japanese a-bomb dosimetry project: personal recollections presented to the lyncean group may 14,...
TRANSCRIPT
Japanese A-Bomb DosimetryProject: Personal Recollections
Presented to the Lyncean GroupMay 14, 2008
ByDean Kaul and Steve Egbert
Hiroshima• Gun Assembly
Device• August 6, 1945• 140,000 Deaths
Estimated
Nagasaki• Implosion Device• August 9, 1945• 80,000 Deaths
Estimated
ABCC History
• 1947: President Truman authorizes NAS to create and manage ABCC– “…undertake a long range, continuing study of the biological and medical effects
of the atomic bomb on man.”• Jim Neel, Jack Schull and others conduct genetic effects studies
– Results Appear in 1956: No apparent genetic effects of radiation exposure• 1955: Francis Committee (Thomas Francis, Felix Moore, Seymour
Jablon)– NAS-organized committee to assess what should be done about ABCC research– Recommendations
• Reorganized program should continue• Unified study plan
– Focus on fixed cohorts of survivors and their children with internal comparison groups– Mortality follow-up– Highlighted need for dose estimates
• 1953-1963: Detailed shielding histories for most survivors– Within 2 km in Nagasaki– Within 1.6km in Hiroshima (42% between 1.6km and 2km)
ABCC/RERF Hiroshima SiteHijiyama Mountain
1950
Today
A Controversial Site!
Life Span Study CohortProximal(Detailed Shielding Histories)
Distal Total
Hiroshima 12,130 39,260 51,390
Nagasaki 4,077 20,524 24,601
Total 16,207 59,784 75,991
Proximal survivors are within ground ranges of
1600m at Hiroshima or 2000m at Nagasaki
Approximately 40% Are Still Alive
ABCC/RERF Follow-up Programs
• Mortality– Based on mandatory nation-wide family registration– Updated on a three-year cycle
• Cancer incidence– Hiroshima & Nagasaki tumor registries (1958 – present)– ABCC pathology program 1958 – 1972– Hiroshima & Nagasaki tissue registries 1973 - present
• Leukemia and related disorders– Leukemia registry 1950 – 1987– Hiroshima & Nagasaki Tumor Registries 1958 – present
• Clinical Examinations– Biennial exams– 70-80% participation through 25 AHS exam cycles– Adapted for use in F1 clinical study (FOCS)
• Mail Surveys– 1965 (Ni-hon-san study men), 1968 (women), 1978, 1991, 200?
Dose Estimation Efforts - Nagasaki1957 (T57) to 1965 (T65)
• T57 – York, USAF
• T65 – Auxier, ORNL
• Empirical Estimates
• Nagasaki Best Candidate for Approach– Similar Bombs
Tested
Dose Estimation Efforts - Hiroshima1957 (T57) to 1965 (T65)
• T57 – York, USAF
• T65 – Auxier, ORNL
• Empirical Estimates
• Hiroshima Poor Candidate for Approach– Similar Bomb
Not Tested
Shielding Experiments: Hardtack (1958), BREN (1962) Bare Reactor Exp., Nevada
• 0.6 Scale of Hiroshima • Bare U-235 Reactor, Co-60• Simulated Japanese
Structure Arrays– Asbestos-Cement Board
465m
343m
686m – 1097m
Structure Shielding• T65: John Auxier – ORNL• Empirical Approach: Hardtack Atmospheric Test and BREN Experiment Data• 9-Parameter Approach (majority of survivors with shielding histories)
– Shielded Dose/Air Dose =A1e-G1+A2G2+A3G3+A4G4+A5G5+A6e-G6+A7e-G7+A8G8 +A9
– Constants, Ai, have been determined by multiple linear regression analysis– Claimed accurate to within ±6% at the 50% confidence level.
• Geometry factors, G, are physical dimensions taken from the shielding "history" of interest
– SP, Penetration distance of the direct radiation through the house
– IFW, Number of interior walls shielding the survivor from the front
– ILW, Number of interior walls shielding the survivor from the side
– LS, Lateral shielding exterior to the house of the survivor
– FS, FSS, Frontal shielding exterior to the house of the survivor
– HF, Height above the air-ground interface
– US, Distance from an open window in the direction of the hypocenter
– FN, Floor number on which survivor is located
Example Shielding History
T65 - The Last Word in Empirical Analysis
‘65-‘76:Advancement of Radiation Transport Calculation Technology
• Large Scale 1 and 2-Dimensional (ANISN, DOT) Neutron and Gamma Ray Atmospheric Transport Calculations– ORNL 4464 Neutron and Secondary Gamma-Ray Transport in
Infinite Homogeneous Air. (Ed Straker, Mike Gritzner)– ORNL 4289 Time-Dependent Neutron and Secondary Gamma-Ray
Transport in an Air-Over-Ground Geometry (Ed Straker, Mike Gritzner)
• Improved Neutron and Gamma Ray Cross Sections– Differential and Integral Measurements
• Using Linear Accelerator Broad Spectrum Source with Time-of-Flight (GA, ORNL)
• Especially n-γ production– Evaluations
• Especially Nitrogen, Oxygen, Iron• ENDF/B-4 (1974)
• Adjoint Monte Carlo Shielding Calculation Technology– MISC: SAIC– VCS/MASH: MAGI/ORNL/SAIC
How SAIC Became Involved:1. 1976-A Controversial Report
• Marrow Dose Calculation Project for DNA– Adjoint Monte Carlo– Application Example
Used LANL (Preeg) Hiroshima Leakage
• ORNL Demands DNA Withdraw Report– Different than T65– DNA Refuses
• ORNL (John Auxier) Defends Its Turf– Attacks Author’s
Credentials– Defends T65 at DOE
How SAIC Became Involved:2. 1978-Nuclear Test Dose
• NTPR-Nuclear Test Personnel Review– Dose Reconstruction
for 100’s of Military Personnel Exposed in Nevada and the Pacific
• Application and Verification of Computational Methods– 1 and 2D Discrete
Ordinates Methods– 3D Adjoint Monte
Carlo Methods (MISC)
• Gives Credibility to Arguments for A-Bomb Survivor Dose Discrepancy
And Then…• 1978 – Rossi and Mays, "Leukemia risk from neutrons," Health Physics
– Neutron RBE = 100; Derived from T65 City Differences in Neutron Dose– Culmination of Numerous Reports Citing A-Bomb Survivors as Basis for More
Stringent Radiation Exposure Regulatory Limitations• 1979 - BEIR III Issued; Immediately Withdrawn due to controversy• 1980 – Bill Loewe & Edgar Mendelsohn, "Revised Estimates of Dose at
Hiroshima and Nagasaki, and Possible Consequences for Radiation Induced Leukemia (Preliminary)", Report D-80-14. (LNL)
– Consistent with Kaul (1977)• 1979 - George Kerr (ORNL) Sponsored by DOE to Assess Possible A-
Bomb Dosimetry Problems– Agrees there is a Problem, Earning the Enmity of John Auxier
• 1980 - Dean Kaul Meets with NAS Seymour Jablon– Jablon Believes there is a Problem with T65
• 1980 - BEIR III Reissued – With Larger Safety Margins• 1981 - DOE Symposium on Neutron Dosimetry
– All Parties Air Their Opinions, including John Auxier• 1983 - DOE Launch a Multi-Million Dollar Program
– John Auxier Chooses Not To Participate
A-Bomb Dosimetry Reassessment Project
• Organizations– SAIC
• Delayed Radiation Free Field• Shielding• Organ Dosimetry• Dosimetry System• Uncertainty
– LANL• Yield• Leakage
– ORNL• Prompt Radiation Free Field• Factory Shielding
– Measurements– LNL
• University of Utah• Oxford University• University of Hiroshima• Nara University• Tokyo University• JNIRS• University of Munich
– RERF• Sample Gathering• Mapping• Hypocenter Location
• SAIC Staff– Gil Binninger– Hud Dolatshahi– Steve Egbert– Mike Gritzner– Dick Hillendahl– Dean Kaul– Tom Kuhn– Mark Otis– Jim Roberts– Bill Scott– Vic Verbinski– Bill Woolson
The Parents of DS86 Hiroshima 1983
Some US Principals in this Photo: Al Lazen, W. Lowder, Robert Christy, Ed Land, Dean Kaul, Dale Preston, Bill Ellett, Seymor JablonBill Woolson, Bill Roesch, Joe PaceGeorge Kerr, Warren Sinclair, Charlie EisenhauerPaul Whalen, Ed Haskell, Fred Seitz
LANL Calculates The Weapons
• Hiroshima (Little Boy)• Yield
– T65: 12.5 kT– DS86: 15 kT
• HOB– T65: 577 m– DS86: 580 m
• Nagasaki (Fat Man)• Yield
– T65: 22 kT– DS86: 21 kT
• HOB– T65: 503 m– DS86: 503 m
Hydro & Leakage Calculations
• Two-Dimensional– Hydrodynamics
• Includes Air Around Weapon
– Leakage• Neutrons• Gamma Rays
140µs
757µs
Neutron Leakage• Hiroshima
– Iron Moderated Spectrum
– Fast Neutrons Between 100keV and 1MeV
– Small Epithermal Component
• Nagasaki– Hydrogen Moderated
and Filtered Spectrum– Fast Neutrons
Between 1MeV and 5MeV
– Very Large Epithermal Component
Hiroshima
Gamma Ray Leakage
• Hiroshima– Fission Gamma
Rays– Iron Inelastic nγ– Iron Shielding
• Nagasaki– Capture Gamma
Rays• Nitrogen• Oxygen• Hydrogen
– Negligible Shielding
Hiroshima
LANL: Replica Project• 2-D Calculations
– Leakage• Included Air & Ground• To ~400m Horizontal
• Replica Project– Hiroshima Weapon
Case– Matching Fissile
Components– Foil Measurements to
Validate Cross Sections (SAIC: Verbinski)
– Approach to Critical to Validate Most Likely Yields
ORNL & SAIC: DS86 Free Field
SAIC: DS86 Shielding• 21 Locations• 16 Directions• 4 Distances• 1344 Unique
Shielding Parameter Combinations
• Rank Partial Correlation Shows– 5 Parameters Effective
• FS• FSS• US• FN• SP
SAIC: DS86 Organ Dosimetry• Basis:ICRP 23; M.
Christy (ORNL); Japan Statistics
• Three Anthropomorphic Phantoms– Infant– Child– Adult
• 3 Postures• 15 Organs• Energy/Angle
Differential Adjoint Leakage from Energy-Differential Average Organ Fluence
DS86 System
RERF Data Base for Individual Survivors
City,Distance
FromGround Zero
Location in House or
Street
Size, Sex, Orientation
Posture
Medical History
Unshielded Radiation
environment
House Shielding
Body Shielding
Doses and Uncertaintie
s
Radiation Risk
Estimates
DS86
SAIC Invents a New Dosimetry System for DS86
• Multi-Component System– Air Transport from
Weapon Leakage– Shield Propagation– Organ Dosimetry
• Doubly-Differential Adjoint Particle Coupling– Energy-Angle
Differential Intermediate Results
– Dose and Scalar Spectra in Organs
• Uncorrelated Components; Unlike T65
Contrasting T65D & DS86 Systems
S"
S'
DS86: Integration of Independent Calculated Components
S E freefield
shield shield
S E shield
man man
E
man
S E S E S E n S dS dE d S E
S E S E E n S dS dE d E
K E E dE Dose
", ", "
*
', ', '
*
" , " , " " , " , " , ' , ' , ' " " " " " ' , ' , '
' , ' , ' ' , ' , ' , ' ' ' ' '
T65D: Multiplication of Interdependent Empirical Components
Dose Dose Shielding Factor Organ Dose Factorman freefield Parameter Globe Factory * *, ,9
DS86 VerificationSulfur Activation
• U of Tokyo– Suspects A-Bomb– Collects Sulfur from
Telephone Poles– Measures S Activation
• Fast Neutron Activation (at Hiroshima)
• Sensitive to Weapon Tilt
• 3D Calculation Required to Match Data
• Large Uncertainty Bands at Large Distances
Sulfur Measurements
0
1
2
0 200 400 600 800 1000 1200 1400
Ground Range
M/C
Sulfur Activaion
0
500
1000
1500
2000
2500
3000
3500
0 200 400 600 800 1000 1200 1400
Ground Range (m)
P-3
2 D
PM
/gr
S A
TB
Measured
DS86
DS86 VerificationCobalt Activation
• Thermal Neutron Activation (at Hiroshima)
• Samples Embedded in Complex Geometry Objects
• Poor Agreement with Calculations
DS86 VerificationEuropium Neutron Activation
• Thermal Activation• Hiroshima
– Calculations High Below Bomb
– Calculations Diverge from Measurements Beyond ~900m Slant Range
– Similar to Co Results
• Nagasaki– Large Spread in
Measurements– Nominal Agreement
with Calculations– Calculations High
Under Bomb
DS86 Accepted Because TLD Measurements Support Calculations Over T65
In Spite of Neutron Problems,No Going Back to T65!
DS86 Status at Release• Gamma Dose, Shielding, Organ Dosimetry Improved
Significantly Over T65D
• The Neutron Discrepancy is the Most Severe of All Outstanding Dose Problems
– Affects all Hiroshima survivors– Cast doubt on the entire dosimetry system
• The Neutron Discrepancy is not the Only Remaining Problem, Others:
– Shielding uncertainty/discrepancy– No dose values for approximately 15% of survivors
• Impact of Problems if Left Unresolved:– High neutron dose uncertainty for most influential data base– Highest uncertainty for Hiroshima portion (2/3 of total data base)– Probable over-estimate of gamma-ray health risk– Inability to establish dose risk relationship at low doses (dose < 100 rads)– No usable data base for neutron, heavy charged particle risk assessment
Celebrating DS86 Completion
• DS86 Approval Announced in Hiroshima
• Japanese Hosts Suggest a Banzai Cheer in Celebration
• Older US Participants Refuse to Participate
And Then…DS86 from 1987 to 1999
• 1987 - DS86 Released• 1990 - BEIR V Released• Unanswered Questions in the 90’s
– Uncertainty Discrepancy• Predicted Uncertainty ~35%• Observed Uncertainty (from bio-dosimetry) ~45% or Greater
– Unresolved Neutron Activation Discrepancy Suggests Neutron Dose Bias at Hiroshima
• Europium• Cobalt
– Japan Courts Denounce DS86 for use in determining survivor compensation
Post-DS86
• Japan Measurements Challenge US Calculations
• DoE Funding Dries Up
• DSWA/DTRA Slips SAIC a Few Bucks to Keep Up Interest
The Problem Worsens
• More Neutron Measurements– Eu-152– Co-60– Cl-36 (AMS)– Ni-63 (AMS)
• Seem Consistent• But Require a
300m Relaxation Length– Calculated
Relaxation Length = 140m
1993: Partial Progress
• ENDF/B-6.2– Air Cross Sections– Iron Cross Sections
• Switch from 46 to 178 Neutron Cross Section Energy Bands
• Nagasaki– Discrepancy under
bomb resolved
• Hiroshima– No improvement
ENDF/B 6.2178 Energy Bands
DS86
1993 Difference AnalysisRequested by DSWA/DTRA
Could More Fast Neutrons Have Leaked From the Hiroshima Weapon?
Popular Japanese Theory:If the case had cracked,neutrons with a near-fissionspectrum might have leakedfrom the waist
+/-30 deg Horizontal Pancake
+/-30 deg Vertical Cone
1E-5
1E-4
1E-3
1E-2
1E-1
1E+0
1E-6 1E-5 1E-4 1E-3 1E-2 1E-1 1E+0 1E+1
Neutron Energy(MeV)
mole
/kt0
/leth
ds86 (ds93)
Calculation
Wild Theories Abound• Japan Suggests
the Bomb Cracked Before Neutrons Were Emitted
• US Tries– Directional
Fission Spectrum Leakage
• Pancake• Funnel-cake
– Spectrum Optimization
• Emissions from a Moving UFO are Seriously Considered 2.3MeV
Finally, Action!
• BEIR 7 is Needed to Support Radiation Regulatory Updates
• BEIR 7 is Put On Hold Because of Unresolved Problems with DS86
• DoE is Moved to Action, Again
Get It Right This Time!
• 2000 – DoE Resumes Dosimetry Program Funding
• 2000 - Hiroshima: Challenged to Solve Problems in One Year
• 2001 – Hiroshima: Japanese Find More Measurements that Disagree with Calculations
• 2001 – Cleveland: German Measurement Agrees with Calculation, No Resolution, Angry Japanese
2001 The Case Against 152 Eu Disagreement
• More Measurements Available at Hiroshima and Nagasaki
• Discrepancy– Exists at Both
Cities– Commencing at
Same Level: ~3.5 Bq/mg
– Inconsistent with NTS Test Comparisons
BUSTER-J ANGLE DOG ACTIVATION CALCULATION AND MEASUREMENT COMPARISON .
1E+13
1E+14
1E+15
1E+16
1E+17
1E+18
1E+19
300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 2100 2200 2300 2400
SLANT RANGE (M)
FLU
EN
CE *
SLA
NT R
AN
GE
2 (N/c
m2 *m
2 )
S32 irdf90
shielded Au(total)
shielded Au(prompt)
shielded Au(delay)
S32n,p (Meas) .299 barn
Au Diff (Meas) 98 barnS32
Au
0.00
0.25
0.50
0.75
1.00
1.25
1.50
1.75
2.00
300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 2100 2200 2300 2400
SLANT RANGE(M)
MEA
S/C
ALC R
ATIO
S32 irdf90
shielded Au(total)
Au M/C Fit
S M/C Fit
Confirmation of Technology
• Nagasaki-Like NTS Test
• Calculations Agree with Measurements– Fast (Sulfur)– Thermal (Gold)
• Calc. Using ENDF/B-6.2 Cross Sections
Final Path to Success!
• 2002 – Hiroshima: Europium and Chlorine Discrepancies Resolved by Japanese, Embarrassed Japanese– New Komura Eu Activation, Nagashima Cl at Hiroshima– Dr. Kosako (U of Tokyo): “What will we tell them?”– Japanese Regain Composure, Challenge Calculators to Explain
Short Range Thermal Neutron Activation Discrepancy• 2003 – Pasadena: HOB Increase Accepted as Answer
to Japanese Challenge– Hiroshima Burst Height Raised from 580m to 600m, based on
Thermal Activation Measurements– Tops of 6 story building near ground zero at Hiroshima, but not
Nagasaki– Hiroshima Yield Changed to 16kT– Hiroshima Hypocenter Changed, Based on New GIS Analysis
Thermal Neutron Discrepancy Resolved
Hiroshima FIA 152Eu & 36Cl (as 152Eu)
0.001
0.01
0.1
1
10
100
1000
0 200 400 600 800 1000 1200 1400 1600Ground Range, m
Act
ivat
ion
Bq
/mg
P reIntercomparison EuDistant EuEu (Int)All Cl (as Eu)DS02DS86
Hiroshima FIA 152Eu & 36Cl (as 152Eu)
10
100
1000
0 100 200 300 400 500Ground Range, m
Act
ivat
ion
Bq
/mg
P reIntercomparison EuDistant EuEu (Int)All Cl (as Eu)DS02DS86
Nagasaki FIA 152Eu
0.001
0.01
0.1
1
10
100
1000
0 200 400 600 800 1000 1200 1400 1600Ground Range, m
Act
ivat
ion
Bq
/mg
Measurement
DS02
DS86
Nagasaki FIA 152Eu
10
100
1000
0 100 200 300 400 500Ground Range, m
Act
ivat
ion
Bq
/mg
Measurement
DS02
DS86
Nagasaki TLD Gamma Dose
-1
0
1
2
3
4
500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 2100 2200Slant Range(m)
M/C
Measurement
Fit
DS02 Gamma Ray Dose Verified Using TLD Meas.
Hiroshima TLD Gamma Dose
-1
0
1
2
3
4
500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 2100 2200
Slant Range(m)
M/C
MeasurementFit
Hiroshima FIA TLD Gamma Dose
0.01
0.1
1
10
100
1000
500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 2100 2200Slant Range, m
Do
se, G
y
Measurement
DS02
Hiroshima FIA TLD Gamma Dose
0.01
0.1
1
10
100
1000
500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 2100 2200Slant Range, m
Do
se, G
y
Measurement
DS02
With Shielding+10%
+10%
Agreement within Uncertainty
Validity of the Assigned Total Uncertainty – The Test
• 41 Survivors• Chromosome Aberration (Cs) Total Dose• Tooth Dose (Lingual) Gamma Dose• DS86 to DS02; DS02 to Custom Location/Shielding (SHLD02)
Validity of the Assigned Total Uncertainty – The Finding
• DS86: Variability Much Larger than DS86/DS02 Uncertainty Assessment
• DS02: Variability Consistent with DS86/DS02 Uncertainty Assessment (±25% to 40%)
• SHLD02: Variability Much Improved
At Last…(DS02)
• 2003 – Hiroshima: DS02 Declared Finished; All Discrepancies Satisfied
• 2004 - DS02 System is Assembled in Hiroshima and Documented
• 2005 - DS02 Report Published
RERF Epidemiology:An Unfinished Story
• Life Span Study– 339 Excess
Cancer Deaths (circa 1990)
– 1 Sv (Sievert) = 100 REM
• Acute 0.2 Sv Risk– Absolute– Relative
• Results Will Continue to Accrue Until ~2028
Table 1. Cancer deaths between 1950 and 1990 among Life Span Study survivors with significant exposures
Dose rangeNumber of cancer
deathsEstimated excess
deathsAttributable fraction
0.005 - 0.2 Sv 3391 63 2% = 100×63/3391
0.2 - 0.5 Sv 646 76 12%
0.5 - 1 Sv 342 79 23%
1 Sv - 308 121 39%
ALL 4687 339 7%
Table 2. Lifetime cancer risks for atomic bomb survivors who received an acute dose of 0.2 Sv.
Age at exposure(yea
rs)Excess lifetime risk
Background lifetime risk
Excess relative risk
Men 10 0.03 (3%) 0.26 12% = 100×0.03/0.26
30 0.02 (2%) 0.28 7%
50 0.01 (1%) 0.18 6%
Women 10 0.05 (5%) 0.19 26%
30 0.03 (3%) 0.20 15%
50 0.01 (1%) 0.15 7%
Room for Improvement?• Gamma Ray Dose Inconsistencies• Survivor Location Improvement
– Use GIS Technology– Create a Geo-Referenced Collage of Pre-Attack
Photos• Custom Shielding Calculation
– Survivor Location According Shielding History– Houses Located According to GIS Collage
• Reduce Uncertainty by Between a Third to a Half
• Improved Biodosimetry– Chromosome Aberations– Electron Spin Resonance
• There Are No Plans for These at This Time
742.0 742.5 743.0 743.5 744.0 744.5 745.0 745.5 746.0 746.5 747.0
1262.0
1261.5
1261.0
1260.5
1260.0
1259.5
1259.0
1258.5
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