The advanced time-delayed γ γ (t) method has been applied to determine half-lives of low-lying st... more The advanced time-delayed γ γ (t) method has been applied to determine half-lives of low-lying states in the N = 50 isotones 94 Ru and 96 Pd. The inferred experimental E2 strengths for the 4 + → 2 + transitions in the two nuclei show a dramatic deviation with respect to the shell model predictions in the (f 5/2 ,p,g 9/2) proton hole space in 100 Sn. The anomalous behavior can be ascribed to a breakdown of the seniority quantum number in the πg n 9/2 configuration due to particle-hole excitations across the N = Z = 50 shell as confirmed by large-scale shell model calculations.
This paper presents the results of the fast neutron irradiation (E n > 0.5 MeV) of an EJ-276 scin... more This paper presents the results of the fast neutron irradiation (E n > 0.5 MeV) of an EJ-276 scintillator performed in the MARIA research reactor with fluence up to 5.3×10 15 particles/cm 2. In our work, four samples with size φ 25.4 mm×5 mm were tested. The changes in the light yield, emission and absorption spectrum and neutron/gamma discrimination using PuBe source before and after irradiation are presented. The figure of merit in neutron/gamma discrimination based on the charge integration method for different neutron fluences and different short gate integration times are determined.
Excited states in the neutron-rich isotope 133 Sn were studied via the β decay of 133 In. Isomer ... more Excited states in the neutron-rich isotope 133 Sn were studied via the β decay of 133 In. Isomer selective ionization using the ISOLDE RILIS enabled the β decays of 133 In gs (I π = 9/2 +) and 133m In (I π = 1/2 −) to be
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2019
Gamma-Beams at the HIγS facility in the USA and anticipated at the ELI-NP facility, now construct... more Gamma-Beams at the HIγS facility in the USA and anticipated at the ELI-NP facility, now constructed in Romania, present unique new opportunities to advance research in nuclear astrophysics; not the least of which is resolving open questions in oxygen formation during stellar helium burning via a precise measurement of the 12 C(α, γ) reaction. Time projection chamber (TPC) detectors operating with low pressure gas (as an active target) are ideally suited for such studies. We review the progress of the current research program and plans for the future at the HIγS facility with the optical readout TPC (O-TPC) and the development of an electronic readout TPC for the ELI-NP facility (ELITPC).
... Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996 (United Sta... more ... Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996 (United States)] ; Ginter, T. ; Stolz ... Subject, 73 NUCLEAR PHYSICS AND RADIATION PHYSICS; BETA DECAY; BRANCHING RATIO; CHARGED PARTICLES; COMPARATIVE EVALUATIONS ...
Deformation and wave function composition of unbound nuclei can be studied using measured fine st... more Deformation and wave function composition of unbound nuclei can be studied using measured fine structure properties of proton emission and microscopic theoretical models. The data on proton radioactivities ^141gsHo and ^145Tm obtained at the HRIBF (Oak Ridge) will be compared to the calculations accounting for the deformation of the potential tunnelled by the emitted protons. The wave function of a 3-mus ^145Tm will be analyzed using a praticle - core vibration model with moderate quadrupole deformation, while more complex interpretation involving triaxiality will be presented for the 4-ms activity of ^141Ho.
Decays of neutron-rich nuclei 82,83 Zn and 82,83 Ga produced in proton-induced fission of 238 U w... more Decays of neutron-rich nuclei 82,83 Zn and 82,83 Ga produced in proton-induced fission of 238 U were studied at the Holifield Radioactive Ion Beam Facility (HRIBF) using on-line mass separation and β-γ spectroscopy techniques. New γ-ray transitions were identified and level schemes, which include states at high excitation energies in the range between 3 to 7 MeV were constructed. These high energy levels were identified to be populated through allowed Gamow-Teller β-transitions, and their structure was interpreted with new shell model calculations. A β-delayed neutron branching ratio of 69±7% was deduced for 82 Zn and revised β-decay half-life values of 82 Zn (155(17)(20) ms) and 83 Zn (122(28) ms) were determined.
HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific r... more HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
Fission and Properties of Neutron-Rich Nuclei, 2013
ABSTRACT The β-decay properties of neutron-rich Cu isotopes produced in proton-induced fission of... more ABSTRACT The β-decay properties of neutron-rich Cu isotopes produced in proton-induced fission of 238U were studied at the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory. The data were collected using high-resolution online mass separation, re-acceleration, and digital β-γ spectroscopy methods. The measured β-delayed neutron properties of 77,78,79Cu will be presented and discussed in comparison with theoretical prediction performed using shell model and continuum random phase approximation approaches [1]…
Fission and Properties of Neutron-Rich Nuclei, 2013
ABSTRACT The β-decay of the N=51 nucleus 81Zn was studied by means of β - γ spectroscopy and from... more ABSTRACT The β-decay of the N=51 nucleus 81Zn was studied by means of β - γ spectroscopy and from isotopically pure beams produced at the HRIBF. We observe several competing β transitions populating 81Ga which are interpreted as allowed Gamow-Teller decays to positive parity, core excited states and first-forbidden decays to negative parity states. The measured β-decay pattern suggests an assignment of Iπ=5/2+ for the 81Zn ground state.
At the PF1B cold neutron beam line at the Institut Laue Langevin, the EXILL array consisting of E... more At the PF1B cold neutron beam line at the Institut Laue Langevin, the EXILL array consisting of EXOGAM, GASP and ILL-Clover detectors was used to perform (n,J) measurements at very high coincidence rates. About ten different reactions were measured in autumn 2012 using a highly collimated cold neutron beam. In spring 2013, the EXOGAM array was combined with 16 LaBr 3 (Ce) scintillators in the EXILL&FATIMA campaign for the measurement of lifetimes using the generalised centroid difference method. We report on the properties of the setups and present first results from both campaigns.
Recent updates on β decay of 75 Zn into 75 Ga are presented with the decay scheme and structure o... more Recent updates on β decay of 75 Zn into 75 Ga are presented with the decay scheme and structure of 75 Ga. The present study utilized a more efficient detector setup along with high purity of the 75 Cu beam in comparison to previous studies with a rate of over 2000 ions/s. The purity of beam which is obtained by using high-resolution isobar separator prevented any member of the decay chain from being dominant and allowed for comparisons of branching rations between the decays. The greater efficiency of the HPGe detector array meant more low energy γ-ray detection from the decays. The γ-γ and β-γ coincidence data obtained from the experiment were collected at the LeRIBSS (Low energy Radioactive Ion Beam Spectroscopy Station) and used to develop a revised decay scheme using an objective method.
A psychological contract comprises of a personal viewpoint about mutual commitments in employment... more A psychological contract comprises of a personal viewpoint about mutual commitments in employment relationships. Unlike a traditional service contract, the psychological contract remains unspoken in the employment relationship between employer and the employees. Employees anticipate, for example, working in a secure and clean environment; to work with qualified and regimented co-workers and to be appreciated for their good work, free from harassment etc. Employers, on the contrary, expect staff to be careful and dedicated; to be trustworthy; and to maintain or enhance the organizational image etc. This shady nature and often conflicting nature of psychological contract can often harm the health of employment relationship. This paper explores the nature of psychological contracts and their significance within the domain of employment relationships. The paper first reviews the general theory of psychological contract, its types and factors governing them. Next, a theoretical examining the research contributions of scholars who have contributed to the literature is being carried out. Finally, the paper thoroughly and critically analyzes the effects of breach or non-conformity of psychological contracts. Psychological contract plays a key role in manipulating workers job related commitment. It must be highlighted that effective observation, agreement and execution of psychological contracts could add to increased levels of workers commitment. Considering the literature studied, it becomes extremely important for the management to be responsive of, and to some degree control, the psychological contracts that the employees may hold. Offering the aggrieved employees a practical psychological contract diminishes the probability that the workforce will see the agreement as void. Increased levels of work independence is also found to reduce incidents of psychological contract breaches.
In this proposal we aim for measuring of proton and alpha emission widths of excited states of Cr... more In this proposal we aim for measuring of proton and alpha emission widths of excited states of Cr above particle emission threshold (E ~ 8 MeV), relevant for explosive nucleosynthesis, by performing a detailed study of the beta delayed particle emission from the parent nucleus, Mn. The new data will also complement and improve the present knowledge on proton emission from the Cr proton-rich nucleus. In this measurement we will benefit from the unique Mn beams available at the ISOLDE facility.
Excited states in 73,75 Ni were investigated through the β decay of 73,75 Co in an experiment per... more Excited states in 73,75 Ni were investigated through the β decay of 73,75 Co in an experiment performed at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University (MSU). The experimental results extended the level scheme of 73 Ni to 3.2-MeV excitation energy and provided the experimental information on excited states in 75 Ni. The β-delayed neutron branching ratio for 73 Co was obtained. The experimental results are discussed in comparison with shell-model calculations.
The β decay of 57 Zn and 58 Zn was investigated in an experiment at the National Superconducting ... more The β decay of 57 Zn and 58 Zn was investigated in an experiment at the National Superconducting Cyclotron Laboratory of Michigan State University. For the first time β-delayed proton emission from 58 Zn was observed with a branching ratio of 0.7(1)%. The proton-energy spectrum allowed for probing the Gamow-Teller strength distribution above the proton-separation energy in the daughter nucleus. Moreover, the absolute branching ration for delayed-proton emission from 57 Zn was found to be compatible with 100%.
Decay of 85 Ga was studied by means of β-neutron-γ spectroscopy. Pure beam of 85 Ga was produced ... more Decay of 85 Ga was studied by means of β-neutron-γ spectroscopy. Pure beam of 85 Ga was produced at the Holifield Radioactive Ion Beam Facility using a resonance ionization laser ion source and a high-resolution electromagnetic separator. The beta-delayed neutron emission probability was measured for the first time, and yielded 70(5)%. An upper limit of 0.1% for beta-delayed two-neutrons emission was also experimentally established for the first time. A detailed decay scheme including absolute γ-ray intensities was obtained. Results are compared with theoretical beta-delayed emission models.
The advanced time-delayed γ γ (t) method has been applied to determine half-lives of low-lying st... more The advanced time-delayed γ γ (t) method has been applied to determine half-lives of low-lying states in the N = 50 isotones 94 Ru and 96 Pd. The inferred experimental E2 strengths for the 4 + → 2 + transitions in the two nuclei show a dramatic deviation with respect to the shell model predictions in the (f 5/2 ,p,g 9/2) proton hole space in 100 Sn. The anomalous behavior can be ascribed to a breakdown of the seniority quantum number in the πg n 9/2 configuration due to particle-hole excitations across the N = Z = 50 shell as confirmed by large-scale shell model calculations.
This paper presents the results of the fast neutron irradiation (E n > 0.5 MeV) of an EJ-276 scin... more This paper presents the results of the fast neutron irradiation (E n > 0.5 MeV) of an EJ-276 scintillator performed in the MARIA research reactor with fluence up to 5.3×10 15 particles/cm 2. In our work, four samples with size φ 25.4 mm×5 mm were tested. The changes in the light yield, emission and absorption spectrum and neutron/gamma discrimination using PuBe source before and after irradiation are presented. The figure of merit in neutron/gamma discrimination based on the charge integration method for different neutron fluences and different short gate integration times are determined.
Excited states in the neutron-rich isotope 133 Sn were studied via the β decay of 133 In. Isomer ... more Excited states in the neutron-rich isotope 133 Sn were studied via the β decay of 133 In. Isomer selective ionization using the ISOLDE RILIS enabled the β decays of 133 In gs (I π = 9/2 +) and 133m In (I π = 1/2 −) to be
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2019
Gamma-Beams at the HIγS facility in the USA and anticipated at the ELI-NP facility, now construct... more Gamma-Beams at the HIγS facility in the USA and anticipated at the ELI-NP facility, now constructed in Romania, present unique new opportunities to advance research in nuclear astrophysics; not the least of which is resolving open questions in oxygen formation during stellar helium burning via a precise measurement of the 12 C(α, γ) reaction. Time projection chamber (TPC) detectors operating with low pressure gas (as an active target) are ideally suited for such studies. We review the progress of the current research program and plans for the future at the HIγS facility with the optical readout TPC (O-TPC) and the development of an electronic readout TPC for the ELI-NP facility (ELITPC).
... Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996 (United Sta... more ... Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996 (United States)] ; Ginter, T. ; Stolz ... Subject, 73 NUCLEAR PHYSICS AND RADIATION PHYSICS; BETA DECAY; BRANCHING RATIO; CHARGED PARTICLES; COMPARATIVE EVALUATIONS ...
Deformation and wave function composition of unbound nuclei can be studied using measured fine st... more Deformation and wave function composition of unbound nuclei can be studied using measured fine structure properties of proton emission and microscopic theoretical models. The data on proton radioactivities ^141gsHo and ^145Tm obtained at the HRIBF (Oak Ridge) will be compared to the calculations accounting for the deformation of the potential tunnelled by the emitted protons. The wave function of a 3-mus ^145Tm will be analyzed using a praticle - core vibration model with moderate quadrupole deformation, while more complex interpretation involving triaxiality will be presented for the 4-ms activity of ^141Ho.
Decays of neutron-rich nuclei 82,83 Zn and 82,83 Ga produced in proton-induced fission of 238 U w... more Decays of neutron-rich nuclei 82,83 Zn and 82,83 Ga produced in proton-induced fission of 238 U were studied at the Holifield Radioactive Ion Beam Facility (HRIBF) using on-line mass separation and β-γ spectroscopy techniques. New γ-ray transitions were identified and level schemes, which include states at high excitation energies in the range between 3 to 7 MeV were constructed. These high energy levels were identified to be populated through allowed Gamow-Teller β-transitions, and their structure was interpreted with new shell model calculations. A β-delayed neutron branching ratio of 69±7% was deduced for 82 Zn and revised β-decay half-life values of 82 Zn (155(17)(20) ms) and 83 Zn (122(28) ms) were determined.
HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific r... more HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
Fission and Properties of Neutron-Rich Nuclei, 2013
ABSTRACT The β-decay properties of neutron-rich Cu isotopes produced in proton-induced fission of... more ABSTRACT The β-decay properties of neutron-rich Cu isotopes produced in proton-induced fission of 238U were studied at the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory. The data were collected using high-resolution online mass separation, re-acceleration, and digital β-γ spectroscopy methods. The measured β-delayed neutron properties of 77,78,79Cu will be presented and discussed in comparison with theoretical prediction performed using shell model and continuum random phase approximation approaches [1]…
Fission and Properties of Neutron-Rich Nuclei, 2013
ABSTRACT The β-decay of the N=51 nucleus 81Zn was studied by means of β - γ spectroscopy and from... more ABSTRACT The β-decay of the N=51 nucleus 81Zn was studied by means of β - γ spectroscopy and from isotopically pure beams produced at the HRIBF. We observe several competing β transitions populating 81Ga which are interpreted as allowed Gamow-Teller decays to positive parity, core excited states and first-forbidden decays to negative parity states. The measured β-decay pattern suggests an assignment of Iπ=5/2+ for the 81Zn ground state.
At the PF1B cold neutron beam line at the Institut Laue Langevin, the EXILL array consisting of E... more At the PF1B cold neutron beam line at the Institut Laue Langevin, the EXILL array consisting of EXOGAM, GASP and ILL-Clover detectors was used to perform (n,J) measurements at very high coincidence rates. About ten different reactions were measured in autumn 2012 using a highly collimated cold neutron beam. In spring 2013, the EXOGAM array was combined with 16 LaBr 3 (Ce) scintillators in the EXILL&FATIMA campaign for the measurement of lifetimes using the generalised centroid difference method. We report on the properties of the setups and present first results from both campaigns.
Recent updates on β decay of 75 Zn into 75 Ga are presented with the decay scheme and structure o... more Recent updates on β decay of 75 Zn into 75 Ga are presented with the decay scheme and structure of 75 Ga. The present study utilized a more efficient detector setup along with high purity of the 75 Cu beam in comparison to previous studies with a rate of over 2000 ions/s. The purity of beam which is obtained by using high-resolution isobar separator prevented any member of the decay chain from being dominant and allowed for comparisons of branching rations between the decays. The greater efficiency of the HPGe detector array meant more low energy γ-ray detection from the decays. The γ-γ and β-γ coincidence data obtained from the experiment were collected at the LeRIBSS (Low energy Radioactive Ion Beam Spectroscopy Station) and used to develop a revised decay scheme using an objective method.
A psychological contract comprises of a personal viewpoint about mutual commitments in employment... more A psychological contract comprises of a personal viewpoint about mutual commitments in employment relationships. Unlike a traditional service contract, the psychological contract remains unspoken in the employment relationship between employer and the employees. Employees anticipate, for example, working in a secure and clean environment; to work with qualified and regimented co-workers and to be appreciated for their good work, free from harassment etc. Employers, on the contrary, expect staff to be careful and dedicated; to be trustworthy; and to maintain or enhance the organizational image etc. This shady nature and often conflicting nature of psychological contract can often harm the health of employment relationship. This paper explores the nature of psychological contracts and their significance within the domain of employment relationships. The paper first reviews the general theory of psychological contract, its types and factors governing them. Next, a theoretical examining the research contributions of scholars who have contributed to the literature is being carried out. Finally, the paper thoroughly and critically analyzes the effects of breach or non-conformity of psychological contracts. Psychological contract plays a key role in manipulating workers job related commitment. It must be highlighted that effective observation, agreement and execution of psychological contracts could add to increased levels of workers commitment. Considering the literature studied, it becomes extremely important for the management to be responsive of, and to some degree control, the psychological contracts that the employees may hold. Offering the aggrieved employees a practical psychological contract diminishes the probability that the workforce will see the agreement as void. Increased levels of work independence is also found to reduce incidents of psychological contract breaches.
In this proposal we aim for measuring of proton and alpha emission widths of excited states of Cr... more In this proposal we aim for measuring of proton and alpha emission widths of excited states of Cr above particle emission threshold (E ~ 8 MeV), relevant for explosive nucleosynthesis, by performing a detailed study of the beta delayed particle emission from the parent nucleus, Mn. The new data will also complement and improve the present knowledge on proton emission from the Cr proton-rich nucleus. In this measurement we will benefit from the unique Mn beams available at the ISOLDE facility.
Excited states in 73,75 Ni were investigated through the β decay of 73,75 Co in an experiment per... more Excited states in 73,75 Ni were investigated through the β decay of 73,75 Co in an experiment performed at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University (MSU). The experimental results extended the level scheme of 73 Ni to 3.2-MeV excitation energy and provided the experimental information on excited states in 75 Ni. The β-delayed neutron branching ratio for 73 Co was obtained. The experimental results are discussed in comparison with shell-model calculations.
The β decay of 57 Zn and 58 Zn was investigated in an experiment at the National Superconducting ... more The β decay of 57 Zn and 58 Zn was investigated in an experiment at the National Superconducting Cyclotron Laboratory of Michigan State University. For the first time β-delayed proton emission from 58 Zn was observed with a branching ratio of 0.7(1)%. The proton-energy spectrum allowed for probing the Gamow-Teller strength distribution above the proton-separation energy in the daughter nucleus. Moreover, the absolute branching ration for delayed-proton emission from 57 Zn was found to be compatible with 100%.
Decay of 85 Ga was studied by means of β-neutron-γ spectroscopy. Pure beam of 85 Ga was produced ... more Decay of 85 Ga was studied by means of β-neutron-γ spectroscopy. Pure beam of 85 Ga was produced at the Holifield Radioactive Ion Beam Facility using a resonance ionization laser ion source and a high-resolution electromagnetic separator. The beta-delayed neutron emission probability was measured for the first time, and yielded 70(5)%. An upper limit of 0.1% for beta-delayed two-neutrons emission was also experimentally established for the first time. A detailed decay scheme including absolute γ-ray intensities was obtained. Results are compared with theoretical beta-delayed emission models.
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Papers by A. Korgul