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12 results on '"Romig, Christopher"'

1. The high-efficiency {\gamma}-ray spectroscopy setup {\gamma}3 at HI{\gamma}S

Author

Löher, Bastian, Derya, Vera, Aumann, Thomas, Beller, Jacob, Cooper, Nathan, Duchene, Marc, Endres, Janis, Fiori, Enrico, Isaak, Johann, Kelley, John, Knörzer, Michael, Pietralla, Norbert, Romig, Christopher, Scheck, Marcus, Scheit, Heiko, Silva, Joel, Tonchev, Anton P., Tornow, Werner, Weller, Henry, Werner, Volker, and Zilges, Andreas

Subjects
Physics - Instrumentation and Detectors, Nuclear Experiment
Abstract

The existing Nuclear Resonance Fluorescence (NRF) setup at the HI{\gamma}S facility at the Triangle Universities Nuclear Laboratory at Duke University has been extended in order to perform {\gamma}-{\gamma} coincidence experiments. The new setup combines large volume LaBr3:Ce detectors and high resolution HPGe detectors in a very close geometry to offer high efficiency, high energy resolution as well as high count rate capabilities at the same time. The combination of a highly efficient {\gamma}-ray spectroscopy setup with the mono-energetic high-intensity photon beam of HI{\gamma}S provides a worldwide unique experimental facility to investigate the {\gamma}-decay pattern of dipole excitations in atomic nuclei. The performance of the new setup has been assessed by studying the nucleus \sulfur at 8.125 MeV beam energy. The {\gamma}-decay branching ratio from the $1^+$ level at 8125.4 keV to the first excited $2^+$ state was determined to 15.7(3)%., Comment: 9 pages, 11 figures

Published
2013
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2. The decay pattern of the Pygmy Dipole Resonance of ��������Ce

Author

Löher, Bastian, Savran, Deniz, Aumann, Thomas, Beller, Jacob, Bhike, Megha, Cooper, Nathan L., Derya, Vera, Duchêne, Marc, Endres, Janis, Hennig, Andreas, Humby, P., Isaak, Johann, Kelley, John H., Knörzer, M., Pietralla, Norbert A., Ponomarev, Vladimir, Romig, Christopher, Scheck, Marcus, Scheit, Heiko, Silva, Joel, Tonchev, Anton P., Tornow, Werner, Wamers, Felix, Weller, Henry R., Werner, Volker, and Zilges, Andreas

Abstract

The decay properties of the Pygmy Dipole Resonance (PDR) have been investigated in the semi-magic N=82 nucleus ��������Ce using a novel combination of nuclear resonance fluorescence and �������coincidence techniques. Branching ratios for transitions to low-lying excited states are determined in a direct and model-independent way both for individual excited states and for excitation energy intervals. Comparison of the experimental results to microscopic calculations in the quasi-particle phonon model exhibits an excellent agreement, supporting the observation that the Pygmy Dipole Resonance couples to the ground state as well as to low-lying excited states. A 10% mixing of the PDR and the [2+1��PDR]is extracted.

Published
2022
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3. Fields Of Blood

Author

Romig, Christopher

Subjects
Fields of Blood: Religion and the History of Violence (Nonfiction work) -- Book reviews, Fields of Blood: Religion and the History of Violence (Nonfiction work) -- Armstrong, Karen, Books -- Book reviews, General interest, Literature/writing, News, opinion and commentary
Abstract

FIELDS OF BLOOD by Karen Armstrong (Knopf). This study of religious violence stretches from the age of Gilgamesh to the present. Seeking to defend religion, Armstrong argues that it acts [...]

Published
2015

4. Investigation of Nuclear Structure with Relative Self-Absorption Measurements

Author

Romig, Christopher

Abstract

In this work, a special application of the nuclear resonance fluorescence technique has been used and further advanced to study nuclear structure effects: so-called relative self-absorption experiments. They allow for the direct determination of ground-state transition widths of excited states, an important quantity for comparisons to model calculations, as well as the level width and the branching ratio to the ground state of individual states in a model-independent way. Two self-absorption measurements have been performed. On the one hand, the absolute excitation widths and the decay pattern of low-lying excited dipole states in the energy regime of the pygmy dipole resonance have been investigated in the nucleus $^{140}$Ce. The results of the nuclear resonance fluorescence measurement, which is part of a self-absorption experiment, as well as of the actual self-absorption measurement are presented for 117 and 104 excited states of $^{140}$Ce, respectively. They are compared to previous measurements and discussed with respect to the statistical model. On the other hand, a high-precision measurement of the self absorption of the $T=1$, $J^{\pi}=0^+_1$ level at an excitation energy of \unit[3563]{keV} in $^6$Li has been conducted. A precisely measured level width of this state can serve as a benchmark for modern ab-inito calculations.

Published
2015

5. Dipole strength distributions from HIGS Experiments

Author

International Symposium on Capture Gamma-Ray Spectroscopy and Related Topics (15. : 2014 : Dresden), Werner, Volker, Cooper, Nathan, Goddard, Phil M., Humby, Peter, Ilieva, Ralista S., Rusev, Gencho, Beller, Jacob, Bernards, Christian, Crider, Benjamin P., Isaak, Johann, Kelley, John H., Kwan, Elaine, Löher, Bastian, Peters, Erin E., Pietralla, Norbert, Romig, Christopher, Savran, Deniz, Scheck, Marcus, Tonchev, Anton P., Tornow, Werner, Yates, Steven W., Zweidinger, Markus, International Symposium on Capture Gamma-Ray Spectroscopy and Related Topics (15. : 2014 : Dresden), Werner, Volker, Cooper, Nathan, Goddard, Phil M., Humby, Peter, Ilieva, Ralista S., Rusev, Gencho, Beller, Jacob, Bernards, Christian, Crider, Benjamin P., Isaak, Johann, Kelley, John H., Kwan, Elaine, Löher, Bastian, Peters, Erin E., Pietralla, Norbert, Romig, Christopher, Savran, Deniz, Scheck, Marcus, Tonchev, Anton P., Tornow, Werner, Yates, Steven W., and Zweidinger, Markus

Abstract

A series of photon scattering experiments has been performed on the double-beta decay partners 76Ge and 76Se, in order to investigate their dipole response up to the neutron separation threshold. Gamma-ray beams from bremsstrahlung at the S-DALINAC and from Compton-backscattering at HIGS have been used to measure absolute cross sections and parities of dipole excited states, respectively. The HIGS data allows for indirect measurement of averaged branching ratios, which leads to significant corrections in the observed excitation cross sections. Results are compared to statistical calculations, to test photon strength functions and the Axel-Brink hypothesis.

Published
2015

6. QPM analysis of 205TI nuclear excitations below the giant dipole resonance

Author

International Symposium on Capture Gamma-Ray Spectroscopy and Related Topics (15. : 2014 : Dresden), Benouaret, Nadia, Beller, Jacob, Isaak, Johann, Kelley, John H., Pai, Haridas, Pietralla, Norbert, Ponomarev, V. Yu., Raut, Rajarshi, Romig, Christopher, Rusev, Gencho, Savran, Deniz, Scheck, Marcus, Schnorrenberger, Linda, Sonnabend, Kerstin, Tonchev, Anton P., Tornow, Werner, Weller, Henry R., Zweidinger, Markus, International Symposium on Capture Gamma-Ray Spectroscopy and Related Topics (15. : 2014 : Dresden), Benouaret, Nadia, Beller, Jacob, Isaak, Johann, Kelley, John H., Pai, Haridas, Pietralla, Norbert, Ponomarev, V. Yu., Raut, Rajarshi, Romig, Christopher, Rusev, Gencho, Savran, Deniz, Scheck, Marcus, Schnorrenberger, Linda, Sonnabend, Kerstin, Tonchev, Anton P., Tornow, Werner, Weller, Henry R., and Zweidinger, Markus

Abstract

We analysed our experimental recent findings of the dipole response of the odd-mass stable nucleus 205Tl within the quasi-particle phonon model. Using the phonon basis constructed for the neighbouring 204Hg and wave function configurations for 205Tl consisting of a mixture of quasiparticle ⊗ N-phonon configurations (N=0,1,2), only one group of fragmented dipole excited states has been reproduced at 5.5 MeV in comparison to the experimental distribution which shows a second group at about 5 MeV. The computed dipole transition strengths are mainly of E1 character which could be associated to the pygmy dipole resonance.

Published
2015

7. Direct determination of ground-state transition widths and natural level widths with the method of relative self absorption

Author

International Symposium on Capture Gamma-Ray Spectroscopy and Related Topics (15. : 2014 : Dresden), Romig, Christopher, Beck, Tobias, Beller, Jacob, Birkhan, Jonny, Endres, Anne, Fritzsche, Matthias, Gayer, Udo, Glorius, Jan, Isaak, Johann, Mertes, Laura, Pai, Haridas, Pietralla, Norbert, Ries, Philipp, Savran, Deniz, Scheck, Marcus, Schnorrenberger, Linda, Sonnabend, Kerstin, Werner, Volker, Zweidinger, Markus, International Symposium on Capture Gamma-Ray Spectroscopy and Related Topics (15. : 2014 : Dresden), Romig, Christopher, Beck, Tobias, Beller, Jacob, Birkhan, Jonny, Endres, Anne, Fritzsche, Matthias, Gayer, Udo, Glorius, Jan, Isaak, Johann, Mertes, Laura, Pai, Haridas, Pietralla, Norbert, Ries, Philipp, Savran, Deniz, Scheck, Marcus, Schnorrenberger, Linda, Sonnabend, Kerstin, Werner, Volker, and Zweidinger, Markus

Abstract

The method of relative self absorption is based on the technique of nuclear resonance fluorescence measurements. It allows for a model-independent determination of ground-state transition widths, natural level widths, and, consequently, of branching ratios to the ground state for individual excitations. Relative self–absorption experiments have been performed on the nuclei 6Li and 140Ce. In order to investigate the total level width for the 0+1, T = 1 level at 3563 keV in 6Li, a high-precision self-absorption measurement has been performed. In the case of 140Ce, self absorption has been applied for the first time to study decay widths of dipole-excited states in the energy regime of the pygmy dipole resonance.

Published
2015

8. The high-efficiency ��-ray spectroscopy setup ��3 at HI��S

Author

L��her, Bastian, Derya, Vera, Aumann, Thomas, Beller, Jacob, Cooper, Nathan, Duchene, Marc, Endres, Janis, Fiori, Enrico, Isaak, Johann, Kelley, John, Kn��rzer, Michael, Pietralla, Norbert, Romig, Christopher, Scheck, Marcus, Scheit, Heiko, Silva, Joel, Tonchev, Anton P., Tornow, Werner, Weller, Henry, Werner, Volker, and Zilges, Andreas

Subjects
FOS: Physical sciences, Instrumentation and Detectors (physics.ins-det), Nuclear Experiment (nucl-ex)
Abstract

The existing Nuclear Resonance Fluorescence (NRF) setup at the HI��S facility at the Triangle Universities Nuclear Laboratory at Duke University has been extended in order to perform ��-�� coincidence experiments. The new setup combines large volume LaBr3:Ce detectors and high resolution HPGe detectors in a very close geometry to offer high efficiency, high energy resolution as well as high count rate capabilities at the same time. The combination of a highly efficient ��-ray spectroscopy setup with the mono-energetic high-intensity photon beam of HI��S provides a worldwide unique experimental facility to investigate the ��-decay pattern of dipole excitations in atomic nuclei. The performance of the new setup has been assessed by studying the nucleus \sulfur at 8.125 MeV beam energy. The ��-decay branching ratio from the $1^+$ level at 8125.4 keV to the first excited $2^+$ state was determined to 15.7(3)%., 9 pages, 11 figures

Published
2013
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9. Decay pattern of the pygmy dipole resonance in 130Te

Author

International Nuclear Physics Conference (25. : 2013 : Firenze, Italy), Isaak, Johann, Beller, Jacob, Fiori, Enrico, Krtička, Milan, Löher, Bastian, Pietralla, Norbert, Romig, Christopher, Rusev, Gencho, Savran, Deniz, Scheck, Marcus, Silva, Joel, Sonnabend, Kerstin, Tonchev, Anton P., Tornow, Werner, Weller, Henry R., Zweidinger, Markus, International Nuclear Physics Conference (25. : 2013 : Firenze, Italy), Isaak, Johann, Beller, Jacob, Fiori, Enrico, Krtička, Milan, Löher, Bastian, Pietralla, Norbert, Romig, Christopher, Rusev, Gencho, Savran, Deniz, Scheck, Marcus, Silva, Joel, Sonnabend, Kerstin, Tonchev, Anton P., Tornow, Werner, Weller, Henry R., and Zweidinger, Markus

Abstract

The electric dipole strength distribution in 130Te has been investigated using the method of Nuclear Resonance Fluorescence. The experiments were performed at the Darmstadt High Intensity Photon Setup using bremsstrahlung as photon source and at the High Intensity -Ray Source, where quasi-monochromatic and polarized photon beams are provided. Average decay properties of 130Te below the neutron separation energy are determined. Comparing the experimental data to the predictions of the statistical model indicate, that nuclear structure effects play an important role even at sufficiently high excitation energies. Preliminary results will be presented.

Published
2014

12. Echo rounds: application of real-time 3-dimensional transesophageal echocardiography in the percutaneous closure of a mitral paravalvular leak.

Author

Azran MS, Romig CB, Locke A, and Whitley WS

Subjects
Cardiac Catheterization, Female, Fluoroscopy, Heart Septal Defects, Atrial diagnostic imaging, Heart Septal Defects, Atrial surgery, Heart Valves surgery, Humans, Middle Aged, Mitral Valve Insufficiency surgery, Monitoring, Intraoperative, Stents, Cardiac Surgical Procedures methods, Echocardiography, Three-Dimensional methods, Echocardiography, Transesophageal methods, Mitral Valve Insufficiency diagnostic imaging
Published
2010
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