Marco Benatar - Academia.edu (original) (raw)

Papers by Marco Benatar

Physics Letters B, 2004

High-energy γ rays produced by the 208 Pb(p, γ ) reaction were measured with the AFRODITE germani... more High-energy γ rays produced by the 208 Pb(p, γ ) reaction were measured with the AFRODITE germanium detector array. The use of Ge instead of NaI detectors improved the energy resolution by more than a factor of 10 in the γ -ray energy range between 10 and 19 MeV. Proton captures into different single particles states in 209 Bi were thus clearly separated, most notably for the i 13/2 high-spin state. The measured excitation functions are in very good agreement with the predictions of the directsemi-direct model, including captures to the i 13/2 state, for which the previous agreement had been poor.

AIP Conference Proceedings

ABSTRACT This paper reports on a test experiment to investigate the viability of using in-beam ga... more ABSTRACT This paper reports on a test experiment to investigate the viability of using in-beam gamma-ray spectroscopy with projectile fragmentation reactions to explore the structure of heavy, neutron-rich nuclei. The experiment used a `thin target' fragmentation reaction with a 30 MeV per nucleon 12C beam on a 30 mg/cm2 self-supporting gold target. The initial analysis has identified a number of previously known discrete cascades in a variety of in-beam reaction products. The decay of products has also been investigated and an initial comparison of their relative yields with predictions from the EPAX parameterisation begun. The relevance and future viability of this method as a complimentary technique to fragmentation-isomer studies to investigate the near-yrast properties of heavy, neutron-rich nuclei is discussed.

High-spin states in 197 Bi were studied with the AFRODITE γ-ray array at iThemba LABS using the 1... more High-spin states in 197 Bi were studied with the AFRODITE γ-ray array at iThemba LABS using the 181 Ta(22 Ne, 6n) reaction at a beam energy of 125 MeV. A new shears band was found and linked to the low-lying states in 197 Bi. Its dynamic moment of inertia, (2) , is considerably larger than the (2) of the shears bands in the neighbouring Pb isotopes. This is probably a result of the involvement of an additional high-K h 9/2 proton orbital.

The Journal of the Dental Association of South Africa = Die Tydskrif van die Tandheelkundige Vereniging van Suid-Afrika, 1991

A critical comparison of three methods for measuring distances between various fiducial points on... more A critical comparison of three methods for measuring distances between various fiducial points on orthodontic plaster casts is presented. The first method consisted of using a vernier caliper by which direct measurements (Dv) of the distances were recorded. The second method consisted of measuring the same casts using a reflex metrograph (Dm), where the co-ordinates of the points relative to two axes were recorded and the distances between various points were calculated. In the third method, reflection holograms of the casts were made, and the same distances were measured on the holographic images (Dh) using the reflex metrograph. The Wilcoxon sign rank test indicated no significant differences (p greater than 0.1) between measurements made by the various techniques. The means of the different distances scored varied within less than 0.5 mm (Dv-Dh), 0.5mm (Dv-Dm) and 0.2mm Dm-Dh). This study indicated that holograms can provide sufficiently accurate representations of orthodontic st...

Physical Review C, 2001

Excited states in 164 Ta were populated in the 142 Nd( 27 Al,5n) 164 Ta reaction and investigated... more Excited states in 164 Ta were populated in the 142 Nd( 27 Al,5n) 164 Ta reaction and investigated using the AFRODITE spectrometer array. The yrast rotational decay sequence up to spin 21 - is identified for the first time and assigned to the π[514]9/2 - ⊗ν[660]1/2 + configuration. A ...

The European Physical Journal A, 2005

Excited states in 175 Yb, 176 Yb and 177 Yb were populated via the bombardment of a 176 Yb target... more Excited states in 175 Yb, 176 Yb and 177 Yb were populated via the bombardment of a 176 Yb target with a 750 MeV 136 Xe beam. Gamma-ray decays from these states were measured with the AFRODITE multi-detector spectrometer. The rotational band previously assigned to the ground state of 177 Yb has been reassigned to the first-excited state of 175 Yb. A new rotational band based on the ground state of 177 Yb is presented, and the band based on the K π = 4 − two-quasiparticle state in 176 Yb has been identified. Also a candidate for the rotational band based on the K π = 8 − , T 1/2 = 11.4(3) s two-quasiparticle state in 176 Yb has been found. Comparisons of gK values derived from in-band branching ratios are consistent with the ν9/2 + [624] assignment to the ground state of 177 Yb, the ν 2 {9/2 + [624] ⊗ 1/2 − [510]} assignment to the K π = 4 − state and with the ν 2 {9/2 + [624] ⊗ 7/2 − [514]} assignment to the K π = 8 − metastable excited state in 176 Yb. PACS. 29.30.Kv X-and γ-ray spectroscopy-23.20.Lv γ transitions and level energies-21.10.-k Properties of nuclei; nuclear energy levels-27.70.+q 150 ≤ A ≤ 189

The European Physical Journal A, 2005

High-spin states in 197 Bi were studied with the AFRODITE γ-ray array at iThemba LABS using the 1... more High-spin states in 197 Bi were studied with the AFRODITE γ-ray array at iThemba LABS using the 181 Ta(22 Ne, 6n) reaction at a beam energy of 125 MeV. A new shears band was found and linked to the low-lying states in 197 Bi. Its dynamic moment of inertia, (2) , is considerably larger than the (2) of the shears bands in the neighbouring Pb isotopes. This is probably a result of the involvement of an additional high-K h 9/2 proton orbital.

The European Physical Journal A - Hadrons and Nuclei, 2003

The Recoil Shadow Anisotropy Method for measuring nanosecond lifetimes is being implemented on th... more The Recoil Shadow Anisotropy Method for measuring nanosecond lifetimes is being implemented on the AFRODITE array and four new isomers were found in 198,200 Bi, 164 Ta and 162 Lu.

The European Physical …, 2005

GK Mabala1,2,a, E. Gueorguieva1,b, JF Sharpey-Schafer1, M. Benatar1,2, RW Fearick2, KI Korir3, JJ... more GK Mabala1,2,a, E. Gueorguieva1,b, JF Sharpey-Schafer1, M. Benatar1,2, RW Fearick2, KI Korir3, JJ Lawrie1, SM Mullins1, SHT Murray1,2, NJ Ncapayi1, RT Newman1, DG Roux1,2,c, FD Smit1, and R. Wyss4 ... 1 iThemba Laboratory for Accelerator Based ...

Physics Letters B, 2004

High-energy γ rays produced by the 208 Pb(p, γ ) reaction were measured with the AFRODITE germani... more High-energy γ rays produced by the 208 Pb(p, γ ) reaction were measured with the AFRODITE germanium detector array. The use of Ge instead of NaI detectors improved the energy resolution by more than a factor of 10 in the γ -ray energy range between 10 and 19 MeV. Proton captures into different single particles states in 209 Bi were thus clearly separated, most notably for the i 13/2 high-spin state. The measured excitation functions are in very good agreement with the predictions of the directsemi-direct model, including captures to the i 13/2 state, for which the previous agreement had been poor.

AIP Conference Proceedings

ABSTRACT This paper reports on a test experiment to investigate the viability of using in-beam ga... more ABSTRACT This paper reports on a test experiment to investigate the viability of using in-beam gamma-ray spectroscopy with projectile fragmentation reactions to explore the structure of heavy, neutron-rich nuclei. The experiment used a `thin target' fragmentation reaction with a 30 MeV per nucleon 12C beam on a 30 mg/cm2 self-supporting gold target. The initial analysis has identified a number of previously known discrete cascades in a variety of in-beam reaction products. The decay of products has also been investigated and an initial comparison of their relative yields with predictions from the EPAX parameterisation begun. The relevance and future viability of this method as a complimentary technique to fragmentation-isomer studies to investigate the near-yrast properties of heavy, neutron-rich nuclei is discussed.

High-spin states in 197 Bi were studied with the AFRODITE γ-ray array at iThemba LABS using the 1... more High-spin states in 197 Bi were studied with the AFRODITE γ-ray array at iThemba LABS using the 181 Ta(22 Ne, 6n) reaction at a beam energy of 125 MeV. A new shears band was found and linked to the low-lying states in 197 Bi. Its dynamic moment of inertia, (2) , is considerably larger than the (2) of the shears bands in the neighbouring Pb isotopes. This is probably a result of the involvement of an additional high-K h 9/2 proton orbital.

The Journal of the Dental Association of South Africa = Die Tydskrif van die Tandheelkundige Vereniging van Suid-Afrika, 1991

A critical comparison of three methods for measuring distances between various fiducial points on... more A critical comparison of three methods for measuring distances between various fiducial points on orthodontic plaster casts is presented. The first method consisted of using a vernier caliper by which direct measurements (Dv) of the distances were recorded. The second method consisted of measuring the same casts using a reflex metrograph (Dm), where the co-ordinates of the points relative to two axes were recorded and the distances between various points were calculated. In the third method, reflection holograms of the casts were made, and the same distances were measured on the holographic images (Dh) using the reflex metrograph. The Wilcoxon sign rank test indicated no significant differences (p greater than 0.1) between measurements made by the various techniques. The means of the different distances scored varied within less than 0.5 mm (Dv-Dh), 0.5mm (Dv-Dm) and 0.2mm Dm-Dh). This study indicated that holograms can provide sufficiently accurate representations of orthodontic st...

Physical Review C, 2001

Excited states in 164 Ta were populated in the 142 Nd( 27 Al,5n) 164 Ta reaction and investigated... more Excited states in 164 Ta were populated in the 142 Nd( 27 Al,5n) 164 Ta reaction and investigated using the AFRODITE spectrometer array. The yrast rotational decay sequence up to spin 21 - is identified for the first time and assigned to the π[514]9/2 - ⊗ν[660]1/2 + configuration. A ...

The European Physical Journal A, 2005

Excited states in 175 Yb, 176 Yb and 177 Yb were populated via the bombardment of a 176 Yb target... more Excited states in 175 Yb, 176 Yb and 177 Yb were populated via the bombardment of a 176 Yb target with a 750 MeV 136 Xe beam. Gamma-ray decays from these states were measured with the AFRODITE multi-detector spectrometer. The rotational band previously assigned to the ground state of 177 Yb has been reassigned to the first-excited state of 175 Yb. A new rotational band based on the ground state of 177 Yb is presented, and the band based on the K π = 4 − two-quasiparticle state in 176 Yb has been identified. Also a candidate for the rotational band based on the K π = 8 − , T 1/2 = 11.4(3) s two-quasiparticle state in 176 Yb has been found. Comparisons of gK values derived from in-band branching ratios are consistent with the ν9/2 + [624] assignment to the ground state of 177 Yb, the ν 2 {9/2 + [624] ⊗ 1/2 − [510]} assignment to the K π = 4 − state and with the ν 2 {9/2 + [624] ⊗ 7/2 − [514]} assignment to the K π = 8 − metastable excited state in 176 Yb. PACS. 29.30.Kv X-and γ-ray spectroscopy-23.20.Lv γ transitions and level energies-21.10.-k Properties of nuclei; nuclear energy levels-27.70.+q 150 ≤ A ≤ 189

The European Physical Journal A, 2005

High-spin states in 197 Bi were studied with the AFRODITE γ-ray array at iThemba LABS using the 1... more High-spin states in 197 Bi were studied with the AFRODITE γ-ray array at iThemba LABS using the 181 Ta(22 Ne, 6n) reaction at a beam energy of 125 MeV. A new shears band was found and linked to the low-lying states in 197 Bi. Its dynamic moment of inertia, (2) , is considerably larger than the (2) of the shears bands in the neighbouring Pb isotopes. This is probably a result of the involvement of an additional high-K h 9/2 proton orbital.

The European Physical Journal A - Hadrons and Nuclei, 2003

The Recoil Shadow Anisotropy Method for measuring nanosecond lifetimes is being implemented on th... more The Recoil Shadow Anisotropy Method for measuring nanosecond lifetimes is being implemented on the AFRODITE array and four new isomers were found in 198,200 Bi, 164 Ta and 162 Lu.

The European Physical …, 2005

GK Mabala1,2,a, E. Gueorguieva1,b, JF Sharpey-Schafer1, M. Benatar1,2, RW Fearick2, KI Korir3, JJ... more GK Mabala1,2,a, E. Gueorguieva1,b, JF Sharpey-Schafer1, M. Benatar1,2, RW Fearick2, KI Korir3, JJ Lawrie1, SM Mullins1, SHT Murray1,2, NJ Ncapayi1, RT Newman1, DG Roux1,2,c, FD Smit1, and R. Wyss4 ... 1 iThemba Laboratory for Accelerator Based ...