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Background simulations: an update G. Luzón S. Cebrián Paris, 14th February 2006 JRA1/N2.

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Presentation on theme: "Background simulations: an update G. Luzón S. Cebrián Paris, 14th February 2006 JRA1/N2."— Presentation transcript:

1 Background simulations: an update G. Luzón S. Cebrián Paris, 14th February 2006 JRA1/N2 ILIAS Meeting Outline: General issues Progress on simulation work: Neutron production by radioactivity Propagation of low energy neutrons Muon-induced neutrons Cosmogenic activation Library of codes

2  Tasks for second and third years: Implementation of MC codes for the relevant backgrounds/instrumentation Optimisation of the codes Design and implementation of the library Analysis of data collected in the background monitoring campaign with MC codes General issues S. Cebrián, JRA1/N2 ILIAS Meeting, Paris, 14 Feb 2006

3 JRA1-WP2 N3-BSNS JRA2(IDEA)WP3-B1 Development of a standard library of background simulation codes BackgroundSimulation,Neutron-Shield and Muon-Vetos and Muon-Vetos Study on Cosmogenic Induced Activity Induced Activity S. Cebrián, JRA1/N2 ILIAS Meeting, Paris, 14 Feb 2006

4  Meetings during last year: Informal meeting at Prague, 7 Feb 2005, at 2nd General ILIAS Meeting Meeting at Valencia, 12 Apr 2005, at N3-N6 Meeting Meeting at Zaragoza, 15 Sep 2005, after TAUP2005 Conference Minutes and transparencies are available at N3 and JRA1 websites:  Next meeting: Informal meeting at Gran Sasso, at 3rd General ILIAS Meeting, 27 Feb – 3 Mar S. Cebrián, JRA1/N2 ILIAS Meeting, Paris, 14 Feb 2006

5  Presentations at conferences during last year: Workshop on Exploring the Physics Frontier at the Deep Underground Laboratories (INT2005 –Seattle) V.A. Kudryavtsev et al. Background Studies for Underground Particle Physics Experiments TAUP 2005 Workshop (Proceedings published in IoP). J. Puimedón et al. Neutrons from rock radioactivity in the new Canfranc underground Laboratory J. Ruz et al. Background shielding for the TPC of the CAST experiment R. Lemrani et al. Update of neutron studies in EDELWEISS S. Cebrián et al. Cosmogenic Cosmogenic activation activation in in germanium Double Beta Decay experiments V.A. Kudryavtsev et al. Background studies for underground particle astrophysics experiments  New papers: “Low energy neutron propagation in MCNPX and GEANT4”, R. Lemrani et al., to be published in NIMA [arXiv:hep-ex/ ] S. Cebrián, JRA1/N2 ILIAS Meeting, Paris, 14 Feb 2006

6 Neutron production from U/Th contamination  Useful codes: SOURCES gives neutron flux and energy spectrum: modified to include alphas with E>6.5 MeV Other codes used to estimate neutron yields do not provide neutron energy spectrum ALPHN html/ccc-0612.html html/ccc-0612.html J. Puimedón et al, TAUP2005 S. Cebrián, JRA1/N2 ILIAS Meeting, Paris, 14 Feb 2006 Progress of work Canfranc

7 Cross-sections added by VK in August 2003: 9- F-19 Vukolov et al.Vopr.At.Nauk.Ob.,4,31(1983)+extrap., vk 13/10/03 11-Na-23 E.B.Norman et al. Nucl. Phys. A390, 561 (1982), vk 19/08/ Si-28 C.W.Cheng et al. Can. J. Phys. 58, 697 (1980), vk, 19/08/03 17-Cl-35 A.J.Howard et al. ApJ, 188, 131 (1974), added by vk, 19/08/03 24-Cr-50 A.J.Morton et al. Nucl. Phys. A573, 276 (1994), vk 9/12/03 25-Mn-55 S.Sudar, S.M.Qaim. Phys. Rev. C, 50, 2408 (1994), vk 9/12/03 26-Fe-54 S.G.Tims et al. Nucl. Phys. A524, 479 (1991), vk 19/08/03 27-Co-59 R.H.Stelson et al. Phys. Rev. B, 133, 911 (1964), vk 19/08/03 28-Ni-60 R.H.Stelson et al. Phys. Re Rev. B, 133, 911 (1964), vk 19/08/03 28-Ni-60 R.H.Stelson et al. Phys. Rev. B, 133, 911 (1964), vk 9/12/03 28-Ni-62 J.L.Zyskind et al. Nucl. Phys. A331, 180 (1979), vk 9/12/03 28-Ni-64 J.L.Zyskind et al. Nucl. Phys. A331, 180 (1979), vk 9/12/03 29-Cu-63 R.H.Stelson et al. Phys. Rev. B, 133, 911 (1964), vk 19/08/03 29-Cu-65 R.H.Stelson et al. Phys. Rev. B, 133, 911 (1964), vk 19/08/03 7- N-14 W. Gruhle et al. Nucl. Phys. A 186 (1972) 257, vk 11/03/04 Updated library of new SOURCES cross sections at code repository S. Cebrián, JRA1/N2 ILIAS Meeting, Paris, 14 Feb 2006  ( ,n) cross sections updated and added in SOURCES Using recent experimental results: Na Making calculations if there is no measurement: 35 Cl, Fe, Cu, Ca, Ti GNASH-FKK (http://www.nea.fr/abs/html/psr-0125.html)http://www.nea.fr/abs/html/psr-0125.html EMPIRE (http://www.nndc.bnl.gov/empire219) Ca, Mghttp://www.nndc.bnl.gov/empire219 Cross-sections added by Rachid Lemrani - July 2005 (calculations with empire-2.19): 12-Mg-24 - new 12-Mg-25 - update 12-Mg-26 - update 14-Si-29 - update 14-Si-30 - update 15- P-31 - update 19- K-39 - new 19- K-40 - new 19- K-41 - new 20-Ca-42 - C.W.Cheng et al Jour. of Physics, Part G (Nucl.and Part.Phys.) 5(1979) Ca-43 - new 20-Ca-44 - new 20-Ca-46 - new 20-Ca-48 - new 22-Ti-46 - new 22-Ti-47 - new 22-Ti-48 - new 22-Ti-49 - new 22-Ti-50 - new

8 R. Lemrani et al., to be published in NIMA [arXiv:hep-ex/ ]. Similar production rates found for Modane and Boulby rock (1.3 n/g/y and 1.5 n/g/y) despite higher radioactivity levels in Modane: lower ( ,n) reaction thresholds in NaCl S. Cebrián, JRA1/N2 ILIAS Meeting, Paris, 14 Feb 2006

9 Propagation of low energy neutrons  Neutron propagation of low energy neutrons through rock, lead and hydrocarbon moderator has been compared for GEANT4, GEANT3 and MCNPX using the same neutron inputs and geometry benchmark R. Lemrani et al., to be published in NIMA [arXiv:hep-ex/ ]. S. Cebrián, JRA1/N2 ILIAS Meeting, Paris, 14 Feb 2006

10  Propagation through rock: neutron spectra from SOURCES at rock boundary NaClModane Maximum differences between codes ~15-20% GEANT4 inelastic cross sections on Cl corrected Smaller neutron flux in Modane due to water content in rock Flux enhancement (50%, 30%) due to backscattering of neutrons when considering real caverns R. Lemrani et al., to be published in NIMA [arXiv:hep-ex/ ]. S. Cebrián, JRA1/N2 ILIAS Meeting, Paris, 14 Feb 2006

11  Propagation through shieldings: neutron energy spectra after various shielding thicknesses (NaCl rock) 0 to 50 g/cm 2 CH 2 30 cm Pb+ 0 to 40 g/cm 2 CH 2 Reasonable agreement between GEANT4- MCNPX: maximum differences after 50 g/cm 2 of CH 2, with MCNPX flux ~50% higher than in GEANT4 R. Lemrani et al., to be published in NIMA [arXiv:hep-ex/ ]. S. Cebrián, JRA1/N2 ILIAS Meeting, Paris, 14 Feb 2006

12 Neutron flux as a function of CH 2 thickness (NaCl rock) ~55 g/cm 2 should suppress low energy neutron flux from environment by more than 6 orders of magnitude Summarizing… Good agreement between GEANT4 and MCNPX for propagation of low energy neutrons: after correction of bug in inelastic cross sections for Cl in GEANT4 library main conclusions do not depend on code R. Lemrani et al., to be published in NIMA [arXiv:hep-ex/ ]. S. Cebrián, JRA1/N2 ILIAS Meeting, Paris, 14 Feb 2006

13 Neutron production + Propagation through rock and scintillator: Neutron production + Propagation through rock and scintillator: comparison of simulations and measurements SOURCES for neutron production and MCNPX for propagation Measurement at Modane R. Lemrani et al., TAUP2005 Shape well described but differences of a factor ~2 in normalization SOURCES produces softer neutron energy spectrum than other calculations: transitions to excited states in SOURCES (probabilities based on calculations) may produce lower energy transfers to neutrons S. Cebrián, JRA1/N2 ILIAS Meeting, Paris, 14 Feb 2006

14 Production of neutrons by muons  Comparison between GEANT4 and FLUKA was made: yields, energy spectrum, lateral distribution, dependance on material See H. M. Araujo et al., Nucl.Instrum.Meth. A545 (2005) ; M. Bauer et al., Proc. IDM2004, p. 494; M. Horn, Valencia meeting April 2005; M. Bauer, Valencia meeting April Agreement between them within a factor ~2 (even better for some materials and energies), although FLUKA prediction is always higher Bertini and Binary GEANT4 models agree within ~20%  Pending problem: some experimental results disagree with GEANT4/FLUKA predictions, being the measured neutron production significantly higher than in calculations Problem forwarded to GEANT4 collaboration Data from experiments (LVD, SNO, KamLAND, Borexino CTF) would be welcome to check neutron production by muons Dedicated experiment to measure neutron flux induced by muons in lead? S. Cebrián, JRA1/N2 ILIAS Meeting, Paris, 14 Feb 2006

15  Other non-ILIAS results: 1.FLUKA validation: calculation of production of 12 B and 16 N in oil- and water-based detectors by (n,p) reactions produced by muon-induced neutrons found to be good agreement with measurements from KamLAND C. Galbiati, J. F. Beacom, Phys. Rev. C 72 (2005) S. Cebrián, JRA1/N2 ILIAS Meeting, Paris, 14 Feb FLUKA correction?: neutron multiplicity modified in muon-induced cascades, increasing neutron yields, despite energy imbalance D. M. Mei and A. Hime, [arXiv:astro-ph/ ] Procedures and conclusions in this work very controversial: see postings at the MonteCarlo mailing list December/ html

16 2.Analysis of computational codes for n/p activation: Monte Carlo or semiempirical codes Detailed report at Cosmogenic activation of materials 1.Collection of available data on production cross sections: Detailed report at Searching for p/n activation cross-sections on targets of interest (Ge, Te) on the literature and from nuclear data libraries Collecting information on: Target materials and product isotopes covered Projectiles allowed Range of applicable energies Physical models included and/or experimental data sets considered for cross-sections Checks with experimental data “Technical” information: language, code source, support,... S. Cebrián, JRA1/N2 ILIAS Meeting, Paris, 14 Feb 2006

17 Activation targets: Te, Ge, Cu Similar methodology: i.To try to find the most reliable evaluation of the excitation functions by nucleons of relevant long-lived products, taking into account all available experimental data and calculations ii.To evaluate production rates at sea level considering a particular cosmic ray spectrum iii.To quantify deviations between experimental data and calculations (for both cross sections and production rates, if possible) 3.Study of particular activation problems, comparing calculations with experimental data when possible S. Cebrián, JRA1/N2 ILIAS Meeting, Paris, 14 Feb 2006 To identify the most reliable codes and the weak points of computations for treating our problems

18 Excitation function by nucleons of 68 Ge in natural Ge S. Cebrián, JRA1/N2 ILIAS Meeting, Paris, 14 Feb 2006 S. Cebrián et al, TAUP2005

19 Production rates (kg -1 d -1 ) in Cu estimated and compared with other results COSMOF&M '04 Heusser'05 (at LNGS) 972,319,9±2,6 30,5 155±35 131,5142,6±7,8 25,72675,5181±16 134,252,218,6±1,8 39±10 4,6±1,6 at LNGS 48,1 185,5 335,1 204,5 68,3 13,6 8,0 LE ME HE 56 Co2,6+18,0+2,322,9 57 Co29,7+55,8+2,888,3 58 Co90,4+65,7+3,5159,6 60 Co81,8+14,2+1,497,4 54 Mn3,6+25,9+332,5 59 Fe4,3+1,9+0,36,5 46 Sc0+2,5+1,33,8 x 2.1 Modified COSMO: L. Baudis, R. W. Schnee, NUSL White Paper, 2002 J. A. Formaggio, C. J. Martoff, Annu. Rev. Nucl. Part. Sci. 54 (2004) 361 G. Heusser, LRT2004, Sudbury, December G. Heusser, M. Laubenstein, H. Neder, to appear in “Radionuclides in the Aquatic environment” (Ed. Povinec) Elsevier, 2005 S. Cebrián, JRA1/N2 ILIAS Meeting, Paris, 14 Feb 2006

20  Global analysis of all the activation studies is underway to conclude about improvements in the considered codes Report (second year deliverable in JRA2) will be available soon Some preliminary conclusions: In GEANT4, at medium-high energies, the model which gives clearly the best results is Bertini cascade Concerning semiempirical codes, YIELDX based on the most updated version of the formulas, should be used Deviations factors F between available measured production cross sections and different calculations have been evaluated: range from ~1.5 to ~2.5 S. Cebrián, JRA1/N2 ILIAS Meeting, Paris, 14 Feb 2006

21 Some preliminary conclusions: Since: 1.production cross sections by neutrons and protons at low energies (<200 MeV) are significantly different in most cases 2.proton flux at low energy is negligible at sea level the following way of evaluating the excitation functions is proposed:  at low enegy, cross sections specifically calculated for neutrons (MENDL library, HMS-ALICE)  at medium-high energies, semiempirical YIELDX calculations S. Cebrián, JRA1/N2 ILIAS Meeting, Paris, 14 Feb 2006 Comparisons of estimated production rates using this recipe with measurements in Ge and Cu are good for some products, deviations up to factor 3 in many cases Further refinements in cross sections at medium energies could be necessary

22 Web-site: (most of the information also available at N3 website) FTP repository: under password, ask account at  General information about codes, links to code web-sites, access to some codes.  Modifications to codes: Updated version of SOURCES with new cross sections Interface between GEANT4 and SOURCES4A Interface between MUSUN and GEANT4  Examples  Repositories: S. Cebrián, JRA1/N2 ILIAS Meeting, Paris, 14 Feb 2006 Library of codes

23  GEANT4 Contact has been established between the GEANT4 Collaboration and the undeground physics community in ILIAS – Main requirements coming from the underground physics community forwarded to GEANT4 – Good will to fulfill them, consistently with the available manpower Production of  -induced neutrons in high-Z materials Propagation of Low Energy neutrons Inelastic scattering of neutrons Interactions of high-energy muons Isotope production S. Cebrián, JRA1/N2 ILIAS Meeting, Paris, 14 Feb 2006 – To go further than just the user feedback to solve bugs and small problems … which on the other hand is very important! Problem with inelastic cross sections for neutrons on Cl solved Patch available by Luciano Pandola for bug for simulation of de- excitation gammas in inelastic process Ge(n,n’)Ge* Bug found on inelastic cross sections of 62 Ni for (n,p) in 62 Cu solved in new G4NDL3.8 !

24 S. Cebrián, JRA1/N2 ILIAS Meeting, Paris, 14 Feb 2006 GEANT4 validation efforts - Geant4 ElectroMagnetic physics models (“standard” and “low energy”) are being validated in a systematic and quantitative way

25 S. Cebrián, JRA1/N2 ILIAS Meeting, Paris, 14 Feb 2006

26 GEANT4 validation efforts - Geant4 ElectroMagnetic physics models (“standard” and “low energy”) are being validated in a systematic and quantitative way - A similar systematic effort has not been performed yet for hadronic physics, but it is ongoing for example for isotope production: reliability and limits of Bertini and Binary cascade models being clarified S. Cebrián, JRA1/N2 ILIAS Meeting, Paris, 14 Feb 2006

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30 Summary and Outlook Very active collaboration in background simulations and cross-checks between ILIAS participants in different fields of interest: This common work is giving rise to code improvements: interfaces between complementary codes, updates of cross sections, communication with GEANT4 Collaboration Further work is pending for validation of codes against background measurements in underground labs S. Cebrián, JRA1/N2 ILIAS Meeting, Paris, 14 Feb 2006 low energy neutron propagation: GEANT4 and MCNPX proved to be compatible muon-induced neutrons: GEANT4 and FLUKA compatible within ~2, but some disagreements with data still to be clarified cosmogenic activation: conclusions on analyzed codes to be delivered neutron production from radioactivity: upgraded SOURCES seems to be the best option

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35 27 Al 42 Ca 48 Ti 23 Na 18 O EMPIRE-II Control Plots: accuracy ~20% R. Lemnrani, ILIAS Common Meeting on MC simulations, Zaragoza, 15 Sept 2005 S. Cebrián, JRA1/N2 ILIAS Meeting, Paris, 14 Feb 2006


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