Quasi-free neutron and proton knockout reactions from light nuclei in a wide neutron-to-proton asymmetry range

The quasi-free scattering reactions 11C(p,2p) and 10,11,12C(p,pn) have been studied in inverse kinematics at beam energies of 300–400 MeV/u at the R3B-LAND setup. The outgoing proton-proton and proton-neutron pairs were detected in coincidence with the reaction fragments in kinematically complete measurements. The efficiency to detect these pairs has been obtained from GEANT4 simulations which were tested using the 12C(p,2p) and 12C(p,pn) reactions. Experimental cross sections and momentum distributions have been obtained and compared to DWIA calculations based on eikonal theory. The new results reported here are combined with previously published cross sections for quasi-free scattering from oxygen and nitrogen isotopes and together they enable a systematic study of the reduction of single-particle strength compared to predictions of the shell model over a wide neutron-to-proton asymmetry range. The combined reduction factors show a weak or no dependence on isospin asymmetry, in contrast to the strong dependency reported in nucleon-removal reactions induced by nuclear targets at lower energies. However, the reduction factors for (p,2p) are found to be 'significantly smaller than for (p,pn) reactions for all investigated nuclei.German Federal Ministry of Education and Research | Ref. BMBF 05P2015RDFN1German Federal Ministry of Education and Research | Ref. 05P15WOFNAEuropean Commission | Ref. FP7, ENSAR, n. 262010Comisión Interministerial de Ciencia y Tecnología (CICYT) | Ref. FPA2012-32443Comisión Interministerial de Ciencia y Tecnología (CICYT) | Ref. FPA2015-64969-07387Comisión Interministerial de Ciencia y Tecnología (CICYT) | Ref. FPA2015-69640-C2-1-PSwedish Research Council | Ref. 621-2011-5324National Science Foundation, EE. UU. | Ref. n. 1415656Department of Energy, EE. UU. | Ref. n. DE-FG02-08ER41533Fundação para a Ciência e a Tecnologia | Ref. PTDC/FIS/ 103902/200

ANTARES: the first undersea neutrino telescope

The ANTARES Neutrino Telescope was completed in May 2008 and is the first operational Neutrino Telescope in the Mediterranean Sea. The main purpose of the detector is to perform neutrino astronomy and the apparatus also offers facilities for marine and Earth sciences. This paper describes the design, the construction and the installation of the telescope in the deep sea, offshore from Toulon in France. An illustration of the detector performance is given

Quasi-free neutron and proton knockout reactions from light nuclei in a wide neutron-to-proton asymmetry range

The quasi-free scattering reactions 11C(p,2p) and 10,11,12C(p,pn) have been studied in inverse kinematics at beam energies of 300–400 MeV/u at the R3B-LAND setup. The outgoing proton-proton and proton-neutron pairs were detected in coincidence with the reaction fragments in kinematically complete measurements. The efficiency to detect these pairs has been obtained from GEANT4 simulations which were tested using the 12C(p,2p) and 12C(p,pn) reactions. Experimental cross sections and momentum distributions have been obtained and compared to DWIA calculations based on eikonal theory. The new results reported here are combined with previously published cross sections for quasi-free scattering from oxygen and nitrogen isotopes and together they enable a systematic study of the reduction of single-particle strength compared to predictions of the shell model over a wide neutron-to-proton asymmetry range. The combined reduction factors show a weak or no dependence on isospin asymmetry, in contrast to the strong dependency reported in nucleon-removal reactions induced by nuclear targets at lower energies. However, the reduction factors for (p,2p) are found to be 'significantly smaller than for (p,pn) reactions for all investigated nuclei. © 2019 The Author

Studies of Dynamic Properties of Shock Compressed FCC Crystals by in Situ Dynamic X-Ray Diffraction

There were 5 laser experiments conducted to date in FY-01 under the ongoing project to study the response of single crystal fcc materials under shock compression. An additional 10 laser shots are planned for August, 2001. This work has focused on developing capability to record diffraction from multiple lattice planes during the passage of a shock through a thin foil of single crystal copper, while simultaneously performing separate shock sample recovery experiments to study the residual deformation structure in the recovered samples

Solid State Experiments at High Pressure and Strain Rates

Experiments have been developed using high powered laser facilities to study the response of materials in the solid state under extreme pressures and strain rates. Details of the target and drive development required for solid state experiments and results from two separate experiments are presented. In the first, thin foils were compressed to a peak pressure of 180 GPa and accelerated. A pre-imposed modulation at the embedded RT unstable interface was observed to grow. The growth rates were fluid-like at early time, but suppressed at later time. This result is suggestive of the theory of localized heating in shear bands, followed by dissipation of the heat, allowing for recovery of the bulk material strength. In the second experiment, the response of Si was studied by dynamic x-ray diffraction. The crystal was observed to respond with uni-axial compression at a peak pressure 11.5-13.5 GPa

X-ray laser radiography of hydrodynamic perturbations due to laser imprint

Extreme ultraviolet (XUV) laser radiography is a technique that allows the investigation of hydrodynamic perturbations with high spatial and temporal resolution. A Ne-like Ge XUV laser with wavelength lambda = 19.6 nm was used as a backlighter for 2 pm thick Al foils, and a Ni-like Sm XUV laser at lambda = 7.3 nm for 2 pm thick CH foils. The imprinted modulation and growth due to a low intensity (I = 5.0(12) to 1.5.10(13) W/cm(2)) 0.53 mu m drive beam incident on the thin foils has been determined. Smoothing techniques were used to minimise the optical perturbations, and the growth rates for the different smoothing schemes are compared. Moreover, single mode perturbation with I = 15, 30, 70 and 90 mu m wavelengths have been investigated to gain better insight into the physical processes of imprinting. XUV laser radiography is also suitable to determine the change in opacity for shock compressed materials. For the investigated conditions, the opacity of Al increases by a factor of 1.4 to 1.6, depending on the drive intensity

Radiography measurements of direct drive imprint in thin Al foils using a bright XUV laser

A saturated XUV laser operating on the J=0-1, 19.6nm transition of Ne-like Germanium provided an excellent source to provide in-line backlighting for 2D imaged radiography. The imprint of a direct drive laser beam and subsequent Rayleigh-Taylor growth of perturbations in a 2 mu m thick Al foil, irradiated with 0.53 mu m laser light at 2-8x10(12) W/cm(2), was investigated. Measurements are presented for the modulation Slue to random phase plate static speckle, SSD smoothed and ISI smoothed speckle. In addition we present a study of single mode optical imprint generated by the interference pattern of a double rectangular aperture

Characterisation of a saturated single frequency Ne-like Ge XUV laser on the J=0->1 transition at 19.6 nm

We report on measurements of a saturated single frequency Ne-like Ge XUV laser on the J = 0->1 transition at 19.6 nm from a refraction compensating double target driven by 150 J of energy from 75 ps Nd-laser pulses. The 19.6 nm line completely dominated the laser output. The output energy was measured to be 0.9 mJ, corresponding to a conversion efficiency of 6x10(-6)