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Japanese A-Bomb Dosimetry Project: Personal Recollections

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.

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Japanese A-Bomb Dosimetry Project: Personal Recollections

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  1. Japanese A-Bomb DosimetryProject: Personal Recollections Presented to the Lyncean Group May 14, 2008 By Dean Kaul and Steve Egbert

  2. Hiroshima • Gun Assembly Device • August 6, 1945 • 140,000 Deaths Estimated

  3. Nagasaki • Implosion Device • August 9, 1945 • 80,000 Deaths Estimated

  4. 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)

  5. ABCC/RERF Hiroshima SiteHijiyama Mountain 1950 A Controversial Site! Today

  6. Life Span Study Cohort Approximately 40% Are Still Alive Proximal survivors are within ground ranges of 1600m at Hiroshima or 2000m at Nagasaki

  7. 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?

  8. Dose Estimation Efforts - Nagasaki1957 (T57) to 1965 (T65) • T57 – York, USAF • T65 – Auxier, ORNL • Empirical Estimates • Nagasaki Best Candidate for Approach • Similar Bombs Tested

  9. 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

  10. Shielding Experiments: Hardtack (1958), BREN (1962) Bare Reactor Exp., Nevada 465m • 0.6 Scale of Hiroshima • Bare U-235 Reactor, Co-60 • Simulated Japanese Structure Arrays • Asbestos-Cement Board 343m 686m – 1097m

  11. 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 Structure Shielding Example Shielding History T65 - The Last Word in Empirical Analysis

  12. ‘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

  13. 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

  14. 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

  15. 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

  16. 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 A-Bomb Dosimetry Reassessment Project

  17. 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 Jablon Bill Woolson, Bill Roesch, Joe Pace George Kerr, Warren Sinclair, Charlie Eisenhauer Paul Whalen, Ed Haskell, Fred Seitz

  18. 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 LANL Calculates The Weapons

  19. Hydro & Leakage Calculations • Two-Dimensional • Hydrodynamics • Includes Air Around Weapon • Leakage • Neutrons • Gamma Rays 140µs 757µs

  20. 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

  21. Gamma Ray Leakage • Hiroshima • Fission Gamma Rays • Iron Inelastic nγ • Iron Shielding • Nagasaki • Capture Gamma Rays • Nitrogen • Oxygen • Hydrogen • Negligible Shielding Hiroshima

  22. 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

  23. ORNL & SAIC: DS86 Free Field

  24. 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

  25. 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

  26. DS86 System RERF Data Base for Individual Survivors City, Distance From Ground Zero Location in House or Street Size, Sex, Orientation Posture Medical History DS86 Unshielded Radiation environment House Shielding Body Shielding Doses and Uncertainties Radiation Risk Estimates

  27. 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

  28. T65D: Multiplication of Interdependent Empirical Components Contrasting T65D & DS86 Systems DS86: Integration of Independent Calculated Components S" S'

  29. 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

  30. DS86 VerificationCobalt Activation • Thermal Neutron Activation (at Hiroshima) • Samples Embedded in Complex Geometry Objects • Poor Agreement with Calculations

  31. 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

  32. DS86 Accepted Because TLD Measurements Support Calculations Over T65 In Spite of Neutron Problems, No Going Back to T65!

  33. 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 DS86 Status at Release

  34. Celebrating DS86 Completion • DS86 Approval Announced in Hiroshima • Japanese Hosts Suggest a Banzai Cheer in Celebration • Older US Participants Refuse to Participate

  35. 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

  36. Post-DS86 • Japan Measurements Challenge US Calculations • DoE Funding Dries Up • DSWA/DTRA Slips SAIC a Few Bucks to Keep Up Interest

  37. 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

  38. 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 DS86 ENDF/B 6.2 178 Energy Bands

  39. 1993 Difference AnalysisRequested by DSWA/DTRA

  40. 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

  41. +/-30 deg Horizontal Pancake +/-30 deg Vertical Cone 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

  42. 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

  43. 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

  44. 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

  45. Confirmation of Technology • Nagasaki-Like NTS Test • Calculations Agree with Measurements • Fast (Sulfur) • Thermal (Gold) • Calc. Using ENDF/B-6.2 Cross Sections

  46. 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

  47. Thermal Neutron Discrepancy Resolved

  48. DS02 Gamma Ray Dose Verified Using TLD Meas. Agreement within Uncertainty +10% With Shielding +10%

  49. 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)

  50. 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

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