The Rare ISotopes INvestigation at GSI project combines the former EUROBALL Ge-Cluster detectors,... more The Rare ISotopes INvestigation at GSI project combines the former EUROBALL Ge-Cluster detectors, the MINIBALL Ge detectors, BaF2-HECTOR detectors, and the fragment separator at GSI for high-resolution in-beam γ-ray spectroscopy measurements with radioactive ...
The excitation function for the elastic scattering reaction p( 18 Ne,p) 18 Ne was measured with t... more The excitation function for the elastic scattering reaction p( 18 Ne,p) 18 Ne was measured with the first radioactive beam from the SPIRAL facility at the GANIL laboratory and with a solid cryogenic hydrogen target. Several broad resonances have been observed, corresponding to new excited states in the unbound nucleus 19 Na. In addition, two-proton emission events have been identified and are discussed.
Page 1. DOI: 10.1140/epjad/i2005-06-159-0 Eur. Phys. J. A 25, s01, 105109 (2005) EPJ A direct el... more Page 1. DOI: 10.1140/epjad/i2005-06-159-0 Eur. Phys. J. A 25, s01, 105109 (2005) EPJ A direct electronic only New structure information on 30Mg, 31Mg and 32Mg H. Mach1a, LM Fraile2,3, O. Tengblad4, R. Boutami4, C. Jollet5 ...
Soil and Sediment Contamination: An International Journal, 2013
ABSTRACT The Cam River mouth (Haiphong Province) is one of the main river mouths of the Red River... more ABSTRACT The Cam River mouth (Haiphong Province) is one of the main river mouths of the Red River System, which is one of the most important water resources in Northern Vietnam. Over the past 50 years, the strong socio-economic development in the area has caused a considerable contamination with heavy metals (Co, Cr, Cu, Mn, Ni, Pb, and Zn) and arsenic. In this study, the vertical and horizontal distributions of heavy metals and arsenic in sediments from the Cam River mouth were investigated. In addition, the history, origin, and degree of contamination were assessed. Normalized (with respect to Al) heavy metal and arsenic concentrations in sediment cores and absolute dates obtained from the 137Cs analysis were used to reconstruct the pollution history of the river mouth. As, Cu, Mn, Pb, and Zn concentrations increase rapidly by approximately two times or more from 1954 to 1975, and then remain nearly unchanged from 1975 until 2008, whereas Co, Cr, and Ni concentrations slightly increase from 1954 until 2008. In addition, background values for heavy metals and arsenic have also been determined with regard to the period before 1954. In the study area, Co, Cr, Cu, Ni, Mn, and Zn are evaluated as minorly enriched, whereas As and Pb are classified as moderately enriched. Generally, the anthropogenic activities in the Haiphong harbor and industrial zone locally contribute to the contamination by heavy metals and arsenic in the Cam River mouth.
The level-mixing resonance technique applied to β-decaying nuclei (β-LMR) is a well-established t... more The level-mixing resonance technique applied to β-decaying nuclei (β-LMR) is a well-established tool for measuring the ground state quadrupole moments of nuclei away from stability. These experiments yield the quadrupole to magnetic moment ratio, provided the electric field ...
... Collectivity and deformation are shown to arise naturally from the increase in the number ...... more ... Collectivity and deformation are shown to arise naturally from the increase in the number ... compared to only 2p for the regular ones) leading to an enhanced protonneutron ... the structure of intruder states using complementary information from magnetic and quadrupole moments ...
ABSTRACT The electric quadrupole moment of 17B and the g-factor of 17C were measured by using the... more ABSTRACT The electric quadrupole moment of 17B and the g-factor of 17C were measured by using the fragmentation-induced nuclear polarization technique combined with the β-NMR method. The experimental quadrupole moment of 17B is found strikingly close to that of the neutron closed-shell isotope 13B, indicating a strong quenching of the neutron E2 core-polarization charge. From the result obtained for the 17C g-factor, we can conclude that the ground-state spin-parity of 17C is 3/2+.
The quadrupole moment of the 11 2 isomer in 196 Pb has been measured by the level mixing spectros... more The quadrupole moment of the 11 2 isomer in 196 Pb has been measured by the level mixing spectroscopy method. This state has a p͑3s 22 1͞2 1h 9͞2 1i 13͞2 ͒11 2 configuration which is involved in most of the shears band heads in the Pb region. The first directly measured value of Q s ͑11 2 ͒ ͑2͒3.41͑66͒ b, coupled to the previously known quadrupole moment of the n͑1i 22 13͞2 ͒12 1 isomer allows us to estimate the quadrupole moment of the 16 2 shears band head as Q s ͑16 2 ͒ 20.32͑10͒ b. The experimental values are compared to tilted axis cranking calculations, giving insight into the validity of the additivity approach to couple quadrupole moments and on the amount of deformation in the shears bands.
ABSTRACT Taking advantage of spin-polarized radioactive nuclear beams obtained from the projectil... more ABSTRACT Taking advantage of spin-polarized radioactive nuclear beams obtained from the projectile fragmentation reaction, magnetic moments and electric quadrupole moments have been studied at RIKEN for light-mass neutron-rich nuclei. In this paper we report on recent results obtained for the electric quadrupole moment Q of ^17B and the magnetic moment mu of ^17C nuclei, measured with the beta-detected NMR technique. The experimentalQ(^17B) obtained is substantially smaller than shell model predictions if we take neutron effective charges around en ≈ 0.5e which are normally employed in the sd shell region. The Q(^17B)_exp value is very close to Q(^13B)_exp and, together with the previous results for Q(^15B), Q(^14B), and Q(^18N), clearly indicates a tendency that the effective charge for neutrons becomes more and more quenched as the degree of neutron excess develops. We discuss also the ground state spin of ^17C from the beta-NMR result obtained for this isotope.
We report on recent results of nuclear moment measurements on exotic nuclei, performed at RIKEN w... more We report on recent results of nuclear moment measurements on exotic nuclei, performed at RIKEN with spin-polarized radioactive nuclear beams. The g-factor for the 17 C ground state is measured to be| g|= 0. 5054±0. 0025. The obtained value is much smaller than those ...
... JM Daugas, R. Grzywacz, M. Lewitowicz, MJ Lopez-Jimenez, F. de Oliveira-Santos, JC Angélique,... more ... JM Daugas, R. Grzywacz, M. Lewitowicz, MJ Lopez-Jimenez, F. de Oliveira-Santos, JC Angélique, L. Axelsson, C. Borcea, C. Longour, and G. Neyens, Phys. Rev. ... Jimenez, F. de Oliveira-Santos, JC Angelique, L. Axelsson, C. Borcea, C. Longour, and G. Neyens, Phys. Rev. ...
We report on the Level Mixing Resonance experiment performed on the fi-decaying 18N nucleus produ... more We report on the Level Mixing Resonance experiment performed on the fi-decaying 18N nucleus produced and aligned in an intermediate-energy fragmentation reaction. From the resonantly induced change in the asymmetry of the fi-decay, measured as a function of a static magnetic field, we derived information on the nuclear moments of the neutron-rich 18 N nucleus. The spectroscopic quadrupole moment IQC 8 N, 1-) I 3.2(3)e fm 2 is compared to mean-field calculations.
In this paper we present the β-level mixing resonance (β-LMR) method as a tool to measure the ini... more In this paper we present the β-level mixing resonance (β-LMR) method as a tool to measure the initial spin-orientation of exotic nuclear beams produced and oriented in a fragmentation reaction. Understanding this spin-orientation process is the key to allow studies of nuclear ...
Exotic Nuclei - EXON-2001 - Proceedings of the International Symposium, 2002
An overview of a series of recent experiments aimed at the determination of the moments of exotic... more An overview of a series of recent experiments aimed at the determination of the moments of exotic nuclei is presented. The spin-orientation: spin-alignment and spin-polarization of the nuclear ensemble, which is produced in fragmentation reactions, is of utmost importance ...
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2001
An extension of the time-integrated atomic decoupling technique to measure g-factors of (sub)nano... more An extension of the time-integrated atomic decoupling technique to measure g-factors of (sub)nanosecond isomers and=or the magnetic hyperfine field induced by highly excited atomic electrons on nuclei recoiling into vacuum is discussed. A high average field B hf ¼ 1080 þ270 À175 T and an average atomic spin J ¼ 2:7ð2Þ is deduced using the known magnetic moment of a 4:05ð7Þ ms isomer in 69 Ge. Such high magnetic fields allow g-factor measurements of (sub)nanosecond states. Ab initio calculations show that the combination of a high average magnetic hyperfine field and a high average atomic spin is only possible if a considerable fraction of the ions is in a metastable excited state. #
By combining two well established methods, the beta-level mixing resonance (beta-LMR) and the bet... more By combining two well established methods, the beta-level mixing resonance (beta-LMR) and the beta-nuclear magnetic resonance (beta-NMR), it is possible to determine the magnetic moment and the quadrupole moment of nuclei with low spin. The combined method can be applied on spin oriented ground state beta-decaying nuclei. It was tested on the known 12B and successfully applied on the neutron
The g-factor of the ground state of 31 Al (T 1/2 = 640 ms) has been measured by the β-NMR techniq... more The g-factor of the ground state of 31 Al (T 1/2 = 640 ms) has been measured by the β-NMR technique on a polarized secondary fragment beam at GANIL, Caen, France. The measured value of |g| = 1.517 is compared with sd-shell model calculations, which allows the assignment of spin and parity I π = 5/2 + to this state. The spectroscopy of neutron-rich Al isotopes on the border of the "island of inversion" is discussed in terms of the persistence of the N = 20 shell closure for Z = 13 nuclei.
The spectroscopic quadrupole moment of the high-spin, high-K five-quasiparticle isomer (K p 35 2 ... more The spectroscopic quadrupole moment of the high-spin, high-K five-quasiparticle isomer (K p 35 2 2 , T 1͞2 750͑80͒ ns, E i 3349 keV) in 179 W has been determined using the level mixing spectroscopy method. A value Q s 4.00͑ 10.83 21.06 ͒e b was derived, which corresponds to an intrinsic quadrupole moment Q 0 4.73͑ 10.98 21.25 ͒e b and to a quadrupole deformation b 2 0.185͑ 10.038 20.049 ͒. These values differ significantly from the deduced ground-state quadrupole moments and are in disagreement with the current theoretical predictions in this mass region.
The Rare ISotopes INvestigation at GSI project combines the former EUROBALL Ge-Cluster detectors,... more The Rare ISotopes INvestigation at GSI project combines the former EUROBALL Ge-Cluster detectors, the MINIBALL Ge detectors, BaF2-HECTOR detectors, and the fragment separator at GSI for high-resolution in-beam γ-ray spectroscopy measurements with radioactive ...
The excitation function for the elastic scattering reaction p( 18 Ne,p) 18 Ne was measured with t... more The excitation function for the elastic scattering reaction p( 18 Ne,p) 18 Ne was measured with the first radioactive beam from the SPIRAL facility at the GANIL laboratory and with a solid cryogenic hydrogen target. Several broad resonances have been observed, corresponding to new excited states in the unbound nucleus 19 Na. In addition, two-proton emission events have been identified and are discussed.
Page 1. DOI: 10.1140/epjad/i2005-06-159-0 Eur. Phys. J. A 25, s01, 105109 (2005) EPJ A direct el... more Page 1. DOI: 10.1140/epjad/i2005-06-159-0 Eur. Phys. J. A 25, s01, 105109 (2005) EPJ A direct electronic only New structure information on 30Mg, 31Mg and 32Mg H. Mach1a, LM Fraile2,3, O. Tengblad4, R. Boutami4, C. Jollet5 ...
Soil and Sediment Contamination: An International Journal, 2013
ABSTRACT The Cam River mouth (Haiphong Province) is one of the main river mouths of the Red River... more ABSTRACT The Cam River mouth (Haiphong Province) is one of the main river mouths of the Red River System, which is one of the most important water resources in Northern Vietnam. Over the past 50 years, the strong socio-economic development in the area has caused a considerable contamination with heavy metals (Co, Cr, Cu, Mn, Ni, Pb, and Zn) and arsenic. In this study, the vertical and horizontal distributions of heavy metals and arsenic in sediments from the Cam River mouth were investigated. In addition, the history, origin, and degree of contamination were assessed. Normalized (with respect to Al) heavy metal and arsenic concentrations in sediment cores and absolute dates obtained from the 137Cs analysis were used to reconstruct the pollution history of the river mouth. As, Cu, Mn, Pb, and Zn concentrations increase rapidly by approximately two times or more from 1954 to 1975, and then remain nearly unchanged from 1975 until 2008, whereas Co, Cr, and Ni concentrations slightly increase from 1954 until 2008. In addition, background values for heavy metals and arsenic have also been determined with regard to the period before 1954. In the study area, Co, Cr, Cu, Ni, Mn, and Zn are evaluated as minorly enriched, whereas As and Pb are classified as moderately enriched. Generally, the anthropogenic activities in the Haiphong harbor and industrial zone locally contribute to the contamination by heavy metals and arsenic in the Cam River mouth.
The level-mixing resonance technique applied to β-decaying nuclei (β-LMR) is a well-established t... more The level-mixing resonance technique applied to β-decaying nuclei (β-LMR) is a well-established tool for measuring the ground state quadrupole moments of nuclei away from stability. These experiments yield the quadrupole to magnetic moment ratio, provided the electric field ...
... Collectivity and deformation are shown to arise naturally from the increase in the number ...... more ... Collectivity and deformation are shown to arise naturally from the increase in the number ... compared to only 2p for the regular ones) leading to an enhanced protonneutron ... the structure of intruder states using complementary information from magnetic and quadrupole moments ...
ABSTRACT The electric quadrupole moment of 17B and the g-factor of 17C were measured by using the... more ABSTRACT The electric quadrupole moment of 17B and the g-factor of 17C were measured by using the fragmentation-induced nuclear polarization technique combined with the β-NMR method. The experimental quadrupole moment of 17B is found strikingly close to that of the neutron closed-shell isotope 13B, indicating a strong quenching of the neutron E2 core-polarization charge. From the result obtained for the 17C g-factor, we can conclude that the ground-state spin-parity of 17C is 3/2+.
The quadrupole moment of the 11 2 isomer in 196 Pb has been measured by the level mixing spectros... more The quadrupole moment of the 11 2 isomer in 196 Pb has been measured by the level mixing spectroscopy method. This state has a p͑3s 22 1͞2 1h 9͞2 1i 13͞2 ͒11 2 configuration which is involved in most of the shears band heads in the Pb region. The first directly measured value of Q s ͑11 2 ͒ ͑2͒3.41͑66͒ b, coupled to the previously known quadrupole moment of the n͑1i 22 13͞2 ͒12 1 isomer allows us to estimate the quadrupole moment of the 16 2 shears band head as Q s ͑16 2 ͒ 20.32͑10͒ b. The experimental values are compared to tilted axis cranking calculations, giving insight into the validity of the additivity approach to couple quadrupole moments and on the amount of deformation in the shears bands.
ABSTRACT Taking advantage of spin-polarized radioactive nuclear beams obtained from the projectil... more ABSTRACT Taking advantage of spin-polarized radioactive nuclear beams obtained from the projectile fragmentation reaction, magnetic moments and electric quadrupole moments have been studied at RIKEN for light-mass neutron-rich nuclei. In this paper we report on recent results obtained for the electric quadrupole moment Q of ^17B and the magnetic moment mu of ^17C nuclei, measured with the beta-detected NMR technique. The experimentalQ(^17B) obtained is substantially smaller than shell model predictions if we take neutron effective charges around en ≈ 0.5e which are normally employed in the sd shell region. The Q(^17B)_exp value is very close to Q(^13B)_exp and, together with the previous results for Q(^15B), Q(^14B), and Q(^18N), clearly indicates a tendency that the effective charge for neutrons becomes more and more quenched as the degree of neutron excess develops. We discuss also the ground state spin of ^17C from the beta-NMR result obtained for this isotope.
We report on recent results of nuclear moment measurements on exotic nuclei, performed at RIKEN w... more We report on recent results of nuclear moment measurements on exotic nuclei, performed at RIKEN with spin-polarized radioactive nuclear beams. The g-factor for the 17 C ground state is measured to be| g|= 0. 5054±0. 0025. The obtained value is much smaller than those ...
... JM Daugas, R. Grzywacz, M. Lewitowicz, MJ Lopez-Jimenez, F. de Oliveira-Santos, JC Angélique,... more ... JM Daugas, R. Grzywacz, M. Lewitowicz, MJ Lopez-Jimenez, F. de Oliveira-Santos, JC Angélique, L. Axelsson, C. Borcea, C. Longour, and G. Neyens, Phys. Rev. ... Jimenez, F. de Oliveira-Santos, JC Angelique, L. Axelsson, C. Borcea, C. Longour, and G. Neyens, Phys. Rev. ...
We report on the Level Mixing Resonance experiment performed on the fi-decaying 18N nucleus produ... more We report on the Level Mixing Resonance experiment performed on the fi-decaying 18N nucleus produced and aligned in an intermediate-energy fragmentation reaction. From the resonantly induced change in the asymmetry of the fi-decay, measured as a function of a static magnetic field, we derived information on the nuclear moments of the neutron-rich 18 N nucleus. The spectroscopic quadrupole moment IQC 8 N, 1-) I 3.2(3)e fm 2 is compared to mean-field calculations.
In this paper we present the β-level mixing resonance (β-LMR) method as a tool to measure the ini... more In this paper we present the β-level mixing resonance (β-LMR) method as a tool to measure the initial spin-orientation of exotic nuclear beams produced and oriented in a fragmentation reaction. Understanding this spin-orientation process is the key to allow studies of nuclear ...
Exotic Nuclei - EXON-2001 - Proceedings of the International Symposium, 2002
An overview of a series of recent experiments aimed at the determination of the moments of exotic... more An overview of a series of recent experiments aimed at the determination of the moments of exotic nuclei is presented. The spin-orientation: spin-alignment and spin-polarization of the nuclear ensemble, which is produced in fragmentation reactions, is of utmost importance ...
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2001
An extension of the time-integrated atomic decoupling technique to measure g-factors of (sub)nano... more An extension of the time-integrated atomic decoupling technique to measure g-factors of (sub)nanosecond isomers and=or the magnetic hyperfine field induced by highly excited atomic electrons on nuclei recoiling into vacuum is discussed. A high average field B hf ¼ 1080 þ270 À175 T and an average atomic spin J ¼ 2:7ð2Þ is deduced using the known magnetic moment of a 4:05ð7Þ ms isomer in 69 Ge. Such high magnetic fields allow g-factor measurements of (sub)nanosecond states. Ab initio calculations show that the combination of a high average magnetic hyperfine field and a high average atomic spin is only possible if a considerable fraction of the ions is in a metastable excited state. #
By combining two well established methods, the beta-level mixing resonance (beta-LMR) and the bet... more By combining two well established methods, the beta-level mixing resonance (beta-LMR) and the beta-nuclear magnetic resonance (beta-NMR), it is possible to determine the magnetic moment and the quadrupole moment of nuclei with low spin. The combined method can be applied on spin oriented ground state beta-decaying nuclei. It was tested on the known 12B and successfully applied on the neutron
The g-factor of the ground state of 31 Al (T 1/2 = 640 ms) has been measured by the β-NMR techniq... more The g-factor of the ground state of 31 Al (T 1/2 = 640 ms) has been measured by the β-NMR technique on a polarized secondary fragment beam at GANIL, Caen, France. The measured value of |g| = 1.517 is compared with sd-shell model calculations, which allows the assignment of spin and parity I π = 5/2 + to this state. The spectroscopy of neutron-rich Al isotopes on the border of the "island of inversion" is discussed in terms of the persistence of the N = 20 shell closure for Z = 13 nuclei.
The spectroscopic quadrupole moment of the high-spin, high-K five-quasiparticle isomer (K p 35 2 ... more The spectroscopic quadrupole moment of the high-spin, high-K five-quasiparticle isomer (K p 35 2 2 , T 1͞2 750͑80͒ ns, E i 3349 keV) in 179 W has been determined using the level mixing spectroscopy method. A value Q s 4.00͑ 10.83 21.06 ͒e b was derived, which corresponds to an intrinsic quadrupole moment Q 0 4.73͑ 10.98 21.25 ͒e b and to a quadrupole deformation b 2 0.185͑ 10.038 20.049 ͒. These values differ significantly from the deduced ground-state quadrupole moments and are in disagreement with the current theoretical predictions in this mass region.
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Papers by G. Neyens