Scintillating double beta decay bolometers

We present the results obtained in the development of scintillating Double Beta Decay bolometers. Several Mo and Cd based crystals were tested with the bolometric technique. The scintillation light was measured through a second independent bolometer. A 140 g CdWO_4 crystal was run in a 417 h live time measurement. Thanks to the scintillation light, the alpha background is easily discriminated resulting in zero counts above the 2615 keV gamma line of Thallium 208. These results, combined with an extremely easy light detector operation, represent the first tangible proof demonstrating the feasibility of this kind of technique.Comment: 15 pages, 8 figure

A tunable, dual mode field-effect or single electron transistor

A dual mode device behaving either as a field-effect transistor or a single electron transistor (SET) has been fabricated using silicon-on-insulator metal oxide semiconductor technology. Depending on the back gate polarisation, an electron island is accumulated under the front gate of the device (SET regime), or a field-effect transistor is obtained by pinching off a bottom channel with a negative front gate voltage. The gradual transition between these two cases is observed. This dual function uses both vertical and horizontal tunable potential gradients in non-overlapped silicon-on-insulator channel

Impact of 40 years poplar cultivation on soil carbon stocks and greenhouse gas fluxes

International audienceWithin the JRC Kyoto Experiment in the Regional Park and UN-Biosphere Reserve "Parco Ticino" (North-Italy, near Pavia), the soil carbon stocks and fluxes of CO2, N2O, and CH4 were measured in a poplar plantation in comparison with a natural mesohygrophilous deciduous forest nearby, which represents the pristine land cover of the area. Soil fluxes were measured using the static and dynamic closed chamber techniques for CH4 N2O, and CO2, respectively. We made further a pedological study to relate the spatial variability found with soil parameters. Annual emission fluxes of N2O and CO2 and deposition fluxes of CH4 were calculated for the year 2003 for the poplar plantation and compared to those measured at the natural forest site. N2O emissions at the poplar plantation were 0.15$plusmn;0.1 g N2O m-2 y-1 and the difference to the emissions at the natural forest of 0.07±0.06 g N2O m-2 y-1 are partly due to a period of high emissions after the flooding of the site at the end of 2002. CH4 consumption at the natural forest was twice as large as at the poplar plantation. In comparison to the relict forest, carbon stocks in the soil under the poplar plantation were depleted by 61% of surface (10 cm) carbon and by 25% down the profile under tillage (45 cm). Soil respiration rates were not significant different at both sites with 1608±1053 and 2200±791 g CO2 m-2 y-1 at the poplar plantation and natural forest, respectively, indicating that soil organic carbon is much more stable in the natural forest. In terms of the greenhouse gas budget, the non-CO2 gases contributed minor to the overall soil balance with only 0.9% (N2O) and -0.3% (CH4 of CO2-eq emissions in the natural forest, and 2.7% (N2O) and -0.2% of CO2-eq. emissions in the poplar plantation. The very high spatial variability of soil fluxes within the two sites was related to the morphology of the floodplain area, which was formed by the historic course of the Ticino river and led to a small-scale (tenth of meters) variability in soil texture and to small-scale differences in elevation. Differences of site conditions are reflected by differences of inundation patterns, ecosystem productivity, CO2 and N2O emission rates, and soil contents of carbon and nitrogen. Additional variability was observed during a flooding event and after fertilisation at the poplar site. Despite of this variability, the two sites are comparable as both originate from alluvial deposits. The study shows that changes in soil carbon stocks and related fertility are the most visible phenomena after 40 years of land use change from a pristine forest to a fast growing poplar plantation. Therefore, the conservation and careful management of existing carbon stocks deserves highest priority in the context of the Kyoto Protocol

A bolometric measurement of the antineutrino mass

High statistics calorimetric measurements of the beta spectrum of 187Re are being performed with arrays of silver perrhenate crystals operated at low temperature. After a modification of the experimental set-up, which allowed to substantially reduce the background of spurious counts and therefore to increase the sensitivity on the electron antineutrino mass, a new measurement with 10 silver perrhenate microbolometers is running since July 2002. The crystals have masses between 250 and 350 micrograms and their average FWHM energy resolution, constantly monitored by means of fluorescence X-rays, is of 28.3 eV at the beta end-point. The Kurie plot collected during 4485 hours x mg effective running time has an end-point energy of 2466.1 +/- 0.8{stat} +/- 1.5 {syst} eV, while the half lifetime of the decay is found to be 43.2 +/- 0.2{stat} +/- 0.1{syst} Gy. These values are the most precise obtained so far for 187Re. From the fit of the Kurie plot we can deduce a value for the squared electron antineutrino mass m(nu)^2 of 147 +/- 237{stat} +/- 90{syst} eV^2. The corresponding 90% C.L. upper limit for m(nu) is 21.7 eV.Comment: 3 pages, 3 figures. Submitted to Phys. Rev. Let

Analysis of a possible application of a new process for oxygen enriched air production

A new process for oxygen enriched air (EA) production has been applied to Claus Process. This process is simple and requires few process units. Matlab and Aspen Hysys have been used for simulations and system sizing. The results demonstrate that it could be an alternative to traditional EA processes from an economical point of view

Diachronic and Synchronic Analysis for Knowledge Creation: Architectural Representation Geared to XR Building Archaeology (Claudius-Anio Novus Aqueduct in Tor Fiscale, the Appia Antica Archaeological Park)

This study summarises research progress to identify appropriate quality methodologies for representing, interpreting, and modelling complex contexts such as the Claudian Aqueduct in the Appian Way Archaeological Park. The goal is to intrinsically integrate (embed) geometric survey (Laser scanning and photogrammetric) with the materials and construction techniques (Stratigraphic Units-SU), semantic models in order to support the design with a better understanding of the artefact considered, and also to give indications that can be implemented in the future in a continuous cognitive process. Volume stratigraphic units in the form of architectural drawings, heritage building information modelling (HBIM) and extended reality (XR) environments have been oriented to comparative analyses based on the research case study's complex morphology. Analysis of geometries' intersection, construction techniques and materials open up new cognitive scenarios, self-feeding a progressive knowledge and making different studies correlatable, avoiding diaspora or incommunicability. Finally, an extended reality (XR) platform aims to enhance tangible and intangible values through new human-computer interaction and information sharing levels