1 Activation by Medium Energy Beams V. Chetvertkova, E. Mustafin, I. Strasik (GSI, B eschleunigerphysik), L. Latysheva, N. Sobolevskiy (INR RAS), U. Ratzinger (IAP, Goethe-University)

2 Content 1. Introduction 2. Method 3. Simulations 4. Experiment 5. Comparison of simulations with experiment 6. Discussion 7. Summary

3 1. Introduction: Why do we study activation Applications Calculation of tolerable beam losses Estimation of activity level in case of accidental losses Verification of Monte Carlo codes Isotope production modules Electronic stopping modules

4 2. Method:Induced activity Scheme of the experiment Irradiation: Energies up to 2 GeV/u Measurements: HPGe detector, 20% efficiency, Energy range: 30keV – 2 MeV Energy resolution at 122 keV – 0.9 keV; at 1.33 MeV – 1.9 keV

5 2. Method: γ- spectroscopy γ-spectrum Decrease of the activity

6 2. Method:Types of targets Foils Cylinders assembled from discs Truncated cylinders

7 Foil target isotope distribution time-evolution of photon fluence Advantages Absorption of gammas in the target could be neglected Decrease of projectile energy could be neglected Activation by secondary particles could be neglected No projectile fragments 2. Method:Types of targets

8 Truncated cylinder (covered with organic material) Fast estimation of the stopping range of projectiles (~ 0.5 mm precision) Aluminum irradiated with 400 MeV/u Argon beam Aluminum irradiated with Uranium beam 500 MeV/u 950 MeV/u

9 2. Method:Types of targets Cylinder assembled from discs Isotope distribution Depth profiles of activation Measurements of stopping range (for certain isotopes) 1.Simulations of the interaction of certain ions with chosen target =>Finding the stopping range 2.Assembling the target 3.Irradiation 4.Measurements of the residual activity => experimental study of the stopping range Activation foils

10 3. Simulations Which Monte Carlo codes we use? FLUKA MARS SHIELD-A (with ATIMA stopping module) What do we simulate? Stopping range Dose rate Photon fluence rate Activation

11 4. Experiment:Irradiations done Stainless steel Copper Aluminum Copper Aluminum Tin Carbon U beam E = 500MeV/u, 1 GeV/u E = 5.6 MeV/u, 500 MeV/u, 950 MeV/u Ar beam E = 500 MeV/u, 1 GeV/u E = 430 MeV/u, 500 MeV/u E = 500 MeV/u U beam

12 4. Experiment:Irradiations planned Aluminum material for monitoring beam intensity Copper Aluminum Stainless steel Isotope distribution (Relative yields) Depth profiling of activation Verification of Monte Carlo codes Ar beam C, N, Xe, Ta beam

13 4. Experiment: Irradiation of Al with Ar ions Foil (0.1 mm) target irradiated with 430 MeV/u Ar Activation of the target Experimen t FLUKA Be-7, nuclei/ion/mm 2.08e-4 ± 7.55e e-4 ± 1.46e-5 Na-22, nuclei/ion/mm 1.64e-4 ± 5.91e e-4 ± 2.84e-5 Na-24, nuclei/ion/mm 1.12e-4 ± 9.39e e-4 ± 1.13e-5 Time evolution of photon fluence and activity An article for NIM B is being prepared Idea: Studying the short living part

14 Generation of radioactive nuclei in foil target SHIELD-A simulations Normalized on σ Be7 (target like nuclei) Y Be7 = 1 Y Na22 = Y Na24 = Experiment: Irradiation of Al with Ar ions

15 4. Experiment: Irradiation of Al with Ar ions IsotopeExperiment*SHIELD-A 7 Be1 ± Na0.78 ± Na0.62 ± Relative yields (*-Preliminary results) Reaction 40 Ar(430MeV/A) + Al Energy spectrum of product nuclei simulated with SHIELD-A Energy dependence of range Simulated with ATIMA

16 4. Experiment: Irradiation of Al with Ar ions Thick (11.062cm) target irradiated with 500 MeV/u Ar Depth profiles of 7 Be Depth profiles of 22 Na An article for NIM B is being prepared

17 4. Experiment: Irradiation of Al with U ions Thickness dependence of number of 237 U The idea: 237 U has approximately the same range as 238 U Observing production of 237 U we could find the range of 238 U An article is planned to be prepared (Al irradiated with 500 MeV/u 238 U +75 ) (Al irradiated with 950 MeV/u 238 U +75 )

18 4. Experiment: Irradiation of Al with U ions Irradiation of 0.1 mm aluminum foils by uranium beams of different energies

19 5. Comparison of Simulations with Experiment Verification of FLUKA, MARS and SHIELD 1. Activation of the target [Bq/(mm/ion)] 2. Energy deposition function [GeV/mm] + range [mm] A.A. Golubev, E. Mustafin et al, Measurement of the energy deposition profile for 238 U ions with specific energy 500 and 950 MeV/u in stainless steel and copper targets, Nuclear Instruments and Methods in Physics Research B 263 (2007) 339–344

20 5. Comparison of Simulations with Experiment:Range 1. Energy deposition function [GeV/mm] + range [mm] Target material equivalent thickness Stainless steel: 262 µm Copper: 235 µm Range, mm E = 500 MeV/uE = 950 MeV/u St. steelCuSt. steelCu Measurement 6.0 ± ± ± ± 0.4 ATIMA PHITS SHIELD SRIM FLUKA

21 5. Comparison of Simulations with Experiment:Range 500 MeV/u U beam Stainless steel target Copper target 950 MeV/u U beam

22 5. Comparison of Simulations with Experiment:Range Measured and calculated penetration depths of 238 U ions in Cu and stainless steel targets Range, mm E = 500 MeV/uE = 950 MeV/u St. steelCuSt. steelCu Measurement 5.7 ± ± ± ± 0.4 SHIELD-A MARS FLUKA

23 6. Discussion:Ideas & Plans Relative yield dependence on energy of the projectile (Ar beam Al target, simulations by FLUKA) Relative yield dependence on the mass number of the projectile (Al foil target, simulations by FLUKA)

24 7. Summary Studies of FAIR relevant materials Production and accumulation of isotopes set the limits for access to the machine Verification of Monte Carlo codes Electron stopping modules Isotope production module