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RSO committee – 1/3/2012

NBI workshop 2012 9/11/2012. ActiWiz – optimizing your nuclide inventory at proton accelerators with a computer code Helmut Vincke, Chris Theis CERN. RSO committee – 1/3/2012 . Contents. Motivation for this project Introduction to “ActiWiz”

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RSO committee – 1/3/2012

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  1. NBI workshop 20129/11/2012 ActiWiz – optimizing your nuclide inventory at proton accelerators with a computer codeHelmut Vincke, Chris TheisCERN RSO committee – 1/3/2012

  2. Contents • Motivation for this project • Introduction to “ActiWiz” • Illustration of the Catalogue: “Radiological Hazard classification of Materials in CERN’s accelerator environments“

  3. Motivation • Beside other aspects also the radiological consequences of the implementation of a material have to be considered • Level of activation depends on the type of the material Project concerning the radiological classification of materials initiated by Dr. Myers (director of accelerators)

  4. Use-case Using brass instead of iron as shielding @ COMPASS-2? Outside: brass vs. iron  significantly worse Next to target: brass vs. iron  equivalent  very strong dependence on radiation environment  need for “CERN specific” assessment in contrast to experience from nuclear industry

  5. Strategy to obtain radiological material guidelines • Categorization of radiation environment • Development of ActiWiz– code assessing radiation risks, dominant nuclides etc., for arbitrary materials • Radiological hazard catalogue for materials

  6. Radiological assessment of materials Time of material present in accelerator (irradiation time) Energy (machine) Position in accelerator Radiological hazard assessmentfor a given material

  7. Categorization of the radiation environments (energy) FLUKA calculations of typicalhadronic particlespectra (p, n, p+, p-) in CERN’saccelerators LHC SPS Linac 4 + Booster PS 160 MeV (Linac4), 1.4 GeV (Booster), 14 GeV/c (PS), 400 GeV/c (SPS), 7 TeV (LHC)

  8. Radiological assessment of materials 35 spectra * 5 irradiation periods * 13 cooling times FLUKA isotope calculations for 69 single components(63 chemical elements + 6 isotopes) 2400 single Monte Carlo simulations  157.000 nuclide inventories (10 GB of data)  ~628.000 hazard factors ActiWiz – software evaluate radiological hazard for arbitrary materials with a few mouse clicks

  9. ActiWiz – program interface 1.) Select energy / location / irradiation times 2.) Define material composition based on 69 fund. components * Many thanks to R. Froeschlfor providing activation data on Zinc

  10. Output of ActiWiz Nuclide inventory & dominant isotopes Safety relevant quantities (activity, H*(10), radiotoxicity)

  11. First example of an ActiWiz application Comparison of ambient dose equivalent for various materials installed in a cable tray @ LHC, operating for 20 years • Copper– Aluminum – Iron – Steel 316L Check nuclide inventory to understand results

  12. Further analysis with ActiWiz “Why is stainless steel so much worse than pure iron?” Steel 316L Iron Aluminum Copper Main contributor to ambient dose equivalent for a cool down of 10 years: Co-60: 99% Co-60: 99% Fe-55: 86% Sc-44: 9% Na-22: 99% Shielding requirements for equipment: defined by dominating energy of the radio-isotopes: Steel 316L Iron Aluminum Copper Co-60: 1.33 MeV 1.17 MeV Co-60: 1.33 MeV 1.17 MeV Fe-55: X-ray due to e Sc-44: 1.15 MeV Na-22: 1.27 MeV Required thickness of concrete shielding for an attenuation of a factor of 10: Steel 316L Iron Aluminum Copper Co-60: 31 cm Co-60: 31 cm Fe-55: / Sc-44: 30 cm Na-22: 31 cm

  13. Global hazard factors  measure of the rad. hazard of material Nuclide inventory for each element (function of energy, location, irradiation & cooling period) Convolution with * activity-to-dose coeff. (operational hazard factor) * exemption limits (waste hazard factor) Individual hazard factors for each element (function of energy, location, irradiation & cooling period) Combine element hazards to compound hazards (function of energy, location, irradiation & cooling period)

  14. Global hazard factors Dependence on cooling period should be transparent to user Introduction of importance factors (empirical)  contribution of the dose originating from interventions after specific cooling periods to the collective annual dose Integration over cooling periods incl. importance factors (1 hour – 20 years)

  15. Material catalogueproduced with ActiWiz Material catalogue Classification of most common materials by the use of global operational and waste hazard factors Catalogue provides guidelines for selection of materials to be used in CERN’s accelerator environment Authors:Robert Froeschl, Stefano Sgobba, Chris Theis, Francesco La Torre, Helmut Vincke and Nick Walter Acknowledgements: J. Gulley, D. Forkel-Wirth, S. Roesler, M. Silari and M. Magistris

  16. Catalogue for the radiological hazard classification of materials • Catalogue consists of three parts: * Many thanks to Luisa Ulrici (DGS-RP-RW) for elaborating and providing the waste disposal guidelines • Provides radiological guidelines via hazard values cannot replace Monte Carlo studies by a specialist for specific cases outside of the generic irradiation scenarios assumed

  17. Catalogue structure Various energies/momenta 160 MeV (Linac4), 1.4 GeV (Booster), 14 GeV/c (PS), 400 GeV/c (SPS), 7 TeV (LHC), energy independent 7 typical radiation fields in an accelerator Various irradiation times 1 day, 1 week, 1 operational year, 20 years, irradiation time independent Materials not addressed by the catalogue can be assessed with the ActiWiz program

  18. Examples for using the catalogue

  19. Example 1 wt-% of hafnium shall be used as an additive to a copper cable. The cables are placed in cable trays attached to the concrete tunnel wall alongside to SPS magnets. Question arising: Is 1% of hafnium in terms of radiological consequences an acceptable choice? Proton Beam • Summary of situation: • Foreseen location: concrete wall beside SPS magnets • Duration of its stay at this position: SPS life time • Material choice: is 1% of hafnium acceptable? • Parameters to be chosen for retrieving the correct data: • Irradiation energy + location: 400 GeV/c; activation occurring close to the concrete tunnel wall (beam loss in bulky material) • Irradiation time: 20 years • Find hazard factor of hafnium in table listing elements per mass unit Hazard factor comparison: Hazard factor comparison Hazard of elements per mass unit: Operational: 1.36(copper) versus 976 (hafnium); Waste: 2.54(copper) versus 51200 (hafnium) 1 wt-% of hafnium in the alloy causes an 7 times higher operational and a 200 times higher waste related radiological hazard than the remaining 99.0 wt-% of copper.  find another additive for the cable

  20. Web-based catalogue: ActiWebhttp://actiweb.cern.ch Interactive web-based catalogue in collaboration with software developer Fernando Leite Pereira (DGS/RP).

  21. Summary • ActiWiz software  allows to quickly quantify radiological hazard of material implemented into CERN’s accelerator environment. • 69 fundamental components and most common metals and construction materials were processed  first version of a catalogue for CERN accelerators (LINAC4, BOOSTER, PS, SPS & LHC radiation environments) • Catalogue provides radiological guidelines supporting the user in the choice of materials to be implemented in the accelerator environment. • Currently we are in the process of promoting the catalogue & getting feedback from users.

  22. Thank you for your attention christian.theis \at\ cern.ch

  23. FLUKA benchmarks Fundamental quantity: calculation of radionuclide production with FLUKA Very well benchmarked & documented: M.Brugger, F.Cerutti, A.Ferrari Ferrari, E.Lebbos, S.Roesler, P.R.Sala,F.Sommerer, V. Vlachoudis, Calculation of Induced radioactivity with the FLUKA Monte Carlo code, ARIA workshop 08 – PSI, (2008). M. Brugger, A. Ferrari, S. Roesler, L. Ulrici, Validation of the FLUKA Monte Carlo code for predicting induced radioactivity at high-energy accelerators, Proc. 7th Int. Conf. on Accelerator Applications - AccApp05, Nucl. Instrum. Meth. A562, 827-829, (2006). M. Brugger, H. Khater, S. Mayer, A. Prinz, S. Roesler, L. Ulrici, Hz. Vincke, Benchmark studies of induced radioactivity produced in LHC materials, Part 1: specific activities, Proc. ICRS-10 (May 2004); Rad. Prot. Dosim. 116, 6-11, (2005). S. Mallows. T. Otto, Measurements of the induced radioactivity at CTF-3, ARIA workshop 08 – PSI, (2008). G. Dissertori, P. Lecomte, D. Luckey, F. Nessi-Tedaldi, F. Pauss, T. Otto, S. Roesler, C. Urscheler, A study of high-energy proton induced damage in cerium fluoride in comparison with measurements in lead tungstate calorimeter crystals, Nuclear Instruments and Methods in Physics Research A, p. 41-48, Vol. 622, (2010). M. Brugger, D. Forkel-Wirth, S. Roesler, J. Vollaire, Studies of induced radioactivity and residual dose rates around beam absorbers of different materials, Proceedings of HB2010, Morschach, Switzerland, (2010). non exhaustive list J. Vollaire, M. Brugger, D. Forkel-Wirth, S. Roesler, P. Vojtyla, Calculation of water activation for the LHC, Nuclear Instruments and Methods in Physics Research A, Volume 562, Issue 2, p. 976-980, (2006).

  24. Categorization of the radiation environments (position) beam impact area within bulky material (e.g. magnet) surrounding the beam impact area adjacent to bulky material surrounding the beam impact area close to concrete tunnel wall (loss on bulky object) behind massive concrete shielding 10 cm lateral distance to a target close to concrete tunnel wall (loss on target)

  25. Example 1 Concrete tunnel A support for a beam loss monitor foreseen to be installed close to LHC magnets has to be designed. A choice between Aluminium 5083 and Steel 316L in terms of materials to be used to build the support has to be made. Proton Beam 7 TeV protons • Summary of situation: • Foreseen location: beside LHC magnet • Duration of its stay at this position: LHC life time • Material choice: either Aluminium 5083 or Steel 316L • Parameters to be chosen for retrieving the correct data: • Irradiation energy + location: 7 TeV; activation occurring adjacent to bulky material (e.g. magnet) surrounding the beam impact area • Irradiation time: 20 years • Compare hazard factors of compounds per unit volume Hazard factor comparison: Operational: 0.227 (Aluminium 5083) versus 2.36(Steel 316L) Waste:0.179 (Aluminium 5083) versus 7.18 (Steel 316L) Aluminium 5083 provides a 10 times lower operational radiological hazard and a 40 times lower waste related hazard factor than Steel 316L.

  26. Example 3/1 For a test lasting one year a container for an LHC collimator has to be built. It was proposed to build the container either of Steel 316L, Titanium Grade6 or Tungsten. What is in terms of radiological consequences the best choice? Concrete tunnel Proton Beam 7 TeV protons • Summary of situation: • Foreseen location: locations close to a collimator • Duration of its stay at this position: 1 operational year (200 days) • Material choice: Steel 316L, Titanium Grade6 or Tungsten ? Parameters to be chosen for retrieving the correct data: Irradiation location: 7 TeV; activation occurring at 10 cm lateral distance to target Irradiation time: 200 days Compare hazard factors of compounds (Steel 316L, Titanium Grade6) and elements (Tungsten) per unit volume respectively. Hazard factor comparison: Operational hazard: 1.72 (Steel 316L) versus 1.06 (Titanium Grade6) versus 3.44 (Tungsten). Waste hazard: 0.819 (Steel 316L) versus 0.972 (Titanium Grade6) versus 2.75 (Tungsten).

  27. Example 3/2 Hazard factor comparison: Operational hazard: 1.72 (Steel 316L) versus 1.06 (Titanium Grade6) versus 3.44 (Tungsten). Waste hazard: 0.819 (Steel 316L) versus 0.972 (Titanium Grade6) versus 2.75 (Tungsten). • First conclusions • Tungsten can be excluded from the choice • Waste and operational hazard ratio inverted  lower external exposure but higher risk of producing radioactive waste How to proceed in such a case: Titanium Grade6 should be taken as material to build the collimator container.

  28. Example 4/1 For a test lasting one year a container for an LHC collimator has to be built. It was proposed to build the container either of Steel 316L, Titanium TiNbor Tungsten. What is in terms of radiological consequences the best choice? Concrete tunnel Proton Beam 7 TeV protons • Summary of situation: • Foreseen location: locations close to a collimator • Duration of its stay at this position: 1 operational year (200 days) • Material choice: Steel 316L, Titanium TiNbor Tungsten ? Parameters to be chosen for retrieving the correct data: Irradiation location: 7 TeV; activation occurring at 10 cm lateral distance to target Irradiation time: 200 days Compare hazard factors of compounds (Steel 316L, Titanium TiNb) and elements (Tungsten) per unit volume respectively. Hazard factor comparison: Operational hazard: 1.72 (Steel 316L) versus 1.63 (Titanium TiNb) versus 3.44 (Tungsten). Waste hazard: 0.819 (Steel 316L) versus 1.91 (Titanium TiNb) versus 2.75 (Tungsten).

  29. Example 4/2 Hazard factor comparison: Operational hazard: 1.72 (Steel 316L) versus 1.63 (Titanium TiNb) versus 3.44 (Tungsten). Waste hazard: 0.819 (Steel 316L) versus 1.91 (Titanium TiNb) versus 2.75 (Tungsten). • First conclusions • Tungsten can be excluded from the choice • Waste and operational hazard ratio inverted  lower external exposure How to proceed in such a case: Call RP for further advice in that matter.

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