35 research outputs found

    Projectile Coulomb excitation with fast radioactive beams

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    5 pages, 5 figures, 1 table.-- PACS nrs.: 23.20.Ck; 27.20.+n.We report a search for γ rays emanating from Coulomb excitation of fast (30-46 MeV/u) radioactive projectiles He-8, Be-11, Be-12, Be-14 interacting with a lead target. These are clearly identified by their Doppler shift. The 320 keV 1/2(-) --> 1/2(+)γ transition from Be-11 was observed with a cross-section of 191 ± 26 mb which is noticeably less than expected from the known lifetime and in the perturbation limit of pure Coulomb excitation. In the other nuclei rather stringent upper limits of 0.01 to 0.2 Weisskopf units, are placed on the hypothetical transition to 1(-) states.We would like to thank F. Geoffroy, R. Hue and L. Petizon for their technical assistance during the experiment, N. Alamanos, G. Baur aud C. Bertulani for discussions and R. Lombard for drawing our attention to the Bertlmann-Martin bound. This work was partly supported by la Région Basse Normandie. One of us, G. Schrieder, would like to thank for the support by the German Federal Minister for Research and Technology (BMFT) under contract 06DA641.Peer reviewe

    Evaluation of the next generation gamma imager

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    Conference of 2013 3rd International Conference on Advancements in Nuclear Instrumentation, Measurement Methods and Their Applications, ANIMMA 2013 ; Conference Date: 23 June 2013 Through 27 June 2013; Conference Code:102802International audienceTowards the end of their life-cycle, nuclear facilities are generally associated with high levels of radiation exposure. The implementation of the ALARA principle requires limiting the radiation exposure of the operating people during the different tasks of maintenance, decontamination and decommissioning. CANBERRA's latest involvement in the provision of nuclear measurement solutions has led, in the framework of a technology transfer agreement with CEA LIST, to the development of a new generation gamma imager. The latter, which is designed for an accurate localization of radioactive hotspots, consists of a pixilated chip hybridized to a 1 mm thick CdTe substrate to record photon pulses and a coded mask aperture allowing for background noise subtraction by means of a procedure called mask/anti-mask, which greatly contributes to the reduced size and weight of the gamma imager as gamma shielding around the detector is less required. The spatial radioactivity map is automatically superimposed onto a pre-recorded photographic (visible) image of the scene of interest. In an effort to evaluate the performances of the new gamma imager, several experimental tests have been performed on a industrial prototype to investigate its detection response, including photon sensitivity and angular resolution, over a wide energy range (at least from 59 keV to 1330 keV). The impact of the background noise was also evaluated together with some future features like energy discrimination and parallax correction. This paper presents and discusses the main results obtained in the above experimental study. A comparison with Monte Carlo simulations using the MCNP code is provided as well
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