132 research outputs found

    A high efficiency, low background detector for measuring pair-decay branches in nuclear decay

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    We describe a high efficiency detector for measuring electron-positron pair transitions in nuclei. The device was built to be insensitive to gamma rays and to accommodate high overall event rates. The design was optimized for total pair kinetic energies up to about 7 MeV.Comment: Accepted for publication by Nucl. Inst. & Meth. in Phys. Res. A (NIM A

    Structure of C 14 and B 14 from the C 14,15 (d, He 3) B 13,14 reactions

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    We have studied the C14,15(d,He3)B13,14 proton-removing reactions in inverse kinematics. The (d,He3) reaction probes the proton occupation of the target ground state, and also provides spectroscopic information about the final states in B13,14. The experiments were performed using C14,15 beams from the ATLAS accelerator at Argonne National Laboratory. The reaction products were analyzed with the HELIOS device. Angular distributions were obtained for transitions from both reactions. The C14-beam data reveal transitions to excited states in B13 that suggest configurations with protons outside the π(0p3/2) orbital, and some possibility of proton cross-shell 0p-1s0d excitations, in the C14 ground state. The C15-beam data confirm the existence of a broad 2- excited state in B14. The experimental data are compared to the results of shell-model calculations

    Investigation of the role of 10^{10}Li resonances in the halo structure of 11^{11}Li through the 11^{11}Li(p, d)10^{10}Li transfer reaction

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    International audienceThe first measurement of the one-neutron transfer reaction 11Li(p,d)10Li performed using the IRIS facility at TRIUMF with a 5.7AMeV11Li beam interacting with a solid H2 target is reported. The 10Li residue was populated strongly as a resonance peak with energy Er=0.62 ±0.04MeV having a total width Γ\Gamma = 0.33 ±0.07MeV. The angular distribution of this resonance is characterized by neutron occupying the 1p1/2orbital. A DWBA analysis yields a spectroscopic factor of 0.67 ±0.12for p1/2 removal strength from the ground state of 11Li to the region of the peak

    Models of Traumatic Cerebellar Injury

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    Traumatic brain injury (TBI) is a major cause of morbidity and mortality worldwide. Studies of human TBI demonstrate that the cerebellum is sometimes affected even when the initial mechanical insult is directed to the cerebral cortex. Some of the components of TBI, including ataxia, postural instability, tremor, impairments in balance and fine motor skills, and even cognitive deficits, may be attributed in part to cerebellar damage. Animal models of TBI have begun to explore the vulnerability of the cerebellum. In this paper, we review the clinical presentation, pathogenesis, and putative mechanisms underlying cerebellar damage with an emphasis on experimental models that have been used to further elucidate this poorly understood but important aspect of TBI. Animal models of indirect (supratentorial) trauma to the cerebellum, including fluid percussion, controlled cortical impact, weight drop impact acceleration, and rotational acceleration injuries, are considered. In addition, we describe models that produce direct trauma to the cerebellum as well as those that reproduce specific components of TBI including axotomy, stab injury, in vitro stretch injury, and excitotoxicity. Overall, these models reveal robust characteristics of cerebellar damage including regionally specific Purkinje cell injury or loss, activation of glia in a distinct spatial pattern, and traumatic axonal injury. Further research is needed to better understand the mechanisms underlying the pathogenesis of cerebellar trauma, and the experimental models discussed here offer an important first step toward achieving that objective

    Studying X-ray burst nucleosynthesis in the laboratory

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    Type I X-ray bursts are the most common explosions in the Galaxy; however, the nucleosynthesis that occurs during the thermonuclear runaway and explosion is poorly understood. In this proceedings we discuss current experimental efforts and techniques that are being used to study X-ray burst nucleosynthesis in the laboratory. Specifically, radioactive ion beam techniques that have recently been developed have allowed the study of some of the most important (α, p) reactions in X-ray bursts for the first time. © Published under licence by IOP Publishing Ltd
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