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Author |
Pavez, C.; Pedreros, J.; Tarifeño-Saldivia, A.; Soto, L. |
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Title |
Observation of plasma jets in a table top plasma focus discharge |
Type |
Journal Article |
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Year |
2015 |
Publication |
Physics of Plasmas |
Abbreviated Journal |
Phys. Plasmas |
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Volume |
22 |
Issue |
4 |
Pages |
040705 - 5pp |
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Abstract |
In the last years, medium size Z-pinch experiments operating at tens of kJ are being used to create supersonic plasma jets. Those experiments are produced with wire arrays and radial foils, and they are conducted in generators based on water-filled transmission lines. Also plasma jets have been observed in small X-pinch experiments operating at 1 kJ. In this work, observations of plasma jets produced in a table top plasma focus device by means of optical and digital interferometry are shown. The device was operated at only similar to 70J, achieving 50 kA in 150 ns. The plasma jets were observed after the pinch, in the region close and on the anode, along the axis. The electron density measured from the jets is in the range 10(24)-10(25) m(-3). From two consecutive plasma images separated 18 ns, the axial jet velocity was measured in the order of 4 x 10(4) m/s. |
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Address |
[Pavez, Cristian; Pedreros, Jose; Tarifeno-Saldivia, Ariel; Soto, Leopoldo] CCHEN, Comis Chilena Energia Nucl, Santiago, Chile, Email: lsoto@cchen.cl |
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Publisher |
Amer Inst Physics |
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Language |
English |
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ISSN |
1070-664x |
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Conference |
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Notes |
WOS:000353837200006 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
2400 |
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Author |
n_TOF Collaboration (Barbagallo, M. et al); Domingo-Pardo, C.; Tain, J.L.; Tarifeño-Saldivia, A. |
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Title |
Be-7(n,alpha)He-4 Reaction and the Cosmological Lithium Problem: Measurement of the Cross Section in a Wide Energy Range at n_TOF at CERN |
Type |
Journal Article |
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Year |
2016 |
Publication |
Physical Review Letters |
Abbreviated Journal |
Phys. Rev. Lett. |
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Volume |
117 |
Issue |
15 |
Pages |
152701 - 7pp |
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Keywords |
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Abstract |
The energy-dependent cross section of the (7)Bed(n,alpha)He-4 reaction, of interest for the so-called cosmological lithium problem in big bang nucleosynthesis, has been measured for the first time from 10 meV to 10 keV neutron energy. The challenges posed by the short half-life of Be-7 and by the low reaction cross section have been overcome at nTOF thanks to an unprecedented combination of the extremely high luminosity and good resolution of the neutron beam in the new experimental area (EAR2) of the nTOF facility at CERN, the availability of a sufficient amount of chemically pure Be-7, and a specifically designed experimental setup. Coincidences between the two alpha particles have been recorded in two Si-Be-7-Si arrays placed directly in the neutron beam. The present results are consistent, at thermal neutron energy, with the only previous measurement performed in the 1960s at a nuclear reactor. The energy dependence reported here clearly indicates the inadequacy of the cross section estimates currently used in BBN calculations. Although new measurements at higher neutron energy may still be needed, the n_TOF results hint at a minor role of this reaction in BBN, leaving the long-standing cosmological lithium problem unsolved. |
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Address |
[Barbagallo, M.; Colonna, N.; Damone, L.; Mastromarco, M.; Mazzone, A.; Tagliente, G.; Variale, V.] Ist Nazl Fis Nucl, Sez Bari, Bari, Italy, Email: nicola.colonna@ba.infn.it |
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Publisher |
Amer Physical Soc |
Place of Publication |
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English |
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ISSN |
0031-9007 |
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Conference |
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Notes |
WOS:000384479300003 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
2822 |
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Author |
n_TOF Collaboration (Wright, T. et al); Domingo-Pardo, C.; Giubrone, G.; Tain, J.L.; Tarifeño-Saldivia, A. |
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Title |
Measurement of the U-238(n,gamma) cross section up to 80 keV with the Total Absorption Calorimeter at the CERN n_TOF facility |
Type |
Journal Article |
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Year |
2017 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
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Volume |
96 |
Issue |
6 |
Pages |
064601 - 11pp |
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Keywords |
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Abstract |
The radiative capture cross section of a highly pure (99.999%), 6.125(2) grams and 9.56(5) x 10(-4) atoms/barn areal density U-238 sample has been measured with the Total Absorption Calorimeter (TAC) in the 185 m flight path at the CERN neutron time-of-flight facility n_TOF. This measurement is in response to the NEA High Priority Request list, which demands an accuracy in this cross section of less than 3% below 25 keV. These data have undergone careful background subtraction, with special care being given to the background originating from neutrons scattered by the 238U sample. Pileup and dead-time effects have been corrected for. The measured cross section covers an energy range between 0.2 eV and 80 keV, with an accuracy that varies with neutron energy, being better than 4% below 25 keV and reaching at most 6% at higher energies. |
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Address |
[Wright, T.; Billowes, J.; Ryan, J. A.; Ware, T.] Univ Manchester, Manchester, Lancs, England, Email: tobias.wright@manchester.ac.uk |
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Publisher |
Amer Physical Soc |
Place of Publication |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2469-9985 |
ISBN |
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Expedition |
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Conference |
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Notes |
WOS:000416848700005 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3392 |
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Permanent link to this record |
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Author |
n_TOF Collaboration (Lerendegui-Marco, J. et al.); Domingo-Pardo, C.; Tain, J.L.; Tarifeño-Saldivia, A. |
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Title |
Radiative neutron capture on Pu-242 in the resonance region at the CERN n_TOF-EAR1 facility |
Type |
Journal Article |
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Year |
2018 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
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Volume |
97 |
Issue |
2 |
Pages |
024605 - 21pp |
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Keywords |
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Abstract |
The spent fuel of current nuclear reactors contains fissile plutonium isotopes that can be combined with uranium to make mixed oxide (MOX) fuel. In this way the Pu from spent fuel is used in a new reactor cycle, contributing to the long-term sustainability of nuclear energy. However, an extensive use of MOX fuels, in particular in fast reactors, requires more accurate capture and fission cross sections for some Pu isotopes. In the case of Pu-242 there are sizable discrepancies among the existing capture cross-section measurements included in the evaluations (all from the 1970s) resulting in an uncertainty as high as 35% in the fast energy region. Moreover, postirradiation experiments evaluated with JEFF-3.1 indicate an overestimation of 14% in the capture cross section in the fast neutron energy region. In this context, the Nuclear Energy Agency (NEA) requested an accuracy of 8% in this cross section in the energy region between 500 meV and 500 keV. This paper presents a new time-of-flight capture measurement on Pu-242 carried out at nTOF-EAR1 (CERN), focusing on the analysis and statistical properties of the resonance region, below 4 keV. The Pu-242(n, gamma) reaction on a sample containing 95(4) mg enriched to 99.959% was measured with an array of four C6D6 detectors and applying the total energy detection technique. The high neutron energy resolution of nTOF-EAR1 and the good statistics accumulated have allowed us to extend the resonance analysis up to 4 keV, obtaining new individual and average resonance parameters from a capture cross section featuring a systematic uncertainty of 5%, fulfilling the request of the NEA. |
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Address |
[Lerendegui-Marco, J.; Guerrero, C.; Quesada, J. M.; Cortes-Giraldo, M. A.; Praena, J.; Sabate-Gilarte, M.] Univ Seville, Dept Fis Atom Mol & Nucl, E-41012 Seville, Spain, Email: cguerrero4@us.es |
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Corporate Author |
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Thesis |
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Publisher |
Amer Physical Soc |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2469-9985 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000424190700001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3474 |
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Permanent link to this record |
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Author |
n_TOF Collaboration (Mendoza, E. et al); Giubrone, G.; Tain, J.L.; Tarifeño-Saldivia, A. |
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Title |
Measurement and analysis of the Am-241 neutron capture cross section at the n_TOF facility at CERN |
Type |
Journal Article |
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Year |
2018 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
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Volume |
97 |
Issue |
5 |
Pages |
054616 - 21pp |
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Keywords |
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Abstract |
The Am-241(n, gamma) cross section has been measured at the nTOF facility at CERN with the nTOF BaF2 Total Absorption Calorimeter in the energy range between 0.2 eV and 10 keV. Our results are analyzed as resolved resonances up to 700 eV, allowing a more detailed description of the cross section than in the current evaluations, which contain resolved resonances only up to 150-160 eV. The cross section in the unresolved resonance region is perfectly consistent with the predictions based on the average resonance parameters deduced from the resolved resonances, thus obtaining a consistent description of the cross section in the full neutron energy range under study. Below 20 eV, our results are in reasonable agreement with JEFF-3.2 as well as with the most recent direct measurements of the resonance integral, and differ up to 20-30% with other experimental data. Between 20 eV and 1 keV, the disagreement with other experimental data and evaluations gradually decreases, in general, with the neutron energy. Above 1 keV, we find compatible results with previously existing values. |
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Address |
[Mendoza, E.; Cano-Ott, D.; Balibrea, J.; Becares, V; Garcia, A. R.; Gonzalez, E.; Lopez, D.; Martinez, T.] Ctr Invest Energet Medioambientales & Tecnol CIEM, Madrid, Spain, Email: emilio.mendoza@ciemat.es |
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Corporate Author |
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Thesis |
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Publisher |
Amer Physical Soc |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2469-9985 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000433032300001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3584 |
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Permanent link to this record |