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13 results on '"Rehm, Karl E."'

1. Near-Earth Supernova Explosions: Evidence, Implications, and Opportunities

Author

Fields, Brian D., Ellis, John R., Binns, Walter R., Breitschwerdt, Dieter, de Nolfo, Georgia A., Diehl, Roland, Dwarkadas, Vikram V., Ertel, Adrienne, Faestermann, Thomas, Feige, Jenny, Fitoussi, Caroline, Frisch, Priscilla, Graham, David, Haley, Brian, Heger, Alexander, Hillebrandt, Wolfgang, Israel, Martin H., Janka, Thomas, Kachelriess, Michael, Korschinek, Gunther, Limongi, Marco, Lugaro, Maria, Marinho, Franciole, Melott, Adrian, Mewaldt, Richard A., Miller, Jesse, Ogliore, Ryan C., Paul, Michael, Paulucci, Laura, Pecaut, Mark, Rauch, Brian F., Rehm, Karl E., Schulreich, Michael, Seitenzahl, Ivo, Sorensen, Mads, Thielemann, Friedrich-Karl, Timmes, Francis X., Thomas, Brian C., and Wallner, Anton

Subjects
Astrophysics - Solar and Stellar Astrophysics, Astrophysics - Earth and Planetary Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, Nuclear Experiment, Physics - Space Physics
Abstract

There is now solid experimental evidence of at least one supernova explosion within 100 pc of Earth within the last few million years, from measurements of the short-lived isotope 60Fe in widespread deep-ocean samples, as well as in the lunar regolith and cosmic rays. This is the first established example of a specific dated astrophysical event outside the Solar System having a measurable impact on the Earth, offering new probes of stellar evolution, nuclear astrophysics, the astrophysics of the solar neighborhood, cosmic-ray sources and acceleration, multi-messenger astronomy, and astrobiology. Interdisciplinary connections reach broadly to include heliophysics, geology, and evolutionary biology. Objectives for the future include pinning down the nature and location of the established near-Earth supernova explosions, seeking evidence for others, and searching for other short-lived isotopes such as 26Al and 244Pu. The unique information provided by geological and lunar detections of radioactive 60Fe to assess nearby supernova explosions make now a compelling time for the astronomy community to advocate for supporting multi-disciplinary, cross-cutting research programs., Comment: 11 pages, 2 figures. Astro2020 Science White Paper submitted to the 2020 Decadal Survey on Astronomy and Astrophysics

Published
2019

2. New AMS method to measure the atom ratio 146Sm/147Sm for a half-life determination of 146Sm

Author

Kinoshita, Norikazu, Paul, Michael, Alcorta, Martín, Bowers, Matthew, Collon, P., Deibel, C., DiGiovine, B., Goriely, Stéphane, Greene, John P., Henderson, Dale J., Jiang, Cheng-Lie, Kashiv, Yoav, Kay, B.P, Lee, H-Y, Marley, Scott, Nakanishi, Takashi, Pardo, Richard C., Patel, Nilesh, Rehm, Karl E., Robertson, Donald, Scott, Roger, Schmitt, Christian, Tang, X.D, Ugalde, Claudio, Vondrasek, Richard C., Kinoshita, Norikazu, Paul, Michael, Alcorta, Martín, Bowers, Matthew, Collon, P., Deibel, C., DiGiovine, B., Goriely, Stéphane, Greene, John P., Henderson, Dale J., Jiang, Cheng-Lie, Kashiv, Yoav, Kay, B.P, Lee, H-Y, Marley, Scott, Nakanishi, Takashi, Pardo, Richard C., Patel, Nilesh, Rehm, Karl E., Robertson, Donald, Scott, Roger, Schmitt, Christian, Tang, X.D, Ugalde, Claudio, and Vondrasek, Richard C.

Abstract

The extinct p-process nuclide 146Sm (t1/2 = 103 ± 5 Myr) is known to have been present in the Early-Solar System and has been proposed as an astrophysical chronometer. 146Sm is also intensely used to date meteorite and planetary differentiation processes, enhancing the importance of an accurate knowledge of the 146Sm half-life. We are engaged in a new determination of the 146Sm half-life in which the 146Sm/147Sm atom ratio is determined by accelerator mass spectrometry at the ATLAS facility of Argonne National Laboratory. In order to reduce systematic errors in the AMS determination of the 146Sm/147Sm ratios (in the range of 10-7-10-9), 146Sm and 147Sm ions were alternately counted in the same detector in the focal plane of a gas-filled magnet, respectively in continuous-wave and attenuated mode. Quantitative attenuation is obtained with the 12 MHz pulsed and ns-bunched ATLAS beam by chopping beam pulses with an RF sweeper in a ratio (digitally determined) down to 1:106. The experiments and preliminary results are discussed. © 2012 Elsevier B.V. All rights reserved., SCOPUS: cp.j, info:eu-repo/semantics/published

Published
2013

3. New AMS Method to Measure the Atom Ratio 146Sm/147Sm for a Half-life Determination of 146Sm

Author

Kinoshita, Norikazu, Paul, Michael, Alcorta, Martín, Bowers, Matthew, Collon, P., Deibel, C., DiGiovine, B., Goriely, Stéphane, Greene, John P., Henderson, Dale J., Jiang, Cheng-Lie, Kashiv, Yoav, Kay, B.P, Lee, H-Y, Marley, Scott, Nakanishi, Takashi, Pardo, Richard C., Patel, Nilesh, Rehm, Karl E., Robertson, Darren, Scott, Ryan, Schmitt, Christian, Tang, X.D, Ugalde, Claudio, Vondrasek, Richard C., Kinoshita, Norikazu, Paul, Michael, Alcorta, Martín, Bowers, Matthew, Collon, P., Deibel, C., DiGiovine, B., Goriely, Stéphane, Greene, John P., Henderson, Dale J., Jiang, Cheng-Lie, Kashiv, Yoav, Kay, B.P, Lee, H-Y, Marley, Scott, Nakanishi, Takashi, Pardo, Richard C., Patel, Nilesh, Rehm, Karl E., Robertson, Darren, Scott, Ryan, Schmitt, Christian, Tang, X.D, Ugalde, Claudio, and Vondrasek, Richard C.

Abstract

The extinct p-process nuclide 146Sm (t1/2 = 103 ± 5 Myr) is known to have been present in the Early-Solar System and has been proposed as an astrophysical chronometer. 146Sm is also intensely used to date meteorite and planetary differentiation processes, enhancing the importance of an accurate knowledge of the 146Sm half-life. We are engaged in a new determination of the 146Sm half-life in which the 146Sm/147Sm atom ratio is determined by accelerator mass spectrometry at the ATLAS facility of Argonne National Laboratory. In order to reduce systematic errors in the AMS determination of the 146Sm/147Sm ratios (in the range of 10 7–10 9), 146Sm and 147Sm ions were alternately counted in the same detector in the focal plane of a gas-filled magnet, respectively in continuous-wave and attenuated mode. Quanti- tative attenuation is obtained with the 12 MHz pulsed and ns-bunched ATLAS beam by chopping beam pulses with an RF sweeper in a ratio (digitally determined) down to 1:106. The experiments and prelimin- ary results are discussed., info:eu-repo/semantics/published

Published
2012

4. New AMS Method to Measure the Atom Ratio 146Sm/147Sm for a Half-life Determination of 146Sm

Author

Kinoshita, Norikazu, Paul, Michael, Alcorta, Martín, Bowers, Matthew, Collon, P., Deibel, C., DiGiovine, S., Goriely, Stéphane, Greene, John P., Henderson, Dale J., Jiang, Cheng-Lie, Kashiv, Yoav, Kay, B.P, Lee, H-Y, Nakanishi, Takashi, Pardo, Richard C., Patel, Nilesh, Rehm, Karl E., Robertson, Donald, Scott, Roger, Schmitt, Christian, Tang, X.D, Vondrasek, Richard C., Kinoshita, Norikazu, Paul, Michael, Alcorta, Martín, Bowers, Matthew, Collon, P., Deibel, C., DiGiovine, S., Goriely, Stéphane, Greene, John P., Henderson, Dale J., Jiang, Cheng-Lie, Kashiv, Yoav, Kay, B.P, Lee, H-Y, Nakanishi, Takashi, Pardo, Richard C., Patel, Nilesh, Rehm, Karl E., Robertson, Donald, Scott, Roger, Schmitt, Christian, Tang, X.D, and Vondrasek, Richard C.

Abstract

info:eu-repo/semantics/published

Published
2011

5. Detection, half-life and production of p-process nuclide 146Sm

Author

Kinoshita, Norikazu, Paul, Michael, Amakawa, H., Collon, P., Goriely, Stéphane, Greene, John P., Hashimoto, T., Henderson, Dale J., Jiang, Cheng-Lie, Jisonna, L., Kashiv, Yoav, Kay, B., Lee, Hsien-Yang, Mitsugashira, T., Nakanishi, Takashi, Nassar, Hisham, Ohtsuki, T., Pardo, Richard C., Patel, Nilesh, Rehm, Karl E., Robertson, Donald, Schmitt, Christian, Scott, Roger, Takahashi, N., Vondrasek, Richard C., Yokoyama, A., Kinoshita, Norikazu, Paul, Michael, Amakawa, H., Collon, P., Goriely, Stéphane, Greene, John P., Hashimoto, T., Henderson, Dale J., Jiang, Cheng-Lie, Jisonna, L., Kashiv, Yoav, Kay, B., Lee, Hsien-Yang, Mitsugashira, T., Nakanishi, Takashi, Nassar, Hisham, Ohtsuki, T., Pardo, Richard C., Patel, Nilesh, Rehm, Karl E., Robertson, Donald, Schmitt, Christian, Scott, Roger, Takahashi, N., Vondrasek, Richard C., and Yokoyama, A.

Abstract

info:eu-repo/semantics/published

Published
2008

6. Wear measurement of highly cross‐linked UHMWPE using a 7Be tracer implantation technique

Author

Wimmer, Markus A., primary, Laurent, Michel P., additional, Dwiwedi, Yasha, additional, Gallardo, Luis A., additional, Chipps, Kelly A., additional, Blackmon, Jeffery C., additional, Kozub, Raymond L., additional, Bardayan, Daniel W., additional, Gross, Carl J., additional, Stracener, Daniel W., additional, Smith, Michael S., additional, Nesaraja, Caroline D., additional, Erikson, Luke, additional, Patel, Nidhi, additional, Rehm, Karl E., additional, Ahmad, Irshad, additional, Greene, John P., additional, and Greife, Uwe, additional

Published
2013
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7. The supernova-nucleosynthesis 40Ca (α,γ) 44Ti reaction

Author

Nassar, Hisham, Paul, Michael, Kashiv, Yoav, Ofan, Avishai, Janssens, Robert V. F., Pardo, Richard C., Rehm, Karl E., Savard, Guy, Scott, Roger, Vondrasek, Richard C., Goriely, Stéphane, Heger, Alexander, Hass, Michael, Nassar, Hisham, Paul, Michael, Kashiv, Yoav, Ofan, Avishai, Janssens, Robert V. F., Pardo, Richard C., Rehm, Karl E., Savard, Guy, Scott, Roger, Vondrasek, Richard C., Goriely, Stéphane, Heger, Alexander, and Hass, Michael

Abstract

The 44Ti (t1/2 = 59 y) nuclide is considered an important signature of core-collapse supernova (SN) nucleosynthesis and has recently been observed as live radioactivity by γ-ray astronomy from the Cas A SN remnant. We investigated in the laboratory the major 44Ti production reaction 40Ca(α,γ)44Ti (E cm ∼ 0.6-1.2 MeV/u) by off-line counting of 44Ti nuclei using accelerator mass spectrometry. The observed yield is significantly higher than inferred from previous prompt γ-spectroscopy experiments. The present data are interpreted in terms of the BRUSLIB statistical model which incorporates a microscopic model of nuclear level densities and of the γ-ray strength function, and a global α-nucleus optical-model potential and confirm the strong suppression in yield expected for (α,γ) reactions on self-conjugate (N =Z) nuclei. The derived astrophysical rate of the 40Ca(α,γ)44Ti reaction is a factor 5-10 higher than calculated in current models. We will present results of stellar calculations in spherical hydrodynamics using this reaction rate, showing an increase of the calculated SN 44Ti yield by a factor ∼ 2 over current estimates. An increase by a factor of ∼ 2 in 44Ti is found also in the calculated fall back material. The yields calculated by multi-dimensional SN explosion calculations proposed to explain the observed 44Ti yield of Cas A, in which parts of deeper layers can be ejected while some of the outer layers fall back, are expected to be enhanced in 44Ti as well., SCOPUS: cp.p, info:eu-repo/semantics/published

Published
2006

8. Ca40(α,γ)Ti44 reaction in the energy regime of supernova nucleosynthesis

Author

Nassar, Hisham, Paul, Michael, Ahmad, Irshad, Ben-Dov, Yair, Caggiano, Jac, Ghelberg, S., Goriely, Stéphane, Greene, John P., Hass, Michael, Heger, Alexander, Heinz, Andreas, Henderson, Dale J., Janssens, Robert V. F., Jiang, Cheng-Lie, Kashiv, Yoav, Nara Singh, Bondili S., Ofan, Avishai, Pardo, Richard C., Pennington, Tad, Rehm, Karl E., Savard, Guy, Scott, Roger, Vondrasek, Richard C., Nassar, Hisham, Paul, Michael, Ahmad, Irshad, Ben-Dov, Yair, Caggiano, Jac, Ghelberg, S., Goriely, Stéphane, Greene, John P., Hass, Michael, Heger, Alexander, Heinz, Andreas, Henderson, Dale J., Janssens, Robert V. F., Jiang, Cheng-Lie, Kashiv, Yoav, Nara Singh, Bondili S., Ofan, Avishai, Pardo, Richard C., Pennington, Tad, Rehm, Karl E., Savard, Guy, Scott, Roger, and Vondrasek, Richard C.

Abstract

SCOPUS: ar.j, info:eu-repo/semantics/published

Published
2006

9. The supernova nucleosynthesis 40Ca(alpha,gamma)44Ti reaction

Author

Nassar, Hisham, Paul, Michael, Kashiv, Yoav, Ofan, Avishai, Janssens, Robert V. F., Pardo, Richard C., Rehm, Karl E., Savard, Gilles, Scott, Roger, Vndrasek, R., Goriely, Stéphane, Heger, Alexander, Hass, Michael, Nassar, Hisham, Paul, Michael, Kashiv, Yoav, Ofan, Avishai, Janssens, Robert V. F., Pardo, Richard C., Rehm, Karl E., Savard, Gilles, Scott, Roger, Vndrasek, R., Goriely, Stéphane, Heger, Alexander, and Hass, Michael

Abstract

info:eu-repo/semantics/published

Published
2006

10. Investigating the astrophysical rp-process through atomic mass measurements

Author

Sharma, Kumar S. (Physics and Astronomy) Barber, Robert C. (Physics and Astronomy) Savard, Guy (Adjunct Professor, Physics and Astronomy) Thomson, Douglas J. (Electrical and Computer Engineering) Rehm, Karl E. (External Examiner, Argonne National Laboratory), Sharma, Kumar S. (Physics and Astronomy), Clark, Jason A, Sharma, Kumar S. (Physics and Astronomy) Barber, Robert C. (Physics and Astronomy) Savard, Guy (Adjunct Professor, Physics and Astronomy) Thomson, Douglas J. (Electrical and Computer Engineering) Rehm, Karl E. (External Examiner, Argonne National Laboratory), Sharma, Kumar S. (Physics and Astronomy), and Clark, Jason A

Abstract

The Canadian Penning Trap (CPT) mass spectrometer at the Argonne National Laboratory makes precise mass measurements of both stable and unstable nuclides. To date, more than 60 radioactive isotopes having half-lives as short as one second have been measured with the CPT with a mass precision approaching 10 ppb. This thesis will present measurements made of nuclides along the rp-process path, which describes a process resulting from a series of rapid proton-capture reactions in an astrophysical environment. One possible site for the rp-process mechanism is an x-ray burst which results from the rapid accretion of hydrogen and helium from one star onto the surface of its neutron star binary companion. Mass measurements are required as key inputs to network calculations used to describe the rp-process in terms of the abundances of the nuclides produced, the light-curve profile of the x-ray bursts, and the energy produced. This thesis will describe the CPT apparatus, explain the method used to make precise mass measurements, and present the masses of the "waiting-point" nuclides 68Se and 64Ge. The mass measurement results, when used in x-ray burst models, confirm both 68Se and 64Ge as waiting-point nuclides which delay the rp-process by approximately 30 s and 7 s respectively.

Published
2005

11. Wear measurement of highly cross-linked UHMWPE using a 7Be tracer implantation technique.

Author

Wimmer, Markus A., Laurent, Michel P., Dwiwedi, Yasha, Gallardo, Luis A., Chipps, Kelly A., Blackmon, Jeffery C., Kozub, Raymond L., Bardayan, Daniel W., Gross, Carl J., Stracener, Daniel W., Smith, Michael S., Nesaraja, Caroline D., Erikson, Luke, Patel, Nidhi, Rehm, Karl E., Ahmad, Irshad, Greene, John P., and Greife, Uwe

Abstract

The very low wear rates achieved with the current highly cross-linked ultrahigh molecular weight polyethylenes (UHMWPE) used in joint prostheses have proven to be difficult to measure accurately by gravimetry. Tracer methods are therefore being explored. The purpose of this study was to perform a proof-of-concept experiment on the use of the radioactive tracer beryllium-7 (7Be) for the determination of in vitro wear in a highly cross-linked orthopedic UHMWPE. Three cross-linked and four conventional UHMWPE pins made from compression-molded GUR 1050, were activated with 109 to 1010 7Be nuclei using a new implantation setup that produced a homogenous distribution of implanted nuclei up to 8.5 μm below the surface. The pins were tested for wear in a six-station pin-on-flat apparatus for up to 7.1 million cycles (178 km). A Germanium gamma detector was employed to determine activity loss of the UHMWPE pins at preset intervals during the wear test. The wear of the cross-linked UHMWPE pins was readily detected and estimated to be 17 ± 3 μg per million cycles. The conventional-to-cross-linked ratio of the wear rates was 13.1 ± 0.8, in the expected range for these materials. Oxidative degradation damage from implantation was negligible; however, a weak dependence of wear on implantation dose was observed limiting the number of radioactive tracer atoms that can be introduced. Future applications of this tracer technology may include the analysis of location-specific wear, such as loss of material in the post or backside of a tibial insert. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 101B: 423-429, 2013. [ABSTRACT FROM AUTHOR]

Published
2013
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12. Half-life of 60Fe

Author

Kutschera, Walter, primary, Billquist, Peter J., additional, Frekers, Dieter, additional, Henning, Walter, additional, Jensen, Kenneth J., additional, Xiuzeng, Ma, additional, Pardo, Richard, additional, Paul, Michael, additional, Rehm, Karl E., additional, Smither, Robert K., additional, Yntema, Jan L., additional, and Mausner, Leonard F., additional

Published
1984
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