Radiation activities and application of ionizing radiation on cultural heritage at ENEA Calliope gamma facility (Casaccia R.C., Rome, Italy)

Abstract Since the 1980s, research and qualification activities are being carried out at the 60Co gamma Calliope plant, a pool-type irradiation facility located at the Research Centre ENEA-Casaccia (Rome, Italy). The Calliope facility is deeply involved in radiation processing research and on the evaluation and characterization of the effects induced by gamma radiation on materials for different applications (crystals, glasses, optical fibres, polymers and biological systems) and on devices to be used in hostile radiation environment such as nuclear plants, aerospace and high energy physics experiments. All the activities are carried out in the framework of international projects and collaboration with industries and research institutions. In the present work, particular attention will be paid to the cultural heritage activities performed at the Calliope facility, focused on two different aspects: (a) conservation and preservation by bio-deteriogen eradication in archived materials, and (b) consolidation and protection by degraded wooden and stone porous artefacts consolidation

Enhanced and shortened Mn 2+ emissions by Cu + co-doping in borosilicate glasses for W-LEDs

A novel pair of transition metal ions Cu+, Mn2+ is co-doped in borosilicate glasses. Both copper and manganese ions exist in lower valence states (Cu+, Mn2+) in the as-prepared glasses. Around 5-time enhanced Mn2+ emission under the UV excitation is observed, which, as demonstrated by excitation spectra and emission decay curves, is due to an energy transfer from Cu+ ions resulting in greatly increased absorption of Mn2+ ions in the UV region, and relaxation on doubly-forbidden transition of Mn2+ leading to the much shortened Mn2+ emission lifetime from millisecond to microsecond level. Besides, a composite white emission is generated by combining the blue-green part from Cu+ ions with the green-red part from Mn2+ ions and it can be effectively tuned from cold to warm by adjusting host glass composition and altering excitation wavelength. Relevant mechanisms are discussed

Improvement of several properties of lead tungstate crystals with different doping ions

A very good radiation resistance of Lead Tungstate crystals is mandatory for their use in the high precision electromagnetic calorimeter of the CMS experiment at LHC. Since the beginning of 1996 we have organised systematic investigations of the parameters influencing the radiation hardness of this crystal. Two classes of parameters have been particularly studied, the first one related to the control of the stoichiometry and structure associated defects, the second one connected with the suppression and the charge compensation of existing defects with different kinds of doping ions. This paper reports about the second part of this study and complements a first paper where the role of the stoichiometry was already discussed. Results of tests are given on a significant statistical sample of full size crystals ( 23cm) which show a considerable improvement in the optical properties and the radiation resistance of appropriately doped crystals

Radiation hardness of Ce-doped sol-gel silica fibers for High Energy Physics applications

The results of irradiation tests on Ce-doped sol-gel silica using X- and g-rays up to 10 kGy are reported, in order to investigate the radiation hardness of this material for high energy physics applications. Sol-gel silica fibers with Ce concentrations of 0.0125 mol% and 0.05 mol% are characterized by means of optical absorption and attenuation length measurements before and after irradiation. The two different techniques give comparable results, evidencing the formation of a main broad radiation-induced absorption band, peaking at about 2.2 eV, related to radiation-induced color centers. The results are compared with those obtained on bulk silica. This study reveals that an improvement of the radiation hardness of Ce-doped silica fibers can be achieved by reducing Ce content inside the fiber core, paving the way for further material development

Energy Resolution Performance of the CMS Electromagnetic Calorimeter

The energy resolution performance of the CMS lead tungstate crystal electromagnetic calorimeter is presented. Measurements were made with an electron beam using a fully equipped supermodule of the calorimeter barrel. Results are given both for electrons incident on the centre of crystals and for electrons distributed uniformly over the calorimeter surface. The electron energy is reconstructed in matrices of 3 times 3 or 5 times 5 crystals centred on the crystal containing the maximum energy. Corrections for variations in the shower containment are applied in the case of uniform incidence. The resolution measured is consistent with the design goals

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost