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1. The measurement of the Pb-206(n,gamma) cross section and stellar implications

Author

Universitat Politècnica de Catalunya. Departament de Física i Enginyeria Nuclear, Universitat Politècnica de Catalunya. GREENER - Grup de recerca d'estudis energètics i de les radiacions, Vaz, P., Ventura, A., Lozano, M., Villamarin, D., Vincente, M.C., Marganiec, J., Tassan-Got, L., Lukic, S., Tavora, L., Massimi, C., Terlizzi, R., Pavlik, A., Patronis, N., Perrot, L., Pavlopoulos, P., Cennini, P., Carrapico, C., Papadopoulos, C., Capote, R., Paradela, C., Cano-Ott, Daniel, Calviño Tavares, Francisco, Pancin, J., Calviani, M., Papachristodoulou, C., Oberhummer, H., Bisterzo, S., O'Brien, S., Berthoumieux, E., Becvar, F., Baumann, P., Chepel, V., Neves, F., Mosconi, M., Marrone, S., Milazzo, P.M., Mengoni, A., Mastinu, P., Vannini, G., Vlachoudis, V., Vlastou, R., Badurek, G., Kossionides, E., Domingo-Pardo, C., Krticka, M., Abbondanno, U., Lamboudis, C., Aerts, G., Leeb, H., Álvarez-Velarde, F., Lindote, A., Andriamonje, S., Lopes, I., Andrzejewski, J., Assimakopoulos, P., Audouin, L., Koehler, P., Wisshak, K., Kerveno, M., Karamanis, D., Walter, S., Karadimos, D., Wiescher, M., Herrera-Martinez, A., Voss, F., Igashira, M., Haight, R., Heil, M., Kaeppeler, F., Jericha, E., Kadi, Y., Guerrero, C., Haas, B., Gunsing, F., Gallino, R., Goncalves, I., Gonzalez-Romero, E., Gramegna, F., Ferrari, A., Ferreira-Marques, R., Fujii, K, Furman, W., Ferrant, L., Embid-Segura, M., Eleftheriadis, C., Dridi, W., Duran, I., David, S., Dillmann, I., Couture, A., Cox, J., Colonna, N., Cortés Rossell, Guillem Pere, Tain, J.L., Tagliente, G., Rullhusen, P., Salgado, J., Rubbia, C., Rudolf, G., Savvidis, I., Stephan, C., Santos, C., Sarchiapone, L., Reifarth, R., Rauscher, T., Quesada, J., Pretel Sánchez, Carme, Plompen, A., Alvarez, A., Plukis, A., Pigni, M.T., Plag, R., Poch Parés, Agustí, Universitat Politècnica de Catalunya. Departament de Física i Enginyeria Nuclear, Universitat Politècnica de Catalunya. GREENER - Grup de recerca d'estudis energètics i de les radiacions, Vaz, P., Ventura, A., Lozano, M., Villamarin, D., Vincente, M.C., Marganiec, J., Tassan-Got, L., Lukic, S., Tavora, L., Massimi, C., Terlizzi, R., Pavlik, A., Patronis, N., Perrot, L., Pavlopoulos, P., Cennini, P., Carrapico, C., Papadopoulos, C., Capote, R., Paradela, C., Cano-Ott, Daniel, Calviño Tavares, Francisco, Pancin, J., Calviani, M., Papachristodoulou, C., Oberhummer, H., Bisterzo, S., O'Brien, S., Berthoumieux, E., Becvar, F., Baumann, P., Chepel, V., Neves, F., Mosconi, M., Marrone, S., Milazzo, P.M., Mengoni, A., Mastinu, P., Vannini, G., Vlachoudis, V., Vlastou, R., Badurek, G., Kossionides, E., Domingo-Pardo, C., Krticka, M., Abbondanno, U., Lamboudis, C., Aerts, G., Leeb, H., Álvarez-Velarde, F., Lindote, A., Andriamonje, S., Lopes, I., Andrzejewski, J., Assimakopoulos, P., Audouin, L., Koehler, P., Wisshak, K., Kerveno, M., Karamanis, D., Walter, S., Karadimos, D., Wiescher, M., Herrera-Martinez, A., Voss, F., Igashira, M., Haight, R., Heil, M., Kaeppeler, F., Jericha, E., Kadi, Y., Guerrero, C., Haas, B., Gunsing, F., Gallino, R., Goncalves, I., Gonzalez-Romero, E., Gramegna, F., Ferrari, A., Ferreira-Marques, R., Fujii, K, Furman, W., Ferrant, L., Embid-Segura, M., Eleftheriadis, C., Dridi, W., Duran, I., David, S., Dillmann, I., Couture, A., Cox, J., Colonna, N., Cortés Rossell, Guillem Pere, Tain, J.L., Tagliente, G., Rullhusen, P., Salgado, J., Rubbia, C., Rudolf, G., Savvidis, I., Stephan, C., Santos, C., Sarchiapone, L., Reifarth, R., Rauscher, T., Quesada, J., Pretel Sánchez, Carme, Plompen, A., Alvarez, A., Plukis, A., Pigni, M.T., Plag, R., and Poch Parés, Agustí

Abstract

The neutron capture cross section of 206Pb has been measured at the CERN n TOF spectrometer using a setup of two C6D6 detectors. In the energy interval from 1 eV to 600 keV the cross section is dominated by resonances, which were analyzed via the R-matrix analysis code SAMMY. In the relevant energy ranges for stellar nucleosynthesis, i.e., at thermal energies of kT = 8 keV and kT = 23 keV, the present Maxwellian average cross section differs by 20% and 9% from the recommended values of Bao et al respectively. From the new cross section the s-abundance of 206Pb could be reliably determined as 70(4)%. This result is of importance in order to test and constrain r-process abundance calculations in the actinide region, because the r-process portion of 206Pb is dominated by α-back decays of short-lived transbismuth isotopes., Peer Reviewed, Postprint (published version)

Published
2008

2. Nuclear physics for the Re/Os clock

Author

Universitat Politècnica de Catalunya. Departament de Física i Enginyeria Nuclear, Universitat Politècnica de Catalunya. GREENER - Grup de recerca d'estudis energètics i de les radiacions, Ventura, A., Villamarin, D., Lamboudis, C., Vincente, M.C., Vlachoudis, V., Lindote, A., Tassan-Got, L., Leeb, H., Tavora, L., Lozano, M., Vannini, G., Carrapico, C., Cennini, P., Cano-Ott, D., Capote, R., Becvar, F., Calviani, M., Tain, J.L., Tagliente, G., Rullhusen, P., Salgado, J., Stephan, C., Rubbia, C., Rudolf, G., Savvidis, I., Santos, C., Sarchiapone, L., Reifarth, R., Rauscher, T., Quesada, J., Plompen, A., Poch Parés, Agustí, Plukis, A., Pretel Sánchez, Carme, Paradela, C., Pavlopoulos, P., Perrot, L., Pigni, M.T., Papadopoulos, C., Pavlik, A., Patronis, N., Baumann, P., Badurek, G., Pancin, J., Audouin, L., Papachristodoulou, C., Assimakopoulos, P., Andriamonje, S., Oberhummer, H., Andrzejewski, J., O'Brien, S., Milazzo, P.M., Álvarez-Velarde, H., Neves, F., Álvarez, H., Abbondanno, U., Gallino, R., Calviño Tavares, Francisco, Mastinu, P., Massimi, C., Lopes, I., Marrone, S., Marganiec, J., Lukic, S., Vaz, P., Vlastou, R., Voss, F., Terlizzi, R., Karadimos, D., Mosconi, M., Karamanis, D., Heil, M., Kerveno, M., Kappeler, F, Koehler, P., Plag, R., Kossionides, E., Mengoni, A., Krticka, M., Fujii, K., Domingo-Pardo, C., Aerts, G., Kadi, Y., The n_TOF Collaboration, Jericha, E., Igashira, M., Wiescher, M., Herrera-Martinez, A., Wisshak, K., Gramegna, F., Walter, S., Guerrero, C., Goncalves, I., Gonzalez-Romero, E., Haight, R., Gunsing, F., Haas, B., Ferrari, A., Furman, W., Ferreira-Marques, R., Duran, I., Eleftheriadis, C., Embid-Segura, M., Ferrant, L., Dahlfors, M., David, S., Dillmann, I., Dridi, W., Cox, J., Couture, A., Cortés Rossell, Guillem Pere, Chepel, V., Colonna, N., Universitat Politècnica de Catalunya. Departament de Física i Enginyeria Nuclear, Universitat Politècnica de Catalunya. GREENER - Grup de recerca d'estudis energètics i de les radiacions, Ventura, A., Villamarin, D., Lamboudis, C., Vincente, M.C., Vlachoudis, V., Lindote, A., Tassan-Got, L., Leeb, H., Tavora, L., Lozano, M., Vannini, G., Carrapico, C., Cennini, P., Cano-Ott, D., Capote, R., Becvar, F., Calviani, M., Tain, J.L., Tagliente, G., Rullhusen, P., Salgado, J., Stephan, C., Rubbia, C., Rudolf, G., Savvidis, I., Santos, C., Sarchiapone, L., Reifarth, R., Rauscher, T., Quesada, J., Plompen, A., Poch Parés, Agustí, Plukis, A., Pretel Sánchez, Carme, Paradela, C., Pavlopoulos, P., Perrot, L., Pigni, M.T., Papadopoulos, C., Pavlik, A., Patronis, N., Baumann, P., Badurek, G., Pancin, J., Audouin, L., Papachristodoulou, C., Assimakopoulos, P., Andriamonje, S., Oberhummer, H., Andrzejewski, J., O'Brien, S., Milazzo, P.M., Álvarez-Velarde, H., Neves, F., Álvarez, H., Abbondanno, U., Gallino, R., Calviño Tavares, Francisco, Mastinu, P., Massimi, C., Lopes, I., Marrone, S., Marganiec, J., Lukic, S., Vaz, P., Vlastou, R., Voss, F., Terlizzi, R., Karadimos, D., Mosconi, M., Karamanis, D., Heil, M., Kerveno, M., Kappeler, F, Koehler, P., Plag, R., Kossionides, E., Mengoni, A., Krticka, M., Fujii, K., Domingo-Pardo, C., Aerts, G., Kadi, Y., The n_TOF Collaboration, Jericha, E., Igashira, M., Wiescher, M., Herrera-Martinez, A., Wisshak, K., Gramegna, F., Walter, S., Guerrero, C., Goncalves, I., Gonzalez-Romero, E., Haight, R., Gunsing, F., Haas, B., Ferrari, A., Furman, W., Ferreira-Marques, R., Duran, I., Eleftheriadis, C., Embid-Segura, M., Ferrant, L., Dahlfors, M., David, S., Dillmann, I., Dridi, W., Cox, J., Couture, A., Cortés Rossell, Guillem Pere, Chepel, V., and Colonna, N.

Abstract

Dating the age of the universe by the β-decay of 187Re (t1/2 = 41.2 Gyr) requires the accurate assessment of the s-process reaction flow. The daughter nucleus 187Os as well as its immediate s-only neighbor 186Os are shielded from the r-process. Therefore, the radiogenic contribution to 187Os can be derived via the local approximation of the s-process, which is well justified in this mass region: ( σ Ns)187 = ( σ Ns)186. Accordingly, accurate Maxwellianaveraged (n, γ ) cross sections have to be known for 186Os and 187Os over the full range of s-process temperatures. Because 187Os has low-lying excited states, which are significantly populated during the s-process, neutron captures on these excited states have to be properly taken into account. The input for the corresponding Hauser–Feshbach calculations can be constrained by deriving the strength functions from a detailed resonance analysis of the measured (n, γ ) cross sections as well as by an additional measurement of the inelastic scattering cross section for the first exited level, which dominates the competition between the capture and scattering channels. This contribution reports on measurements of the neutron capture cross sections of 186Os, 187Os and 188Os from the eV region to 1MeV at the CERN/n TOF facility and of the inelastic scattering cross section of 187Os around 30 keV at the Karlsruhe 3.7 MV Van de Graaff accelerator. Based on these results and on a detailed resonance analysis, improved Maxwellian-averaged cross sections were obtained for thermal energies between 5 keV and 100 keV. The implications of these results for the Re/Os clock are discussed., Peer Reviewed, Postprint (published version)

Published
2008

3. Neutron reactions and nuclear cosmo-chronology

Author

Universitat Politècnica de Catalunya. Departament de Física i Enginyeria Nuclear, Universitat Politècnica de Catalunya. GREENER - Grup de recerca d'estudis energètics i de les radiacions, Tagliente, G., Taín Enríquez, José Luis, Ketlerov, V., Tassan-Got, L., Tavora, L., Konovalov, V., Salgado, J., Koehler, P., Sarchiapone, L., Krticka, M., Savvidis, I., Rauscher, T., Reifarth, R., Plompen, A., Perrot, L., Pavlopoulos, P., Papadopoulos, C., Paradela, C., Patronis, N., Pavlik, A., O'Brien, S., Baumann, P., Pancin, J., Papachristodoulou, C., Neves, F., Moreau, C., Oshima, M., Oberhummer, H., Berthoumieux, E., Becvar, F., Mastinu, P.F., Milazzo, P.M., Badurek, G., Marques, L., Audouin, L., Marrone, S., Assimakopoulos, P., Lukic, S., Andrzejewski, J., Marganiec, J., Kossionides, E., Andriamonje, S., Álvarez-Velarde, F., Álvarez-Pol, H., Bisterzo, S., Lozano, M, Lopes, I., Lindote, A., Leeb, H., Lamboudis, C., Stephan, C., Vannini, G., Vaz, P., Abbondanno, U., Isaev, S., Mosconi, M., Jericha, E., Heil, M., Kadi, Y., Kappeler, F., Karamanis, D., Mengoni, A., Karadimos, D., Plag, R., Kerveno, M., Fujii, K., Aerts, G., Terlizzi, R., Wendler, H., Wiescher, M., Voss, F., Walter, S., Igashira, M., Vlachoudis, V., Herrera-Martinez, A., Vlastou, R., Haight, R., Villamarin, D., Haas, B., Vincente, M.C., Wisshak, K., Goverdovski, A., Ventura, A., Gramegna, F., Goncalves, I., Gonzalez-Romero, E., Gunsing, F., Griesmayer, E., Guerrero, C., Embid-Segura, M., Ferrari, A., Ferrant, L., Domingo-Pardo, C., Dridi, W., Duran, I., Eleftheriadis, C., Dahlfors, M., David, S., Dillmann, I., Dolfini, R., Cox, J., Couture, A., Colonna, N., Chiaveri, E., Cortés Rossell, Guillem Pere, Cennini, P., Chepel, V., Capote, R., Carrillo de Albornoz, A., Calviño Tavares, Francisco, Cano-Ott, D., Rullhusen, P., Rudolf, G., Pretel Sánchez, Carme, Quesada, J., Plukis, A., Poch Parés, Agustí, Rosetti, M., Rubbia, C., Universitat Politècnica de Catalunya. Departament de Física i Enginyeria Nuclear, Universitat Politècnica de Catalunya. GREENER - Grup de recerca d'estudis energètics i de les radiacions, Tagliente, G., Taín Enríquez, José Luis, Ketlerov, V., Tassan-Got, L., Tavora, L., Konovalov, V., Salgado, J., Koehler, P., Sarchiapone, L., Krticka, M., Savvidis, I., Rauscher, T., Reifarth, R., Plompen, A., Perrot, L., Pavlopoulos, P., Papadopoulos, C., Paradela, C., Patronis, N., Pavlik, A., O'Brien, S., Baumann, P., Pancin, J., Papachristodoulou, C., Neves, F., Moreau, C., Oshima, M., Oberhummer, H., Berthoumieux, E., Becvar, F., Mastinu, P.F., Milazzo, P.M., Badurek, G., Marques, L., Audouin, L., Marrone, S., Assimakopoulos, P., Lukic, S., Andrzejewski, J., Marganiec, J., Kossionides, E., Andriamonje, S., Álvarez-Velarde, F., Álvarez-Pol, H., Bisterzo, S., Lozano, M, Lopes, I., Lindote, A., Leeb, H., Lamboudis, C., Stephan, C., Vannini, G., Vaz, P., Abbondanno, U., Isaev, S., Mosconi, M., Jericha, E., Heil, M., Kadi, Y., Kappeler, F., Karamanis, D., Mengoni, A., Karadimos, D., Plag, R., Kerveno, M., Fujii, K., Aerts, G., Terlizzi, R., Wendler, H., Wiescher, M., Voss, F., Walter, S., Igashira, M., Vlachoudis, V., Herrera-Martinez, A., Vlastou, R., Haight, R., Villamarin, D., Haas, B., Vincente, M.C., Wisshak, K., Goverdovski, A., Ventura, A., Gramegna, F., Goncalves, I., Gonzalez-Romero, E., Gunsing, F., Griesmayer, E., Guerrero, C., Embid-Segura, M., Ferrari, A., Ferrant, L., Domingo-Pardo, C., Dridi, W., Duran, I., Eleftheriadis, C., Dahlfors, M., David, S., Dillmann, I., Dolfini, R., Cox, J., Couture, A., Colonna, N., Chiaveri, E., Cortés Rossell, Guillem Pere, Cennini, P., Chepel, V., Capote, R., Carrillo de Albornoz, A., Calviño Tavares, Francisco, Cano-Ott, D., Rullhusen, P., Rudolf, G., Pretel Sánchez, Carme, Quesada, J., Plukis, A., Poch Parés, Agustí, Rosetti, M., and Rubbia, C.

Abstract

The -decay of 187Re (t1/2 = 42.3 Gyr) represents a suited cosmo-chronometer for the age of the r-process abundances, since the radiogenic part of the daughter isotope 187Os is defined by the difference between the solar 187Os abundance and s-process contribution to 187Os. The latter component can be determined via the s-process systematics based on the stellar neutron capture cross sections of 186Os and 187Os. The laboratory cross section of 187Os requires a significant correction for the effect of the low-lying excited state at 9.75 keV, which is strongly populated under stellar conditions. This theoretical correction can be improved by an experimental cross section for inelastic scattering to the 9.75 keV state. High resolution time-of-flight measurements of (n, ) cross sections of 186,187,188Os from 1 eV to 1 MeV at CERN n TOF facility are reported. The inferred stellar cross sections differ from previously recommended values. In addition, the inelastic scattering cross section has been measured at 30 keV neutron energy via time-of-flight at the Karlsruhe 3.7 MV Van de Graaff. The implications of these results for the Re/Os clock are discussed., Peer Reviewed, Postprint (published version)

Published
2007

4. Status and outlook of the neutron time-of-flight facility n_TOF at CERN

Author

Universitat Politècnica de Catalunya. Departament de Física, Universitat Politècnica de Catalunya. ANT - Advanced Nuclear Technologies Research Group, Universitat Politècnica de Catalunya. GREENER - Grup de recerca d'estudis energètics i de les radiacions, Gunsing, Frank, Abbondanno, U, Aerts, G, Alvarez, H, Alvarez Velarde, Francisco, Andriamonje, S, Assimakopoulos, P, Audouin, Ludmila, Badurek, G., Dolfini, R., Ferrant, L., Domingo Pardo, César, Dridi, W., Calviño Tavares, Francisco, Cortés Rossell, Guillem Pere, Duran, I., Ferrari, A., Ferreira-Marques, R., Frais-Koelbl, H., Furman, W., Fujii, K, Jericha, E., Goncalves, I., Gonzalez Romero, E., Goverdovski, A., Karamanis, D., Gramegna, F., Griesmayer, E., Haas, B., Haight, R., Kerveno, M., Herrera Martinez, Aura, Igashira, M., Isaev, S., Kappeler, F, Kadi, Y, Karadimos, D., Ketlerov, V., Koehler, Paul E., Konovalov, V., Kossionides, E., Krticka, M., Mengoni, A, Lampoudis, C., Leeb, H., Lindote, A., Neves, F., Lopes, I., Marrone, S., Lukic, S., Marganiec, J., Marques, L., Oberhummer, H., Martínez, T., Mastinu, P., Massimi, Cristian, Milazzo, P.M., Moreau, C, Mosconi, M., O'Brien, S., Oshima, M., Pancin, J., Papachristodoulou, C., Papadopoulos, C., Rauscher, Thomas, Paradela, C., Patronis, N., Pavlik, A., Rudolf, G., Pavlopoulos, P., Perrot, L., Pigni, M.T., Plag, R., Plompen, A., Plukis, A., Rullhusen, P., Pretel Sánchez, Carme, Poch Parés, Agustí, Quesada, J., Reifarth, R., Rubbia, C., Rosetti, M., Sarchiapone, L., Salgado, J., Savvidis, I., Stephan, C., Tagliente, G., Walter, S., Tassan-Got, L., Tavora, L., Becvar, F., Terlizzi, R., Vannini, Gianni, Vaz, P., Ventura, Alberto, Villamarin, D., Vincente, M.C., Berthoumieux, Eric, Vlastou, R., Vlachoudis, V., Voss, F., Wendler, H., Wiescher, M., Wisshak, K., Cano-Ott, D, Capote Noy, Roberto, Albornoz, A.C. de, Cennini, P., Eleftheriadis, C., Chepel, V., Chiaveri, E., Colonna, Nicola, Couture, A., Cox, J., Dahlfors, M., David, S., Dillmann, Iris, Lozano, Manuel, Guerrero, Carlos, Taín Enríquez, José Luis, Universitat Politècnica de Catalunya. Departament de Física, Universitat Politècnica de Catalunya. ANT - Advanced Nuclear Technologies Research Group, Universitat Politècnica de Catalunya. GREENER - Grup de recerca d'estudis energètics i de les radiacions, Gunsing, Frank, Abbondanno, U, Aerts, G, Alvarez, H, Alvarez Velarde, Francisco, Andriamonje, S, Assimakopoulos, P, Audouin, Ludmila, Badurek, G., Dolfini, R., Ferrant, L., Domingo Pardo, César, Dridi, W., Calviño Tavares, Francisco, Cortés Rossell, Guillem Pere, Duran, I., Ferrari, A., Ferreira-Marques, R., Frais-Koelbl, H., Furman, W., Fujii, K, Jericha, E., Goncalves, I., Gonzalez Romero, E., Goverdovski, A., Karamanis, D., Gramegna, F., Griesmayer, E., Haas, B., Haight, R., Kerveno, M., Herrera Martinez, Aura, Igashira, M., Isaev, S., Kappeler, F, Kadi, Y, Karadimos, D., Ketlerov, V., Koehler, Paul E., Konovalov, V., Kossionides, E., Krticka, M., Mengoni, A, Lampoudis, C., Leeb, H., Lindote, A., Neves, F., Lopes, I., Marrone, S., Lukic, S., Marganiec, J., Marques, L., Oberhummer, H., Martínez, T., Mastinu, P., Massimi, Cristian, Milazzo, P.M., Moreau, C, Mosconi, M., O'Brien, S., Oshima, M., Pancin, J., Papachristodoulou, C., Papadopoulos, C., Rauscher, Thomas, Paradela, C., Patronis, N., Pavlik, A., Rudolf, G., Pavlopoulos, P., Perrot, L., Pigni, M.T., Plag, R., Plompen, A., Plukis, A., Rullhusen, P., Pretel Sánchez, Carme, Poch Parés, Agustí, Quesada, J., Reifarth, R., Rubbia, C., Rosetti, M., Sarchiapone, L., Salgado, J., Savvidis, I., Stephan, C., Tagliente, G., Walter, S., Tassan-Got, L., Tavora, L., Becvar, F., Terlizzi, R., Vannini, Gianni, Vaz, P., Ventura, Alberto, Villamarin, D., Vincente, M.C., Berthoumieux, Eric, Vlastou, R., Vlachoudis, V., Voss, F., Wendler, H., Wiescher, M., Wisshak, K., Cano-Ott, D, Capote Noy, Roberto, Albornoz, A.C. de, Cennini, P., Eleftheriadis, C., Chepel, V., Chiaveri, E., Colonna, Nicola, Couture, A., Cox, J., Dahlfors, M., David, S., Dillmann, Iris, Lozano, Manuel, Guerrero, Carlos, and Taín Enríquez, José Luis

Abstract

The neutron time-of-flight facility n_TOF at CERN, fully operational since 2002, combines a high instantaneous neutron flux with high energy resolution. The wide energy range and the high neutron flux per time-of-flight burst result in a much enhanced signal to background ratio for neutron capture of radioactive isotopes and makes this facility well suited for the measurement of high quality neutron-induced reaction cross-sections. Neutrons are created by spallation reactions induced by a pulsed 20 GeV/c proton beam impinging on a lead target. A 5 cm water slab surrounding the lead target serves as a coolant and at the same time as a moderator of the spallation neutron spectrum, providing a wide energy spectrum from 0.1 eV to about 250 MeV. By the end of 2005, a first phase of data taking has been successfully terminated. Fission and capture experiments have been performed on a variety of isotopes of interest for nuclear astrophysics, advanced nuclear technologies and for basic nuclear physics. The instrumentation developed for this facility consists of parallel plate avalanche counter and fission ionization chamber detectors for the fission experiments and of low mass C6D6 detectors and a 4 pi BaF2 total absorption calorimeter for capture experiments. A new data acquisition system, based on sampling of the detector signals, has been developed to cope with the high count rates and to minimize the effective dead time to only a few tens of nanosecond. A second phase of data taking is planned to start in 2007, after an upgrade of the spallation target. On the longer term, the construction of a flight path at 20 m resulting in an increased neutron flux of about a factor of 100 opens new possibilities., Postprint (published version)

Published
2007

5. Status and outlook of the neutron time-of-flight facility n_TOF at CERN

Author

Gunsing, F., Abbondanno, U., Aerts, G., Álvarez, H., Álvarez-Velarde, F., Andriamonje, S., Andrzejewski, Józef, Assimakopoulos, P., Audouin, L., Badurek, G., Baumann, P., Goncalves, I., González-Romero, E., Goverdovski, A., Karamanis, D., Heil, M., Gramegna, F., Griesmayer, E., Guerrero, C., Haas, B., Kerveno, M., Leeb, H., Herrera-Martínez, A., Igashira, M., Isaev, S., Kappeler, F., Kadi, Y., Karadimos, D., Ketlerov, V., Marrone, S., Koehler, P., Konovalov, V., Lindote, A., Kossionides, E., Krticka, M., Mengoni, A., Lampoudis, C., Neves, F., Lopes, I., Oberhummer, H., Lozano, M., Lukic, S., Marganiec, J., Marques, L., Martínez Pérez, Trinitario, Pavlik, A., Massimi, C., Mastinu, P., Milazzo, P. M., Moreau, C., Mosconi, M., O'Brien, S., Oshima, M., Plukis, A., Pancin, J., Papachristodoulou, C., Rudolf, G., Papadopoulos, C., Rauscher, T., Paradela, Cristina, Patronis, N., Pavlopoulos, P., Perrot, L., Rullhusen, P., Pigni, M. T., Plag, R., Plompen, A., n_TOF Collaboration, Poch, A., Tavora, L., Pretel, C., Quesada, J., Reifarth, R., Rosetti, M., Rubbia, C., Salgado, J., Sarchiapone, L., Vincente, M. C., Savvidis, I., Stephan, C., Becvar, F., Tagliente, G., Walter, S., Taín, José Luis, Tassan-Got, L., Terlizzi, R., Vannini, G., Berthoumieux, Eric, Vaz, P., Ventura, A., Villamarin, D., Vlachoudis, V., Vlastou, R., Cortés Rossell, Guillem, Voss, F., Wendler, H., Wiescher, M., Wisshak, K., Calvino, F., Cano Ott, Daniel, Dolfini, R., Capote, R., Albornoz, A. C. de, Cennini, P., Couture, A., Eleftheriadis, C., Chepel, V., Chiaveri, E., Colonna, N., Cox, J., Ferrant, L., Dahlfors, M., David, S., Dillmann, I., Domingo Pardo, César, Dridi, W., Durán, I., Haight, R., Ferrari, A., Ferreira-Marques, R., Frais-Koelbl, H., Fujii, K., Furman, W., Jericha, E., Gunsing, F., Abbondanno, U., Aerts, G., Álvarez, H., Álvarez-Velarde, F., Andriamonje, S., Andrzejewski, Józef, Assimakopoulos, P., Audouin, L., Badurek, G., Baumann, P., Goncalves, I., González-Romero, E., Goverdovski, A., Karamanis, D., Heil, M., Gramegna, F., Griesmayer, E., Guerrero, C., Haas, B., Kerveno, M., Leeb, H., Herrera-Martínez, A., Igashira, M., Isaev, S., Kappeler, F., Kadi, Y., Karadimos, D., Ketlerov, V., Marrone, S., Koehler, P., Konovalov, V., Lindote, A., Kossionides, E., Krticka, M., Mengoni, A., Lampoudis, C., Neves, F., Lopes, I., Oberhummer, H., Lozano, M., Lukic, S., Marganiec, J., Marques, L., Martínez Pérez, Trinitario, Pavlik, A., Massimi, C., Mastinu, P., Milazzo, P. M., Moreau, C., Mosconi, M., O'Brien, S., Oshima, M., Plukis, A., Pancin, J., Papachristodoulou, C., Rudolf, G., Papadopoulos, C., Rauscher, T., Paradela, Cristina, Patronis, N., Pavlopoulos, P., Perrot, L., Rullhusen, P., Pigni, M. T., Plag, R., Plompen, A., n_TOF Collaboration, Poch, A., Tavora, L., Pretel, C., Quesada, J., Reifarth, R., Rosetti, M., Rubbia, C., Salgado, J., Sarchiapone, L., Vincente, M. C., Savvidis, I., Stephan, C., Becvar, F., Tagliente, G., Walter, S., Taín, José Luis, Tassan-Got, L., Terlizzi, R., Vannini, G., Berthoumieux, Eric, Vaz, P., Ventura, A., Villamarin, D., Vlachoudis, V., Vlastou, R., Cortés Rossell, Guillem, Voss, F., Wendler, H., Wiescher, M., Wisshak, K., Calvino, F., Cano Ott, Daniel, Dolfini, R., Capote, R., Albornoz, A. C. de, Cennini, P., Couture, A., Eleftheriadis, C., Chepel, V., Chiaveri, E., Colonna, N., Cox, J., Ferrant, L., Dahlfors, M., David, S., Dillmann, I., Domingo Pardo, César, Dridi, W., Durán, I., Haight, R., Ferrari, A., Ferreira-Marques, R., Frais-Koelbl, H., Fujii, K., Furman, W., and Jericha, E.

Abstract

The neutron time-of-flight facility n_TOF at CERN, fully operational since 2002, combines a high instantaneous neutron flux with high energy resolution. The wide energy range and the high neutron flux per time-of-flight burst result in a much enhanced signal to background ratio for neutron capture of radioactive isotopes and makes this facility well suited for the measurement of high quality neutron-induced reaction cross-sections., Neutrons are created by spallation reactions induced by a pulsed 20 GeV/c proton beam impinging on a lead target. A 5 cm water slab surrounding the lead target serves as a coolant and at the same time as a moderator of the spallation neutron spectrum, providing a wide energy spectrum from 0.1 eV to about 250 MeV., By the end of 2005, a first phase of data taking has been successfully terminated. Fission and capture experiments have been performed on a variety of isotopes of interest for nuclear astrophysics, advanced nuclear technologies and for basic nuclear physics., The instrumentation developed for this facility consists of parallel plate avalanche counter and fission ionization chamber detectors for the fission experiments and of low mass C6D6 detectors and a 4 pi BaF2 total absorption calorimeter for capture experiments. A new data acquisition system, based on sampling of the detector signals, has been developed to cope with the high count rates and to minimize the effective dead time to only a few tens of nanosecond., A second phase of data taking is planned to start in 2007, after an upgrade of the spallation target. On the longer term, the construction of a flight path at 20 in resulting in an increased neutron flux of about a factor of 100 opens new possibilities.

Published
2007

6. Measurement of the neutron capture cross section of the s-only isotope Pb-204 from 1 eV to 440 keV

Author

Domingo Pardo, César, Abbondanno, U., Aerts, G., Álvarez-Pol, H., Álvarez-Velarde, F., Andriamonje, S., Andrzejewski, Józef, Assimakopoulos, P., Audouin, L., Badurek, G., Baumann, P., Lamboudis, C., Leeb, H., Lindote, A., Lopes, I., Neves, F., Lozano, M., Lukic, S., Marganiec, J., Marrone, S., Mengoni, A., Perrot, L., Milazzo, P. M., Moreau, C., Oberhummer, H., Oshima, M., O'Brien, S., Pancin, J., Papachristodoulou, C., Rauscher, T., Papadopoulos, C., Paradela, Cristina, Plag, R., Patronis, N., Rudolf, G., Pavlik, A., Pavlopoulos, P., Plompen, A., Plukis, A., Rullhusen, P., Poch, A., Pretel, C., Quesada, J., n_TOF Collaboration, Reifarth, R., Vaz, P., Rosetti, M., Rubbia, C., Salgado, J., Sarchiapone, L., Savvidis, I., Stephan, C., Tagliente, G., Walter, S., Taín, José Luis, Tassan-Got, L., Ventura, A., Tavora, L., Becvar, F., Terlizzi, R., Vannini, G., Villamarin, D., Vincente, M. C., Berthoumieux, Eric, Vlachoudis, V., Vlastou, R., Voss, F., Wendler, H., Wiescher, M., Dahlfors, M., Wisshak, K., Bisterzo, S., Calvino, F., Cano Ott, Daniel, Capote, R., Carrapico, C., Eleftheriadis, C., Cennini, P., Chepel, V., Chiaveri, E., David, S., Colonna, N., Cortés Rossell, Guillem, Couture, A., Cox, J., Dillmann, I., Embid-Segura, M., Dolfini, R., Dridi, W., Durán, Ignacio, Ferrant, L., Ferrari, A., Ferreira-Marques, R., Haight, R., Fitzpatrick, L., Frais-Koelbl, H., Fujii, K., Furman, W., Gallino, R., Jericha, E., Goncalves, I., González-Romero, E., Goverdovski, A., Gramegna, F., Heil, M., Griesmayer, E., Guerrero, C., Gunsing, F., Haas, B., Kadi, Y., Herrera-Martínez, A., Igashira, M., Isaev, S., Kappeler, F., Karamanis, D., Karadimos, D., Kerveno, M., Mastinu, P., Ketlerov, V., Koehler, P., Konovalov, V., Kossionides, E., Mosconi, M., Krticka, M., Domingo Pardo, César, Abbondanno, U., Aerts, G., Álvarez-Pol, H., Álvarez-Velarde, F., Andriamonje, S., Andrzejewski, Józef, Assimakopoulos, P., Audouin, L., Badurek, G., Baumann, P., Lamboudis, C., Leeb, H., Lindote, A., Lopes, I., Neves, F., Lozano, M., Lukic, S., Marganiec, J., Marrone, S., Mengoni, A., Perrot, L., Milazzo, P. M., Moreau, C., Oberhummer, H., Oshima, M., O'Brien, S., Pancin, J., Papachristodoulou, C., Rauscher, T., Papadopoulos, C., Paradela, Cristina, Plag, R., Patronis, N., Rudolf, G., Pavlik, A., Pavlopoulos, P., Plompen, A., Plukis, A., Rullhusen, P., Poch, A., Pretel, C., Quesada, J., n_TOF Collaboration, Reifarth, R., Vaz, P., Rosetti, M., Rubbia, C., Salgado, J., Sarchiapone, L., Savvidis, I., Stephan, C., Tagliente, G., Walter, S., Taín, José Luis, Tassan-Got, L., Ventura, A., Tavora, L., Becvar, F., Terlizzi, R., Vannini, G., Villamarin, D., Vincente, M. C., Berthoumieux, Eric, Vlachoudis, V., Vlastou, R., Voss, F., Wendler, H., Wiescher, M., Dahlfors, M., Wisshak, K., Bisterzo, S., Calvino, F., Cano Ott, Daniel, Capote, R., Carrapico, C., Eleftheriadis, C., Cennini, P., Chepel, V., Chiaveri, E., David, S., Colonna, N., Cortés Rossell, Guillem, Couture, A., Cox, J., Dillmann, I., Embid-Segura, M., Dolfini, R., Dridi, W., Durán, Ignacio, Ferrant, L., Ferrari, A., Ferreira-Marques, R., Haight, R., Fitzpatrick, L., Frais-Koelbl, H., Fujii, K., Furman, W., Gallino, R., Jericha, E., Goncalves, I., González-Romero, E., Goverdovski, A., Gramegna, F., Heil, M., Griesmayer, E., Guerrero, C., Gunsing, F., Haas, B., Kadi, Y., Herrera-Martínez, A., Igashira, M., Isaev, S., Kappeler, F., Karamanis, D., Karadimos, D., Kerveno, M., Mastinu, P., Ketlerov, V., Koehler, P., Konovalov, V., Kossionides, E., Mosconi, M., and Krticka, M.

Abstract

The neutron capture cross section of Pb-204 has been measured at the CERN n_TOF installation with high resolution in the energy range from 1 eV to 440 keV. An R-matrix analysis of the resolved resonance region, between 1 eV and 100 keV, was carried out using the SAMMY code. In the interval between 100 keV and 440 keV we report the average capture cross section. The background in the entire neutron energy range was reliably determined from the measurement of a Pb-208 sample. Other systematic effects in this measurement were investigated and precisely corrected by means of detailed Monte Carlo simulations. We obtain a Maxwellian average capture cross section for Pb-204 at kT=30 keV of 79(3) mb, in agreement with previous experiments. However our cross section at kT=5 keV is about 35% larger than the values reported so far. The implications of the new cross section for the s-process abundance contributions in the Pb/Bi region are discussed.

Published
2007

7. Resonance capture cross section of Pb-207

Author

Universitat Politècnica de Catalunya. Departament de Física i Enginyeria Nuclear, Universitat Politècnica de Catalunya. GREENER - Grup de recerca d'estudis energètics i de les radiacions, Sarchiapone, L., Savvidis, I., Kerveno, M., Stephan, C., Tagliente, G., Koehler, P., Rubbia, C., Ketlerov, V., Rudolf, G., Kossionides, E., Rullhusen, P., Goncalves, I., Gallino, R., Ferreira-Marques, R., Fitzpatrick, L., Frais-Koelbl, H., Fujii, K., Eleftheriadis, C., Embid-Segura, M., Ferrant, L., Ferrari, A., Poch Parés, Agustí, Duran, I., Dridi, W., Dolfini, R., David, S., Dillmann, I., Cox, J., Dahlfors, M., Colonna, N., Couture, A., Chiaveri, E., Perrot, L., Cortés Rossell, Guillem Pere, Rosetti, M., Reifarth, R., Plompen, A., Plag, R., Quesada, J., Rauscher, T., Pretel Sánchez, Carme, Plukis, A., Pavlopoulos, P., Pavlik, A., Patronis, N., Mosconi, M., Pancin, J., Wisshak, K., Papachristodoulou, C., Wiescher, M., Papadopoulos, C., Paradela, C., The nTOF Collaborat, Oberhummer, H., Oshima, M., O'Brien, S., Wendler, H., Moreau, C., Milazzo, P.M., Neves, F., Voss, F., Cennini, P., Carrapico, C., Mastinu, P., Capote, R., Mengoni, A., Cano-Ott, D., Marganiec, J., Bisterzo, S., Konovalov, V., Marrone, S., Calviño Tavares, Francisco, Lozano, M., Berthoumieux, E., Lukic, S., Becvar, F., Baumann, P., Badurek, G., Chepel, V., Lopes, I., Salgado, J., Lindote, A., Leeb, H., Lamboudis, C., Krticka, M., Taín Enríquez, José Luis, Tassan-Got, L., Audouin, L., Isaev, S., Domingo-Pardo, C., Jericha, E., Abbondanno, U., Kadi, Y., Aerts, G., Kaeppeler, F., Álvarez-Pol, H., Karamanis, D., Álvarez-Velarde, F., Karadimos, D., Andriamonje, S., Andrzejewski, J., Assimakopoulos, P., Vlachoudis, V., Vlastou, R., Villamarin, D., Vincente, M.C., Igashira, M., Vaz, P., Herrera-Martinez, A., Ventura, A., Heil, M., Terlizzi, R., Haight, R., Vannini, G., Walter, S., Gramegna, F., Tavora, L., Griesmayer, E., Gonzalez-Romero, E., Goverdovski, A., Haas, B., Guerrero, C., Gunsing, F., Furman, W., Universitat Politècnica de Catalunya. Departament de Física i Enginyeria Nuclear, Universitat Politècnica de Catalunya. GREENER - Grup de recerca d'estudis energètics i de les radiacions, Sarchiapone, L., Savvidis, I., Kerveno, M., Stephan, C., Tagliente, G., Koehler, P., Rubbia, C., Ketlerov, V., Rudolf, G., Kossionides, E., Rullhusen, P., Goncalves, I., Gallino, R., Ferreira-Marques, R., Fitzpatrick, L., Frais-Koelbl, H., Fujii, K., Eleftheriadis, C., Embid-Segura, M., Ferrant, L., Ferrari, A., Poch Parés, Agustí, Duran, I., Dridi, W., Dolfini, R., David, S., Dillmann, I., Cox, J., Dahlfors, M., Colonna, N., Couture, A., Chiaveri, E., Perrot, L., Cortés Rossell, Guillem Pere, Rosetti, M., Reifarth, R., Plompen, A., Plag, R., Quesada, J., Rauscher, T., Pretel Sánchez, Carme, Plukis, A., Pavlopoulos, P., Pavlik, A., Patronis, N., Mosconi, M., Pancin, J., Wisshak, K., Papachristodoulou, C., Wiescher, M., Papadopoulos, C., Paradela, C., The nTOF Collaborat, Oberhummer, H., Oshima, M., O'Brien, S., Wendler, H., Moreau, C., Milazzo, P.M., Neves, F., Voss, F., Cennini, P., Carrapico, C., Mastinu, P., Capote, R., Mengoni, A., Cano-Ott, D., Marganiec, J., Bisterzo, S., Konovalov, V., Marrone, S., Calviño Tavares, Francisco, Lozano, M., Berthoumieux, E., Lukic, S., Becvar, F., Baumann, P., Badurek, G., Chepel, V., Lopes, I., Salgado, J., Lindote, A., Leeb, H., Lamboudis, C., Krticka, M., Taín Enríquez, José Luis, Tassan-Got, L., Audouin, L., Isaev, S., Domingo-Pardo, C., Jericha, E., Abbondanno, U., Kadi, Y., Aerts, G., Kaeppeler, F., Álvarez-Pol, H., Karamanis, D., Álvarez-Velarde, F., Karadimos, D., Andriamonje, S., Andrzejewski, J., Assimakopoulos, P., Vlachoudis, V., Vlastou, R., Villamarin, D., Vincente, M.C., Igashira, M., Vaz, P., Herrera-Martinez, A., Ventura, A., Heil, M., Terlizzi, R., Haight, R., Vannini, G., Walter, S., Gramegna, F., Tavora, L., Griesmayer, E., Gonzalez-Romero, E., Goverdovski, A., Haas, B., Guerrero, C., Gunsing, F., and Furman, W.

Abstract

The radiative neutron capture cross section of 207Pb has been measured at the CERN neutron time of flight installation n TOF using the pulse height weighting technique in the resolved energy region. The measurement has been performed with an optimized setup of two C6D6 scintillation detectors, which allowed us to reduce scattered neutron backgrounds down to a negligible level. Resonance parameters and radiative kernels have been determined for 16 resonances by means of an R-matrix analysis in the neutron energy range from 3 keV to 320 keV. Good agreement with previous measurements was found at low neutron energies, whereas substantial discrepancies appear beyond 45 keV. With the present results, we obtain an s-process contribution of 77±8% to the solar abundance of 207Pb. This corresponds to an r-process component of 23 ± 8%, which is important for deriving the U/Th ages of metal poor halo stars., Peer Reviewed, Postprint (published version)

Published
2006

8. Estimation of radioecological sensitivity

Author

Howard, B.J., Strand, P., Assimakopoulos, P., Bréchignac, F., Gasco, C., Métivier, H., Moberg, L., Smith, J.T., Tamponnet, C., Trueba, C., Voigt, G., Wright, S.M., Howard, B.J., Strand, P., Assimakopoulos, P., Bréchignac, F., Gasco, C., Métivier, H., Moberg, L., Smith, J.T., Tamponnet, C., Trueba, C., Voigt, G., and Wright, S.M.

Abstract

After the release of radionuclides into the environment it is important to be able to readily identify major routes of radiation exposure, the most highly exposed individuals or populations and the geographical areas of most concern. There have been significant recent improvements in our capability to estimate spatial variation in the environmental behaviour of radionuclides through better understanding of the underlying processes and an ability to spatially apply this knowledge by integrating relevant spatial information in the form of digital data sets using geographical information systems. Thus, it is now possible to refine the estimation of spatial variation in radiation exposure, both for routine releases and in accident situations. Within a recent EC-funded concerted action (the Radioecological Sensitivity Forum), there has been a renewed consideration of the concept of radioecological sensitivity with a particular focus on identifying sensitive areas as well as processes and communities. The concept should be relevant for both terrestrial and aquatic ecosystems, and might even be applied for consideration of doses to biota, although the current focus has been restricted to a consideration of human exposure. The conclusions of the action are outlined, considering the potential usefulness of the concept, and methods by which it can be applied. A framework for the estimation of radioecological sensitivity is proposed and the various measures by which it can be considered, including (i) aggregated transfer coefficients, (ii) action loads, (iii) fluxes and (iv) individual exposure of humans are discussed. The importance of spatial and temporal consideration of each of these outputs is emphasized.

Published
2002

9. Estimation of radioecological sensitivity

Author

Howard, B.J., Strand, P., Assimakopoulos, P., Bréchignac, F., Gasco, C., Métivier, H., Moberg, L., Smith, J.T., Tamponnet, C., Trueba, C., Voigt, G., Wright, S.M., Howard, B.J., Strand, P., Assimakopoulos, P., Bréchignac, F., Gasco, C., Métivier, H., Moberg, L., Smith, J.T., Tamponnet, C., Trueba, C., Voigt, G., and Wright, S.M.

Abstract

After the release of radionuclides into the environment it is important to be able to readily identify major routes of radiation exposure, the most highly exposed individuals or populations and the geographical areas of most concern. There have been significant recent improvements in our capability to estimate spatial variation in the environmental behaviour of radionuclides through better understanding of the underlying processes and an ability to spatially apply this knowledge by integrating relevant spatial information in the form of digital data sets using geographical information systems. Thus, it is now possible to refine the estimation of spatial variation in radiation exposure, both for routine releases and in accident situations. Within a recent EC-funded concerted action (the Radioecological Sensitivity Forum), there has been a renewed consideration of the concept of radioecological sensitivity with a particular focus on identifying sensitive areas as well as processes and communities. The concept should be relevant for both terrestrial and aquatic ecosystems, and might even be applied for consideration of doses to biota, although the current focus has been restricted to a consideration of human exposure. The conclusions of the action are outlined, considering the potential usefulness of the concept, and methods by which it can be applied. A framework for the estimation of radioecological sensitivity is proposed and the various measures by which it can be considered, including (i) aggregated transfer coefficients, (ii) action loads, (iii) fluxes and (iv) individual exposure of humans are discussed. The importance of spatial and temporal consideration of each of these outputs is emphasized.

Published
2002

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