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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.

A series of Cu+/Eu3+ co-doped borosilicate glasses have been successfully prepared by melt-quenching method. As proved by transmission spectra, the copper ions are univalent in the investigated borosilicate glasses. Under ultraviolet (UV) excitation at 325 nm, the emission intensity of Eu3+ increased by nearly double due to a large overlapping between the Cu+ and Eu3+ emission peaks. The decreased excitation intensity in UV region and shortened emission lifetime of Cu+ in association with presence of Eu3+ ions consistently suggest an energy transfer process from Cu+ to Eu3+ ions. On the other hand, the partially allowed transition of Cu+ makes contribution to the red emission of Eu3+ at 611 nm in Cu+/Eu3+ co-doped samples, thus shortening the lifetime from the conventional millisecond (∼1.86 ms) to the microsecond (up to around 37 μs) regime. Besides, tunable light is realized by combining the blue-green emission from Cu+ ions with the orange-red one from Eu3+ ions. The light can be continuously tuned by changing the Cu+/Eu3+ concentration ratio, indicating that the present novel Cu+/Eu3+ co-doped borosilicate glasses are potential as fast response and tunable photoluminescence materials.

The use of proteins as natural biopolymers are sensibly increasing in several application fields such as food industry, packaging and environment protection. In particular, rice proteins (RP) present good nutritional, hypoallergenic and healthful properties very interesting for human consumption. Since ionizing radiation can be successfully applied on protein containing systems involved in different industrial processes, this work aims to determine the effect of gamma radiation on 5 wt%–7.5 wt% RP aqueous solutions in a wide range of absorbed doses up to around 40 kGy. The changes of RP secondary and tertiary structures and their chemical composition were followed by UV–VIS absorbance spectroscopy, luminescence analysis and pH measurements. The experimental data showed the occurrence of the unfolding of RP chains with the increase of the absorbed dose and the formation of new molecules, due to the reaction among tryptophane and tyrosine amino acids and the radical species induced by gamma radiation. The results are also confirmed by the modification of the pH values measured for the irradiated solutions. © 2018 Elsevier Ltd

PLAnetary Transits and Oscillations of stars (PLATO) is a medium sized mission (M3) selected by the European Space Agency (ESA) for launch in 2026. The PLATO payload includes 26 telescopes all based on a six-element refractive optical scheme. Some components will be eventually manufactured by S-FPL51, N-ICZFS11 and S-FTM16 glass whose radiation resistance is partially or totally unknown. The radiation-resistance properties of such materials have been investigated by using a Co-60 gamma-rays source as probe. Each optical component has been characterized by a depth profile curve which describes the transmission loss as a function of the thickness in dependence of the impinging dose. A model to simulate the throughput of the whole instrument has been developed and used to verify the instrument performance considering different stellar spectra. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

The new SuperKEKB collider will be an upgrade of the existing KEKB electron-positron asymmetric machine, with a target luminosity of 8×1035 cm-2s-1, about 40 times greater than the previous one. The accelerator upgrade is based on the novel low-emittance »nanobeams» scheme. The detector will also be upgraded to cope with the higher luminosity, pile-up and occupancy. We report on the development of the new pure CsI calorimeter for the forward region. An intensive R&D has been carried out to study the performance of pure CsI crystals with Large Area Avalanche Photodiodes readout (LAAPD). Results on the signal to noise ratio for different sensors and front end electronics configurations will be presented as well as the use of filters and wavelength shifters. Measurements with a source, simulating the background machine, have been performed and will also be presented. © 2017 IOP Publishing Ltd and Sissa Medialab.

The present work is focused on the γ-radiation induced polymerization of ethyl methacrylate (EMA) and methyl acrylate (MA) monomers mixture to obtain a co-polymer with specific features. The effect of the irradiation parameters (radiation absorbed dose, dose rate) and of the environmental atmosphere on the features of the final products was investigated. Attenuated Total Reflectance - Fourier Transform Infrared Spectroscopy (ATR-FTIR) and Nuclear Magnetic Resonance high-resolution analyses of hydrogen and carbon nuclei (1H and 13C NMR) were applied to follow the γ-induced modifications by monitoring the co-polymerization process and allowed the irradiation parameters optimization. Diffusion-Ordered NMR (DOSY-NMR) data were used to evaluate the co-polymers polydispersity and polymerization degree. Since the last parameter is strongly influenced by the γ radiation and environmental conditions, a comparison among samples prepared and irradiated in air and under nitrogen atmosphere was carried out. In presence of oxygen, higher radiation was required to obtain a full solid co-polymer since a partial amount of energy released to the samples was involved in competitive processes, i.e. oxygen-containing free radicals formation and primary radicals recombination. Irrespectively to the environmental atmosphere, more homogeneous samples in term of polymerization degree dispersion was achieved at lower dose rates. At radiation absorbed doses higher than those needed for the formation of the co-polymer, while in case of samples irradiated in air heavy depolymerization was verified, a sensible increase of the samples stability was attained if the irradiation was performed under nitrogen atmosphere. © 2017 Elsevier Ltd

The new SuperKEKB collider will be an upgrade of the existing KEKB electron-positron asymmetric collider, with a target luminosity of 8 × 10 35 cm − 2 s − 1 , about 40 times greater than the previous one. The accelerator upgrade is based on the novel low-emittance “nanobeams” scheme. The detector will also be upgraded to cope with the higher luminosity, pile-up and occupancy. We report on the development of the new pure CsI calorimeter for the forward region. An intensive R&D has been carried out to study the performance of pure CsI crystals with Avalanche Photodiodes readout. Results on the signal to noise ratio for different sensors and front end electronics configurations will be presented. A matrix of 16 crystals has been tested with the electron beam at the BTF facility in Frascati. Results in terms of energy resolution of this prototype will also be discussed.

Photochromic glasses have attracted increasing interests as switchable lenses and radiation dosimeters. Here, we report on a new and cheap photochromatic material, Mn2+ activated borophosphate glass which can be readily prepared by the conventional melt-quenching method. The photochromic properties are characterized by differential absorption spectra, and the photochromism stems from the conversion of Mn2+ to Mn3+ when the glass samples are exposed to gamma-rays. Our results show that the photochromism can be controlled by modifying the glass structure and optical basicity through adding of alkali (Na2O) and alkali-earth (SrO, BaO and CaO) oxides. © 2014 Elsevier B.V. All rights reserved.

Optical systems employed in high-energy environments are subjected to high doses of ionizing radiation and the stability of their optical properties is required to avoid a possible failure of the experiments. Radiation hard glasses are widely used as substrates or windows in high-energy applications, due to their resistance in hostile environments where energetic particles and γ rays are present. In this work, radiation-resistant commercial glass samples were irradiated by 60Co γ rays from 50 to 3 × 105 Gy absorbed doses and at three different dose rates. The optical properties of the samples were measured to evaluate the gamma irradiation effects and the damage recovery after the end of irradiation. A dependence on the irradiation dose rates was found. © 2015 American Ceramic Society and Wiley Periodicals, Inc.

In the present work, series of silver doped Ge-Ga-S-AgI chalcohalide glasses have been prepared and their optical transmission spectra are compared before and after γ-ray irradiation at different doses. The differential transmission spectra of the irradiated samples with and without Ag doping have been compared to characterize the γ-ray irradiation induced red-shift of electronic absorption and formation of color centers. Ag doping plays an important role in increasing γ-ray irradiation resistance of the chalcohalide glasses due to its specific effect on the valence band and the network structure of glasses. © 2014 Elsevier B.V. All rights reserved.

The CMS electromagnetic calorimeter (ECAL) comprises 75848 scintillating lead tungstate crystals. 61200 crystals are contained in the ECAL Barrel section and are read out by avalanche photodiode (APD) with internal gain of about 50. This gain is achieved with a high voltage (HV) of about 400 Volts. The gain stability requirement implies a supply voltage stable to within 0.01%. We describe our experience with the installed Barrel HV power supply system, which has been used for data taking since 2008.

Most of the high energy physics experiments require their detectors to be embedded in a high intensity magnetic field. In particular the biggest of them, ATLAS, running in the CERN Large Hadron Collider (LHC) particle accelerator, generates a field of 2 T by means of a gigantic toroidal magnet working in open air. Its future phase 2 upgrade plans to move the DC/DC power supplies from the present positions on the external balconies directly on the detectors, where the field is of the order of 1 T. This presentation describes the development of samples made of special magnetic material for inductor cores suitable to work in such an environment. Starting from iron-silicon powders, at FN plant a plastic forming process, based on powder extrusion, injection moulding and sintering, was developed. To get the best compromise between the forming process requirements (good coupling among the metallic powder and the organic components to assure the right mouldability) and the debinding and sintering conditions, several mixtures (with different percentages and kind of organic additives) were experimented. A proper mould was designed and realized to get torous-shaped prototypes. The preliminary results of the physical-microstructural characterization performed on the first prototypes made will be shown. © 2013 Owned by the authors, published by EDP Sciences.

The influence of γ-ray irradiation on the optical properties of Bi2O3-B2O3-SiO2 glass has been investigated. Broadband infrared (IR) emission at 1310 nm with a FWHMover 200 nm is observed in the γ-ray irradiated glass. The IR luminescence depends on the γ-ray irradiation dose and the concentration of Bi 2O3. The thermal stability of the γ-ray irradiated IR luminescence center is studied, and the origin of the IR luminescence center has been suggested. © 2013 Optical Society of America.

International audience; Nanophase separation in the bulk Ge-As-Se chalcogenide glasses was observed by SEM and supported by XRD and IR measurements. Effects of nanophase separation on glass transition temperature (Tg), microhardness (Hv), optical band gap (Eopt) and thermal expansion coefficient (α) were investigated in terms of glass rigidity transitions. According to the correlations between the properties and average coordination number Z, it is established that nanophase separation becomes more intensive when Z is larger than 2.64.

International audience; In this work, multiple effects of γ-ray irradiation on properties of bulk Ge-As-Se chalcogenide glasses were studied. Increased density (ρ), thermal expansion coefficient (α) and decreased optical band gap (Eopt) were observed after irradiation, depending on glass compositions. Glasses with stoichiometric (GeSe2)100−x(As2Se3)x compositions showed linear correlations between As2Se3 proportion x and irradiation sensitivity, which is expressed by Δρ/ρ, Δα/α and ΔEopt/Eopt. Nonstoichiometric glasses (Ge2Se3)100−x(As2Se3)x exhibited irregular variations. The phenomena are discussed in terms of chemical bonds transition and structural evolution under γ-ray irradiation.

Gamma radiation induced absorption processes of various scintillating materials were studied at room temperature. Single crystal of PbWO 4 , Ce-doped YAlO 3 and Ce(Pr)-doped Y(Lu) 3 Al 5 O 12 were irradiated by 60 Co and doses ranging between 1-500 Gy. Broad induced absorption spectra obtained were decomposed into separate Gaussian components and tentatively ascribed to specific color centres. Supporting thermoluminescence and electron paramagnetic resonance experiments were performed to reveal the nature of charge carrier traps. The influence of codoping by aliovalent ions is also shown and discussed.

We investigated Czochralski-grown YAG:Pr single crystal as a potential novel scintillator. Optical characteristics including photoluminescence, radioluminescence, scintillation decay, radiation damage and thermoluminescence were measured. Their dependence on the dopant concentration was studied. The radiation damage results show that with increasing concentration of Pr the radiation damage reduces. Thermoluminescence above room temperature shows the dominant glow curve peak around 250 °C. Comparing to YAG:Ce scintillator an advantage of YAG:Pr is its much faster scintillation decay (16-17 ns at room temperature) and an absence of slow components in the decay. Therefore YAG:Pr appears as potentially interesting scintillator material. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

The barrel part of the CMS electromagnetic calorimeter consists of about 75 000 Lead Tungstate (PbWO 4 ) crystals arranged in 36×4 modules which are assembled in two Regional Centres, in Rome and at CERN. Two automatic machines have been designed to check the crystal quality before assembly. The main crystal characteristics are compared to a set of specifications included in the contract with the crystal producers. The measurement stability and cross-calibration between the two machines is a fundamental issue, which has to be monitored throughout the construction phase. This paper describes comparisons between measurements made at the two regional centres to ensure a consistent and reliable crystal quality control.

Optical characterization of scintillating phosphate and silicates glasses is presented including absorption, emission spectra and decay kinetics. A new concept of energy transfer sensitization is developed, based on nearly resonant energy migration through a rare earth ion subsystem (Gd 3+ ions at sufficiently high concentration) in the glass matrix, followed by a single-step transfer towards the emission centers created by Ce 3+ or Tb 3+ doping. While Ce 3+ doping in phosphates results in emission spectra in the near UV-violet, the Tb 3+ doping in silicates gives a four-band spectrum with a dominating one at 545 nm. Intense UV irradiation produces a reduction of emission intensity in phosphate glasses.

Avalanche photodiodes have been chosen as photon sensors for the electromagnetic calorimeter of the CMS experiment at the LHC. These sensors should operate in the 4 T magnetic field of the experiment. Because of the high neutron radiation in the detector extensive studies have been done by the CMS collaboration on the APD neutron radiation damage. The characteristics of these devices after irradiation have been analyzed, with particular attention to the quantum efficiency and the dark current. The recovery of the radiation-induced dark current has been studied carefully at room temperature and at slightly lower and higher temperatures. The temperature dependence of the annealing has been evaluated.

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 (23 cm) which show a considerable improvement in the optical properties and the radiation resistance of appropriately doped crystals.

In the framework of its search for new heavy, fast and radiation hard scintillators for calorimetry at future colliders, the Crystal Clear Collaboration performed a systematic investigation of the properties and of the scintillation and radiation damage mechanisms of CeF 3 monocrystals. Many samples of various dimensions up to 3 × 3 × 28 cm 3 were produced by industry and characterised in the laboratories by different methods such as: optical transmission, light yield and decay time measurements, excitation and emission spectra, gamma and neutron irradiations. The results of these measurements are discussed. The measured light yield is compared to the theoretical expectations. Tests in high energy electron beams on a crystal matrix were also performed. The suitability of CeF 3 for calorimetry at high rate machines is confirmed. Production and economical considerations are discussed.

A systematic investigation of the properties of cerium fluoride monocrystals has been performed by the “Crystal Clear” collaboration in view of a p