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1. Ion beam techniques for nuclear waste management

Author

Schiffer Markus, Stolz Alexander, Strub Erik, Herb Susan, Dewald Matthias, Margreiter Raphael, Papst Timm-Florian, Geusen Kevin, Jakobi Yannik, Hackenberg Gereon, Mueller-Gatermann Claus, Heinze Stefan, and Dewald Alfred

Subjects
Physics, QC1-999
Abstract

An automated CO2 gas handling and injection system was developed. It is designed to dilute CO2 samples with blank gas in a mixing volume. The system is intended to be used for the characterization and quantification of 14C content in reactor graphite with accelerator mass spectrometry. A 100 kV accelerator system was developed to measure samples with high 14C content, to test the gas injection system and to measure the 3H content from gaseous releases of reactor graphite. Additionally, the Tandetron model 4130 was purchased from the Max-Planck Institute for Biogeochemistry Jena (Germany) and a concept was developed for installation at the accelerator building of the University of Cologne. With the new 3 MV system, new isotopic ratio measurements and ion beam techniques for material analysis can be performed. The system will be used for nuclear waste management measurements of isotopes, e.g. 3H, 14C, 36Cl, 41Ca and 55Fe, which are difficult to measure with other techniques.

Published
2020
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2. Structural investigation of neutron-deficient Pt isotopes: the case of 178Pt

Author

Fransen Christoph, Mammes Franziska, Bark Robert, Braunroth Thomas, Buthelezi Zinhle, Dewald Alfred, Dinoko Tshepo, Förtsch Siegie, Hackstein Matthias, Jolie Jan, Jones Pete, Lawrie Elena, Litzinger Julia, Müller-Gatermann Claus, Newman Richard, Saed-Samii Nima, Sharpey-Schafer John F., Shirinda Obed, Smit Ricky, Warr Nigel, Wiedeking Mathis, and Zell Karl-Oskar

Subjects
Physics, QC1-999
Abstract

Lifetime measurements with the recoil distance Doppler-shift technique have been performed to determine yrast E2 transition strengths in 178Pt. The experimental data are related to those on neighboring Pt isotopes, especially recent data on 180Pt, and compared to calculations within the interacting boson model and a Hartree-Fock Bogoliubov approach. These models predict prolate deformed ground states in Pt isotopes close to neutron midshell consistent with the experimental findings. Further, evidence was found that the prolate intruder structure observed in neutron-deficient Hg isotopes that is minimum in energy in 182Hg becomes the ground state configuration in 178Pt and neighboring 180Pt with nearly identical transition quadrupole moments. The new data on 178Pt are further discussed in the context of the systematics along the Pt isotopic chain with respect to a possible sharp shape transition towards a weakly deformed or a quasi-vibrational ground state whereas the prolate structure increases in energy in 174,176Pt and becomes an intruder configuration similar to, for example, 180,182Hg.

Published
2019
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3. Preliminary results of lifetime measurements in neutron-rich 53Ti

Author

Goldkuhle Alina, Fransen Christoph, Dewald Alfred, Alahari Navin, Beckers Marcel, Birkenbach Benedikt, Blazhev Andrey, Braunroth Thomas, Clément Emmanuel, De France Gilles, Dudouet Jérémie, Eberth Jürgen, Hess Herbert, Jacquot Bertrand, Kim Yung-Hee, Lemasson Antoine, Lenzi Silvia Monica, Li Hongjie, Ljungvall Joa, Litzinger Julia, Michelagnoli Caterine, Müller-Gatermann Claus, Napoli Daniel Ricardo, Nara Singh Bondili Sreenivasa, Perez-Vidal Rosa Maria, Ralet Damian, Reiter Peter, Rejmund Maurycy, Vogt Andreas, Warr Nigel, Zell Karl Oskar, and Zielińska Magda

Subjects
Physics, QC1-999
Abstract

To study the nuclear structure of neutron-rich titanium isotopes, a lifetime measurement was performed at the Grand Accélérateur National d'Ions Lourds (GANIL) facility in Caen, France. The nucleiwere produced in a multinucleon-transfer reaction by using a 6.76 MeV/u 238U beam. The Advanced Gamma Tracking Array (AGATA) was employed for the γ-ray detection and target-like recoils were identified event-by-event by the large-acceptance variable mode spectrometer (VAMOS++). Preliminary level lifetimes of the (5/2−) to 13/2− states of the yrast band in the neutron-rich nucleus 53Ti were measured for the first time employing the recoil distance Doppler-shift (RDDS) method and the compact plunger for deep inelastic reactions. The differential decay curve method (DDCM) was used to obtain the lifetimes from the RDDS data.

Published
2019
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4. Lifetime measurement of the 2₁⁺ state in ⁷⁴Rb and isospin properties of quadrupole transition strengths at N = Z

Author

Morse, C., Iwasaki, Hironori, Lemasson, Antoine, Dewald, Alfred, Braunroth, Thomas, Bader, V. M., Baugher, Travis R., Bazin, Daniel, Berryman, J. S., Campbell, Christopher M., Gade, Alexandra, Langer, Christoph, Lee, I. Yang, Loelius, C., Lunderberg, E., Recchia, Francesco, Smalley, D., Stroberg, Steven Ragnar, Wadsworth, Robert, Walz, Christopher, Weisshaar, Dirk, Westerberg, A., Whitmore, Kenneth, Wimmer, K., Morse, C., Iwasaki, Hironori, Lemasson, Antoine, Dewald, Alfred, Braunroth, Thomas, Bader, V. M., Baugher, Travis R., Bazin, Daniel, Berryman, J. S., Campbell, Christopher M., Gade, Alexandra, Langer, Christoph, Lee, I. Yang, Loelius, C., Lunderberg, E., Recchia, Francesco, Smalley, D., Stroberg, Steven Ragnar, Wadsworth, Robert, Walz, Christopher, Weisshaar, Dirk, Westerberg, A., Whitmore, Kenneth, and Wimmer, K.

Abstract

Self-conjugate nuclei in the A ≈ 70–80 region have attracted a great deal of attention due to phenomena such as shape coexistence and increasing collectivity along the N=Zline. We investigate the structure of nuclei in this region through lifetime measurements using the GRETINA array. The first implementation of the Differential Recoil Distance Doppler Shift technique with fast radioactive beams is demonstrated and verified through a measurement of the well-known B(E2; 2₁⁺→ 0₁⁺)transition strength in ⁷⁴Kr. The method is then applied to determine the B(E2; 2₁⁺→ 0₁⁺) transition strength in ⁷⁴Rb, the heaviest odd–odd N=Z nucleus for which this quantity has been determined. This result and extended systematics along N=Z suggest the dominance of the isoscalar part of the quadrupole transition strengths in self-conjugate nuclei, as well as the possible presence of shape coexistence in ⁷⁴Rb.

Published
2022

5. Lifetime measurements of excited states in ¹⁶³W and the implications for the anomalous B(E2) ratios in transitional nuclei

Author

Lewis, M. C., Joss, D. T., Sayğı, Bahadır, Page, Robert D., Cullen, David M., Barber, L., Giles, Michael, Simpson, John J., Al-Aqeel, M. A. M., Badran, H., Braunroth, Thomas, Briscoe, Andy D., Calverley, T., Dewald, Alfred, Doncel, M., Grahn, Tuomas, Greenlees, Paul, Henrich, Corinna, Herzáň, Andrej, Herzberg, Rolf Dietmar, Higgins, Edward J., Hilton, J., Ilieva, Stoyanka, Julin, Rauno, Juutinen, Sakari, Keatings, James Michael, Kröll, Thorsten, Labiche, Marc A., Mashtakov, Konstantin R., Nara Singh, Bondili S., Parr, Edward J., Partanen, J., Paul, Edward S., Rahkila, Panu M., Sandzelius, M., Sarén, Jan J., Scholey, Cath S., Siciliano, Marco, Spagnoletti, Pietro, Stolze, S. M., Szwec, Stuart V., Taylor, Michael J., Uusitalo, Juha, Lewis, M. C., Joss, D. T., Sayğı, Bahadır, Page, Robert D., Cullen, David M., Barber, L., Giles, Michael, Simpson, John J., Al-Aqeel, M. A. M., Badran, H., Braunroth, Thomas, Briscoe, Andy D., Calverley, T., Dewald, Alfred, Doncel, M., Grahn, Tuomas, Greenlees, Paul, Henrich, Corinna, Herzáň, Andrej, Herzberg, Rolf Dietmar, Higgins, Edward J., Hilton, J., Ilieva, Stoyanka, Julin, Rauno, Juutinen, Sakari, Keatings, James Michael, Kröll, Thorsten, Labiche, Marc A., Mashtakov, Konstantin R., Nara Singh, Bondili S., Parr, Edward J., Partanen, J., Paul, Edward S., Rahkila, Panu M., Sandzelius, M., Sarén, Jan J., Scholey, Cath S., Siciliano, Marco, Spagnoletti, Pietro, Stolze, S. M., Szwec, Stuart V., Taylor, Michael J., and Uusitalo, Juha

Abstract

This letter reports lifetime measurements of excited states in the odd-N nucleus 163W using the recoil-distance Doppler shift method to probe the core polarising effect of the i13/2 neutron orbital on the underlying soft triaxial even-even core. The ratio B(E2:21/2⁺ → 17/2⁺)/B(E2:17/2⁺ → 13/2⁺) is consistent with the predictions of the collective rotational model. The deduced B(E2) values provide insights into the validity of collective model predictions for heavy transitional nuclei and a geometric origin for the anomalous B(E2) ratios observed in nearby even-even nuclei is proposed.

Published
2022

6. 14C AMS measurement of gas diluted reactor graphite using a Gas Injection System

Author

Gwozdz, Martina, Margreiter, Raphael, Pabst, Timm-Florian, Hackenberg, Gereon, Eberhardt, Klaus, Heinze, Stefan, Herb, Susan, Schiffer, Markus, Stolz, Alexander, Strub, Erik, Muecher, Dennis, Dewald, Alfred, Gwozdz, Martina, Margreiter, Raphael, Pabst, Timm-Florian, Hackenberg, Gereon, Eberhardt, Klaus, Heinze, Stefan, Herb, Susan, Schiffer, Markus, Stolz, Alexander, Strub, Erik, Muecher, Dennis, and Dewald, Alfred

Abstract

For the final disposal of reactor graphite a quantitative characterization of its radioactivity is needed. In this work an emphasis is placed on the isotope 14C, an isotope accessible to AMS measurements. Reactor graphite can be highly activated and therefore difficult to measure without the risk of contaminating the AMS setup. Using an Elemental Analyzer (EA), a Gas Injection System (GIS) and the 6 MV AMS system of the Institute for Nuclear Physics, University of Cologne, we automated the measurement process for gaseous, diluted samples. The presented work shows the first steps to verify the possibility of gas dilution and provides a comparison to samples with known concentrations of 14C. In the future, our system will provide a high sample throughput of gas-diluted probes with high activities.

Published
2022

7. Lifetimes and electromagnetic transition strength in 124Ba

Author

Trichkova Mariya, Beckers Marcel, Gladnishki Kalin, Dewald Alfred, Blazhev Andrey, Müller-Gatermann Claus, Fransen Christoph, Jolie Jan, Kalaydjieva Desislava, Rainovski Georgi, and Zell Karl-Oskar

Subjects
Physics, QC1-999
Abstract

Lifetimes of excited states of 124Ba were measured by the Recoil Distance Doppler Shift (RDDS) technique. The γ-ray coincidence data were analysed by the Differential Decay Curve method (DDCM). The trend of the experimentally deduced normalized B(E2) values reveals a drop at the 8+1 state, which may be caused by structural changes in the backbending region.

Published
2018
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8. Method developments for accelerator mass spectrometry at CologneAMS, Mn-53/He-3 burial dating and ultra-small (CO2)-C-14 samples

Author

Schiffer, Markus, Stolz, Alexander, Lopez, Damian Alejandro, Spanier, Richard, Herb, Susan, Mueller-Gatermann, Claus, Heinze, Stefan, Binnie, Steven, Melchert, Jan, Kivel, Niko, Schumann, Dorothea, Rethemeyer, Janet, Dunai, Tibor, Dewald, Alfred, Schiffer, Markus, Stolz, Alexander, Lopez, Damian Alejandro, Spanier, Richard, Herb, Susan, Mueller-Gatermann, Claus, Heinze, Stefan, Binnie, Steven, Melchert, Jan, Kivel, Niko, Schumann, Dorothea, Rethemeyer, Janet, Dunai, Tibor, and Dewald, Alfred

Abstract

Accelerator mass spectrometry (AMS) has a great potential for various geological applications. The precision and sensitivity is directly linked to technical developments. Therefore CologneAMS, the center for accelerator mass spectrometry of the University of Cologne (Dewald et al., 2013a, 2013b), does extensive work on method developments for isotopic ratio measurement, for new applications and to improve the precision. We present two important technical developments: (1) dating of sediments with Mn-53 and (2) ultra-small (CO2)-C-14 samples. (1) The age determination of discontinuously deposited sediments by measurement of cosmogenic Mn-53 and He-3 concentration in iron-titaniumoxides (hematite, magnetite, titanomagnetite, ilmenite), where the measurement of the medium mass isotope Mn-53 is difficult because of the interfering isobar Cr-53. It can be measured at only 2 laboratories worldwide. The new AMS system at the Cologne 10 MV FN tandem accelerator is therefore designed especially for the measurement of medium mass isotopes, e.g. Mn-53. It provides the opportunity to use several detector systems in different combinations: degrader foils with an electrostatic analyzer, a 4 m time-of-flight system, a new 135 degrees gas-filled magnet, different gas ionization detectors and a projectile x-ray detector. With the implementation of the new 135 degrees gas-filled magnet to the 10 MV FN-Tandem accelerator AMS beamline the first tests have shown an increase in transmission and reduction of blank value in comparrison to the measurement with the degrader foil technique (Schiffer et al. 2018). The background level was reduced by a factor of 3.3 and the error normalized sensitivity (Schiffer et al. 2018) was increased by a factor of 1.6. (2) For the measurement of extremely low carbon from cosmogenic in-situ produced C-14 or from C-14 content of bulk sediments, with 0.01% carbon, technical developments are required to measure low concentrations in terrestrial rocks of 100,0

Published
2020

9. ColPuS, a new multi-isotope plutonium standard for Accelerator Mass Spectrometry

Author

Dittmann, Bjoern-Alexander, Buompane, Raffaele, Chamizo, Elena, Christl, Marcus, Dewald, Alfred, Dunai, Tibor, Feuerstein, Claus, Fifield, Keith, Frohlich, Michaela, Heinze, Stefan, Marzaioli, Fabio, Muenker, Carsten, Petraglia, Antonio, Sirignano, Carmina, Strub, Erik, Synal, Hans-Arno, Terrasi, Filippo, Tims, Stephen, Wallner, Anton, Dittmann, Bjoern-Alexander, Buompane, Raffaele, Chamizo, Elena, Christl, Marcus, Dewald, Alfred, Dunai, Tibor, Feuerstein, Claus, Fifield, Keith, Frohlich, Michaela, Heinze, Stefan, Marzaioli, Fabio, Muenker, Carsten, Petraglia, Antonio, Sirignano, Carmina, Strub, Erik, Synal, Hans-Arno, Terrasi, Filippo, Tims, Stephen, and Wallner, Anton

Abstract

A new multi-isotope plutonium standard for isotopic ratio measurements with Accelerator Mass Spectrometry (AMS) was created by gravimetric mixing of different single-isotope standards provided by IRMM (Pu-239, Pu-240, Pu-242, Pu-244). This standard material has been measured at the AMS facilities at Canberra (Australia), Cologne (Germany), Caserta (Italy), Sevilla (Spain) and Zurich (Switzerland). Additionally, the material was characterized using a Neptune MC-ICPMS (multi-collector inductively coupled plasma mass spectrometry) at the joint Cologne-Bonn isotope facility. The results of this laboratory intercomparison are presented and consensus values for the isotope compositions of the standard material are proposed.

Published
2019

10. Carbonate and silicate intercomparison materials for cosmogenic Cl-36 measurements

Author

Mechernich, Silke, Dunai, Tibor J., Binnie, Steven A., Goral, Tomasz, Heinze, Stefan, Dewald, Alfred, Schimmelpfennig, Irene, Keddadouche, Karim, Aumaitre, Georges, Bourles, Didier, Marrero, Shasta, Wilcken, Klaus, Simon, Krista, Fink, David, Phillips, Fred M., Caffee, Marc W., Gregory, Laura C., Phillips, Richard, Freeman, Stewart P. H. T., Shanks, Richard, Sarikaya, M. Akif, Pavetich, Stefan, Rugel, Georg, Merchel, Silke, Akcar, Naki, Yesilyurt, Serdar, Ivy-Ochs, Susan, Vockenhuber, Christof, Mechernich, Silke, Dunai, Tibor J., Binnie, Steven A., Goral, Tomasz, Heinze, Stefan, Dewald, Alfred, Schimmelpfennig, Irene, Keddadouche, Karim, Aumaitre, Georges, Bourles, Didier, Marrero, Shasta, Wilcken, Klaus, Simon, Krista, Fink, David, Phillips, Fred M., Caffee, Marc W., Gregory, Laura C., Phillips, Richard, Freeman, Stewart P. H. T., Shanks, Richard, Sarikaya, M. Akif, Pavetich, Stefan, Rugel, Georg, Merchel, Silke, Akcar, Naki, Yesilyurt, Serdar, Ivy-Ochs, Susan, and Vockenhuber, Christof

Abstract

Two natural mineral separates, labeled CoCal-N and CoFsp-N, have been prepared to serve as intercomparison material (ICM) for in situ-produced cosmogenic Cl-36 and natural chlorine (Cl-nat) analysis. The sample CoCal-N is derived from calcite crystals in a Namibian lag deposit, while the sample CoFsp-N is derived from a single crystal of alkali-feldspar from a Namibian pegmatite. The sample preparation took place at the University of Cologne and a rotating splitter was used to obtain homogeneous splits of both ICMs. Forty-five measurements of CoCal-N (between 1 and 16 per facility) and forty-four measurements of CoFsp-N (between 2 and 20 per facility) have been undertaken by ten target preparation laboratories measured by seven different AMS facilities. The internal laboratory scatter of the Cl-36 concentrations indicates no overdispersion for half of the laboratories and 3.9 to 7.3% (1 sigma) overdispersion for the others. We show that the CoCal-N and CoFsp-N splits are homogeneous regarding their Cl-36 and Cl-nat concentrations. The grand average (average calculated from the average of each laboratory) yields initial consensus Cl-36 concentrations of (3.74 +/- 0.10) x 10(6) at Cl-36/g (CoCal-N) and (2.93 +/- 0.07) x 10(6) at Cl-36/g (CoFsp-N) at 95% confidence intervals. The coefficient of variation is 5.1% and 4.2% for CoCal-N and CoFsp-N, respectively. The Cl-nat concentration corresponds to the lower and intermediate range of typical rock samples with (0.73 +/- 0.18) mu/g in CoCal-N and (73.9 +/- 6.8) mu/g in CoFsp-N. We discuss the most relevant points of the sample preparation and measurement and the chlorine concentration calculation to further approach inter-laboratory comparability. We propose to use continuous measurements of the ICMs to provide a valuable quality control for future determination of Cl-36 and Cl-nat concentrations.

Published
2019

11. EXPLORING SAMPLE SIZE LIMITS OF AMS GAS ION SOURCE C-14 ANALYSIS AT COLOGNEAMS

Author

Melchert, Jan Olaf, Stolz, Alexander, Dewald, Alfred, Gierga, Merle, Wischhoefer, Philipp, Rethemeyer, Janet, Melchert, Jan Olaf, Stolz, Alexander, Dewald, Alfred, Gierga, Merle, Wischhoefer, Philipp, and Rethemeyer, Janet

Abstract

Increasing demands for small-scale radiocarbon (C-14) analyses required the installation of a SO-110 B type ion source (HVE Europa B.V.) at our 6 MV Tandetron AMS (HVE) dedicated for the direct injection of CO2 using either the gas injection system (GIS) from Ionplus AG or a EuroVector EA 3000 elemental analyzer (EA). We tested both systems with multiple series of C-14-free and modern standards (2.5-50 mu g C) combusted in quartz ampoules or EA containers and were able to quantify exogenous C introduced. In EA-GIS-AMS analysis exogenous C is mainly derived from the EA sample containers. Blank values for 50 mu g C combusted in solvent-cleaned tin (Sn) vessels were 0.0127 +/- 0.0012 (FC)-C-14 (boats) and 0.0090 +/- 0.0010 (FC)-C-14 (capsules), while they were much higher for thermally cleaned silver (Ag) capsules. The processing of gas samples for GIS-AMS yields similar blank values corresponding to 0.30 +/- 0.08 mu g exogenous C with 0.93 +/- 0.23 (FC)-C-14 consisting of 0.28 mu g C modern and 0.02 mu g C fossil C. The combustion of larger amounts of blank material (1 mg C) in a single quartz tube split into aliquots gives lower blanks (0.0064 +/- 0.0008 (FC)-C-14; 50 mu g C). Thus, C-14 analysis of small, gaseous samples is now possible at CologneAMS.

Published
2019

12. ColPuS, a new multi-isotope plutonium standard for Accelerator Mass Spectrometry

Author

Chamizo, Elena [0000-0001-8266-6129], Dittmann, Björn-Alexander, Buompane, Raffaele, Chamizo, Elena, Christl, M., Dewald, Alfred, Dunai, T., Feuerstein, Claus, Fifield, Keith, Fröhlich, Michaela, Heinze, Stefan, Marzaioli, Fabio, Münker, Carsten, Petraglia, Antonio, Sirignano, Carmina, Strub, Erik, Synal, Hans-Arno, Terrasi, Filippo, Tims, Stephen, Wallner, A., Chamizo, Elena [0000-0001-8266-6129], Dittmann, Björn-Alexander, Buompane, Raffaele, Chamizo, Elena, Christl, M., Dewald, Alfred, Dunai, T., Feuerstein, Claus, Fifield, Keith, Fröhlich, Michaela, Heinze, Stefan, Marzaioli, Fabio, Münker, Carsten, Petraglia, Antonio, Sirignano, Carmina, Strub, Erik, Synal, Hans-Arno, Terrasi, Filippo, Tims, Stephen, and Wallner, A.

Abstract

A new multi-isotope plutonium standard for isotopic ratio measurements with Accelerator Mass Spectrometry (AMS) was created by gravimetric mixing of different single-isotope standards provided by IRMM (Pu-239, Pu-240, Pu-242, Pu-244). This standard material has been measured at the AMS facilities at Canberra (Australia), Cologne (Germany), Caserta (Italy), Sevilla (Spain) and Zurich (Switzerland). Additionally, the material was characterized using a Neptune MC-ICPMS (multi-collector inductively coupled plasma mass spectrometry) at the joint Cologne-Bonn isotope facility. The results of this laboratory intercomparison are presented and consensus values for the isotope compositions of the standard material are proposed.

Published
2019

13. Ion beam techniques for nuclear waste management.

Author

Mitchell, A.J., Pavetich, S., Koll, D., Schiffer, Markus, Stolz, Alexander, Strub, Erik, Herb, Susan, Dewald, Matthias, Margreiter, Raphael, Papst, Timm-Florian, Geusen, Kevin, Jakobi, Yannik, Hackenberg, Gereon, Mueller-Gatermann, Claus, Heinze, Stefan, and Dewald, Alfred

Subjects
RADIOACTIVE wastes, ION beams, WASTE management, ACCELERATOR mass spectrometry, GRAPHITE
Abstract

An automated CO2 gas handling and injection system was developed. It is designed to dilute CO2 samples with blank gas in a mixing volume. The system is intended to be used for the characterization and quantification of 14C content in reactor graphite with accelerator mass spectrometry. A 100 kV accelerator system was developed to measure samples with high 14C content, to test the gas injection system and to measure the 3H content from gaseous releases of reactor graphite. Additionally, the Tandetron model 4130 was purchased from the Max-Planck Institute for Biogeochemistry Jena (Germany) and a concept was developed for installation at the accelerator building of the University of Cologne. With the new 3 MV system, new isotopic ratio measurements and ion beam techniques for material analysis can be performed. The system will be used for nuclear waste management measurements of isotopes, e.g. 3H, 14C, 36Cl, 41Ca and 55Fe, which are difficult to measure with other techniques. [ABSTRACT FROM AUTHOR]

Published
2020
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14. Preliminary results of lifetime measurements in neutron-rich 53Ti.

Author

de Angelis, G., Corradi, L., Goldkuhle, Alina, Fransen, Christoph, Dewald, Alfred, Alahari, Navin, Beckers, Marcel, Birkenbach, Benedikt, Blazhev, Andrey, Braunroth, Thomas, Clément, Emmanuel, De France, Gilles, Dudouet, Jérémie, Eberth, Jürgen, Hess, Herbert, Jacquot, Bertrand, Kim, Yung-Hee, Lemasson, Antoine, Lenzi, Silvia Monica, and Li, Hongjie

Subjects
NEUTRONS, TITANIUM isotopes, NUCLEAR structure, INELASTIC scattering, SPECTROMETERS
Abstract

To study the nuclear structure of neutron-rich titanium isotopes, a lifetime measurement was performed at the Grand Accélérateur National d'Ions Lourds (GANIL) facility in Caen, France. The nucleiwere produced in a multinucleon-transfer reaction by using a 6.76 MeV/u 238U beam. The Advanced Gamma Tracking Array (AGATA) was employed for the γ-ray detection and target-like recoils were identified event-by-event by the large-acceptance variable mode spectrometer (VAMOS++). Preliminary level lifetimes of the (5/2−) to 13/2− states of the yrast band in the neutron-rich nucleus 53Ti were measured for the first time employing the recoil distance Doppler-shift (RDDS) method and the compact plunger for deep inelastic reactions. The differential decay curve method (DDCM) was used to obtain the lifetimes from the RDDS data. [ABSTRACT FROM AUTHOR]

Published
2019
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15. Structural investigation of neutron-deficient Pt isotopes: the case of 178Pt.

Author

de Angelis, G., Corradi, L., Fransen, Christoph, Mammes, Franziska, Bark, Robert, Braunroth, Thomas, Buthelezi, Zinhle, Dewald, Alfred, Dinoko, Tshepo, Förtsch, Siegie, Hackstein, Matthias, Jolie, Jan, Jones, Pete, Lawrie, Elena, Litzinger, Julia, Müller-Gatermann, Claus, Newman, Richard, Saed-Samii, Nima, Sharpey-Schafer, John F., and Shirinda, Obed

Subjects
NEUTRONS, DOPPLER effect, PLATINUM isotopes, QUADRUPOLE moments, TRANSITION state theory (Chemistry)
Abstract

Lifetime measurements with the recoil distance Doppler-shift technique have been performed to determine yrast E2 transition strengths in 178Pt. The experimental data are related to those on neighboring Pt isotopes, especially recent data on 180Pt, and compared to calculations within the interacting boson model and a Hartree-Fock Bogoliubov approach. These models predict prolate deformed ground states in Pt isotopes close to neutron midshell consistent with the experimental findings. Further, evidence was found that the prolate intruder structure observed in neutron-deficient Hg isotopes that is minimum in energy in 182Hg becomes the ground state configuration in 178Pt and neighboring 180Pt with nearly identical transition quadrupole moments. The new data on 178Pt are further discussed in the context of the systematics along the Pt isotopic chain with respect to a possible sharp shape transition towards a weakly deformed or a quasi-vibrational ground state whereas the prolate structure increases in energy in 174,176Pt and becomes an intruder configuration similar to, for example, 180,182Hg. [ABSTRACT FROM AUTHOR]

Published
2019
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16. Transition probabilities in neutron-rich 80,82Se and the role of the {\nu}g9/2 orbital

Author

Litzinger, J, Blazhev, Andrey, Dewald, Alfred, Didierjean, Francois, Duchene, G, Fransen, C., Lozeva, R, Verney, D, De Angelis, G., Bazzacco, Dino, Birkenbach, B., Bottoni, S., Bracco, Angela, Braunroth, T, Cederwall, B., Corradi, Lorenzo, Crespi, F.C.L., Désesquelles, Pierre, Eberth, Jürgen, Ellinger, E., Farnea, Enrico, Fioretto, E., Gernhauser, Roman, Goasduff, A, Görgen, Andreas, Gottardo, Andrea, Grebosz, J, Hackstein, Matthias, Hess, Herbert, Ibrahim, Fadi, Jolie, J, Jungclaus, Andrea, Kolos, K, Korten, Wolfram, Leoni, Silvia, Lunardi, Santo, Maj, Adam, Menegazzo, R., Mengoni, Daniele, Michelagnoli, Caterina, Mijatovic, T., Million, Bénédicte, Möller, O, Modamio, Victor, Montagnoli, G., Montanari, D., Morales, Ana Isabel, Napoli, D.R., Niikura, Megumi, Pietralla, Norbert A., Pollarolo, G., Pullia, A., Quintana, B., Recchia, Francesco, Reiter, Peter, Rosso, D., Sahin, Eda, Salsac, Marie Delphine, Scarlassara, F., Söderström, Pär Anders, Stefanini, AM, Stezowski, Olivier, Szilner, Suzana, Theisen, Christophe, Valiente-Dobón, Jose Javier, Vandone, V, and Vogt, A.

Abstract

Transition probabilities of intermediate-spin yrast and non-yrast excitations in 80,82Se were investigated in a recoil distance Doppler-shift (RDDS) experiment performed at the Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro. The Cologne Plunger device for deep inelastic scattering was used for the RDDS technique and was combined with the AGATA Demonstrator array for the γ -ray detection and coupled to the PRISMA magnetic spectrometer for an event-by-event particle identification. In 80Se, the level lifetimes of the yrast (6+ 1 ) and (8+ 1 ) states and of a non-yrast band feeding the yrast 4+ 1 state are determined. A spin and parity assignment of the head of this sideband is discussed based on the experimental results and supported by large-scale shell-model calculations. In 82Se, the level lifetimes of the yrast 6+ 1 state and the yrare 4+ 2 state and lifetime limits of the yrast (10+ 1 ) state and of the 5− 1 state are determined. Although the experimental results contain large uncertainties, they are interpreted with care in terms of large-scale shell-model calculations using the effective interactions JUN45 and jj44b. The excited states’ wave functions are investigated and discussed with respect to the role of the neutron g9/2 orbital.

Published
2018

17. Evidence for coexisting shapes through lifetime measurements in 98Zr

Author

Singh, Purnima, Korten, Wolfram, Hagen, Trine Wiborg, Görgen, Andreas, Grente, Lucie, Salsac, Marie Delphine, Farget, F., Braunroth, T, Bruyneel, Bart, Celikovic, I, Clement, E, de France, G., Delaune, O, Dewald, Alfred, Dijon, Aurore, Delaroche, Jean Paul, Girod, Michel, Hackstein, Matthias, Jacquot, Bertrand, Libert, J., Litzinger, J, Ljungvall, Joa, Louchart, C, Gottardo, Andrea, Michelagnoli, Caterina, Napoli, D.R., Otsuka, Takaharu, Pillet, N., Recchia, Francesco, Rother, Wolfram, Sahin, Eda, Siem, Sunniva, Sulignano, B, Togashi, T., Theisen, Christophe, and Valiente-Dobón, Jose Javier

Subjects
Nuclear Experiment
Abstract

The lifetimes of the first excited 2þ, 4þ, and 6þ states in 98Zr were measured with the recoil-distance Doppler shift method in an experiment performed at GANIL. Excited states in 98Zr were populated using the fission reaction between a 6.2 MeV=u 238U beam and a 9 Be target. The γ rays were detected with the EXOGAM array in correlation with the fission fragments identified by mass and atomic number in the VAMOS++ spectrometer. Our result shows a very small BðE2; 2þ 1 → 0þ 1 Þ value in 98Zr, thereby confirming the very sudden onset of collectivity at N ¼ 60. The experimental results are compared to large-scale Monte Carlo shell model and beyond-mean-field calculations. The present results indicate the coexistence of two additional deformed shapes in this nucleus along with the spherical ground state.

Published
2018

18. Evidence for Coexisting Shapes through Lifetime Measurements in Zr98

Author

Singh, Purnima, Korten, Wolfram, Hagen, T. W., Gorgen, Andreas, Grente, Lucie, Salsac, Marie Delphine, Farget, Fanny, Clement, Emmanuel, de France, Gilles, Braunroth, Thomas, Bruyneel, Bart, Čeliković, Igor T., Delaune, Olivier, Dewald, Alfred, Dijon, A., Delaroche, Jean Paul, Girod, Michel, Hackstein, Matthias, Jacquot, Bertrand, Libert, J., Litzinger, J., Ljungvall, Joa, Louchart, C., Gottardo, Andrea, Michelagnoli, Caterina, Muller-Gatermann, C, Napoli, Daniel R., Otsuka, Takaharu, Pillet, Nathalie, Recchia, Francesco, Rother, Wolfram, Sahin, E., Siem, Sunniva, Sulignano, Barbara, Togashi, Tomoaki, Tsunoda, Yuhsuke, Theisen, Christophe, Valiente-Dobon, Jose Javier, Singh, Purnima, Korten, Wolfram, Hagen, T. W., Gorgen, Andreas, Grente, Lucie, Salsac, Marie Delphine, Farget, Fanny, Clement, Emmanuel, de France, Gilles, Braunroth, Thomas, Bruyneel, Bart, Čeliković, Igor T., Delaune, Olivier, Dewald, Alfred, Dijon, A., Delaroche, Jean Paul, Girod, Michel, Hackstein, Matthias, Jacquot, Bertrand, Libert, J., Litzinger, J., Ljungvall, Joa, Louchart, C., Gottardo, Andrea, Michelagnoli, Caterina, Muller-Gatermann, C, Napoli, Daniel R., Otsuka, Takaharu, Pillet, Nathalie, Recchia, Francesco, Rother, Wolfram, Sahin, E., Siem, Sunniva, Sulignano, Barbara, Togashi, Tomoaki, Tsunoda, Yuhsuke, Theisen, Christophe, and Valiente-Dobon, Jose Javier

Abstract

The lifetimes of the first excited 2+, 4+, and 6+ states in Zr98 were measured with the recoil-distance Doppler shift method in an experiment performed at GANIL. Excited states in Zr98 were populated using the fission reaction between a 6.2 MeV/u U238 beam and a Be9 target. The γ rays were detected with the EXOGAM array in correlation with the fission fragments identified by mass and atomic number in the VAMOS++ spectrometer. Our result shows a very small B(E2;21+→01+) value in Zr98, thereby confirming the very sudden onset of collectivity at N=60. The experimental results are compared to large-scale Monte Carlo shell model and beyond-mean-field calculations. The present results indicate the coexistence of two additional deformed shapes in this nucleus along with the spherical ground state. © 2018 American Physical Society.

Published
2018

19. Lifetimes of excited states in triaxially deformed 107Tc and 109,111,113Rh

Author

Hagen, T. W., Gorgen, Andreas, Korten, Wolfram, Grente, Lucie, Salsac, Marie Delphine, Farget, Fanny, Braunroth, Thomas, Bruyneel, Bart, Čeliković, Igor T., Clement, Emmanuel, de France, Gilles, Delaune, Olivier, Dewald, Alfred, Dijon, A., Hackstein, Matthias, Jacquot, Bertrand, Litzinger, J., Ljungvall, Joa, Louchart, C., Michelagnoli, Caterina, Napoli, Daniel R., Recchia, Francesco, Rother, Wolfram, Sahin, E., Siem, Sunniva, Sulignano, Barbara, Theisen, Christophe, Valiente-Dobon, Jose Javier, Hagen, T. W., Gorgen, Andreas, Korten, Wolfram, Grente, Lucie, Salsac, Marie Delphine, Farget, Fanny, Braunroth, Thomas, Bruyneel, Bart, Čeliković, Igor T., Clement, Emmanuel, de France, Gilles, Delaune, Olivier, Dewald, Alfred, Dijon, A., Hackstein, Matthias, Jacquot, Bertrand, Litzinger, J., Ljungvall, Joa, Louchart, C., Michelagnoli, Caterina, Napoli, Daniel R., Recchia, Francesco, Rother, Wolfram, Sahin, E., Siem, Sunniva, Sulignano, Barbara, Theisen, Christophe, and Valiente-Dobon, Jose Javier

Abstract

Lifetimes of excited states in Tc-107, Rh-109, Rh-111, and Rh-113 were measured at GANIL using the Recoil-Distance Doppler Shift method. The neutron-rich nuclei were produced in fission reactions in inverse kinematics with a U-238 beam impinging on a Be-9 target. Fission fragments were identified event-by-event in the ray-tracing spectrometer VAMOS++ and correlated with prompt gamma rays observed around the target position with the EXOGAM Ge detector array. Several lifetimes were obtained for states in the positiveparity yrast bands in the four nuclei and compared to triaxial particle-rotor calculations. The results clarify the configuration for the strongest positive-parity band in Tc-107 and suggest a gradual increase of triaxial deformation with atomic number Z, reaching almost maximum triaxiality for the neutron-rich Rh nuclei.

Published
2018

20. Evolution of nuclear shapes in odd-mass yttrium and niobium isotopes from lifetime measurements following fission reactions

Author

Hagen, T. W., Görgen, Andreas, Korten, Wolfram, Grente, Lucie, Salsac, Marie Delphine, Farget, Fanny, Ragnarsson, Ingemar, Braunroth, Thomas, Bruyneel, Bart, Čeliković, Igor T., Clement, Emmanuel, de France, Gilles, Delaune, Olivier, Dewald, Alfred, Dijon, A., Hackstein, Matthias, Jacquot, Bertrand, Litzinger, J., Ljungvall, Joa, Louchart, C., Michelagnoli, Caterina, Napoli, Daniel R., Recchia, Francesco, Rother, Wolfram, Sahin, Eda, Siem, Sunniva, Sulignano, Barbara, Theisen, Christophe, Valiente-Dobon, Jose Javier, Hagen, T. W., Görgen, Andreas, Korten, Wolfram, Grente, Lucie, Salsac, Marie Delphine, Farget, Fanny, Ragnarsson, Ingemar, Braunroth, Thomas, Bruyneel, Bart, Čeliković, Igor T., Clement, Emmanuel, de France, Gilles, Delaune, Olivier, Dewald, Alfred, Dijon, A., Hackstein, Matthias, Jacquot, Bertrand, Litzinger, J., Ljungvall, Joa, Louchart, C., Michelagnoli, Caterina, Napoli, Daniel R., Recchia, Francesco, Rother, Wolfram, Sahin, Eda, Siem, Sunniva, Sulignano, Barbara, Theisen, Christophe, and Valiente-Dobon, Jose Javier

Abstract

Lifetimes of excited states in Y-99, Y-101, Nb-101, Nb-103, and Nb-105 were measured in an experiment using the recoil distance Doppler shift method at GANIL (Grand Accelerateur National dIons Lourds). The neutron-rich nuclei were produced in fission reactions between a U-238 beam and a Be-9 target. Prompt gamma rays were measured with the EXOGAM array and correlated with fission fragments that were identified in mass and atomic number with the VAMOS++ spectrometer. The measured lifetimes, together with branching ratios, provide B(M1) and B(E2) values for the strongly coupled rotational bands built on the [422] 5/2(+) ground state in the Y and Nb nuclei with neutron number N GT = 60. The comparison of the experimental results with triaxial particle-rotor calculations provides information about the evolution of the nuclear shape in this mass region.

Published
2017

21. Lifetimes and electromagnetic transition strength in 124Ba.

Author

Arsenyev, N., Bezbakh, A., Rogov, I., Shneidman, T., Vdovin, A., Trichkova, Mariya, Beckers, Marcel, Gladnishki, Kalin, Dewald, Alfred, Blazhev, Andrey, Müller-Gatermann, Claus, Fransen, Christoph, Jolie, Jan, Kalaydjieva, Desislava, Rainovski, Georgi, and Zell, Karl-Oskar

Subjects
BARIUM compounds, ELECTROMAGNETIC fields, STRENGTH of materials, EXCITED states, DOPPLER effect
Abstract

Lifetimes of excited states of 124Ba were measured by the Recoil Distance Doppler Shift (RDDS) technique. The γ-ray coincidence data were analysed by the Differential Decay Curve method (DDCM). The trend of the experimentally deduced normalized B(E2) values reveals a drop at the 8+1 state, which may be caused by structural changes in the backbending region. [ABSTRACT FROM AUTHOR]

Published
2018

22. Lifetime Measurments of Excited States in Neutron-Rich Fission Fragments

Author

Hagen, T. W., Grente, Lucie, Gorgen, Andreas, Salsac, Marie Delphine, Korten, Wolfram, Farget, Fanny, Braunroth, Thomas, Bruyneel, Bart, Čeliković, Igor T., Clement, Emmanuel, de France, Gilles, Delaune, Olivier, Dewald, Alfred, Dijon, A., Hackstein, Matthias, Jacquot, Bertrand, Litzinger, J., Ljungvall, Joa, Louchart, C., Michelagnoli, Caterina, Napoli, Daniel R., Navin, A., Recchia, Francesco, Rejmund, M., Rother, Wolfram, Sahin, Eda, Siem, Sunniva, Sulignano, Barbara, Theisen, Christophe, Valiente-Dobon, Jose Javier, Hagen, T. W., Grente, Lucie, Gorgen, Andreas, Salsac, Marie Delphine, Korten, Wolfram, Farget, Fanny, Braunroth, Thomas, Bruyneel, Bart, Čeliković, Igor T., Clement, Emmanuel, de France, Gilles, Delaune, Olivier, Dewald, Alfred, Dijon, A., Hackstein, Matthias, Jacquot, Bertrand, Litzinger, J., Ljungvall, Joa, Louchart, C., Michelagnoli, Caterina, Napoli, Daniel R., Navin, A., Recchia, Francesco, Rejmund, M., Rother, Wolfram, Sahin, Eda, Siem, Sunniva, Sulignano, Barbara, Theisen, Christophe, and Valiente-Dobon, Jose Javier

Abstract

Lifetimes of short-lived excited states in a wide range of neutron-rich fission fragments were measured using the recoil distance Doppler shift (RDDS) technique, which was applied to fusion-fission reactions in inverse kinematics for the first time. The fission fragments were identified event-by-event in mass, charge, and atomic number using the VAMOS magnetic spectrometer at GANIL. Gamma rays originating from the fission fragments were measured with the EXOGAM array of Ge Clover detectors around the target position. Using a degrader, the change in the Doppler shift of the gamma ray allows the application of the RDDS method. Details of the experimental technique will be discussed and the status for the ongoing analysis for odd-mass yttrium isotopes will be presented.

Published
2016

23. Separation of Be and Al for AMS using single-step column chromatography

Author

Binnie, Steven A., Dunai, Tibor J., Voronina, Elena, Goral, Tomasz, Heinze, Stefan, Dewald, Alfred, Binnie, Steven A., Dunai, Tibor J., Voronina, Elena, Goral, Tomasz, Heinze, Stefan, and Dewald, Alfred

Abstract

With the aim of simplifying AMS target preparation procedures for TCN measurements we tested a new extraction chromatography approach which couples an anion exchange resin (WBEC) to a chelating resin (Beryllium resin) to separate Be and Al from dissolved quartz samples. Results show that WBEC-Beryllium resin stacks can be used to provide high purity Be and Al separations using a combination of hydrochloric/oxalic and nitric acid elutions. Be-16 and Al-26 concentrations from quartz samples prepared using more standard procedures are compared with results from replicate samples prepared using the coupled WBEC-Beryllium resin approach and show good agreement. The new column procedure is performed in a single step, reducing sample preparation times relative to more traditional methods of TCN target production. (C) 2015 The Authors. Published by Elsevier B.V.

Published
2015

24. Probing collectivity in Zn isotopes with one particle or hole outside the N=40 subshell closure

Author

Čeliković, Igor T., Dijon, A., Clement, Emmanuel, de France, Gilles, Van Isacker, P., Ljungvall, Joa, Dewald, Alfred, Fransen, C., Georgiev, G., Gorgen, Andreas, Gottardo, Andrea, Hackstein, Matthias, Hagen, T. W., Louchart, C., Napiorkowski, P., Obertelli, A., Recchia, Francesco, Rother, Wolfram, Siem, Sunniva, Sulignano, Barbara, Ujić, Predrag, Valiente-Dobon, Jose Javier, Zielinska, M., Čeliković, Igor T., Dijon, A., Clement, Emmanuel, de France, Gilles, Van Isacker, P., Ljungvall, Joa, Dewald, Alfred, Fransen, C., Georgiev, G., Gorgen, Andreas, Gottardo, Andrea, Hackstein, Matthias, Hagen, T. W., Louchart, C., Napiorkowski, P., Obertelli, A., Recchia, Francesco, Rother, Wolfram, Siem, Sunniva, Sulignano, Barbara, Ujić, Predrag, Valiente-Dobon, Jose Javier, and Zielinska, M.

Abstract

The nuclear structure of the odd-mass Zn-69 and Zn-71 isotopes, with one hole or one particle outside the N = 40 subshell closure, has been investigated by measuring the lifetime of excited states using the recoil distance Doppler-shift method. The nuclei of interest were produced in a deep-inelastic reaction in inverse kinematics with a U-238 beam impinging on a Zn-70 target. Single-particle and collective states were found to coexist at low energy in Zn-69 and Zn-71.

Published
2015

26. First direct lifetime measurement of the 2(1)(+) state in Zn-72,Zn-74: New evidence for a shape transition between N=40 and N=42 close to Z=28

Author

Niikura, M., Mouginot, B., Franchoo, S., Matea, I., Stefan, I., Verney, D., Azaiez, F., Assie, Marlène, Bednarczyk, P., Borcea, C., Burger, A., Burgunder, G., Buta, Anna, Caceres, L., Clement, Emmanuel, Coquard, L., de Angelis, G., de France, Gilles, Santos, F. de Oliveira, Dewald, Alfred, Dijon, A., Dombradi, Z., Fiori, E., Fransen, C., Friessner, G., Gaudefroy, L., Georgiev, G., Grèvy, Stéphane, Hackstein, Matthias, Harakeh, M. N., Ibrahim, F., Kamalou, O., Kmiecik, M., Lozeva, R., Maj, A., Mihai, C., Moeller, O., Myalski, S., Negoita, Florin, Pantelica, Dan, Perrot, L., Pissulla, Th., Rotaru, F., Rother, Wolfram, Scarpaci, J. A., Stodel, C., Thomas, J. C., Ujić, Predrag, Niikura, M., Mouginot, B., Franchoo, S., Matea, I., Stefan, I., Verney, D., Azaiez, F., Assie, Marlène, Bednarczyk, P., Borcea, C., Burger, A., Burgunder, G., Buta, Anna, Caceres, L., Clement, Emmanuel, Coquard, L., de Angelis, G., de France, Gilles, Santos, F. de Oliveira, Dewald, Alfred, Dijon, A., Dombradi, Z., Fiori, E., Fransen, C., Friessner, G., Gaudefroy, L., Georgiev, G., Grèvy, Stéphane, Hackstein, Matthias, Harakeh, M. N., Ibrahim, F., Kamalou, O., Kmiecik, M., Lozeva, R., Maj, A., Mihai, C., Moeller, O., Myalski, S., Negoita, Florin, Pantelica, Dan, Perrot, L., Pissulla, Th., Rotaru, F., Rother, Wolfram, Scarpaci, J. A., Stodel, C., Thomas, J. C., and Ujić, Predrag

Abstract

We report here the first direct lifetime measurement of the 2(1)(+) state in Zn-72,Zn-74. The neutron-rich beam was produced by in-flight fragmentation of Ge-76 at the Grand Accelerateur National dIons Lourds and separated with the LISE spectrometer. The 2(1)(+) state was excited by inelastic scattering and knock-out reaction on a CD2 target and its lifetime was measured by the recoil-distance Doppler-shift method with the Koln plunger device combined with the EXOGAM detectors. The lifetimes of the 2(1)(+) states in Zn-72,Zn-74 were determined to be 17.9(18) and 27.0(24) ps, which correspond to reduced transition probabilities B(E2; 2(1)(+)- GT 0(+)) = 385(39) and 370(33) e(2) fm(4), respectively. These values support the idea of a systematic maximum of collectivity at N = 42 for Zn, Ge, and Se nuclei. In addition, the available systematics in the neighboring nuclei point toward a transition from a spherical oscillator at N = 40 to complete gamma-softness at N = 42.

Published
2012

27. Collectivity of Po196 at low spin

Author

Grahn, T., Dewald, Alfred, Greenlees, Paul, Jakobsson, U., Jolie, Jan, Jones, P.M., Julin, Rauno, Juutinen, Sakari, Ketelhut, S., Kröll, Th, Krücken, Reiner, Leino, Matti, Maierbeck, Peter, Melon, Barbara, Nyman, Marjut, Page, R., Peura, Pauli, Pissulla, Th, Rahkila, Panu, Saren, J., Scholey, Cath, Sorri, J., Uusitalo, Juha, Bender, Michaël, Heenen, Paul-Henri, Grahn, T., Dewald, Alfred, Greenlees, Paul, Jakobsson, U., Jolie, Jan, Jones, P.M., Julin, Rauno, Juutinen, Sakari, Ketelhut, S., Kröll, Th, Krücken, Reiner, Leino, Matti, Maierbeck, Peter, Melon, Barbara, Nyman, Marjut, Page, R., Peura, Pauli, Pissulla, Th, Rahkila, Panu, Saren, J., Scholey, Cath, Sorri, J., Uusitalo, Juha, Bender, Michaël, and Heenen, Paul-Henri

Abstract

Absolute electromagnetic transition probabilities in Po196 have been measured using the recoil distance Doppler-shift technique. The lifetimes of the three lowest yrast states in Po196 were extracted from singles γ-ray spectra by using the recoil-decay tagging method. In addition, configuration mixing calculations of angular momentum projected mean-field states have been carried out for Po196. The present study sheds light on the onset of collectivity and mixing of competing structures in neutron-deficient Po nuclei. © 2009 The American Physical Society., SCOPUS: ar.j, info:eu-repo/semantics/published

Published
2009

28. Lifetimes of intruder states in 186Pb, 188Pb and 194Po

Author

Grahn, T., Dewald, Alfred, Möller, Oliver, Julin, Rauno, Beausang, C. W., Christen, S., Darby, I. G., Eeckaudt, S., Greenlees, P. T., Görgen, Andreas, Helariutta, Kerttuli, Jolie, Jan, Jones, Peter, Juutinen, Sakari, Kettunen, T., Kröll, Th, Krücken, Reiner, Le Coz, Y., Leino, Matti, Leppänen, Ari Pekka, Maierbeckg, P., Meyerd, D. A., Melonc, B., Nieminena, P., Nymana, M., Pageb, R. D., Pakarinen, Janne, Petkovh, P., Rahkilaa, P., Sahac, B., Sandzelius, M., Saréna, J., Scholeya, C., Uusitalo, Juha, Bender, Michaël, Heenen, Paul-Henri, Grahn, T., Dewald, Alfred, Möller, Oliver, Julin, Rauno, Beausang, C. W., Christen, S., Darby, I. G., Eeckaudt, S., Greenlees, P. T., Görgen, Andreas, Helariutta, Kerttuli, Jolie, Jan, Jones, Peter, Juutinen, Sakari, Kettunen, T., Kröll, Th, Krücken, Reiner, Le Coz, Y., Leino, Matti, Leppänen, Ari Pekka, Maierbeckg, P., Meyerd, D. A., Melonc, B., Nieminena, P., Nymana, M., Pageb, R. D., Pakarinen, Janne, Petkovh, P., Rahkilaa, P., Sahac, B., Sandzelius, M., Saréna, J., Scholeya, C., Uusitalo, Juha, Bender, Michaël, and Heenen, Paul-Henri

Abstract

Lifetimes of prolate intruder states in 186Pb and 188Pb and oblate intruder states in 194Po have been determined through recoil distance Doppler-shift lifetime measurements. Deformation parameters of, SCOPUS: ar.j, info:eu-repo/semantics/published

Published
2008

29. Proton and alpha-particle capture reactions at sub-Coulomb energies relevant to the p process

Author

Harissopulos, Sotirios, Lagoyannis, Anastasios, Spyrou, Artemis, Zarkadas, Ch, Galanopoulos, S., Perdikakis, Georgios, Becker, Hans Werner, Rolfs, Claus, Strieder, Frank, Kunz, Rino, Fey, M., Hammer, Johann Wolfgang, Dewald, Alfred, Zell, Karl Oskar, von Brentano, Peter, Julin, Rauno, Demetriou, Paraskevi, Harissopulos, Sotirios, Lagoyannis, Anastasios, Spyrou, Artemis, Zarkadas, Ch, Galanopoulos, S., Perdikakis, Georgios, Becker, Hans Werner, Rolfs, Claus, Strieder, Frank, Kunz, Rino, Fey, M., Hammer, Johann Wolfgang, Dewald, Alfred, Zell, Karl Oskar, von Brentano, Peter, Julin, Rauno, and Demetriou, Paraskevi

Abstract

Several cross-section measurements of proton as well as α-particle capture reactions in the Se-Sb region have been carried out at sub-Coulomb energies with the aim to obtain global input parameters for Hauser-Feshbach (HF) calculations. Some of the results are compared with HF calculations using various optical model potentials and nuclear level densities. © 2005 IOP Publishing Ltd., SCOPUS: cp.j, info:eu-repo/semantics/published

Published
2005

30. Systematic measurements of proton- and alpha-capture cross sections relevant to the modelling of the p process

Author

Harissopulos, Sotirios, Spyrou, Artemis, Lagoyannis, Anastasios, Zarkadas, Ch, Becker, Hans Werner, Rolfs, Claus, Strieder, Frank, Hammer, Johann Wolfgang, Dewald, Alfred, Zell, Karl Oskar, von Brentano, Peter, Julin, Rauno, Demetriou, Paraskevi, Goriely, Stéphane, Harissopulos, Sotirios, Spyrou, Artemis, Lagoyannis, Anastasios, Zarkadas, Ch, Becker, Hans Werner, Rolfs, Claus, Strieder, Frank, Hammer, Johann Wolfgang, Dewald, Alfred, Zell, Karl Oskar, von Brentano, Peter, Julin, Rauno, Demetriou, Paraskevi, and Goriely, Stéphane

Abstract

Several in-beam cross section measurements of proton- as well as α-capture reactions in the Se-Sb region have been carried out to obtain global input parameters for Hauser-Feshbach (HF) calculations. In total, 20 (p,γ) and 7 (α, γ) reactions were measured. We compare some of these results with Hauser-Feshbach calculations using various optical model potentials and nuclear level densities. © 2005 Elsevier B.V. All rights reserved., SCOPUS: ar.j, info:eu-repo/semantics/published

Published
2005

31. Lifetime measurements of normal deformed states in Lu-165(71)

Author

Andgren, Karin, Podolyak, Zsolt, Dewald, Alfred, Xu, Fu-Rong, Algora, Alejandro, Cederwall, Bo, et al., Andgren, Karin, Podolyak, Zsolt, Dewald, Alfred, Xu, Fu-Rong, Algora, Alejandro, Cederwall, Bo, and et al.

Abstract

Picosecond lifetimes of medium spin states in Lu-165 were measured for the first time. The reaction used to populate the nucleus of interest was La-139(Si-30,4n)Lu-165 at a beam energy of 135 MeV. The beam was provided by the XTU-tandem accelerator of Laboratori Nazionali di Legnaro, Italy. By using the differential decay curve method, lifetimes of 19 states in four different rotational bands were obtained. Therefrom the B(E2) values and the transitional quadrupole moments were deduced. The obtained Q(t) for the different bands are compared with total Routhian surface (TRS) calculations and particle-rotor-model calculations. The TRS calculations predict different axial symmetric shapes for the bands built on the 9/2(-)[514], 9/2(+)[404], and 1/2(-)[541] configurations, with a gamma softness for the 9/2(-)[514] configuration. This band has also been studied using the particle-rotor model, the results of which, however, are consistent with a triaxial shape with a gamma value of -15(p)., QC 20100621

Published
2005
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32. A systematic study of proton capture reactions in the Se-Sb region at energies relevant to the p process

Author

Harissopulos, Sotirios, Galanopulos, S., Demetriou, Paraskevi, Spyrou, Artemis, Kriembardis, G., Kokkoris, Michael, Karydas, Andreas Germanos, Zarkadas, Ch, Kunz, Rino, Fey, M., Hammer, Johann Wolfgang, Gyurky, Gy, Fulop, Zsolt, Somorjai, Endre, Dewald, Alfred, Zell, Karl Oskar, von Brentano, Peter, Julin, Rauno, Goriely, Stéphane, Harissopulos, Sotirios, Galanopulos, S., Demetriou, Paraskevi, Spyrou, Artemis, Kriembardis, G., Kokkoris, Michael, Karydas, Andreas Germanos, Zarkadas, Ch, Kunz, Rino, Fey, M., Hammer, Johann Wolfgang, Gyurky, Gy, Fulop, Zsolt, Somorjai, Endre, Dewald, Alfred, Zell, Karl Oskar, von Brentano, Peter, Julin, Rauno, and Goriely, Stéphane

Abstract

A systematic investigation of (p,γ) cross sections of nuclei from Se to Sb is presented. In-beam cross section measurements were carried out at Ep=1.4-5 MeV by using an array of 4 HPGe detectors of 100% relative efficiency shielded with BGO crystals. The S factors obtained are compared with the predictions of the statistical model code MOST., SCOPUS: ar.j, info:eu-repo/semantics/published

Published
2003

33. A systematic study of proton-capture cross sections in the Se-Sb region with relevance to the p-process nucleosynthesis

Author

Harissopulos, Sotirios, Demetriou, Paraskevi, Galanopulos, S., Kokkoris, Michael, Kriembardis, G., Tsagari, P., Spyrou, Artemis, Kalyva, G., Zakadas, C., Karydas, Andreas Germanos, Hammer, Johann Wolfgang, Kunz, Rino, Fey, M., Somorjai, Endre, Gyurky, Gy, Fulop, Zsolt, Dewald, Alfred, Zell, Karl Oskar, von Brentano, Peter, Julin, Rauno, Goriely, Stéphane, Harissopulos, Sotirios, Demetriou, Paraskevi, Galanopulos, S., Kokkoris, Michael, Kriembardis, G., Tsagari, P., Spyrou, Artemis, Kalyva, G., Zakadas, C., Karydas, Andreas Germanos, Hammer, Johann Wolfgang, Kunz, Rino, Fey, M., Somorjai, Endre, Gyurky, Gy, Fulop, Zsolt, Dewald, Alfred, Zell, Karl Oskar, von Brentano, Peter, Julin, Rauno, and Goriely, Stéphane

Abstract

info:eu-repo/semantics/published

Published
2003

34. Cross sections of (p, γ) reactions of N = 50 nuclei relevant to p-process

Author

Harissopulos, Sotirios, Somorjai, Endre, Goriely, Stéphane, Kasemann, S., Dewald, Alfred, Zell, Karl Oskar, Galanopoulos, S., Tsagari, P., Demetriou, Paraskevi, Kuburas, G., Paradellis, Th, Kunz, Rino, Hammer, Josef Wolfgang, Gyurky, Gy, Harissopulos, Sotirios, Somorjai, Endre, Goriely, Stéphane, Kasemann, S., Dewald, Alfred, Zell, Karl Oskar, Galanopoulos, S., Tsagari, P., Demetriou, Paraskevi, Kuburas, G., Paradellis, Th, Kunz, Rino, Hammer, Josef Wolfgang, and Gyurky, Gy

Abstract

The proton capture reactions 89Y(p,γ)90Zr and 88Sr(p,γ)89Y have been investigated at energies Ep = 1.5-3.5 MeV via an array of 4 HPGe detectors of ≈100% rel. efficiency. The resulting cross sections as well as the existing data on the 90Zr(p,γ)91Nb and 92Mo(p,γ)93Tc reactions are compared with improved statistical model calculations carried out using the MOST code., SCOPUS: ar.j, info:eu-repo/semantics/published

Published
2001

35. Cross sections of (p,gamma) reactions of N=50 nuclei relevant to p-process

Author

Harissopulos, Sotirios, Galanopulos, S., Tsagari, P., Demetriou, Paraskevi, Kuburas, G., Paradellis, Th, Kunz, Rino, Hammer, Johann Wolfgang, Gyurky, Gy, Somorjai, Endre, Goriely, Stéphane, Kasemann, S., Dewald, Alfred, Zelle, K.O., Harissopulos, Sotirios, Galanopulos, S., Tsagari, P., Demetriou, Paraskevi, Kuburas, G., Paradellis, Th, Kunz, Rino, Hammer, Johann Wolfgang, Gyurky, Gy, Somorjai, Endre, Goriely, Stéphane, Kasemann, S., Dewald, Alfred, and Zelle, K.O.

Abstract

info:eu-repo/semantics/published

Published
2001

38. ColPuS , a new multi-isotope plutonium standard for Accelerator Mass Spectrometry

Author

Stefan Heinze, Elena Chamizo, Antonio Petraglia, C. Feuerstein, Michaela B. Fröhlich, Tibor Dunai, Björn-Alexander Dittmann, Keith Fifield, Hans-Arno Synal, Fabio Marzaioli, Marcus Christl, Raffaele Buompane, Anton Wallner, F. Terrasi, Stephen G. Tims, Erik Strub, Carmina Sirignano, Carsten Münker, Alfred Dewald, Dittmann, Björn-Alexander, Buompane, Raffaele, Chamizo, Elena, Christl, Marcu, Dewald, Alfred, Dunai, Tibor, Feuerstein, Clau, Fifield, Keith, Fröhlich, Michaela, Heinze, Stefan, Marzaioli, Fabio, Münker, Carsten, Petraglia, Antonio, Sirignano, Carmina, Strub, Erik, Synal, Hans-Arno, Terrasi, Filippo, Tims, Stephen, Wallner, Anton, and Chamizo, Elena [0000-0001-8266-6129]

Subjects
Nuclear and High Energy Physics, Materials science, Mixing (process engineering), chemistry.chemical_element, 01 natural sciences, Plutonium isotopic standard, 03 medical and health sciences, ddc:530, AMS, Inductively coupled plasma mass spectrometry, Instrumentation, 030304 developmental biology, Standard material, Nuclear and High Energy Physic, 0303 health sciences, Isotope, 010401 analytical chemistry, Radiochemistry, 0104 chemical sciences, Plutonium, Isotopic ratio, chemistry, MC-ICPMS, Gravimetric analysis, Consensus value, Accelerator mass spectrometry
Abstract

A new multi-isotope plutonium standard for isotopic ratio measurements with Accelerator Mass Spectrometry (AMS) was created by gravimetric mixing of different single-isotope standards provided by IRMM (Pu-239, Pu-240, Pu-242, Pu-244). This standard material has been measured at the AMS facilities at Canberra (Australia), Cologne (Germany), Caserta (Italy), Sevilla (Spain) and Zurich (Switzerland). Additionally, the material was characterized using a Neptune MC-ICPMS (multi-collector inductively coupled plasma mass spectrometry) at the joint Cologne-Bonn isotope facility. The results of this laboratory intercomparison are presented and consensus values for the isotope compositions of the standard material are proposed.

Published
2019
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