High Frequency top-down Junction-less Silicon Nanowire Resonators

We report here the first realization of top-down silicon nanowires (SiNW) transduced by both junction-less field effect transistor (FET) and the piezoresistive (PZR) effect. The suspended SiNWs are among the smallest top-down SiNWs reported to date, featuring widths down to ~20nm. This has been achieved thanks to a 200mm-wafer-scale, VLSI process fully amenable to monolithic CMOS co-integration. Thanks to the very small dimensions, the conductance of the silicon nanowire can be controlled by a nearby electrostatic gate. Both the junction-less FET and the previously demonstrated PZR transduction have been performed with the same SiNW. These self-transducing schemes have shown similar signal-to-background ratios, and the PZR transduction has exhibited a relatively higher output signal. Allan deviation AD of the same SiNW has been measured with both schemes, and we obtain AD~20ppm for the FET detection and AD~3ppm for the PZR detection at room temperature and low pressure. Orders of magnitude improvements are expected from tighter electrostatic control via changes in geometry and doping level, as well as from CMOS integration. The compact, simple topology of these elementary SiNW resonators opens up new paths towards ultra-dense arrays for gas and mass sensing, time keeping or logic switching systems in SiNW-CMOS platform

Spectroscopic studies of Dy-168,170 using CLARA and PRISMA

Preliminary results from an experiment aiming at Dy-170. Submitted to the LNL Annual Report 2008.Comment: 2 pages, 4 figures, Submitted to the LNL Annual Report 200

Intruder negative-parity states of neutron-rich Si33

Yrast states in the neutron-rich 1433Si19 nucleus have been studied using binary grazing reactions produced by the interaction of a 215-MeV beam of S36 ions with a thin Pb208 target. An experimental setup that combines the large-acceptance magnetic spectrometer PRISMA and the high-efficiency γ-ray detection array CLARA was used in the experiment. Four new γ-ray photopeaks at energies of 971, 1724, 1772, and 2655 keV were observed and assigned to the Si33 level scheme. The experimental level scheme is compared with the results of 1ω p-sd-pf large-scale shell-model calculations using the recently developed PSDPFB effective interaction; good agreement is obtained. The structure of the populated states of Si33 is discussed within the context of an odd neutron coupled to states of the Si32 core. © 2010 The American Physical Society.This work was supported in part by the EPSRC (UK) and by the European Union under Contract No. RII3-CT-2004-506065. Five of us (D.O., M.B., A.H., K.K., and A.P.)acknowledge financial support from the EPSRC. Z.M.W acknowledges support from ORSAS and from the University of the West of Scotland. A.J. acknowledges financial supportfrom the Spanish Ministerio de Ciencia e Innovación under Contract Nos. FPA2007-66069 and FPA2009-13377-C02-02. Zs.D. acknowledges the financial support from OTKA Project No. K68801.Peer Reviewe

First in-beam γ -ray study of the level structure of neutron-rich S 39

International audienceThe neutron-rich S39 nucleus has been studied using binary grazing reactions produced by the interaction of a 215-MeV beam of S36 ions with a thin Pb208 target. The magnetic spectrometer, PRISMA, and the γ-ray array, CLARA, were used in the measurements. Gamma-ray transitions of the following energies were observed: 339, 398, 466, 705, 1517, 1656, and 1724 keV. Five of the observed transitions have been tentatively assigned to the decay of excited states with spins up to (11/2−). The results of a state-of-the-art shell-model calculation of the level scheme of S39 using the SDPF-U effective interaction are also presented. The systematic behavior of the excitation energy of the first 11/2− states in the odd-A isotopes of sulfur and argon is discussed in relation to the excitation energy of the first excited 2+ states of the adjacent even-A isotopes. The states of S39 that have the components in their wave functions corresponding to three neutrons in the 1f7/2 orbital outside the N=20 core have also been discussed within the context of the 0 ℏω shell-model calculations presented here

Gamma-ray spectroscopy of 1738^{38}_{17}Cl using grazing reactions

Excited states of $^{38}_{17}$Cl$_{21}$ were populated in grazing reactions during the interaction of a beam of $^{36}_{16}$S$_{20}$ ions of energy 215 MeV with a $^{208}_{82}$Pb$_{126}$ target. The combination of the PRISMA magnetic spectrometer and the CLARA $\gamma$-ray detector array was used to identify the reaction fragments and to detect their decay via $\gamma$-ray emission. A level scheme for $^{38}$Cl is presented with tentative spin and parity assignments. The level scheme is discussed within the context of the systematics of neighboring nuclei and is compared with the results of state-of-the-art shell model calculations.Comment: 8 pages, 6 figures and 2 tables Changes: Table II and Figure 5 have been update

Prodigious submarine landslides during the inception and early growth of volcanic islands

Volcanic island inception applies large stresses as the ocean crust domes in response to magma ascension and is loaded by eruption of lavas. There is currently limited information on when volcanic islands are initiated on the seafloor, and no information regarding the seafloor instabilities island inception may cause. The deep sea Madeira Abyssal Plain contains a 43 million year history of turbidites among which many originate from mass movements in the Canary Islands. Here, we investigate the composition and timing of a distinctive group of turbidites that we suggest represent a new unique record of large-volume submarine landslides triggered during the inception, submarine shield growth, and final subaerial emergence of the Canary Islands. These slides are predominantly multi-stage and yet represent among the largest mass movements on the Earth’s surface up to three or more-times larger than subaerial Canary Islands flank collapses. Thus whilst these deposits provide invaluable information on ocean island geodynamics they also represent a significant, and as yet unaccounted, marine geohazard