was estimated to be 3 mrem (factor of 0.03 times environmental monitoring station 

measured photon dose) and the neutron dose was estimated to be 52 mrem (factor of 0.37 times 

environmental monitoring station measured neutron dose).

It was stated that the RTNS was operating at a neutron yield of 1.5 × 1012 n/s when the operational 

surveys were made. This was approximately half of the yield at which the RTNS was often run. 

Therefore, the yearly doses would be approximately a factor of 2 greater. 

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Willhoite, S. B., 1980, “Survey to Determine Yearly Neutron Dose at the 212 Bus Stop Due to 

Operation of the RTNS,” University of California, Lawrence Livermore Laboratory, Livermore, 

California, February 22. [SRDB Ref ID: 15087]

1980

Described measurements of the neutron and gamma dose at the bus stop. The average neutron 

dose rates observed for the locations and operating conditions surveyed were:

RTNS neutron yield

Average neutron dose rate (μrem/hr)

RTNS Bus stop

2 × 1012 n/s 257 14

3 × 1012 n/s 410 20

Based on this study, the conversion factor for determining the yearly neutron dose at the 212 bus stop 

gave the yearly neutron dose at the RTNS environmental monitoring, which was 5% of the RTNS 

fenceline neutron dose. Neutron energy spectra measurements noted in the report indicated that 

17% of the total neutron dose was attributable to neutrons of approximately 14 MeV and 18% of the 

was the result of neutrons below 1 MeV.

LLL (Lawrence Livermore Laboratory), 1980, “Neutron Survey of 3MeV Van de Graff,” University of 

California, Livermore, California, June 30. [SRDB Ref ID: 15086]

Contained measurement results of surveys done with the LLNL remmeter. The meter was positioned 

directly below the target changer.

Straume, T., 1980, Radiation Safety Program for Site 300, University of California, Lawrence 

Livermore Laboratory, Livermore, California, September. [SRDB Ref ID: 72845]

External radiation hazards identified include:

Location Radiation source

Normal exposure 

potential (mR/hr)

B 809 1-MeV LINAC 0

B 809

300-kV X-ray 0

150-kV X-ray 0

50-kV X-ray 0

110-kV X-ray 0

Co-60, 310-Ci 

source

0

B 812E Co-60, 56 Ci 0

Co-60, 77 Ci 0

B 823 13-MeV LINAC < 2.5a

B 851 LINAC <10a

Klystronsb 0

a. Time personnel spent in these areas is controlled.

b. Dose rate is from one klystron only—there were a total of 

five in the LINAC room.

Ozaki, C., 1980–1981, notes pertaining to the cyclotron and ICT, University of California, Lawrence 

Livermore Laboratory, Livermore, California. [SRDB Ref ID: 15090]

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There are results of a November 4, 1980, area survey with the ICT beam output of 2 × 1012 n/s. The 

measurement locations and results follow: 

Position

Dose

Gamma (mR/hr) Neutron (mrem/hr)

1 0.5 8

2 0.4 1

3 0.5 0

4 0.2 0

5 0.3 0

6 0.3 0.3

7 0.3 0.2

8 0.5 0.7

9 0.5 2.0

10 1.3 4.0

11 0.3 0.1

12 0 0.1

13 0 0.1

14 0.1 0.2

Griffith, R. V., and D. E. Hankins, 1980, “A Systematic Approach to Personnel Neutron Monitoring,” 

March, UCRL-82658, University of California, Lawrence Livermore Laboratory, Livermore, 

California. [SRDB Ref ID: 72240]

Described personnel neutron dosimetry methods and the use of workplace neutron dose and spectra 

measurements to calibrate dosimetry system.

Ozaki, C. 1981, [TLD Radiation Survey of] “ICT Rabbit System, Trailer 939-940,” University of 

California, Lawrence Livermore Laboratory, Livermore, California, April 7. [SRDB Ref ID: 

15084]

1981

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Contained measurements of the Trailer 939-940 ICT Rabbit System per the following diagram.

The measurements were made by placing six TLD packets at the locations noted above on March 16, 

1981, and collecting these packets on March 27, 1981. The ICT Rabbit System was operated for 

approximately 80 hours. The results are:

Location Dose (rem)

1 0.003

2 0.002

3 0.002

4 0.002

5 0.001

6 0.002

Lascurettes, N., 1981, “Audit Report No. 1230 – Use of Dosimeters,” letter to D. Nielsen (Lawrence 

Livermore National Laboratory), University of California Systemwide Administration, Berkeley, 

California, August 31. [SRDB Ref ID: 21458]

Included a cover letter, an attached audit report, and an attached response to audit findings. 

Leahy, E. J., 1982, “4 MeV X-Ray Dose Rate Measurements,” memorandum to R. Hoblitzell, 

University of California, Lawrence Livermore National Laboratory, Livermore, California, April 

1. [SRDB Ref ID: 15076]

1982

Measurements were made using the 4-MeV X-ray unit in space B-9 of Building 239. The 

measurements were made with a Victoreen 660 Digital Exposure Measurement and Compliance 

Meter. The following figure shows measurements that were made for the condition.

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The results were:

Detector 

position

Detector 

indication (R/hr)

1 1608

2 & 3 13.8

4 5.6

5 1.9

6 1.3

Hankins, D. E., 1982, Evaluation of the Neutron Dose Received by Personnel at the LLNL, UCID19385, University of California, Lawrence Livermore Laboratory, Livermore, California, May 1. 

[SRDB Ref ID: 72180]

Documented the techniques being used to evaluate the neutron exposures received by personnel at 

LLNL. Two types of evaluations were discussed covering the use of the routine personnel dosimeter 

and of the albedo neutron dosimeter. Included in the report are field survey results that were used to 

determine the calibration factors applied to the dosimeter readings. Calibration procedures were 

discussed and recommendations were made on calibration and evaluation procedures. This report 

contained substantial workplace measurement data and analysis.

Leahy, E. J., 1983, “Dosimetry System Cycle Changes,” memorandum to All Health Physicists, 

University of California, Lawrence Livermore National Laboratory, Livermore, California, 

October 3. [SRDB Ref ID: 14026]

1983

Described a planned change in LLNL dosimetry system to a Panasonic system. Only personnel on 

monthly and quarterly dosimeter exchange cycles would receive a Panasonic dosimeter with a 

window to measure beta and low-energy photons. The inventory of new dosimeters was limited. To 

provide adequate dosimetry coverage, personnel dosimetry exchange cycles had to be altered. 

Those persons on a quarterly exchange cycle who were not receiving significant exposures of 

penetrating radiation and no skin exposures could be changed to semiannual dosimeter exchange. 

Those on a semiannual cycle receiving “skin”-type exposures or having the potential for such 

exposure would be changed to quarterly. 

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Meadors, O. L., J. P. Harris, and A. J. Toy, 1983, “LLNL Incident Analysis Report,” memorandum to C. 

Gatrousis, University of California, Lawrence Livermore National Laboratory, Livermore, 

California, July 5. [SRDB Ref ID: 15031, p. 2]

Described expectations of shipments between LLNL and NTS. External radiation levels and 

removable (nonfixed) radioactive contamination levels should conform to DOT regulations 49 CFR 

173.393 and 173.397. Containers with external contamination (any detectable quantity above 

background) were not to be shipped. 

Myers, D. S., 1984, “Neutron Doses @212,” University of California, Lawrence Livermore National 

Laboratory, Livermore, California, February 16. [SRDB Ref ID: 15083]

1984

Noted neutron dose rates for Building 212 as follows:

A note stated that according to measurements by Willhoite in February 1980, the neutron dose from 

the ICT was 20 times higher at station 5 than station 3. 

Davis, J., 1984, “Fence Line Doses at Building 212,” memorandum to J. Shearer, University of 

California, Lawrence Livermore National Laboratory, Livermore, California, July 5. [SRDB Ref 

ID: 15064, p. 3]

Described events that led to the increase in dose at the 212 Building fenceline monitors during 1983. 

Apparently water-filled cans that had been fabricated and installed over the target in the early 1970s 

for purposes of reducing the dose rate had been removed, resulting in the increased dose. High-flux 

runs had been made generally off-shift to minimize exposure to personnel. The high-flux experiment 

was stated to be finished and the cans replaced over the target assembly.

Myers, D. S., 1984, “Neutron Doses at the Building 212 Perimeter Fence,” memorandum to W. J. 

Silvers, University of California, Lawrence Livermore National Laboratory, Livermore, 

California, June 22. [SRDB Ref ID: 15064, p. 5]

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A table of annual neutron doses was included as follows:

Perimeter neutron doses at Building 212

Year Annual dose (mrem)

1983 113

1982 36

1981 33

1980 85

1979 80

1978 137

1977 550

1976 600

1975 700

Myers, D. S., 1984, “Summary of Radiation Levels at the Fence Adjacent to Building 212,” 

memorandum to J. C, Davis, Lawrence Livermore Laboratory, Livermore, California, October 

15. [SRDB Ref ID: 15074]

Described quarterly measured neutron and photon doses as follows:

Radiation doses at Building 212 fence

Quarter

Dose equivalent (mrem)

Neutrona Gammab

1 38.0 15

2 2.8 11

3 3.0 11

a. The normal neutron background was 

approximately 1 to 1.5 mrem per quarter.

b. The normal gamma background was 

approximately 11 to 12 mrem per quarter.

The DOE fenceline maximum allowed dose per year was 500 mrem but also needed to comply with 

as-low-as-reasonably-achievable (ALARA) objectives. Achieving the lower fenceline dose of about 

2 mrem per quarter over background likely represented meeting the ALARA objective. 

Thorngate, J. H., and R. V. Griffith, 1985, “Neutron Spectrometers for Radiation Monitoring at 

Lawrence Livermore National Laboratory,” Radiation Protection Dosimetry, volume 10, number 

1, pp. 125–135.

1985

Described a system for measuring neutron spectra developed at LLNL that combined a liquid

scintillation detector for neutrons above 0.3 MeV with a multisphere system for lower energies. The 

resultant combination provided spectra suitable for radiation protection purposes from thermal 

energies to 20 MeV. Measurements using these techniques were made at LLNL and several other 

locations.

LLNL (Lawrence Livermore National Laboratory), 1985, Radiation Safety Program – Building 251, 

Heavy Elements Facility, University of California, Lawrence Livermore National Laboratory, 

Livermore, California, August 21. [SRDB Ref ID: 15034]

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Described the LLNL ALARA program and the external dosimetry monitoring program. All employees 

and visitors at LLNL were issued a TLD. The TLD change frequency was dependent on the amount 

of time an individual was expected to work with sources of ionizing radiation. The LLNL Panasonic 

TLD allowed selection of phosphors to measure neutron as well as beta and gamma radiations. 

CR-39 track-etch neutron badges were assigned to workers at Building 251 who worked with neutronemitting radionuclides. All dosimeter results that had a positive reading were reported to the 

appropriate health physicist. Any neutron exposure, monthly dosimeter reading higher than 

300 mrem, or quarterly dosimeter reading higher than 100 mrem had to be investigated by the health 

physicist. A written report was issued to document the investigation results. The facility Health and 

Safety Technician also reviewed all doses for people working in Building 251. Nuclear accident 

dosimeters were used at Building 251.

LLNL (Lawrence Livermore National Laboratory), 1985, Radiation Safety Program, Building 151, 

University of California, Livermore, California, August 21. [SRDB Ref ID: 15030]

Same external radiation monitoring program wording for this facility as shown above for Building 251.

Griffith, R. V., 1986, “LLNL Site Perimeter Neutron Dose Results for the Period January 3 to March 

31, 1986,” memorandum to R. Buddemeier, University of California, Lawrence Livermore 

National Laboratory, Livermore, California, April 14. [SRDB Ref ID: 15064, p. 7]

1986

Reported dose equivalent measurement results at the indicated site perimeter locations during the 

first quarter of calendar year 1986 as follows:

Location

Dose equivalent (mrem)

Dose Monthly dose rate

1 0.9 0.3

2 1.1 0.4

3 14.0 4.8

4 1.1 0.4

5 2.1 0.7

6 1.3 0.5

7 0.9 0.3

8 1.4 0.5

The measurements were made using fission track foils in Anderson Braun remmeters. The result for 

location 3 raised the question of whether the water-filled cans had been removed.

Gordon, L. E., 1987, “1986 Chemistry and Materials Science Radiation Safety Report of the Tritium 

Facility,” memorandum to A. L. Buerer, University of California, Lawrence Livermore National 

Laboratory, Livermore, California, March 16. [SRDB Ref ID: 14070]

1987

This facility was in Building 331 and tritium constituted the primary radiological hazard. This 

memorandum described briefly the Hazards Control Department Hazards Information, Recording and 

Control (HIRAC) database for safety recommendations received from the various disciplines 

regarding potential hazards.

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Mansfield, W. G., 1987, “1986 Summary Annual Report – AVLIS Radiological Safety,” memorandum 

to M. Chew, University of California, Lawrence Livermore National Laboratory, Livermore, 

California, March 16. [SRDB Ref ID: 15044]

The highest individual doses to the hand, skin, and whole body by AVLIS personnel during 1987 were 

0.379, 0.12, and 0.05 rem, respectively. Doses to the hand received during uranium handling and 

pod cleaning continued to dominate.

Hankins, D. E., S. Homann, and J. Westermark, 1988, “The LLNL CR-39 Personnel Neutron 

Dosemeter,” Radiation Protection Dosimetry, volume 23, number 1, pp. 195–198.

1988

Described a personnel neutron dosimetry system based on the electrochemical etching of CR-39 

plastic at elevated temperatures. The system, relative to others, was more accurate for varied neutron 

spectra, had less energy dependence and less fading, and had fewer reading problems.

Trent, M., 1988, “Nuclear Chemistry Radiation Safety Program; 1987 Annual Report,” memorandum 

with attachments to S. Velen, University of California, Lawrence Livermore National 

Laboratory, Livermore, California, March 8. [SRDB Ref ID: 15028]

Buildings 151 and 281 were covered in one report while Building 251 was reported separately

because operations in Building 251 were very different from those in the rest of Nuclear Chemistry.

The total WB dose assigned to Building 151 and 281 during 1987 was 2.344 person-rem. The total is 

almost evenly divided with 1.22 rem assigned to Building 151 and 1.124 rem from operations in 

Building 281. As in the past, most of the dose in Building 151 resulted from weapons debris analysis 

in the Dissolving Wing. However 0.529 rem resulted from heavy elements research conducted in 

Building 251. In Building 281, most of the WB dose resulted from experiments conducted at Building 

292, the RTNS II facility. There were some individuals working in Building 151 who received most of 

their doses while working in Building 251.

LLNL (Lawrence Livermore National Laboratory), Operational Health Physics Program for the 170 

Complex, Revised, University of California, Livermore, California, April 1. [SRDB Ref ID: 

15043]

Described monitoring requirements and frequency for several types of radiation safety activities.

Mansfield, W. G., 1988, “1987 Annual Radiological Safety Report – Building 331,” memorandum to R. 

M. Latimer University of California, Lawrence Livermore National Laboratory, Livermore, 

California, April 5. [SRDB Ref ID: 14071]

Described collective dose, which was essentially all from tritium.

Shingleton, K. L., 1989 “Radiation Dose Summary for Nuclear Chemistry, 1988,” memorandum to C. 

Lagerquist, University of California, Lawrence Livermore National Laboratory, Livermore, 

California, May 3. [SRDB Ref ID: 15029]

1989

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In summary, 29 people received WB doses, the largest of which was 435 mrem. A total of 

2.429 person-rem was accrued. Twenty-six people received hand doses, the largest of which was 

2.666 rem. The collective annual dose to the hands was 11.781 rem. Three people received skin 

doses, the largest of which was 99 mrem. The total skin dose received by these three workers was 

129 mrem. 

Hankins, D. E., S. G. Homann, and B. Buddemeier, 1989, Personnel Neutron Dosimetry Using 

Electrochemically Etched CR-39 Foils, UCRL-53833, Revision 1, University of California, 

Lawrence Livermore National Laboratory, Livermore, California, December. [SRDB Ref ID: 

72184]

Described LLNL personnel neutron dosimetry system based on the CR-39 track-etch dosimeter. The 

CR-39 system had several advantages in comparison with other systems, especially when varied 

neutron spectra were encountered. CR-39 did not have the severe energy dependence that existed 

with albedo neutron dosimeters, and it did not have the fading and reading problems encountered with 

NTA film. The energy response of CR-39 to neutrons was fairly flat from about 150 keV to 5 MeV, but 

dropped by about 60% in the 13- to 16-MeV range. The sensitivity of the dosimetry system was about 

4.5 tracks/cm2

-mrem, with a background equivalent to about 3 mrem for new CR-39 foils. The limit of 

sensitivity was approximately 6 mrem. 

Hankins, D. E., 1991, “LLNL Neutron Dosimetry,” Eleventh DOE Workshop on Personnel Neutron 

Dosimetry, June 3-7, 1991, Las Vegas, Nevada, PNL-SA-21596, U.S. Department of Energy, 

Assistant Secretary for Environment, Safety and Health, Washington, D.C., p. 5. [SRDB Ref 

ID: 10804]

1991

Article stated that at LLNL only a small number of workers received neutron exposure. With few 

exceptions, the exposure was to workers at the LLNL plutonium facility. The exposures were primarily 

to neutrons from (1) the spontaneous fission of fissile materials and (2) oxides of fissile material. The 

neutron energies ranged from a fission spectrum, due to work with plutonium without shielding, down 

to a lightly moderated spectrum, due to work in shielded gloveboxes. Personnel who worked in the 

plutonium vaults were exposed to a neutron spectrum containing a large component of roomscattered and thermal-energy neutrons.

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