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Journal Articles

Benchmarking of calculated projectile fragmentation cross-sections using the 3-D, MC codes PHITS, FLUKA, HETC-HEDS, MCNPX_HI, and NUCFRG2

Sihver, L.*; Mancusi, D.*; Niita, Koji*; Sato, Tatsuhiko; Townsend, L.*; Farmer, C.*; Pinsky, L.*; Ferrari, A.*; Cerutti, F.*; Gomes, I.*

Acta Astronautica, 63(7-10), p.865 - 877, 2008/10

 Times Cited Count:32 Percentile:86.99(Engineering, Aerospace)

A reliable and accurate particle and heavy ion transport code is an essential implement in the design study of accelerator facilities as well as for other various applications such as, spallation neutron sources, rare isotopes production, and radiation protection. Today several particle and heavy ion MC transport codes exist, e.g. PHITS, HETC-HEDS, SHIELD-HIT, GEANT4, FLUKA, and MCNPX. In this paper, we present an extensive bench marking of the calculated projectile fragmentation cross sections from the reactions of 200-1000 MeV/n $$^{4}$$He, $$^{12}$$C, $$^{4}$$N, $$^{6}$$O, $$^{20}$$Ne, $$^{28}$$Si,$$^{40}$$Ar, and $$^{56}$$Fe, which are relevant to space radioprotection, using PHITS, FLUKA, HETC-HEDS, and MCNPX_HI, against measurements performed by C. Zeitlin et al, at LBNL. The influence of the different models used in the different transport codes on the calculated results is discussed.

Journal Articles

Monte Carlo modelling of Germanium detectors for the measurement of low energy photons in internal dosimetry; Results of an international comparison

G$'o$mez-Ros, J.-M.*; de Carlan, L.*; Franck, D.*; Gualdrini, G.*; Lis, M.*; L$'o$pez, M. A.*; Moraleda, M.*; Zankl, M.*; Badal, A.*; Capello, K.*; et al.

Radiation Measurements, 43(2-6), p.510 - 515, 2008/02

 Times Cited Count:25 Percentile:82.59(Nuclear Science & Technology)

This communication summarizes the results concerning the Monte Carlo modeling of Germanium detectors for the measurement of low energy photons arising from the "International comparison on MC modeling for in vivo measurement of Americium in a knee phantom" organized within the EU Coordination Action CONRAD (Coordinated Network for Radiation Dosimetry) as a joint initiative of EURADOS working groups 6 (computational dosimetry) and 7 (internal dosimetry).

Journal Articles

Measurement of the neutron capture cross section of the $$s$$-only isotope $$^{204}$$Pb from 1 eV to 440 keV

Domingo-Pardo, C.*; Abbondanno, U.*; Aerts, G.*; $'A$lvarez, H.*; Alvarez-Velarde, F.*; Andriamonje, S.*; Andrzejewski, J.*; Assimakopoulos, P.*; Audouin, L.*; Badurek, G.*; et al.

Physical Review C, 75(1), p.015806_1 - 015806_9, 2007/01

 Times Cited Count:33 Percentile:87.03(Physics, Nuclear)

The neutron capture cross section of $$^{204}$$Pb has been measured at the CERN n_TOF installation with high resolution in the energy range from 1 eV to 440 keV. In the interval between 100 keV and 440 keV we report the average cross section. The background in the entire energy range was reliably determined from the measurement of a $$^{208}$$Pb sample. We obtain a Maxwellian average capture cross section for $$^{204}$$Pb at $$kT$$ = 30 keV of 79(3) mb, in agreement with previous experiments. However our cross section at $$kT$$ = 5 keV is about 35 % larger than the values reported so far. The implications of the new cross section for the $$s$$-process abundance contributions in the Pb/Bi region are discussed.

Journal Articles

Resonance capture cross section of $$^{207}$$Pb

Domingo-Pardo, C.*; Abbondanno, U.*; Aerts, G.*; $'A$lvarez, H.*; Alvarez-Velarde, F.*; Andriamonje, S.*; Andrzejewski, J.*; Assimakopoulos, P.*; Audouin, L.*; Badurek, G.*; et al.

Physical Review C, 74(5), p.055802_1 - 055802_6, 2006/11

 Times Cited Count:24 Percentile:81.37(Physics, Nuclear)

The radiative neutron capture cross section of $$^{207}$$Pb has been measured at the CERN n_TOF facility using the pulse height weighting technique in the resoleved region. The measurement has been performed with an optimized setup of two $$C_{6}D_{6}$$ scintillation detectors, which allowed us to reduce scattered neutron backgrounds down to a negligible level. Resonance parameters have been determined for 16 resonances by means of an R-matrix analysis in the neutron energy range from 3 keV to 320 keV. Good agreement with previous measurements was found at low neutron energies, whereas substantial discrepancies appear beyond 45 keV. With the present results, we obtain an s-process contribution of 77$$pm$$8 % to the solar abundance of $$^{207}$$Pb.

Journal Articles

New measurement of neutron capture resonances in $$^{209}$$Bi

Domingo-Pardo, C.*; Abbondanno, U.*; Aerts, G.*; $'A$lvarez, H.*; Alvarez-Velarde, F.*; Andriamonje, S.*; Andrzejewski, J.*; Assimakopoulos, P.*; Audouin, L.*; Badurek, G.*; et al.

Physical Review C, 74(2), p.025807_1 - 025807_10, 2006/08

 Times Cited Count:44 Percentile:90.47(Physics, Nuclear)

The neutron capture cross section of $$^{209}$$Bi has been measured at the CERN n_TOF facility by employing the pulse-height-weighting technique. Improvements over previous measurements are mainly because of an optimized detection system, which led to a practically negligible neutron sensitivity. Because $$^{209}$$Bi is the last stable isotope in the reaction path of the stellar s-process, the Maxwellian averaged capture cross section is important for the recycling of the reaction flow by alpha decays. In the relevant stellar range of thermal energies between $$kT$$ = 5 and 8 keV our new capture rate is about 16% higher than the presently accepted value used for nucleosynthesis calculations. The present cross section measurement is also of relevance for the design of accelerator driven systems based on a liquid metal Pb/Bi spallation target.

Journal Articles

Neutron capture cross section of $$^{232}$$Th measured at the n_TOF facility at CERN in the unresolved resonance region up to 1 MeV

Aerts, G.*; Abbondanno, U.*; $'A$lvarez, H.*; Alvarez-Velarde, F.*; Andriamonje, S.*; Andrzejewski, J.*; Assimakopoulos, P.*; Audouin, L.*; Badurek, G.*; Baumann, P.*; et al.

Physical Review C, 73(5), p.054610_1 - 054610_10, 2006/05

We have measured the neutron capture reaction yield of $$^{232}$$Th at the neutron tim-of-flight facility n_TOF at CERN in the energy range from 1 eV to 1 MeV. The average capture cross section has been extracted in the energy range from 4 keV up to 1 MeV with an overall accuracy better than 4 %. An independent IAEA evaluation shows good agreement with the data.

Journal Articles

Neutron capture cross section of $$^{232}$$Th measured at the n_TOF facility at CERN in the unresolved resonance region up to 1 MeV

Aerts, G.*; Abbondanno, U.*; $'A$lvarez, H.*; Alvarez-Velarde, F.*; Andriamonje, S.*; Andrzejewski, J.*; Assimakopoulos, P.*; Audouin, L.*; Badurek, G.*; Baumann, P.*; et al.

Physical Review C, 73(5), p.054610_1 - 054610_10, 2006/05

 Times Cited Count:42 Percentile:89.92(Physics, Nuclear)

We have measured the neutron capture reaction yield of $$^{232}$$Th at the neutron time-of-flight facility n_TOF at CERN in the energy range from 1 eV to 1 MeV. The average capture cross section has been extracted in the energy range from 4 keV up to 1 MeV with an overall accuracy better than 4%. An independent IAEA evaluation shows good agreement with the data.

Journal Articles

Measurement of the resonance capture cross section of $$^{204,206}$$Pb and termination of the $$s$$-process

Domingo-Pardo, C.*; O'Brien, S.*; Abbondanno, U.*; Aerts, G.*; $'A$lvarez, H.*; Alvarez-Velarde, F.*; Andriamonje, S.*; Andrzejewski, J.*; Assimakopoulos, P.*; Audouin, L.*; et al.

AIP Conference Proceedings 819, p.288 - 292, 2006/03

The neutron capture cross sections of $$^{204}$$Pb and $$^{206}$$Pb have been measured at the CERN n_TOF installation using the time of flight method with the pulse height weighting technique. In a preliminary analysis of $$^{204}$$Pb we have determined by first time the capture cross sections for two strong $$s$$-wave resonances below 2.5 keV. In $$^{206}$$Pb we have determined capture cross sections for a large number of resonances, which were not reported in the two previous capture measurements. We discuss preliminary implications of the new cross sections in the stellar nucleosynthesis of the Pb isotopes.

Journal Articles

Measurement of $$^{139}$$La($$n$$,$$gamma$$) cross section

Terlizzi, R.*; Abbondanno, U.*; Aerts, G.*; $'A$lvarez, H.*; Alvarez-Velarde, F.*; Andriamonje, S.*; Andrzejewski, J.*; Assimakopoulos, P.*; Audouin, L.*; Badurek, G.*; et al.

AIP Conference Proceedings 819, p.283 - 287, 2006/03

We measured the neutron capture cross section of $$^{139}$$La relative to $$^{197}$$Au in the energy range of 0.6 eV to 9 keV at n_TOF, the neutron time-of-flight facility at CERN. The data were fitted using R-matrix formalism to extract resonance parameters which were used to calculate average level spacings. The data were used to determine Maxwellian-averaged neutron capture cross sections which, in turn, were used to calculate the $$^{139}$$La abundance synthesized in a steller model of the main component of the $$s$$ process.

Journal Articles

Neutron cross section measurements at n-TOF for ADS related studies

Mastinu, P. F.*; Abbondanno, U.*; Aerts, G.*; $'A$lvarez, H.*; Alvarez-Velarde, F.*; Andriamonje, S.*; Andrzejewski, J.*; Assimakopoulos, P.*; Audouin, L.*; Badurek, G.*; et al.

Journal of Physics; Conference Series, 41, p.352 - 360, 2006/00

A neutron Time-of-Flight facility (n_TOF) is operative at CERN since 2001. The innovative features of the neutron beam, in particular the high instantaneous flux, the wide energy range, the high resolution and the low background, makes this facility unique for measurements of neutron induced reactions relevant to the field of Emerging Nuclear Technologies, as well as to Nuclear Astrophysics and fundamental Nuclear Physics. The scientific motivations that have led to the construction of this new facility are here presented.

Journal Articles

Measurements at n_TOF of the neutron capture cross section of minor actinides relevant to the nuclear waste transmutation

Cano-Ott, D.*; Abbondanno, U.*; Aerts, G.*; $'A$lvarez, H.*; $'A$lvarez-Velarde, F.*; Andriamonje, S.*; Andrzejewski, J.*; Assimakopoulos, P.*; Audouin, L.*; Badurek, G.*; et al.

AIP Conference Proceedings 769, p.1442 - 1445, 2005/05

Accurate and reliable neutron cross section data for actinides are necessary for the proper design, safety reguartion and precise performance assessment of transmutaion devices. In particular, the neutron capture cross sections of $$^{237}$$Np, $$^{240}$$Pu and $$^{243}$$Am play a key role in the design and optimization of a strategy for the Nuclear Waste Transmutation. The listed cross sections have been measured in 2004 at n_TOF with a high accuracy due to a combination of features unique in the world.

Journal Articles

High-resolution study of $$^{237}$$Np fission cross section from 5 eV to 1 MeV

Furman, W.*; Cennini, P.*; Ketlerov, V.*; Goverdovski, A.*; Konovalov, V.*; Abbondanno, U.*; Aerts, G.*; $'A$lvarez, H.*; Alvarez-Velarde, F.*; Andriamonje, S.*; et al.

AIP Conference Proceedings 769, p.1039 - 1042, 2005/05

A series of measurements of $$^{237}$$Np fission cross section have been performed at the CERN spallation neutron source facility n_TOF. A fast ionization chamber was used as a fission fragment detector. Total experimental uncertainties are determined to be at the level of 3%. Analysis of experimental data in the neutron energy from 5 eV to 1 MeV showed a systematic deviation from the evaluated data (ENDF/B-VI). This discrepancy amounts to up to the factor of 3 for resolved resonances in the neutron energy range of 5 eV - 2 keV, and is in good agreement with some previous experiments. A similar disagreement at the level of 6-7% was found for higher energies around the threshold. This energy range is essential for the transmutation of neptunium in ADS or fast reactors. It is concluded that an updated evaluation of nuclear data for $$^{237}$$Np is required.

Journal Articles

Key features of the ITER-FEAT magnet system

Okuno, Kiyoshi; Bessette, D.*; Ferrari, M.*; Huguet, M.*; Jong, C.*; Kitamura, Kazunori*; Krivchenkov, Y.*; Mitchell, N.*; Takigami, Hiroyuki*; Yoshida, Kiyoshi; et al.

Fusion Engineering and Design, 58-59, p.153 - 157, 2001/11

 Times Cited Count:2 Percentile:19.67(Nuclear Science & Technology)

no abstracts in English

Oral presentation

ICRU review of operational quantities for external radiation exposure; Time for a change ?

Bartlett, D.*; Dietze, G.*; Hertel, N.*; Bordy, J.-M.*; Endo, Akira; Gualdrini, G.*; Pelliccioni, M.*; Ambrosi, P.*; Siebert, B.*; Veinot, K.*; et al.

no journal, , 

The ICRU operational quantities for area and personal monitoring have been in use for more than 20 years and are currently under review by an ICRU committee. Special attention has been given to inconsistencies in the application of these quantities and the relationship of the existing operational quantities to the newly released ICRP116 conversion coefficients for equivalent dose and effective dose. Previously reference values of these quantities were computed using the kerma approximation for photons and neutrons incident on the ICRU phantom. The kerma approximation is not applicable when the range of secondary charged particles in the phantom is greater than the depth at which the absorbed dose is being computed. Various options in the definitions of the operational quantities and their application are being considered. The current status of the report will be presented in light of the special consideration that is required to minimize the impact on radiation monitoring practice.

Oral presentation

ICRU Committee proposal on operational quantities for external radiation exposure

Hertel, N. E.*; Bartlett, D. T.*; Dietze, G.*; Bordy, J.-M.*; Endo, Akira; Gualdrini, G.*; Pelliccioni, M.*; Ambrosi, P.*; Siebert, B. R. L.*; Veinot, K.*; et al.

no journal, , 

The International Commission on Radiation Units and Measurements (ICRU) defines a set of operational quantities for use in radiation measurements that provides assessment of the protection quantities recommended by International Commission for Radiological Protection (ICRP). The ICRU operational quantities in current use was defined about 30 years ago. ICRU Report Committee 26 has examined the rationale for operational quantities taking into account the changes in the definitions of the protection quantities and the changes in the fields of application of the operational quantities and protection quantities. The considerations have included the range of types and energies of particles contributing to doses to workers and members of the public. The relationship of the existing recommended operational quantities to the protection quantities has been investigated, as has the impact of changes in routine measurement practice, including instrument design and calibration. The committee has proposed a set of operational quantities which differs from the previous quantities. The major change in the proposed set of quantities is the redefinition of the operational quantities for area monitoring from doses computed at a depth in the ICRU sphere to ones based on particle fluence and the relationship to the protection quantities, effective dose, and equivalent dose to the lens of the eye, and local skin.

15 (Records 1-15 displayed on this page)
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