Gaël Perrin

Cross section, vector and some tensor polarization data have been measured in the elastic scattering of 30 MeV polarized douterons by 10 nuclei: 12C, 28Si, 40Ca, 56Fe, 58Ni, 64Zn, 90Zr, 118Sn, 120Sn, 208Pb. Best-fit optical model parameters are deduced in an analysis without tensor potential and smooth average parameters are given. Real and imaginary volume integral and mean-square radii are calculated. The effect of a TR tensor potential is studied. It is shown that its effect is small on the tensor parameters T20 and T22, but that it is needed to give flt the tensor quantity X2 = T22−√32T20.

Inelastic scattering spectra from the (3He, 3He′) reaction at 108.5 MeV have been measured down to 1.85° scattering angle on 90Zr and 208Pb, allowing a giant monopole resonance study in these nuclei. DWBA analysis is reported.

The monopole strength has been investigated in nuclei with mass A ⩽ 60 by inelastic scattering of 108.5 MeV 3He particles at very small angles. A monopole transition has been found very close to the giant quadrupole resonance in 27Al, 40Ca, 56Fe and 58,60Ni. The energy of this transition is discussed in relation with the systematics of the giant monopole resonance, and DWBA analysis is reported.

Inelastic $^{12}\mathrm{C}$ and $^{14}\mathrm{N}$ scattering experiments have been performed on $^{90}\mathrm{Zr}$ and $^{208}\mathrm{Pb}$ at ${E}_{^{12}\mathrm{C}}=120$ MeV, and on $^{40}\mathrm{Ca}$, $^{90}\mathrm{Zr}$, $^{197}\mathrm{Au}$, $^{208}\mathrm{Pb}$, and $^{209}\mathrm{Bi}$ at ${E}_{^{14}\mathrm{N}}=161$ MeV. Giant resonances are observed in all spectra. An angular distribution has been measured on a $^{208}\mathrm{Pb}$ target, for which distorted-wave Born-approximation analysis is presented.

Measurements for the elastic scattering of polarized deuterons from 40Ca and 56Fe at 30 MeV and from 90Zr and 208Pb at 28.8 MeV are presented. Angular distributions of the cross section, of the vector analyzing power iT11 and of the quantity T22−√32T20 were deduced. Analyses of the data in terms of the optical model present evidence for the deuteron-nucleus tensor interaction.

Differential cross-sections and analyzing powers from inelastic scattering of 22.3, 26.7 and 30.5 MeV polarized protons exciting the 1+, T = 0 state in 12C(12.71 MeV) have been measured. The rapid energy variation of the data is explained by virtual excitation of giant resonances in 12C. The analyses were made using an antisymmetrized DWA in which both one and two step processes were included.

The elastic and inelastic (4.44 MeV, ${2}^{+}$) scattering of 608 MeV $^{16}$O${+\mathrm{}}^{12}$C has been measured up to 36\ifmmode^\circ\else\textdegree\fi{} in the c.m. frame. Although the angular distributions are strongly dominated by far side contributions, this feature does not remove the continuous ambiguity in the optical model parameters. The calculated value for ${\ensuremath{\sigma}}_{R}$, 1337\ifmmode\pm\else\textpm\fi{}22 mb, agrees with nuclear transparency predictions.

Angular distributions of the vector polarization of deuterons elastically scattered by 12C have been measured at 20.5, 25.2 and 29.5 MeV. Asymmetries were measured with semiconductor telescopes. The beam polarization was determined simultaneously with a carbon polarimeter whose analysing power was calibrated by means of the d-4He scattering. Differential cross sections at 20.5 and 29.5 MeV are also presented. The results are analyzed in terms of the optical model. Two energy dependent average potentials are deduced.

The reaction 116Sn(d, t)115Sn up to 7.5 MeV excitation energy has been studied at 40 MeV incident energy using a vector polarized deuteron beam. The measured analyzing power reveals strong J-dependence effects and has been used to clearly assign the spin of a number of low-lying states in the 115Sn nucleus. At higher excitation energy, a broad and fragmented bump is observed between 3.7 and 6.0 MeV in 115Sn. This work reports on one of the first attempts to determine the spin of such structure through polarization measurements. The analyzing power data indicates a mixing of spins J = 92, 12, in agreement with the excitation of the 1g92 and 2p12 inner neutron-hole strengths in the 115Sn nucleus. In addition, some 2p32 components are observed around ~ 4.6 MeV excitation energy.

Analyzing powers measured in the study of 112Sn(d, t) at 40 MeV bombarding energy show strong J-dependence and have been used to clearly assign the spin of a number of low-lying states in the residual nucleus. At high excitation energy (3.5–6 MeV). the inner-hole strength is shared between clearly isolated peaks on one hand and a fragmented structure on the other. This work reports on the determination of the spin of the inner-hole states and consequently on a more precise measurement of the overlapping regions between 1g92, 2p12, 2p32 Subshell components. The analyzing power data shows that the group of peaks located between 3.4 and 4.5 MeV consist of spins J = 92 + 12, in agreement with the excitation of the 1g12 and 2p12 inner- hole strengths in 111Sn. In addition a substantial amount of the 2p32 component is observed between 4.5 and 6.0 MeV. The results of the data analysis allow us to clearly eastablish the spreading of the 1g92 innerhole strength and to a lesser extent the strong fragmentation of the 2p12 and 2p32 inner-hole subshells.

Neutron hole states were investigated in the $^{207,206,205}\mathrm{Pb}$ isotopes up to 25 MeV excitation energy using the ($^{3}\mathrm{He}$,$\ensuremath{\alpha}$) reaction at 100 MeV incident energy with 100 keV energy resolution. Above the well-matched low-lying levels corresponding to high angular momentum transfers, new peaks are identified. In addition, three gross structures, riding on a continuous background, are observed in each of the three isotopes, with some fine structures showing up to 10 MeV excitation energy. For $^{207}\mathrm{Pb}$, angular distributions have been obtained for the low-lying levels as well as for the deeply bound hole states. The data have been analyzed with distorted-wave Born-approximation calculations and spectroscopic factors extracted. It has been found that the low-lying levels do not exhaust the $1i\frac{13}{2}$ and $1h\frac{9}{2}$ neutron hole strengths. Corrections for exact finite-range effects, form factor shapes, and indirect pickup contributions have been calculated, and modify significantly the $2f\frac{7}{2}$ spectroscopic measured strength but not the $1i\frac{13}{2}$ and the $1h\frac{9}{2}$ ones. Most of the $1i\frac{13}{2}$ and $1h\frac{9}{2}$ missing strengths are found in the "bump" located at about 5 MeV excitation energy. The highly fragmented bump observed at about 8 MeV excitation energy is shown to arise from $1h\frac{11}{2}$ neutron pickup exhausting 45% of the sum-rule limit. Finally, the very smooth structure extending to 21 MeV excitation energy is tentatively attributed to $1g\frac{7}{2}+1g\frac{9}{2}$ neutron holes with 80% of the total strength. In $^{207}\mathrm{Pb}$, the four first isobaric analog states are observed as narrow structures around 20 MeV excitation energy.NUCLEAR REACTIONS $^{208,207,206}\mathrm{Pb}$ ($^{3}\mathrm{He}$, $\ensuremath{\alpha}$), $E=101.75$ MeV; measured $\ensuremath{\sigma}({E}_{\ensuremath{\alpha}}, \ensuremath{\theta})$, $^{207,206,205}\mathrm{Pb}$ deduced levels, $\mathrm{Ex}$, $l$, $J$, $\ensuremath{\pi}$, ${C}^{2}S$; $^{207,206,205}\mathrm{Pb}$ inner shell spectroscopic factors: enriched targets, magnetic spectrometer.

Spectra of 48Ti, 56Fe, 59Co and 60Ni have been investigated for excitation energies of 10–20 MeV by inelastic scattering of 80 MeV 3He particles. Broad peaks with excitation energies of about 63±1 A−13 MeV and FWHM of 6 MeV have been observed. Much narrower satellite peaks occur at excitation energies about 51±1 A−13 MeV. The angular distributions of the sum of these peaks were compared to extended optical model DWBA calculations which confirm the predominant L = 2 character of the GR. A tentative assignment of L = 2 or 4 was made for the 13.5 MeV satellite peak in 56Fe. We see no definite evidence for the presence of an L = 1 GR component.

The observation of Higgs boson production in association with a top quark-antiquark pair is reported, based on a combined analysis of proton-proton collision data at center-of-mass energies of √s = 7, 8, and 13 TeV, corresponding to integrated luminosities of up to 5.1, 19.7, and 35.9  fb^(-1), respectively. The data were collected with the CMS detector at the CERN LHC. The results of statistically independent searches for Higgs bosons produced in conjunction with a top quark-antiquark pair and decaying to pairs of W bosons, Z bosons, photons, τ leptons, or bottom quark jets are combined to maximize sensitivity. An excess of events is observed, with a significance of 5.2 standard deviations, over the expectation from the background-only hypothesis. The corresponding expected significance from the standard model for a Higgs boson mass of 125.09 GeV is 4.2 standard deviations. The combined best fit signal strength normalized to the standard model prediction is 1.26^(+0.31)_(−0.26).

The neutron multidetector DéMoN has been used to investigate the symmetric splitting dynamics in the reactions 58,64Ni + 208Pb with excitation energies ranging from 65 to 186 MeV for the composite system. An analysis based on the new backtracing technique has been applied on the neutron data to determine the two-dimensional correlations between the parent composite system initial thermal energy (ECNth) and the total neutron multiplicity (νtot), and between pre- and post-scission neutron multiplicities (νpre and νpost, respectively). The νpre distribution shape indicates the possible coexistence of fast-fission and fusion-fission for the system 58Ni + 208Pb (Ebeam = 8.86 A MeV). The analysis of the neutron multiplicities in the framework of the combined dynamical statistical model (CDSM) gives a reduced friction coefficient β = 23 ± 1225 × 1021 s−1, above the one-body dissipation limit. The corresponding fission time is τf = 40 ± 2046 × 10−21s.

Abstract Angular distributions of the differential cross section and of the vector and tensor analyzing powers were measured for the elastic scattering of 28.6 MeV polarized deuterons from 120 Sn. The data could be fitted satisfactorily by optical-model calculations. The agreement with the experimental values of the tensor quantity T 22 −( 3 2 ) 1 2 T 20 was improved by inclusion of a tensor term T R in the optical potential. Cross sections and vector analysing powers were also measured for the inelastic scatterings from the 1,18 MeV (2 + ) and 2.44 MeV (3 − ) states. An acceptable description of the data was obtained by coupled-channels calculations in the framework of the vibrational model.

The cross section for K+ meson production in collisions of 36Ar ions on a 48Ti target has been measured at an incident energy of 92 MeV per nucleon. A description of the experimental set-up is given. Twelve events attributed to monoenergetic muons following the decay of stopped kaons have been identified. From these events, one infers a production cross section of 240 pb. Data are briefly discussed.

The nuclei 89Zr and 91Mo have been investigated up to an excitation energy of about 25 MeV using the (3He, alpha ) reaction at 97.3 MeV incident energy. In addition to the well known low-lying levels and analogue states strongly excited groups of levels centered around 4.4 MeV are confirmed to belong to the 1f7/2 neutron inner shell in 89Zr, with a maximum of about 50% of the sum rule strength. A corresponding group, with comparable strength, is found for the first time in 91Mo at nearly the same excitation energy. In addition, and for both nuclei, two much smoother structures are observed lying under and beyond the analogue states. The authors discuss their possible attribution to the 1f7/2 T< mixing strength and to 1f7/2 T> components respectively. Contributions from 1d inner shells are also considered. In both nuclei, new IAS fragments have been identified.

Strong transitions to high spin states are observed in the study of the (\ensuremath{\alpha},d) reaction at 218 MeV on closed shell heavy nuclei. It is shown that the highest spin valence valence n-p strength in the residual nuclei $^{92}\mathrm{Nb}$, $^{122}\mathrm{Sb}$, $^{146}\mathrm{Eu}$, and $^{210}\mathrm{Bi}$ is shared between a first strongly excited fragment and higher lying groups. The valence plus outer shell (${\ensuremath{\nu}}_{13/2}$\ifmmode\times\else\texttimes\fi{}\ensuremath{\pi}${\mathit{h}}_{11/2}$${)}_{12}^{\mathrm{\ensuremath{-}}}$ strength is tentatively identified in $^{122}\mathrm{Sb}$.

The isoscalar giant resonance region has been investigated in $^{58}\mathrm{Ni}$, $^{92}\mathrm{Mo}$, and $^{120}\mathrm{Sn}$ nuclei by inelastic scattering of $^{4}\mathrm{He}$ particles at small angles where the quadrupole and monopole states can be distinguished through their angular distributions. A monopole resonance is observed in the three nuclei, exhausting, respectively, 23%, 85%, and 110% of the E0 energy weighted sum rule.

Differential cross section and analyzing power angular distributions have been measured for transitions to low-lying bound states with Jπ = 2+, 3−, 4+ and 5−, and the giant resonance region from 6 to 27 MeV excitation energy. Collective model calculations using a full Thomas form factor reproduce the data fairly well. The so-called LEOR turns out not to be seen as pure E3 in (p, p′). In the giant resonance region the data do not reveal the presence of a sizeable monopole strength, 10–20% of the energy-weighted sum rule at most. There is strong indication for a mixture of E2 (18% of the EWSR) and E4 (16% of the EWSR). Calculations were also carried out using RPA (1p1h) wave functions. They reproduce the experimental data rather poorly, except for the general behaviour of the cross-section angular distributions.

Abstract Differential cross sections and analyzing powers for the inelastic scattering of polarized protons from 16O leading to the 2− state at 8.88 MeV excitation have been measured at incident energies of 31.7, 33.8, 35.8, 36.8 and 39.9 MeV. These data have been analyzed using a distorted wave theory in which the effects of virtual excitation of E1, E2 and E3 giant resonances as doorway states are included explicitly. This analysis shows that the strong energy variation in the data between 30 and 40 MeV may be predominantly due to a new isoscalar E3 resonance with the contributions from the E1 and E2 resonances corroborating earlier findings.

Gamma spectrometry is a passive nondestructive assay method used to quantify radionuclides present in nuclear objects. Basic methods using empirical calibration with a standard to quantify the activity of nuclear materials by determining the calibration coefficient are ineffective on nonreproducible nuclear objects such as waste packages. Package specifications such as composition or geometry change from one package to another and exhibit large variability of objects. The current standard quantification process uses numerical modeling of the measured scene with few available data such as geometry or composition, in particular density, material, screen, geometric shape, matrix composition, matrix, and source distribution. Some of them are strongly dependent on package data knowledge and operator backgrounds. The French Atomic Energy Commission (CEA) is developing a methodology to quantify nuclear materials in waste packages and waste drums without operator adjustment and internal package configuration knowledge. This method suggests combining a stochastic approach which uses, among others, surrogate models available to simulate the gamma attenuation behavior, a Bayesian approach considering conditional probability densities and prior information of problem inputs, and Markov Chain Monte Carlo (MCMC) algorithms which solve inverse problems, with gamma ray emission radionuclide spectra, and the outside dimensions of the objects of interest. The methodology has been tested to quantify actinide activity with a low bulk density matrix, weakly attenuating compositions, without information on the distribution of the source in terms of actinide masses and materials composing the drums. Activity uncertainties are taken into account.

Low momentum pion production is measured at an angle of 0° in 16O induced reactions. Strong Coulomb effects on the ratios π−π+ are observed. Charge distributions of reaction products are extracted. Pions are produced by an intermediate system whose charge and velocity are given in agreement with the participant zone predicted in a simple geometrical participant-spectator picture. Effects due to projectile fragments are also observed, and are dominant in light mass systems.

Inelastic scattering of 110 MeV $^{3}\mathrm{He}$ particles is used to probe the quadrupole strength in the even Mo isotopes. The peak position of the giant quadrupole resonance is found to decrease more rapidly than predicted by the ${A}^{\ensuremath{-}\frac{1}{3}}$ law, a behavior very similar to that exhibited by the photonuclear giant dipole resonance. The width and strength of the giant quadrupole resonance are practically constant in $^{92}\mathrm{Mo}$ through $^{100}\mathrm{Mo}$.NUCLEAR REACTIONS $^{100,98,96,94,92}\mathrm{Mo}$($^{3}\mathrm{He}$, $^{3}\mathrm{He}$\ensuremath{'}), $E=110$ MeV: Measured $\ensuremath{\sigma}(E,\ensuremath{\theta})$. Position, width, and strength of the giant quadrupole resonance deduced.

Measurements are reported of γ-γ coincidence and γ-γ angular correlation on 49Ti after thermal neutron capture. New cascades have been identified, and the spins of the three first excited states in 49Ti have been determined. Some relations between the spins of other excited states and between the mixing parameters δ are also given.

Differential cross-section and vector analyzing-power angular distributions were measured at ${\mathit{E}}_{\mathit{p}\ensuremath{\rightarrow}}$ =58 MeV for the $^{90}\mathrm{Zr}$(p\ensuremath{\rightarrow},d${)}^{89}$Zr reaction in the angular range from 6\ifmmode^\circ\else\textdegree\fi{} to 50\ifmmode^\circ\else\textdegree\fi{} and up to 10 MeV excitation energy, with 80 keV energy resolution. In addition to the transitions to low-lying states, the spectra display strong clusters of states from ${\mathit{E}}_{\mathit{x}}$=3.5 to 7 MeV. The observed fine structure was used to define energy bins for which cross sections and analyzing powers were obtained. The latter allowed spin and parity assignments for deep-lying hole states. Spectroscopic factors were deduced from standard distorted-wave Born approximation calculations. From the vector analyzing-power measurements, it was shown that most of the strength observed above 3.5 MeV belongs to the 1${\mathit{f}}_{7/2}$ inner neutron hole orbital.

Abstract The first four isobaric analog states in 207 Pb, T > = 45 2 , were found around E x = 20 MeV with the reaction 208 Pb(τ, α) 207 Pb at 102 MeV incident energy. The excitation energies, widths and angular distributions were measured. Spectroscopic factors were deduced by DWBA analysis.

Proton stripping (13C, 12B) and pick-up reactions (13C, 14N) on targets of 12C, 27Al, 58Ni and 90Zr have been measured at 30 MeV/n. At these high incident energies new features appear in the population of final states due to the high relative velocities: (i) strong favouring of large l-values; (ii) strong selectivity in the population of spin-orbit partners, (iii) population of states and continua at high excitation energies. A DWBA analysis gives satisfactory agreement for the relative and absolute strength of the transitions. The properties of high energy induced transfer reactions are reviewed in their qualitative and quantitative aspects, i.e. the dependence on bound state and scattering parameters, incident energy. The population of unbound states and their relation to quasi-free reactions and break-up reactions is discussed.

Energy spectra for the reactions (13C, 13N) and (13C, 14N) on 12C, 27Al, 58Ni and 90Zr at 30 MeV/N in the angular range of 1.8° ⩽ θlab ⩽ 5.6° have been measured. The three-body continuum has been calculated for these reactions and its contribution to the spectra is discussed quantitatively by unfolding two-body and three-body contributions. The 14N energy spectrum obtained with the 12C target shows prominent structures in the high-energy region which can be very well explained by the three-body channel (13C, 15N+ → 14N + n). It is concluded that almost all the continuum in the spectra of the reactions (13C, 14N) comes from the pick-up and decay process. The three-body contribution to the continuum of the charge-exchange (13C, 13N) reactions is found to be smaller and a large part of the continuum is the result of the two-body reaction.

Strong enhancements of two-neutron hole states are observed in a (α, 6He) reaction study at 218 MeV on 208Pb and 114Sn target nuclei. Selective population of high-spin states, characteristic patterns of the angular distributions and successful direct one-step analysis of the data are the main attractive features of the (α, 6He) process at high incident energy. As illustrative examples, spin and configurations of levels or structures in 206Pb and 114Sn are reported.

Two-neutron-hole excitations have been investigated via the (p,t) reaction at 168 MeV on $^{208}\mathrm{Pb}$ and $^{116}\mathrm{Sn}$ targets, up to \ensuremath{\sim}25 and \ensuremath{\sim}17 MeV excitation energy, respectively. The kinematic conditions strongly favor high L transfer values (L\ensuremath{\sim}10 for Sn and L\ensuremath{\sim}13 for Pb). High-spin stretched states are found to dominate the spectra with an even stronger enhancement for J=[(${l}_{1}$+(1/2)(${l}_{2}$-1) states. Angular distributions and standard local zero-range distorted-wave Born approximation analysis have been performed for $^{206}\mathrm{Pb}$. Such analysis has been extended to the $^{114}\mathrm{Sn}$ data taken at two angles. The zero-range normalization constant ${D}_{0}^{2}$ is found to be significantly smaller than that usually adopted at low incident energy, ${D}_{0}^{2}$\ensuremath{\sim}6 instead of \ensuremath{\sim}22. The high-spin stretched states of the valence multiplets are distributed from 2.2 MeV up to 6.1 MeV in $^{206}\mathrm{Pb}$, whereas they are clustered between \ensuremath{\sim}3.0 and 3.7 MeV in $^{114}\mathrm{Sn}$. New spectroscopic information gained for ${J}^{\ensuremath{\pi}}$\ensuremath{\ge}6 levels or structures in $^{206}\mathrm{Pb}$ and $^{114}\mathrm{Sn}$ is discussed together with that of previous studies, especially the (\ensuremath{\alpha}${,}^{6}$He) results at high incident energy. Such comparisons show that configuration mixing is larger than predicted for the higher-energy transitions in $^{206}\mathrm{Pb}$. No significant concentration of valence plus deep hole states could be found in $^{206}\mathrm{Pb}$, whereas the previously known one valence plus one deep bump in $^{114}\mathrm{Sn}$ exhibits a maximum at \ensuremath{\sim}7.3 MeV here mainly attributed to the state in agreement with the prediction of the quasiparticle phonon model.

With a polarized proton beam, the differential cross section and the proton analyzing power of the p+3H elastic scattering at 19 and 30 MeV have been measured and compared to the p+3He data. The proton analyzing power of the latter scattering has also been measured at 30 MeV to supplement the existing data. Real phase shifts from a preliminary analysis are deduced for both of the scatterings.

Abstract The inelastic scattering of 600 MeV 20Ne from 208Pb has been reinvestigated. Cross sections for giant resonance excitation have been extracted and analysed in terms of DWBA. No evidence has been found for higher excitation energy structures.

MAtrix of Cells of superfluid 3He (MACHe3) is a project of a new detector for direct Dark Matter (DM) search. A cell of superfluid 3He has been developed and the idea of using a large number of such cells in a high granularity detector is proposed. This paper presents, after a brief description of the superfluid 3He cell, the simulation of the response of different matrix configurations allowing to define an optimum design as a function of the number of cells and the volume of each cell. The background rejection, for several configurations, is presented both for neutrons and γ-rays of various kinetic energies.

Angular distributions for polarized proton inelastic scattering cross sections along with the analysing power for the reaction 16O(p, p′)16O∗(2−, 8.88 MeV) at Ep=42.5, 44.0 and 49.3 MeV have been measured. A semidirect reaction analysis augments the evidence for octupole giant resonance strength in the 30 to 50 MeV energy region.

The giant resonance regions of $^{144,154}\mathrm{Sm}$, $^{159}\mathrm{Tb}$, $^{165}\mathrm{Ho}$, $^{169}\mathrm{Tm}$, and $^{208}\mathrm{Pb}$ have been investigated by inelastic scattering of 80-MeV $^{3}\mathrm{He}$ ions. The shapes of the resonance structure were observed to be quite similar for each target studied here. Comparison of the experimental cross sections with energy-weighted sum rules implies that the observed structure is probably comprised of more than just an isoscalar $E2$ excitation.NUCLEAR REACTIONS $^{144,154}\mathrm{Sm}$ $^{159}\mathrm{Tb}$, $^{165}\mathrm{Ho}$, $^{169}\mathrm{Tm}$, and $^{208}\mathrm{Pb}$($^{3}\mathrm{He}$, $^{3}\mathrm{He}$'), ${E}_{^{3}\mathrm{He}}\ensuremath{\approx}80$ MeV, ${E}_{x}=0\ensuremath{-}40$ MeV; measured $\ensuremath{\sigma}({E}_{x}, \ensuremath{\theta})$; discuss giant resonances.

Vector $i{T}_{11}$ and tensor $Q=(\frac{1}{2\sqrt{2}})({T}_{20}+\sqrt{6}{T}_{22})$ and $R=(\frac{1}{2\sqrt{2}})({T}_{20}\ensuremath{-}\sqrt{6}{T}_{22})$ analyzing powers have been measured in the elastic scattering of 20.4-, 25.2-, and 29.9-MeV polarized deuterons by protons. Comparison is made with Faddeev-equation calculations including spin-dependent nucleon-nucleon interactions. Qualitative agreement is obtained for all the measured quantities only when both the spin-dependent nucleon-nucleon $P$-wave forces and the tensor ($^{3}S_{1}\ensuremath{-}^{3}D_{1}$) force are taken into account.

The cross sections for K+ meson production in collisions of 36Ar on 12C, natTi and 181Ta at an incident energy of 92 MeV per nucleon have been measured. A description of the set-up and of the method is given ; it is based on measurement of the muon decay of the positive kaon. At such a low incident energy the K+ production seems to be more sensitive to the available energy in the center of mass of the nucleus-nucleus system than to the coulomb corrected incident energy normalized to the production threshold in a free nucleon-nucleon process.

Abstract Differential cross section and analyzing power angular distributions for the elastic scattering and inelastic scattering to the 2+ state at 4.44 MeV and the 1+ state at 12.7 MeV have been measured at incident proton energies varying from 19.15 to 23.34 MeV in 200 keV steps. Elastic scattering data are analyzed using an averaged optical model. Coupled-channel calculations reproduce roughly the 2+ data. The rapid variation of the data concerning the 1+ state is explained by virtual excitation of giant resonances. For each value of the incident energy, the coupling strength for each resonance is found by fitting the experimental angular distributions. The analysis assuming a weak coupling in the compound system gave a satisfactory fit to the cross section but a poor reproduction of the analyzing power. The assumption of a strong coupling in the 13N system allowed a good fit of all data. The angular distributions are dominated by the E1 resonance, whose 1 2 + component exhausting more than 37 % of the energy weighted sum rule, explains the isotropy of the cross section below 22 MeV. A 7 2 + resonance (15 % EWSR) is located at 19.9 MeV. The 5 2 − resonance with its maxima at 20.2 and 21.4 MeV, exhausts about 18 % of the sum rule, which is in good agreement with the results of previous works.

Angular distributions have been measured of asymmetries produced by vector polarized deuterons scattered by 12C at 20.5, 25.2 and 29.5 MeV. The absolute normalization has been performed by comparison with the d-4He elastic scattering at 15 MeV.

The giant quadrupole resonance and the low-lying quadrupole transition have been investigated in $^{58}\mathrm{Ni}$, $^{92}\mathrm{Mo}$, $^{120}$,124Sn, $^{140}\mathrm{Ce}$, and $^{208}\mathrm{Pb}$ by inelastic scattering of 108.5 MeV $^{3}\mathrm{He}$ particles at very small angles. Anomalous rise of the giant quadrupole resonance cross section is observed to 0\ifmmode^\circ\else\textdegree\fi{}. Distorted-wave Born approximation calculations are reported. Possible interpretations of the anomalous effect are discussed.

The cross section and analyzing power of the 6Li(p, pα)2H three-body reaction have been measured for seven angles of the p-α quasi-free system. The sensitive of this type of measurement as a test of the reaction mechanism is emphasized.

The experiments have been performed with the Grenoble Isochronous Cyclotron beam, focused on a 4 mg/cm ~ thin foil target of natural silicon. The scattered deuterons are detected by two 3 mm thick Si(Li) detectors, mounted on the two rotable arms of a chamber of 65 cm internal diameter. The positioning accuracy of the arms is 0.05 ~ Each detector has an angular resolution of • ~ delimited by a 4 • 8 mm tanta lum diaphragm. A monitoring detector is fixed at 45 ~ and a Faraday cup collects the beam charge. The detectors are cooled to about 2 0 ~ Each detector is connected to a charge preamplifier which gives rise to an analogue channel and a logic channel. This logic channel used an antipile-eup circuit which eliminates the pile-up effects by cancelling the pulse arriving at interval of t ime less than 30 ~s. The spectra from the multichalmel analyser are stored on magnetic tapes and handled by a PD1)-9 computer. An example of the spectra obtained is given in Fig. I. The overall energy resolution is (I00--150) keV. The beam energy is measured with a (CD2) ~ thin foil target, by crossover techniques. The angular distributions of deuterons scattered from the ground state, the first 2+-state and the 6.88 MeV level are shown in Fig. 2 together with the optical model and DWBA calculations. The first excited level of 2ssi has been well explained by Hartree-Fock and HartreeFoek-Bogoliubov calculations (1) as a rotational state of the ground band. Some recent experiments and calculations suggested an oblate deformation (2.3). :For the 6.88 level, gamma-ray double and triple angular-correlation measurements (4) from the 2:Al(p, T)2sSi reaction let to the spin-3 assignment and suggested the od,t narity, supported by some transfer reactions, particularly the 27 Al(aiie, d)2ssi reaction (a). According to the Blair

A simple model is proposed for the diffusion-controlled release of radioactive nuclei implanted into a metal. Experiments using a tungsten target bombarded by 25 keV 135,137–141Xe1+ ions have been conducted in order to make a comparison with this model. Experimental results agree with the expected behaviour and the Arrhenius relation is obeyed over the temperature range with an activation energy EA = 110 kJ/mole and a pre-exponential factor D0 = 1.4 × 10−11 cm2/s.

The $^{16}\mathrm{O}$${+}^{12}$C reaction at an incident energy E/A of 38 MeV has been investigated experimentally. Singles energy spectra and the angular distribution of reaction residues having 3\ensuremath{\le}Z\ensuremath{\le}9 were measured. A small low-energy cutoff in the spectra combined with measurements at large angles (up to 70\ifmmode^\circ\else\textdegree\fi{}) allowed a study of the systematics involved in the production of low-energy reaction residues. A target-related origin is proposed for these yields. Cascade model calculations are presented which support this hypothesis.

${K}^{+}$ production far below the free nucleon-nucleon threshold has been investigated in collisions of ${}^{36}\mathrm{Ar}$ on ${}^{12}\mathrm{C},$ ${}^{\mathrm{nat}}\mathrm{Ti},$ and ${}^{181}\mathrm{Ta}$ targets at an incident energy of 92 MeV per nucleon. The cross sections for ${K}^{+}$ production have been inferred from the observed muon decays of positive kaons. The results are discussed in the framework of a participant-spectator model and are compared to proton induced ${K}^{+}$ production and to subthreshold pion production experiments.

We use PIONIER data from the ESO archive and GRAVITY data that were obtained in June 2017 with the four 8m telescopes. We use a parametric disk model and the 3D radiative transfer code MCFOST to reproduce the Spectral Energy Distribution and match the interferometric observations. To match the SED , our model requires a stellar luminosity of 2.5 Lsun, higher than any previously determined values. Such a high value is needed to accommodate the circumstellar extinction caused by the highly inclined disk, which has been neglected in previous studies. While using an effective temperature of 4800 K determined through high-resolution spectroscopy, we derive a stellar radius of 2.29 Rsun. These revised fundamental parameters, when combined with the mass estimates available , lead to an age of 0.5-2.0 Ma for RY Lup, in better agreement with the age of the Lupus association than previous determinations. Our disk model nicely reproduces the interferometric GRAVITY data and is in good agreement with the PIONIER ones. We derive an inner rim location at 0.12~au from the central star. This model corresponds to an inclination of the inner disk of 50deg, which is in mild tension with previous determinations of a more inclined outer disk from SPHERE (70 deg in NIR) and ALMA(67 $\pm$5 deg) images, but consistent with the inclination determination from the ALMA CO spectra (55$\pm$5deg). Increasing the inclination of the inner disk to 70 deg leads to a higher line-of-sight extinction and therefore requires a higher stellar luminosity of 4.65 Lsun to match the observed flux levels. This luminosity would translate to a stellar radius of 3.13~Rsun, leading to an age of 2-3~Ma, and a stellar mass of about 2 Msun, in disagreement with the observed dynamical mass estimate of 1.3-1.5 Msun. Critically, this high-inclination inner disk model also fails to reproduce the visibilities observed with GRAVITY.

Negative pion production cross-sections are measured at 38, 65 and 93 MeV per nucleon in O + Al reaction. Rough estimations of the total cross sections are given and compared to previous neutral pion data. Double differential cross sections at 93 and 65 MeV/u show enhancement for pions with velocity close to the beam. At variance no effect is observed at 38 MeV, where π− and π0 distributions are identical. Fewπ + detected at 38 MeV support this result. This indicates that at the lowest incident energy nearly the whole projectile participates in the production reaction.

MACHe3 (MAtrix of Cells of superfluid He3) is a project of a new detector for direct Dark Matter (DM) search, using superfluid as a sensitive medium. An experiment on a prototype cell has been performed and the first results reported here are encouraging to develop of a multicell prototype. In order to investigate the discovery potential of MACHe3, and its complementarity with other DM detectors, a phenomenological study done with the DarkSUSY code is shown.

MACHe3 (MAtrix of Cells of superfluid He3) is a project of a new detector for direct Dark Matter (DM) search. A cell of superfluid He3 has been developed and the idea of using a large number of such cells in a high granularity detector is proposed.This contribution presents, after a brief description of the superfluid He3 cell, the simulation of the response of different matrix configurations allowing to define an optimum design as a function of the number of cells and the volume of each cell. The exclusion plot and the predicted interaction cross-section for the neutralino as a photino are presented.

MACHe3 (MAtrix of Cells of superfluid 3 He) is a project of a new detector for direct Dark Matter Search.The idea is to use superfluid 3 He as a sensitive medium.The existing device, the superfluid 3 He cell, will be briefly introduced.Then a description of the MACHe3 project will be presented, in particular the background rejection and the neutralino event rate that may be achieved with such a device.

MACHe3 (MAtrix of Cells of superfluid 3He) is a project of a new detector for direct Dark Matter (DM) search. A cell of superfluid 3He has been developed and the idea of using a large number of such cells in a high granularity detector is proposed. This contribution presents, after a brief description of the superfluid 3He cell, the simulation of the response of different matrix configurations allowing to define an optimum design as a function of the number of cells and the volume of each cell. The exclusion plot and the predicted interaction cross-section for the neutralino as a photino are presented.

La region des resonances geantes a ete etudiee avec un faisceau d'3He de 80 MeV. Nous avons observe plusieurs resonances se decomposant au moins en un pic a 13,3 MeV d'excitation et large d'environ 0,9 MeV et une large structure centree a Ex = 16,6 MeV ayant une forme de Lorentz. La distribution angulaire de cette structure est raisonnablement bien reproduite par un calcul de DWBA avec L = 2 (resonance geante quadrupolaire) qui epuiserait plus de 60 % de la regle de somme E2 isoscalaire ponderee par l'energie.

The Grenoble variable energy cyclotron is equipped with a source giving vector- and tensor-polarized deuterons. This source is on the top of the cyclotron and the polarized beam is injected through a hole drilled in the upper pole piece. In a reference frame where the quantization axis is along the magnetic field, the beam polarization can be described by a vector-polarization parameter and a tensor-polarization parameter. They are related to the spherical tensor moments, defined in a reference frame with the quantization axis along the direction of the particle. The maximum theoretically achievable polarization for a beam is both vector- and tensor-polarized. The beam energy can be measured by crossover techniques with uncertainty of order of 200 keV. The given uncertainties include both systematic and statistical errors. When no error bar is given, the uncertainty is of the order of the dot size.

Publisher Summary This chapter presents the comparison between p + 3 H and p + 3 He elastic scatterings. With a polarized proton beam, the differential cross -section σ(θ) and the proton analyzing power P p (θ) of the p+ 3 H elastic scattering at19 and 30 MeV is measured and compared to the p+ 3 He data. The P p (θ) of the latter scattering is also measured at 30 MeV to supplement the existing data. A Ti-tritium thin foil target, a helium-3 cell, and Si(Li) detectors are used. The beam polarization, the direction of which is reversed every 0.2 sec by RF techniques is monitored by a carbone polarimeter. The Tombrello formula, which has also been described in the chapter, is applied in a preliminary analysis that neglects the isospin dependence and the absorption effects. The scattering matrix diagonalization uses the phase shifts, the spin and tensor coupling parameters. The optimized phase shifts are very sensitive to the coupling parameters. The order of magnitude of these phase shifts is in agreement with the results from resonating-group calculations.

The investigation of giant resonances (GR) has been a central goal of many experimental and theoretical studies 1). One way to get information about these GR is to study their contributions as virtual intermediate states in inelastic transitions to low lying levels in nuclei.

Direct knock-out reactions are often used to calculate nuclear properties such as the reduced widths of clusters in nuclei. This is usually done through the quasi-free scattering (QFS) approximation. But the kinematics favoring such simple mechanisms allows also more complicated rescatterings to take place which will make the extracted nuclear information incorrect. One type of experiment which indicates if the one-pole approximation is correct is the so-called Treiman-Yang (TY) test 1,2). But this method has serious draw-backs: its validity is a necessary but not sufficient condition and, moreover, the corresponding experiments are rather difficult to make. Two such experim.nts have been done on the 6Li(p,pd) 4He reaction, one between 40 and 50 MeV 3) for which the TY test was shown to be valid and one at 19 MeV 4) where it was also found valid except for high momentum transfer (\(\left| {\vec p} \right| >40\) MeV/c).

The 2H(p, 2p)n cross section has been measured at 15 MeV in a non-coplanar geometry. Experimental results were compared with the solution of the Faddeev equations in configuration space with the S-wave local potential of Malfliet and Tjon, in the hope of detecting an effect connected with the 3H problem.

The systematics of the excitation energy of the giant dipole, monopole, and quadrupole resonances are shown to exhibit an isotopic effect. For a given element, the excitation energy of the transition decreases faster with the increasing neutron number than the empirical laws fitting the overall data. This effect is discussed in terms of the available models.

Charge exchange reactions induced by 12C and 13C are discussed on a 12C target nucleus. Comparison of cross sections for the population of dicrete states and of the continuum gives information which determines the selectivity of these reactions with respect to various modes with and without spin-flip.

The properties of charge exchange reactions induced by13C projectiles of 30 MeV/u are discussed. Spectra on12C as target have been measured and are used to illustrate the properties of the (13C,13N) and (13C,13B) reactions. Both reactions show selective population of states, the (13C,13B) reactions favours the spin-flip (Δs=1) transitions.The Giant Dipole Resonance is strongly excited in both reactions.

This paper presents group discussions taking place within multidisciplinary topical network 33 of the CNRS Information and Communication Science and Technology (STIC) Department. It attempts to clarify the concept of document in its transtion to electronic form, based on research which tends to privilege form (as a material or immaterial object), sign (as meaningful object) or medium (as communication vector). Each of these terms reflects the radical transformations that are taking place. Their superposition stresses the importance of multidisciplinarity for a lucid and complete analysis of the concept and how it is changing.