Étude des résonances de la réaction 31P(p, γ) 32S dans le domaine d'énergie Ep = 1100-1600 keV

In the energy range Ep = 1 100-1 600 keV of the 31P(p, γ)32S reaction, twelve resonances were studied, five of which were new. The strengths of these resonances and the gamma decay of the resonance levels were determined, as well as the energies and branching ratios of the bound levels of 32S.La réaction 31P(p, γ)32S a été étudiée dans le domaine d'énergie Ep = 1 100-1 600 keV. Les forces et les schémas de désexcitation de douze résonances, dont cinq nouvelles, ont été déterminés ainsi que les énergies et rapports d'embranchement d'un certain nombre de niveaux liés de 32 S

Nuclear Shapes at High Angular Momentum

Multiplicities as a function of {gamma}-ray energy have been measured for continuum {gamma}-ray spectra produced in argon- and calcium-induced reactions. A peak sometimes occurs in the multiplicity spectrum, indicating a correlation between {gamma}-ray energy and multiplicity (spin). This correlation can be explained by rotational motion of the nucleus, suggesting basically prolate nuclear shapes. Absence of structure in the multiplicity spectrum is interpreted to indicate non-collective motion, and hence spherical or oblate shapes

Response functions of Fuji imaging plates to monoenergetic protons in the energy range 0.6-3.2 MeV

We have measured the responses of Fuji MS, SR, and TR imaging plates (IPs) to protons with energies ranging from 0.6 to 3.2 MeV. Monoenergetic protons were produced with the 3.5 MV AIFIRA (Applications Interdisciplinaires de Faisceaux d'Ions en Région Aquitaine) accelerator at the Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG). The IPs were irradiated with protons backscattered off a tantalum target. We present the photo-stimulated luminescence response of the IPs together with the fading measurements for these IPs. A method is applied to allow correction of fading effects for variable proton irradiation duration. Using the IP fading corrections, a model of the IP response function to protons was developed. The model enables extrapolation of the IP response to protons up to proton energies of 10 MeV. Our work is finally compared to previous works conducted on Fuji TR IP response to protons

High power lasers in nuclear physics : towards new generation experiments

Poster de Medhi Tarisie

Structures magnétiques de Cr3X4 (X = S, Se, Te)

The pseudo-hexagonal monoclinic compounds Cr3X4 = □ Cr2+I (Cr3+II)2 X24-(X = S, Se, Te) belong to a deformed (space group I/2m) NiAs-type. Vacancy ordering in the cation lattice takes place in (1 01) planes. With the hypothesis of isotropic exchange, the possible magnetic configurations are derived theoretically. The observed configurations belong to the propagation vector k0 = [1/2 0 1/2], implying a doubling of the chemical cell in the a and c direction. In Cr3S 4, ferromagnetic sheets parallel to the (1 0 1) planes, alternate in the succession □ CrII (+) CrI (—) Cr II (+) □ CrII (-) CrI (+) CrII (—). Spins are parallel to [101]. TN is ≈ 280 °K ; Θp = 547 °K. Cr3Se 4 has the same configuration with spins in the (101) plane and T N ≈ 80 °K ; Θp = — 6 °K. At very low temperatures (4.2 °K) a weak component (~10 %) □ CrII (+) CrI (+) CrII (+) □ CrII (—) CrI (—) CrII (—) is observed. Cr3Te 4 has a ferromagnetic Curie temperature Tc = 329 °K. At temperatures below 80 °K, a weak antiferromagnetic component is superimposed on the strong ferromagnetism, which explains the decrease of the magnetization below 80 °K. In the three compounds, the Curie constant is near to the theoretical spin-only value.Les composés monocliniques pseudo-hexagonaux (groupe I/2m) Cr3X4 = □ Cr2+I (Cr3+II)2 X24- (X = S, Se, Te) dérivent du type NiAs. Les lacunes □ ordonnées du réseau des cations se trouvent dans des plans (101). Dans l'hypothèse d'interactions isotropes, on déduit théoriquement les configurations magnétiques possibles. Les configurations antiferromagnétiques observées appartiennent au vecteur de propagation k0 = [1/2 0 1/2], c'est-à-dire la maille magnétique est double de la maille chimique selon a et c. Dans Cr3S 4, des couches ferromagnétiques, parallèles au plan des lacunes (101) se succèdent selon [1 0 1] dans l'ordre □ CrII (+) Cr I (-) CrII (+) □ CrII (—) Cr I (+) CrII (—). Les spins sont parallèles à [101]. On a TN ≈ 280 °K ; Θp = — 547 °K. Dans Cr3Se 4, on a la même configuration, le spin étant dans le plan (101) avec TN ≈ 80 °K et Θp = — 6 °K. Aux très basses températures (4,2 °K) on observe une faible composante (~ 10 %) □ CrII (+) CrI (+) CrII (+) □ CrII (-) CrI (-) CrII (-). Cr3Te 4 a une température de Curie ferromagnétique Tc = 329 °K. Aux températures inférieures à 80 °K, une faible composante antiferromagnétique se superpose à la forte composante ferromagnétique ce qui explique la décroissance de l'aimantation au-dessous de 80 °K. Dans les trois composés, la constante de Curie est proche de la valeur théorique, calculée pour le spin seul

NATALIE : a mutidetector diagnostic to characteriza laser produced particle beams. Applications

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