Japanese A-Bomb Dosimetry Project: Personal Recollections Presented to the Lyncean Group May 14, 2008 By Dean 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. 6 km in Hiroshima (42% between 1. 6 km and 2 km)
ABCC/RERF Hiroshima Site Hijiyama Mountain 1950 A Controversial Site! Today
Life Span Study Cohort Proximal Distal Total Hiroshima 12, 130 39, 260 51, 390 Nagasaki 4, 077 20, 524 24, 601 Total 16, 207 59, 784 75, 991 (Detailed Shielding Histories) Approximately 40% Are Still Alive Proximal survivors are within ground ranges of 1600 m at Hiroshima or 2000 m at Nagasaki
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 F 1 clinical study (FOCS) • Mail Surveys – 1965 (Ni-hon-san study men), 1968 (women), 1978, 1991, 200?
Dose Estimation Efforts - Nagasaki 1957 (T 57) to 1965 (T 65) • T 57 – York, USAF • T 65 – Auxier, ORNL • Empirical Estimates • Nagasaki Best Candidate for Approach – Similar Bombs Tested
Dose Estimation Efforts - Hiroshima 1957 (T 57) to 1965 (T 65) • T 57 – York, USAF • T 65 – Auxier, ORNL • Empirical Estimates • Hiroshima Poor Candidate for Approach – Similar Bomb Not Tested
Shielding Experiments: Hardtack (1958), BREN (1962) Bare Reactor Exp. , Nevada 465 m 343 m • 0. 6 Scale of Hiroshima • Bare U-235 Reactor, Co-60 • Simulated Japanese Structure Arrays – Asbestos-Cement Board 686 m – 1097 m
Structure Shielding • • • T 65: 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 =A 1 e-G 1+A 2 G 2+A 3 G 3+A 4 G 4+A 5 G 5+A 6 e-G 6+A 7 e-G 7+A 8 G 8 +A 9 – 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 Example Shielding History – 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 T 65 - 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 T 65 – DNA Refuses • ORNL (John Auxier) Defends Its Turf – Attacks Author’s Credentials – Defends T 65 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 2 D Discrete Ordinates Methods – 3 D Adjoint Monte Carlo Methods (MISC) • Gives Credibility to Arguments for ABomb Survivor Dose Discrepancy
And Then… • 1978 – Rossi and Mays, "Leukemia risk from neutrons, " Health Physics – Neutron RBE = 100; Derived from T 65 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 ABomb 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 T 65 • • 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 System Uncertainty – LANL • • Yield Leakage – ORNL • • Prompt Radiation Free Field Factory Shielding – Measurements – LNL • • University of Utah Oxford 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 DS 86 Hiroshima 1983 Some US Principals in this Photo: Al Lazen, W. Lowder, Robert Christy, Ed Land, Dean Kaul, Dale Preston, Bill Ellett, Seymor Jablon Bill Woolson, Bill Roesch, Joe Pace George Kerr, Warren Sinclair, Charlie Eisenhauer Paul Whalen, Ed Haskell, Fred Seitz
LANL Calculates The Weapons • Hiroshima (Little Boy) • Nagasaki (Fat Man) • Yield – T 65: 12. 5 k. T – DS 86: 15 k. T • HOB – T 65: 577 m – DS 86: 580 m – T 65: 22 k. T – DS 86: 21 k. T • HOB – T 65: 503 m – DS 86: 503 m
Hydro & Leakage Calculations • Two. Dimensional 140µs – Hydrodynamics • Includes Air Around Weapon – Leakage • Neutrons • Gamma Rays 757µs
Neutron Leakage • Hiroshima – Iron Moderated Spectrum – Fast Neutrons Between 100 ke. V and 1 Me. V – Small Epithermal Component • Nagasaki – Hydrogen Moderated and Filtered Spectrum – Fast Neutrons Between 1 Me. V and 5 Me. V – 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 ~400 m 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: DS 86 Free Field
SAIC: DS 86 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: DS 86 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
DS 86 System RERF Data Base for Individual Survivors City, Distance From Ground Zero Location in House or Street Size, Sex, Orientation Posture Unshielded Radiation environment House Shielding Body Shielding DS 86 Doses and Uncertainties Medical History Radiation Risk Estimates
SAIC Invents a New Dosimetry System for DS 86 • 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 T 65
Contrasting T 65 D & DS 86 Systems T 65 D: Multiplication of Interdependent Empirical Components DS 86: Integration of Independent Calculated Components S" S'
DS 86 Verification Sulfur Activation • U of Tokyo – Suspects A-Bomb – Collects Sulfur from Telephone Poles – Measures S Activation • Fast Neutron Activation (at Hiroshima) • Sensitive to Weapon Tilt • 3 D Calculation Required to Match Data • Large Uncertainty Bands at Large Distances
DS 86 Verification Cobalt Activation • Thermal Neutron Activation (at Hiroshima) • Samples Embedded in Complex Geometry Objects • Poor Agreement with Calculations
DS 86 Verification Europium Neutron Activation • Thermal Activation • Hiroshima – Calculations High Below Bomb – Calculations Diverge from Measurements Beyond ~900 m Slant Range – Similar to Co Results • Nagasaki – Large Spread in Measurements – Nominal Agreement with Calculations – Calculations High Under Bomb
DS 86 Accepted Because TLD Measurements Support Calculations Over T 65 In Spite of Neutron Problems, No Going Back to T 65!
DS 86 Status at Release • Gamma Dose, Shielding, Organ Dosimetry Improved Significantly Over T 65 D • 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 DS 86 Completion • DS 86 Approval Announced in Hiroshima • Japanese Hosts Suggest a Banzai Cheer in Celebration • Older US Participants Refuse to Participate
And Then… DS 86 from 1987 to 1999 • 1987 - DS 86 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 DS 86 for use in determining survivor compensation
Post-DS 86 • Japan Measurements Challenge US Calculations • Do. E 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 300 m Relaxation Length – Calculated Relaxation Length = 140 m
1993: Partial Progress • ENDF/B-6. 2 – Air Cross Sections – Iron Cross Sections • Switch from 46 to 178 Neutron Cross Section Energy Bands • Nagasaki DS 86 – Discrepancy under bomb resolved • Hiroshima – No improvement ENDF/B 6. 2 178 Energy Bands
1993 Difference Analysis Requested 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-fission spectrum might have leaked from the waist
Wild Theories Abound • Japan Suggests the Bomb Cracked Before Neutrons Were Emitted • US Tries +/-30 deg Horizontal Pancake +/-30 deg Vertical Cone – Directional Fission Spectrum Leakage • Pancake • Funnel-cake – Spectrum Optimization • Emissions from a Moving UFO are Seriously Considered 2. 3 Me. V
Finally, Action! • BEIR 7 is Needed to Support Radiation Regulatory Updates • BEIR 7 is Put On Hold Because of Unresolved Problems with DS 86 • Do. E is Moved to Action, Again
Get It Right This Time! • 2000 – Do. E 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
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 580 m to 600 m, based on Thermal Activation Measurements – Tops of 6 story building near ground zero at Hiroshima, but not Nagasaki – Hiroshima Yield Changed to 16 k. T – Hiroshima Hypocenter Changed, Based on New GIS Analysis
Thermal Neutron Discrepancy Resolved
DS 02 Gamma Ray Dose Verified Using TLD Meas. Agreement within Uncertainty +10% With Shielding +10%
Validity of the Assigned Total Uncertainty – The Test • • 41 Survivors Chromosome Aberration (Cs) Total Dose Tooth Dose (Lingual) Gamma Dose DS 86 to DS 02; DS 02 to Custom Location/Shielding (SHLD 02)
Validity of the Assigned Total Uncertainty – The Finding • DS 86: Variability Much Larger than DS 86/DS 02 Uncertainty Assessment • DS 02: Variability Consistent with DS 86/DS 02 Uncertainty Assessment (± 25% to 40%) • SHLD 02: Variability Much Improved
At Last…(DS 02) • 2003 – Hiroshima: DS 02 Declared Finished; All Discrepancies Satisfied • 2004 - DS 02 System is Assembled in Hiroshima and Documented • 2005 - DS 02 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 range Number of cancer deaths Estimated excess deaths Attributable 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 exposu re(year s) 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
Difference From Army Map
Скачать презентацию Japanese A-Bomb Dosimetry Project Personal Recollections Presented to
70db5019aae22c4097d8af8b50680161.ppt