1. Activation by Heavy-Ion Beams
HICforFAIR Workshop
Beam physics for FAIR 2012
Activation by Heavy-Ion Beams
Vera Chetvertkova
GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt, Germany
J. W. Goethe Universität Frankfurt am Main, IAP, Germany

2. Introduction
Activation of the accelerator components caused by the beam losses
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
Vera Chetvertkova “Activation by Heavy Ion Beams

3. Introduction
Activation gets higher with increasing energies and intensities
Necessity of quantifying the residual activity induced by beam particles per unit thickness
Activation studies at GSI:
stainless steel and copper targets irradiated by U beams at 500 MeV/A and 950 MeV/A [1], [2]
copper targets irradiated by Ar beams at 500 MeV/A and 1 GeV/A [3].
[1] Fertman et al., , Nucl. Instr. Meth. Phys. Res. B, 260 (2007) 579.
[2] Strasik et al., Nucl. Instr. Meth. Phys. Res. B, 266 (2008) 3443.
[3] Strasik et al., Nucl. Instr. Meth. Phys. Res. B 268 (2010) 573
Vera Chetvertkova “Activation by Heavy Ion Beams

4. Introduction
Proton beam-loss criterion “An average beam loss of 1 W/m in the uncontrolled area should be a reasonable limit for hands-on maintenance.“ [4]
1 W/m ≈ 6.24 × 109 protons/s/m at 1 GeV; Irradiation time: 100 days
Dose rate < 1 mSv/h;
4 hours after the end of operation
30 cm away from the component surface
[4] Beam Halo and Scraping The 7th ICFA Mini-workshop on High Intensity High Brightness Hadron Beams Wisconsin, USA, September 13-15, 1999
Vera Chetvertkova “Activation by Heavy Ion Beams

5. Introduction Beam pipe Bulky target
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]

6. Introduction simulation code: FLUKA (2008) beam energy: 500 MeV/u
Isotope inventory in the target
The time-evolution of the activity can be described by means of a generic curve.
cooling time: 1 day
[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. Introduction 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]

8. Calculated using MC transport codes:
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

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: Activation studies for accelerator applications
Conclusion

10. Experimental technique
Activation experiment
Scheme of the experiment
Beam
Target
Experimental Cave
HPGe
detector g
Measurement Room

11. 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

12. Experimental technique: Types of targets
Complementary experiments for checking
the position of the stopping range
Truncated cylinder (covered with organic material)
Aluminum irradiated with
Uranium beam
500 MeV/u
950 MeV/u
Fast estimation of the stopping range of the projectiles (~ 0.5 mm precision)

13. 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)

14. 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

15. Experimental technique: Irradiation
GSI: SIS18: Cave HHD
Extracted beam
Projectiles: N, Ar, U
Energies: MeV/A
Intensities: ≤ 4∙1010 ions/sec
Measurements of the beam cross-section: profile-meter
Measurements of the beam intensity: current transformer

16. Experimental technique: Measurements
Gamma-spectroscopy:
HPGe detector
Calibration:
22Na, 60Co, 137Cs, 152Eu
Spectra acquisitions:
started several hours to several months after the end of irradiation
U (500 MeV/A) + Al

17. Experimental technique: Analysis of the γ-spectra

18. Experimental technique: Uncertainty Assessment
Peak net area
Half-life and gamma emission probability [
Absolute efficiency of the detector
uncertainty of the calibration source (< 2 %),
uncertainty of the peak net area (< 2%)
uncertainty of fitting the curve (1% - 7%).
Thickness of the activation foil (< 0.5%)
Total intensity of the beam on the target
uncertainty of current transformer (~ 3%)
Depth uncertainty and resolution
uncertainty of the foil position in the target (~ 0.05 mm).
Uncertainty of the foil thickness (< 0.5%)

19. EXPERIMENTAL RESULTS AND COMPARISON WITH THE SIMULATIONS: Activation of Aluminum
430 MeV/u, 500 MeV/u
14N
500 MeV/u
238U
120 MeV/u
200 MeV/u,300 MeV/u 400MeV/u, 500 MeV/u
600 MeV/u, 700 MeV/u 800 MeV/u, 950 MeV/u
27Al
Foil, thick target

20. EXPERIMENTAL RESULTS AND COMPARISON WITH THE SIMULATIONS: Activation of Aluminum
500 MeV/A Nitrogen beam
Nuclide
Experiment, Nucl/ion
FLUKA, Nucl/ion
7Be
22Na
24Na

21. Single-foil experiment
EXPERIMENTAL RESULTS AND COMPARISON WITH THE SIMULATIONS: Activation of Aluminum
430 MeV/A Argon beam
Single-foil experiment
7Be, nuclide/ion/mm
22Na, nuclide/ion/mm
24Na, nuclide/ion/mm
Experiment
2.08·10-4 ± 1.29·10-5
1.62·10-4 ± 8.86·10-6
1.11·10-4 ± 5.63·10-6
FLUKA
2.01·10-4 ± 1.13·10-5
1.62·10-4 ± 1.58·10-5
1.10·10-4 ± 1.13·10-5

22. 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
22Na

23. Single-foil experiment
EXPERIMENTAL RESULTS AND COMPARISON WITH THE SIMULATIONS: Activation of Aluminum
120  950 MeV/A Uranium beams
Single-foil experiment

24. EXPERIMENTAL RESULTS AND COMPARISON WITH THE SIMULATIONS: Activation of Aluminum
500 MeV/A Uranium beam
237U
7Be

25. EXPERIMENTAL RESULTS AND COMPARISON WITH THE SIMULATIONS: Activation of Aluminum
500 MeV/A Uranium beam
Experiment, Nucl/ion
FLUKA, Nucl/ion
SHIELD Nucl/ion
7Be
0.0145
0.0164
0.0214
22Na
0.0369
0.0336
0.1017
227Th
1.297·10-4
4.656·10-4
3.007·10-4
230Pa
1.771·10-4
3.241·10-4
4.779·10-4
233Pa
8.365·10-4
0.0017
237U
0.0066
Experiment
FLUKA
83Rb
16.625·10-4
8.946·10-4
99Mo
2.690·10-4
2.512·10-4
127Xe
1.317·10-3
1.291·10-3
141Ce
13.440·10-4
4.193·10-4
149Gd
4.741·10-4
5.124·10-4
169Yb
12.071·10-4
9.464·10-4
185Os
3.535·10-4
9.227·10-4
188Pt
2.152·10-4
5.716·10-4
202Tl
2.479·10-5
2.092·10-5
205Bi
2.044·10-4
9.311·10-4
206Po
1.969·10-4
10.407·10-4
 The experimental and calculated number of nuclides is quoted 7 days after the end of irradiation

26. EXPERIMENTAL RESULTS AND COMPARISON WITH THE SIMULATIONS: Activation of Copper
500 MeV/u
14N
500 MeV/u
natCu
thick target

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

28. EXPERIMENTAL RESULTS AND COMPARISON WITH THE SIMULATIONS: Activation of Copper
500 MeV/A Nitrogen beam
Nuclide
Experiment, Nucl/ion
FLUKA, Nucl/ion
SHIELD, Nucl/ion
7Be
0.0022
0.0045
22Na
1.862·10-4
1.897·10-4
2.803·10-4
51Cr
0.0046
0.0034
0.0024
54Mn
0.0055
0.0050
0.0018
59Fe
7.022·10-4
5.595·10-4
6.832·10-4
56Co
0.0025
0.0036
0.0088
57Co
0.0090
0.0119
0.0095
65Zn
6.660·10-4
3.706·10-4
0.0012
46Sc
8.836·10-4
6.606·10-4
58Co
0.0122
0.0133
60Co
0.0051
 The experimental and calculated number of nuclides is quoted 7 days after the end of irradiation

29. EXPERIMENTAL RESULTS AND COMPARISON WITH THE SIMULATIONS: Activation of Copper
500 MeV/A Argon beam
59Fe
22Na

30. EXPERIMENTAL RESULTS AND COMPARISON WITH THE SIMULATIONS: Activation of Copper
500 MeV/A Argon beam
Nuclide
Experiment, Nucl/ion
FLUKA, Nucl/ion
SHIELD-A Nucl/ion
7Be
0.0207
0.0166
0.0266
22Na
0.0039
0.0026
0.0049
48V
0.0157
0.0132
0.0161
51Cr
0.0445
0.0293
0.0206
54Mn
0.0546
0.0470
59Fe
0.0079
0.0051
0.0060
56Co
0.0263
0.0345
0.0023
57Co
0.1006
0.1152
0.0837
65Zn
0.0075
0.0037
0.0115
46Sc
0.0080
0.0057
58Co
0.1225
0.1295
60Co
0.062
0.0515
 The experimental and calculated number of nuclides is quoted 7 days after the end of irradiation

31. 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 MeV/A
To calculate activation at long irradiation times (20 years)

32. Activation studies for accelerator applications
The Limits of Applicability of the Heavy-Ion Beam Loss Criterion
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

33. 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 (2011)
beam energy: 50 MeV/u
Irradiation time: 20 years
simulation code: FLUKA (2008)
beam energy: 500 MeV/u
Irradiation time: 100 days
copper

34. 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.

35. Activation studies for accelerator applications
Study of the least activated materials used in accelerator constructions
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

36. Activation studies for accelerator applications
Total activities of the bulky targets irradiated by
1 GeV proton beam with intensity 5·1010 protons/sec
Code: FLUKA
Irradiation time: 100 days
Irradiation time: 20 years

37. Activation studies for accelerator applications
Maximum dose rate at the distance 40 cm from the surface of the target, irradiated by 1 GeV 5·1010 protons/sec.
Code: FLUKA
Irradiation time: 100 days
Irradiation time: 20 years

38. Conclusion New experimental data on activation of
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.