1. Induced-activity experiment:
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. Monte Carlo transport codes by Activation Experiments”
PhD thesis:
“Verification of
Monte Carlo transport codes by
Activation Experiments”

3. Introduction Beam losses Activation of the accelerator components
Increased dose rates in the vicinity of the irradiated materials
Restrictions on the hands-on maintenance of the machine
Necessity of designing the accelerator shielding to 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 of 1 W/m in 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 hours after the end of operation
30 cm away from the component surface 4

5. 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
Bulky target
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, (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, (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, (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: Goal of the work
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
GSI: SIS18: Cave HHD
Projectiles: N, Ar, U
Energies: AMeV
Intensities: ≤ 4∙1010 ions/sec
Spectra acquisitions:
started several hours to several months after the end of irradiation
Measurements of
the beam cross-section: profile-meter
the beam intensity: current transformer 13

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

15. EXPERIMENTAL RESULTS AND COMPARISON WITH THE SIMULATIONS: Activation of Aluminum
500 MeV/A Argon beam
Experiment, Nucl/ion
FLUKA, Nucl/ion
MARS, Nucl/ion
SHIELD, Nucl/ion
7Be ± ± ±
±0.0008
22Na ± ± ±
±0.0032 15

16. Single-foil experiment
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
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. Activation studies for accelerator applications
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) 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 500 MeV/A,
Duration of irradiation 100 days.
Energy 50 MeV/A,
Duration of irradiation 20 years. 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
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
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