1. BROOKHAVEN SCIENCE ASSOCIATES Radiological Design Considerations of Synchrotron Radiation Facilities P.K. Job Radiation Physicist National Synchrotron Light Source Project Brookhaven National Laboratory

2. BROOKHAVEN SCIENCE ASSOCIATES Radiological Design Considerations for Synchrotron Radiation Facilities Radiation Shielding Analysis of the Accelerator Enclosures and Beamlines Activation and Radiation Damage Analysis of the Accelerator Components Environmental Impact of Accelerator Operations like Soil, Air and Water Activation Skyshine Estimates due to High Beam Loss Points like Beam Dumps, Injection Septa etc.

3. BROOKHAVEN SCIENCE ASSOCIATES Radiation Shielding Analysis of Accelerators Radiation Sources at the SR Facilities Shielding Design Objectives Calculational Tools and Procedures Accelerator Shielding Examples Beamline Shielding Summary Comments

4. BROOKHAVEN SCIENCE ASSOCIATES Radiation Sources at SR Facilities Bremsstrahlung (High Energy Photons) produced in EM shower due to the beam loss e + e - Charged Particles generated in the EM shower Neutrons produced in EM shower due to photonuclear interactions Synchrotron Radiation (x-rays ) generated by dipoles and insertion devices 50 GeV e- in Pb

5. BROOKHAVEN SCIENCE ASSOCIATES Properties of EM Shower 6 GeV e - on concrete

6. BROOKHAVEN SCIENCE ASSOCIATES Shielding Design Objectives Regulatory Documents at BNL Code of Federal Regulations 10 CFR 835 DOE Accelerator Order 420.2B Site Radiation Control Manual NSLS Design Criteria Accelerator Enclosures< 1000 mrem/y Experimental Stations<100 mrem/y On site non-NSLS staff< 25 mrem/y BNL Site Boundary< 5 mrem/y

7. BROOKHAVEN SCIENCE ASSOCIATES Calculational Tools and Procedures Semi-empirical Methods – Swanson’s Formalism (thick target approximation) Analytical Simulation Programs – SHIELD11 (1-D, 4 group simulation program for EM shower) – PHOTON (1-D, Multi-energy Simulation program for x-ray shielding) – STAC8 (1-D, Multi-energy Simulation program for x-ray shielding) Monte Carlo Simulation Programs – EGS4 (3-D, Multi-energy simulation program for electrons-gammas) – MCNPX (3-D, Multi-group, Multi-particle program) – FLUKA (3-D, Multi-group, Multi-particle program)

8. BROOKHAVEN SCIENCE ASSOCIATES Swanson’s Formalism Thick target approximation for bulk shielding calculations

9. BROOKHAVEN SCIENCE ASSOCIATES Swanson’s Formalism Radiation Component Dose equivalent factors(mrem.m 2 /J) (Swanson) Dose equivalent factors(mrem.m 2 /J) (Sullivan) Bremsstrahlung2.801.39 Giant Resonance Neutrons 0.630.27 High Energy Neutrons 0.0750.043 Radiation Dose equivalent Factors at transverse direction from a thick target SHIELD11 computer program adopts similar methodology with additional neutron groups for bulk shielding calculations of the accelerator enclosures

10. BROOKHAVEN SCIENCE ASSOCIATES PHOTON Program for Synchrotron Radiation PHOTON is a 1-dimensional multi-energy analytical simulation program for x-ray shielding Generate Bending Magnet Radiation Spectrum Simulate Photon Transport by Compton Scattering (isotropic) and photo-absorption through different materials Calculate Scattered Photon Flux as a function of Energy and Angle Convert the Resulting Photon Flux into Dose Rate For x-ray Beamline Shielding Design

11. BROOKHAVEN SCIENCE ASSOCIATES STAC8 Program for Synchrotron Radiation STAC8 is a 1-Dimensional multi-energy program for x-ray shielding Generate Bending Magnet and Undulator Radiation Spectrum Generate Monochromatic Undulator Beams with fixed Bandwidths Simulate Photon Transport by Compton Scattering (anisotropic), Rayleigh Scattering and Photo-absorption Calculate scattered photon flux as a function of energy and angle Convert the flux into dose rate. For x-ray Beamline Shielding Design

12. BROOKHAVEN SCIENCE ASSOCIATES Electron Gamma Shower Program (EGS4) Simulates Electron-Gamma Coupled Monte Carlo Transport through different materials and geometry by the following interactions; (cross sections generated from physics models) Photoelectric Effect Compton and Rayleigh Scattering Pair Production (electron and nuclear field) Multiple Elastic Scattering Bremsstrahlung Production Moller and Bhabha Scattering Annihilation of Electron-Positron Pairs Continuous Slowing Down (Bethe-Bloch) Note: No photonuclear interactions

13. BROOKHAVEN SCIENCE ASSOCIATES MCNPX Monte Carlo Program for Photons and Neutrons Multi-group, Multi-dimensional Monte-Carlo program  Models the interactions of radiation/particles (34 particle kinds)  Heavy ions are being added  Uses both table and model physics for cross sections  All standard and 150-MeV neutron, proton, photonuclear libraries  Photon, Electron physics (upto 1 GeV)  Bertini, ISABEL, CEM, INCL, and FLUKA  3-Dimensional, continuous energy, fully time-dependent  Supported on UNIX, PC Windows, Mac G5  Auto configuration, build system  FORTRAN90/95, dynamic allocation  Distributed memory and parallel processing

14. BROOKHAVEN SCIENCE ASSOCIATES FLUKA Monte Carlo Program for Photons and Neutrons

15. BROOKHAVEN SCIENCE ASSOCIATES Bulk Shielding Calculations Shielding specifications are based upon maximum allowed design dose criteria (1000 mrem/year or 100 mrem/year) Recommendations based upon 2000 work-hours of exposure per year on contact at the exterior of the bulk shielding Analysis for bremsstrahlung, Giant Resonance Neutrons and High Energy Neutrons has been done separately Input : Beam loss assumptions Attenuation lengths of materials

16. BROOKHAVEN SCIENCE ASSOCIATES Beam Loss Assumptions at NSLS-II

17. BROOKHAVEN SCIENCE ASSOCIATES Beam Loss Assumptions at NSLS-II

18. BROOKHAVEN SCIENCE ASSOCIATES Beam Loss Assumptions at Other SR Facilities

19. BROOKHAVEN SCIENCE ASSOCIATES Bulk Shielding Comparison Bulk Shields at Floor Side

20. BROOKHAVEN SCIENCE ASSOCIATES Bulk Shielding Comparison At NSLS-II HD concrete was replaced by equivalent ND concrete

21. BROOKHAVEN SCIENCE ASSOCIATES Radiation Dose due to Scattering from a Scraper Beam at 1 mm from the edge of the 10 mm Cu scraper Scraper FLUKA Calculations with Dipole Field

22. BROOKHAVEN SCIENCE ASSOCIATES Radiation Dose due to Scattering from Scraper- FLUKA Results Beam HD Concrete

23. BROOKHAVEN SCIENCE ASSOCIATES Top-off Injection Accident - FLUKA Simulations Fixed Mask FOE Collimator Photon Shutter Collimator Safety Shutters

24. BROOKHAVEN SCIENCE ASSOCIATES FLUKA Results - Beam on the FE Mask (SS Open) Total Dose Equivalent Rates Beam Mask

25. BROOKHAVEN SCIENCE ASSOCIATES FLUKA Results - Beam on the FE Mask (SS Open) Neutron Dose Equivalent Rates Beam Mask

26. BROOKHAVEN SCIENCE ASSOCIATES Top-off Accident Analysis (FLUKA Simulations) Injected Beam in the First Optics Enclosure FOE

27. BROOKHAVEN SCIENCE ASSOCIATES Total Dose Equivalent Rates (FLUKA Results) Injected Beam in the First Optics Enclosure

28. BROOKHAVEN SCIENCE ASSOCIATES Neutron Dose Equivalent Rates (FLUKA Results) Injected Beam in the First Optics Enclosure

29. BROOKHAVEN SCIENCE ASSOCIATES Radiation Dose to Insertion Devices – MCNP Calculations

30. BROOKHAVEN SCIENCE ASSOCIATES Radiation Dose to Insertion Devices – MCNP Results

31. BROOKHAVEN SCIENCE ASSOCIATES Beamline Shutter Thickness - EGS4 Calculation

32. BROOKHAVEN SCIENCE ASSOCIATES Beamline Shutter Thickness- EGS4 Results

33. BROOKHAVEN SCIENCE ASSOCIATES Bremsstrahlung Scattering in Hutches -EGS4 results

34. BROOKHAVEN SCIENCE ASSOCIATES SR Scattering in the Hutches –STAC8 Calculations

35. BROOKHAVEN SCIENCE ASSOCIATES Typical STAC8 Results for Hutches

36. BROOKHAVEN SCIENCE ASSOCIATES A Word of Caution A variety of well benchmarked, accurate simulation tools are available for the shielding design of electron storage rings The simulation is probably the most accurate step in the assessment process. The beam loss estimations and attenuation lengths are often less precise than the simulation. In many cases a quick and purposely simplified simulation which is made in time may be more valuable than a detailed and accurate simulation which may be costly and take time to complete. In all cases the real cost of a detailed simulation must be balanced against the extra cost which might be engendered if conservative, empirical methods are used. However, in some cases it may be self-defeating to offer such accurate simulations when other parameters in the problem are known with much less precision.