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Cosmogenic induced activity

Cosmogenic induced activity. IDEA (Integrated Double-beta decay European Activities). Task coordinators: Maura Pavan, Susana Cebrián. Susana Cebrián scebrian@unizar.es University of Zaragoza (Spain). Zaragoza, 7 th -8 th November 2005. Implementation plan. Outline of the talk

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Cosmogenic induced activity

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  1. Cosmogenic induced activity IDEA (Integrated Double-beta decay European Activities) Task coordinators: Maura Pavan, Susana Cebrián Susana Cebrián scebrian@unizar.es University of Zaragoza (Spain) Zaragoza, 7th-8th November 2005

  2. Implementation plan • Outline of the talk • Simulation-based work • Irradiations tests • Outlook and summary S. Cebrián, Cosmogenic Induced Activity IDEA meeting, Zaragoza, November 2005

  3. General issues • MEETINGS: • Common Meeting on Monte Carlo studies (JRA1 / N3 / JRA2) held in Zaragoza, on 15th September 2005 • (minutes and transparencies available at http://www.unizar.es/ilias/JRA1/05.htm) • Interest on copper activation by JRA1 • Interface with GEANT4 Collaboration CONFERENCES: Talk on “Cosmogenic activation in germanium Double Beta Decay Experiments” by s. Cebrián et al at TAUP2005 Conference, Zaragoza (Spain), September 2005 (available at http://ezpc00.unizar.es/taup2005/talks.htm) S. Cebrián, Cosmogenic Induced Activity IDEA meeting, Zaragoza, November 2005

  4. Simulation-based work GOAL: Identification of the most reliable codes and of the weak points of computations for treating our problems in order to improve them Studies for relevant activation problems in DBD using different codes and comparing with data when possible: Te, Ge In the first year … • Activation study for Cu • Improvements in GEANT4 In the last six months … S. Cebrián, Cosmogenic Induced Activity IDEA meeting, Zaragoza, November 2005

  5. Calculations based on semiempirical Silberberg & Tsao formulas: YIELDX p >100 MeV • Monte Carlo calculations: MENDL-2 (using versions of ALICE) p <200 MeV, n <100 MeV • Activation study for Cu • Why copper? • Common material in set-ups of rare event experiments • A large amount of experimental data for production cross sections! • Similar work to that done for Te and Ge: • Comparison of excitation functions to find the most reliable evaluation for relevant products using: • Measurements with beams: • protons: lots of data at EXFOR database • neutrons !!!:E. J. Kim et al, J. Nucl. Sci. Tech. 36 (1999) 29-40 • Calculation of production rates of induced nuclei S. Cebrián, Cosmogenic Induced Activity IDEA meeting, Zaragoza, November 2005

  6. Activation study for Cu: excitation functions YIELDX works very well at E>200-300 MeV but overestimates below MENDL for n is above results from Kim’99 MENDL for p gives good agreement with measurements at low energy 57Co production in nat Cu S. Cebrián, Cosmogenic Induced Activity IDEA meeting, Zaragoza, November 2005

  7. In MENDL predictionsproduction by neutrons is higher and with lower threshold than by protons MENDL results for n seem to be below Kim’99 data Much worse agreement between measurements and calculations 60Co production in nat Cu S. Cebrián, Cosmogenic Induced Activity IDEA meeting, Zaragoza, November 2005

  8. Deviation factors At low energies there can be significant differences in F between products Our selection for the excitation functions in Cu: at low energies (<100 MeV): MENDL results for neutrons, normalized to experimental data when possible at higher energies: experimental data for protons combined with YIELDX very important to reproduce experimental production rates! S. Cebrián, Cosmogenic Induced Activity IDEA meeting, Zaragoza, November 2005

  9. E>20 MeV: • 4.5 10-3 n/cm2/s • Activation study for Cu: production rates • Cosmic neutron spectrum: parameterization based on measurements • J. F. Ziegler, IBMJournal of Research and Development 42 (1998) 1. S. Cebrián, Cosmogenic Induced Activity IDEA meeting, Zaragoza, November 2005

  10. Production rates (kg-1d-1) Contributions up to 100 MeV (LE), 100-1000 MeV (ME) and above 1 GeV (HE) Calculations based on modified COSMO L. Baudis, R. W. Schnee, NUSL White Paper, 2002 Deduced from experimental data (Fisher et al., PLB 218 (1989) 257) J. A. Formaggio, C. J. Martoff, Annu. Rev. Nucl. Part. Sci. 54 (2004) 361 Measurements following a long exposure at LNGS surface G. Heusser, LRT2004, Sudbury, December 2004. G. Heusser, M. Laubenstein, H. Neder, to appear in “Radionuclides in the Aquatic environment” (Ed. Povinec) Elsevier, 2005 Thanks are due to G. Heusser for informing us on their measurements S. Cebrián, Cosmogenic Induced Activity IDEA meeting, Zaragoza, November 2005

  11. x 2.1 • Production rates (kg-1d-1) 58Co production not understood: measured production cross sections for n and for p higher than for 60Co but this is not true for production rates Differences are understandable if just semiempirical cross sections are considered: for 60Co low energy neutron contribution is missed Discrepancies for other products could be (qualitatively) understood mainly due to the selected excitation functions at medium energies: based on p measurements not continuous with n measurements at lower energies Extremely high rates justified by Chernobyl S. Cebrián, Cosmogenic Induced Activity IDEA meeting, Zaragoza, November 2005

  12. Summary of the activation study in Cu • Deviations between measured production cross sections (for p and even for n) and calculations (using YIELDX and MENDL library) have been evaluated for different products. • Semiempirical calculations reproduce quite well cross sections above ~300 MeV, but they cannot be the only source of information to derive reliable production rates • For the production of some nuclei, the use at low energiesof the excitation function specific for neutrons is essential • Apart from 58Co, some discrepancies between our calculated production rates and the direct measurements at Gran Sasso could be understandable and could be reduced if some information of cross sections for neutrons at medium energies (hundreds of MeV) was available. S. Cebrián, Cosmogenic Induced Activity IDEA meeting, Zaragoza, November 2005

  13. Improvements in GEANT4 • Contact has been established between ILIAS MC working groups and the GEANT4 Collaboration to pass on to them underground physics interests on simulations Ongoing validation effort regarding isotope production within the GEANT4 Collaboration S. Cebrián, Cosmogenic Induced Activity IDEA meeting, Zaragoza, November 2005

  14. Calculationsfor Ge using GEANT4 • Irradiation experiment Aleksandrov’91 simulated obtaining production s • with 660 MeV protons • on natural Ge • using different GEANT4 models (Bertini and Binary cascades) and semiempirical YIELDX # Z A 1 4 7 2 11 24 3 19 42 4 19 43 5 21 43 6 21 44 7 21 44 8 21 46 9 21 47 10 21 48 11 23 48 12 24 51 13 25 52 14 25 54 15 25 56 16 26 59 17 27 55 18 27 56 19 27 57 20 27 58 21 27 60 22 27 61 23 28 57 24 29 61 25 29 67 26 30 62 27 30 65 28 30 69 29 30 71 30 30 72 31 31 66 32 31 67 33 31 68 34 31 72 35 31 73 36 32 66 37 32 68 38 32 69 39 32 75 40 33 71 41 33 72 42 33 74 • J. P. Wellisch, nucl-th/0306006, nucl-th/0306008, nucl-th/0306016 S. Cebrián, Cosmogenic Induced Activity IDEA meeting, Zaragoza, November 2005

  15. Global deviation factor from Aleksandrov’91 results • YIELDX gives better agreement than GEANT4 • Bertini model seems to work better than Binary cascade, as found in Te simulations (Heidelberg presentation)and in the GEANT4 Collaboration validations S. Cebrián, Cosmogenic Induced Activity IDEA meeting, Zaragoza, November 2005

  16. Irradiation tests GOAL: to measure the production cross-sections and/or rates of production with n/p beams on the targets of interest Essential to validate calculations with codes Some crucial questions regarding activation in Te, Ge were identified giving rise to possible irradiation tests In the first year … • Experiment at CERN on TeO2 • Proposals for Ge experiment In the last six months … S. Cebrián, Cosmogenic Induced Activity IDEA meeting, Zaragoza, November 2005

  17. Experiment at CERN on TeO2 • Initial problem COSMO predicted a high production cross section of 60Co in Te between 1-3 GeV Disagreement with YIELDX calculations and measurement for 1.85 GeV p at Berkeley by Bardayan’97 60Co production in nat Te Irradiation experiment proposed and already carried out at CERN with 1.4 GeV p S. Cebrián, Cosmogenic Induced Activity IDEA meeting, Zaragoza, November 2005

  18. preliminary! • Features of experiment • Two long gamma countings (several days) performed • Results • Activation yields of many different products identified (Rb, Rh, Sn, In, Sb isotopes) including 60Co • Complete evaluation of production cross sections and comparison with YIELDX calculations (together with results of a previous irradiation at 24 GeV also at CERN) underway • 60Co production cross sections (mb): Sensitivity of CUORE to 130Te DBD is not jeopardized by cosmogenic 60Co in crystals and YIELDX calculations in good agreement with measurements S. Cebrián, Cosmogenic Induced Activity IDEA meeting, Zaragoza, November 2005

  19. Proposals for Ge irradiation experiment • An irradiation experiment with germanium as target is being planned • target sample: natural or enriched? • projectile: n or p? • energy beam: mono-energetic? • facility and time: for irradiation and for gamma-counting • to shed light on 68Ge activation (there are important discrepancies between calculated and experimental production rates) low energy neutron beams would be highlyrecommended • the use of both natural and enriched targets would be advisable • Several possible experiments have been analyzed: • facilities, beam features, cost • actvivity yields and possible counting S. Cebrián, Cosmogenic Induced Activity IDEA meeting, Zaragoza, November 2005

  20. IRRADIATION S. Cebrián, Cosmogenic Induced Activity IDEA meeting, Zaragoza, November 2005

  21. Activity ratios: 10000 : 50 : 1 : 0.001 Only X-ray counting possible Very massive samples required Sample=detector approach: + higher efficiency for measuring the yield, allowing lower neutron fluxes - irradiation of components other than Ge crystal - not easy continuity for enriched samples S. Cebrián, Cosmogenic Induced Activity IDEA meeting, Zaragoza, November 2005

  22. Outlook S. Cebrián, Cosmogenic Induced Activity IDEA meeting, Zaragoza, November 2005

  23. Summary • A study of activation in Cu using available experimental data and different calculations is underway, allowing a better validation of codes. • GEANT4 has started a validation effort for isotope production • An irradiation test on Te has been carried out at CERN and preliminary results are available for 60Co. • Different options for an irradiation experiment with Ge have been studied. S. Cebrián, Cosmogenic Induced Activity IDEA meeting, Zaragoza, November 2005

  24. 68Ge production in nat Ge S. Cebrián, Cosmogenic Induced Activity IDEA meeting, Zaragoza, November 2005

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