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Moscow State University Department: Nuclear Physics Master thesis: “Photodisintegration of Bi209”

Vera Chetvertkova. Moscow State University Department: Nuclear Physics Master thesis: “Photodisintegration of Bi209” Induced-activity experiment: Beam: Bremsstrahlung Target: thin foil Gamma-spectroscopy: Types of radio-nuclides Amount of radio-nuclides

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Moscow State University Department: Nuclear Physics Master thesis: “Photodisintegration of Bi209”

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  1. Vera Chetvertkova • Moscow State University • Department: Nuclear Physics • Master thesis: • “Photodisintegration of Bi209” • Induced-activity experiment: Beam: Bremsstrahlung Target: thin foil • Gamma-spectroscopy: Types of radio-nuclides Amount of radio-nuclides Yields of the photonuclear reactions

  2. PhD thesis: “Verification of Monte Carlo transport codes by Activation Experiments”

  3. Introduction Beam lossesActivation of the accelerator components Increased dose ratesin the vicinity of the irradiated materials Restrictions on the hands-on maintenanceof the machine Necessity of designing the accelerator shieldingto avoid personnel exposure Activation – one of the main intensity limiting factors for high energy and high intensity hadron accelerators 3

  4. Introduction: The “1 W/m” criterion for proton accelerators [Beam Halo and Scraping The 7th ICFA Mini-workshop on High Intensity High Brightness Hadron Beams Wisconsin, USA, September 13-15, 1999] “An average beam loss of1 W/min the uncontrolled area should be a reasonable limit for hands-on maintenance." 1 W/m ≈ 6.24 × 109 protons/s/m at 1 GeV Irradiation of a bulky target Proton beam energy: 1 GeV Beam power: 1 W/m Irradiation time: 100 days Dose rate < 1 mSv/h 4 hoursafter the end of operation 30 cmaway from the component surface 4

  5. Beam pipe Bulky target Introduction: The Heavy-Ion Beam Loss Criteria Primary beams: 1H,4He,12C,20Ne,40Ar,84Kr,132Xe,197Au,238U Beam energy: 200 MeV/u – 1 GeV/u Beam losses: 1 W/m irradiation time: 100 days cooling times: 0 days, 4 hours, 1 day, 1 week,2 months, 1 year, 10 years simulation codes: FLUKA (2008) Beam-pipe material: stainless steel Wall thickness: 2 mm Length: 10 m, diameter: 10 cm Beam angle of incidence: 1 mrad Bulky target material: copper, stainless steel Diameter:20 cm, length:60 cm [I. Strasik, E. Mustafin, M. Pavlovic, Residual activity induced by heavy ions and beam-loss criteria for heavy-ion accelerators, Physical Review Special Topics – Accelerators and Beams 13, 071004 (2010)] [I. Strasik et al., Activation and beam-loss criteria for “hands-on” maintenance on heavy ion accelerators, in Proc. of SATIF10, Geneva, Switzerland, 2-4 June 2010, p.129] 5

  6. Introduction: The Heavy-Ion Beam Loss Criteria simulation code: FLUKA (2008) beam energy:500 MeV/u cooling time: 1 day The time-evolution of the activity can be described by means of a generic curve. Isotope inventory in the target [I. Strasik, E. Mustafin, M. Pavlovic, Residual activity induced by heavy ions and beam-loss criteria for heavy-ion accelerators, Physical Review Special Topics – Accelerators and Beams 13, 071004 (2010)] [I. Strasik et al., Activation and beam-loss criteria for “hands-on” maintenance on heavy ion accelerators, in Proc. of SATIF10, Geneva, Switzerland, 2-4 June 2010, p.129] 6

  7. Introduction: The Heavy-Ion Beam Loss Criteria Bulky target scenario simulation code: FLUKA 2008 Ap(1GeV) –normalized activity induced by 1 GeV proton beam Ai(E) - normalized activity induced by the beam of interest at given energy [I. Strasik, E. Mustafin, M. Pavlovic, Residual activity induced by heavy ions and beam-loss criteria for heavy-ion accelerators, Physical Review Special Topics – Accelerators and Beams 13, 071004 (2010)] [I. Strasik et al., Activation and beam-loss criteria for “hands-on” maintenance on heavy ion accelerators, in Proc. of SATIF10, Geneva, Switzerland, 2-4 June 2010, p.129] 7

  8. Introduction • Calculated using MC transport codes: • FLUKA • SHIELD • Verification at different projectile-target combinations is needed Goal of the work Obtain new information on interactions of heavy ions for verification of Monte Carlo transport codes 8

  9. Contents Experimental technique Preliminary simulations Types of targets Irradiation and Measurements Analysis of the Gamma-spectra Uncertainty Assessment Experimental results and comparison with the simulations Activation of aluminum Activation of copper Discussion Conclusion 9

  10. Experimental technique: Preliminary simulations Simulations of the interaction of certain ions with chosen material • Finding the stopping range • Choosing the target geometry • Finding the nuclide production rates Choosing the irradiation condition • Choosing the measurement times 10

  11. Experimental technique: Types of targets • Thick target • Studying the isotope inventory, • The depth distribution, • The stopping range of certain ions (e.g. uranium) Activation foils 11

  12. Experimental technique: Types of targets • Single-foil target • Studying the isotope inventory, esp. short lived nuclides • (Manual handling is possible shortly after the end of the irradiation) 12

  13. Experimental technique: Irradiation & Measurements Spectra acquisitions: started several hours to several months after the end of irradiation GSI: SIS18: Cave HHD Projectiles: N, Ar, U Energies: 85-935 AMeV Intensities: ≤ 4∙1010 ions/sec Measurements of the beam cross-section: profile-meter Measurements of the beam intensity: current transformer 13

  14. EXPERIMENTAL RESULTS AND COMPARISON WITH THE SIMULATIONS: Activation of Aluminum 40Ar 430 AMeV, 500 AMeV 14N 500 AMeV 238U 85 AMeV - 935 AMeV 27Al Foil, thick target 14

  15. EXPERIMENTAL RESULTS AND COMPARISON WITH THE SIMULATIONS: Activation of Aluminum 500 MeV/A Argon beam 15

  16. EXPERIMENTAL RESULTS AND COMPARISON WITH THE SIMULATIONS: Activation of Aluminum 85  935 MeV/A Uranium beams Single-foil experiment 16

  17. EXPERIMENTAL RESULTS AND COMPARISON WITH THE SIMULATIONS: Activation of Aluminum 500 MeV/A Uranium beam 17

  18. EXPERIMENTAL RESULTS AND COMPARISON WITH THE SIMULATIONS: Activation of Copper 40Ar 500 AMeV 14N 500 AMeV natCu thick target 18

  19. EXPERIMENTAL RESULTS AND COMPARISON WITH THE SIMULATIONS: Activation of Copper 500 MeV/A Nitrogen beam 19

  20. Scaling law is possible because of the same isotope inventory (generic curve) Scaling law could be violated At low energies At long irradiation times The goal: To calculate activation of a bulky target by different ions at energies below 200 AMeV To calculate activation at long irradiation times (20 years) Activation studies for accelerator applications 20

  21. Activation studies for accelerator applications Primary beams: 1H, 4He, 12C, 20Ne, 40Ar, 84Kr, 132Xe, 197Au, 238U Beam energies: 50 MeV/u, 100 MeV/u, 200 MeV/u Irradiation time: 20 years Cooling times: 0 hours, 4 hours,1 day, 1 week, 2 months, 1 year, 2 years, 5 years, 10 years, 20 years, 50 years Target materials: Carbon, Aluminum, Iron, Copper, Lead Target radius: 20 cm, Target thickness: 60 cm 21

  22. Activation studies for accelerator applications The Limits of Applicability of the Heavy-Ion Beam Loss Criterion Bulky target scenario cooling time: 1 day simulation code: FLUKA (2008) beam energy: 500 MeV/u Irradiation time: 100 days simulation code: FLUKA (2011) beam energy: 50 MeV/u Irradiation time: 20 years copper 22

  23. Activation studies for accelerator applications Time evolution of the total residual activity Energy 50 MeV/A, Duration of irradiation 20 years. Energy 500 MeV/A, Duration of irradiation 100 days. 23

  24. Activation studies for accelerator applications Primary beams: 1H Beam energies: 1 GeV/u Irradiation times: 100 days, 20 years Target materials: C, Al, Cr, Ti, Mn, Fe, Cu, Ni, Nb,Mo, Pb Target radius: 20 cm, Target thickness: 60 cm 24

  25. Activation studies for accelerator applications Code: FLUKA 2011.2 Irradiation time: 100 days Irradiation time: 20 years 25

  26. Activation studies for accelerator applications Maximum dose rate at the distance 30 cm from the target surface, irradiated by 1 GeV protons Code: FLUKA 2011.2 Irradiation time: 100 days Irradiation time: 20 years 26

  27. Conclusion • New experimental data on activation of • Comparison of the obtained data with simulations average discrepancies: ~5% FLUKA, ~30% MARS, ~50% SHIELD • Limits of applicability of the heavy-ion beam-loss criteria: energy ~ 100 MeV/A • The least activated materials used in accelerator applications Carbon, Aluminum, Titanium, Manganese, Iron => Thin-foil aluminum targets 430 MeV/A argon beam; 120 – 950 MeV/A uranium beams; => Thick aluminum targets 500 MeV/A nitrogen beam; 500 MeV/A argon beam; 500 MeV/A uranium beam; • => Thick copper target • 500 MeV/A nitrogen beam. 27

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