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During the International Thermonuclear Experimental Reactor (ITER) reactor operation time, the plasma will give rise to high energy neutron and gamma flux, and this intense radiation field will result in serious radiation damage and activation effects on various detectors components. In this paper, neutron detector candidates for the ITER radial neutron camera (RNC), i.e., scintillator components [crystal and plastic scintillators, optical windows, and photomultipliers (PMTs)] and single-crystal diamond detectors, were investigated to establish their radiation hardness and stability under gamma irradiation. Radiation test was carried out at the Italian National Agency for New Technologies, Energy and Sustainable Economic Development Calliope plant (Casaccia R.C., Rome, Italy). The facility is a pool-type irradiation plant equipped with a 60Co source (energy = 1.25 MeV). Gamma radiation tests were performed in the dark and at room temperature for different total absorbed doses, as required for the application in ITER RNC. Scintillators, PMTs, and optical windows were irradiated up to around 100-kGy absorbed dose, while single-crystal diamond detectors up to around 5 MGy. Scintillators and optical windows transmittance measurements were performed in the UV-VIS range (300–700 nm), paying particular attention to the behavior at 390 and 420 nm (scintillating emission wavelengths). Samples were measured in the dark before and after irradiation and their performances were monitored at room temperature for some weeks in order to study the damage recovery in different conditions. For plastic scintillators, photobleaching and optical bleaching followed by thermal annealing processes in air were made to reduce the radiation damage. Quantum efficiency measurements were performed on the PMTs, and the pulse-height spectra and pulse shape capability of the scintillators were investigated by using gamma and neutron sources. The most relevant results of this paper concern the radiation damage observed in scintillators and diamond detectors. The crystalline scintillator sample showed much less radiation resistance than plastic scintillators. A strong damage to the silver deposition of the diamond contacts was observed already at 1.0 MGy, almost leading to contact destruction at 4.7 MGy.

The Radial Neutron Camera (RNC) of ITER (International Thermonuclear Experimental Reactor) is a multichannel detection system designed to measure the uncollided neutron flux from the fusion plasma , providing information on the neutron emissivity profiles and source strength. Fission chambers and diamond detectors are candidate detectors for the RNC In-port subsystem. This is a high radiation environment (up to ∼ 5 MGy gamma dose and ∼ 2 × 10 16 n/cm2 neutron fluence) where about 500 baking cycles up to 240 °C are foreseen over the whole ITER lifetime. In order to assess the feasibility of using diamond detectors in such harsh conditions, and to study the best technological solutions, we are currently performing a set of tests to understand the behavior of diamond detectors under radiation and thermal stresses: (1) thermal stress tests at constant temperature of 240 °C and thermal cycling between 100 °C and 240 °C; (2) gamma-hardness test up to a total dose of 4.7 MGy; (3) neutron-hardness test (limited to 2 × 10 14 n/cm2 in this work).

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.

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.

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.

In the present work, photochromism of WO 3 –P 2 O 5 glass under gamma-ray irradiation was reported. As-prepared glass samples with different WO 3 content are all optically transparent in the visible wavelength range thanks to the addition of a small amount of oxidizing couple Sb 2 O 3 –NaNO 3 . The photochromic properties are identified by transmission spectra of the glasses before and after irradiation. The results show that the irradiation induced darkening results from the reduction of W 6+ to W 5+ or W 4+ . The existence of WO 6 clusters in glasses of high WO 3 content is proved by XPS, which is the main reason for the obvious photochromic effects. The WO 3 –P 2 O 5 glass is a promising candidate in gamma-ray sensitive detector.

To study an alternative to BaF2, as the crystal choice for the Mu2e calorimeter, thirteen pure CsI crystals from Opto Materials and ISMA producers have been characterized by determining their light yield (LY) and longitudinal response uniformity (LRU), when read with a UV extended PMT. The crystals show a LY of ~ 100 p.e./MeV (~ 150 p.e./MeV) when wrapped with Tyvek and coupled to the PMT without (with) optical grease. The LRU is well represented by a linear slope that is on average around -0.6 %/cm. The timing performances of the Opto Materials crystal, read with a UV extended MPPC, have been evaluated with minimum ionizing particles. A timing resolution of ~ 330 ps (~ 440 ps) is achieved when connecting the photosensor to the MPPC with (without) optical grease. The crystal radiation hardness to a ionization dose has also been studied for one pure CsI crystal from SICCAS. After exposing it to a dose of 900 Gy, a decrease of 33% in the LY is observed while the LRU remains unchanged., Presented at Frontier Detectors for Frontier Physics,13th Pisa Meeting on Advanced Detectors, 24-30 May 2015 (2 pages, 4 figures)

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

Changes in the UV-visible spectra of undoped and Dy/Eu singly doped oxyfluoride glasses with varying PbF2/CdF2 content were studied under high doses of gamma irradiation. The unirradiated undoped and doped glasses exhibited strong UV absorption and characteristic absorption bands due to the presence of rare earth ions. Gamma irradiation caused loss of transmission and red shift in the cut-off wavelength for the undoped and doped samples. The radiation induced absorption coefficient and energy band gap depicted variation due to the nature of rare earth as well as the host matrix. The rare earth addition affected the physical properties (density, refractive index, molar volume) and the structure of the studied glasses revealed by Fourier Transform Infrared Spectroscopy. © 2014 Published by Elsevier Ltd.

Optical properties and irradiation resistance of heavy metal oxide tellurite glasses in the TeO2-PbO-Bi2O3-B2O3 system doped with different ions are investigated. The results indicate that the matrix glass has a moderate UV cut-off edges at about 386 nm wavelength. The UV cut-off positions are obviously shifted to red by the addition of Ce4+. The introduction of Cr3+, Ce4+ and Ni2+ into the matrix glass exerts positive influences on irradiation resistance of glasses and cerium plays the most pronounced role. Such phenomena are mainly attributed to the variable valences of these cations. (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

The In Vessel Viewing System (IVVS) is a fundamental remote handling equipment, which will be used to make a survey of the status of the blanket first wall and divertor plasma facing components. A design and testing activity is ongoing, in the framework of a Fusion for Energy (F4E) grant agreement, to make the IVVS probe design compatible with ITER operating conditions and in particular, but not only, with attention to neutrons and gammas fluxes and both space constraints and interfaces. The paper describes the testing activity performed on the customized piezoelectric motors and the main components of the actuating system of the IVVS probe with reference to ITER gamma radiation conditions. In particular the test is performed on the piezoelectric motor, optical encoder and small scale optical samples.The test is carried out on the ENEA Calliope gamma irradiation facility at ITER relevant gamma fields at rate of about 2.5 kGy/h and doses of 4 MGy. The paper reports in detail the setup arrangement of the test campaign in order to verify significant working capability of the IVVS actuating components and the results are shown in terms of functional performances and parameters. The overall test campaign on IVVS actuating system will be completed on other ENEA testing facilities in order to verify compatibility to Magnetic field, neutrons and thermal vacuum ITER typical environmental working conditions. © 2013 Elsevier B.V.

The γ-irradiation effects on cellulose structure and on its interaction with moisture were investigated. Pure cellulose paper samples were γ-irradiated in the range 0-1000 kGy. Particular attention was paid on the investigation at low absorbed doses (up to 10 kGy). Thermogravimetric analysis (TG-DTG) and Fourier Transform Infrared Spectroscopy (FTIR and ATR-FTIR) were used as complementary techniques to investigate the modifications induced by γ-irradiation on cellulose. The IR spectra confirm that the breakage of the glycosidic bonds and the formation of CO bonds are related to the oxidative degradation that is a function of the increase of the absorbed dose. At absorbed dose

The effect of copper ion doping on the γ-ray irradiation resistance of Mn2+ and Pr3+ doped phosphate glasses has been studied. UV-visible transmission spectra and photoluminescence spectra have been measured before and after γ-irradiation to characterize the radiation-induced defects. The electron paramagnetic resonance spectra of the irradiated samples with, and without Cu ions have been compared to show the ability of Cu ions to suppress the generation of radiation-induced color centers. The differential transmission spectra and the radiation-induced absorption coefficients have also been calculated for discussion of the observed phenomena. The much improved γ-irradiation resistance of Mn2+ and Pr3+ doped phosphate glasses has been demonstrated through CuO co-doping. © 2013 Elsevier B.V. All rights reserved.

The new facility SuperKEKB 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 that of KEKB. The detector will also be upgraded to cope with the higher luminosity, pile-up and occupancy. We report here on the design and development of the new pure CsI calorimeter for the forward region. An intensive R&D is being carried on to study the performance of pure CsI crystals with Avalanche Photodiodes readout. Results about the relative energy resolution of this detector, along with radiation hardness studies of all the components, are presented. A matrix of 16 crystals has been put on an electron beam at the BTF facility in Frascati and results in terms of energy resolution of this prototype are also discussed.

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 changes in Raman spectra of alkali borate glasses with and without Al2O3 under high dose of gamma irradiation have been reported. Glasses with composition xK2O.yAl2O3.(1–x–y)B2O3 (x = 20 or 30 mol%; y = 0, 10 or 15 mol%), have been prepared by melt-quenching technique. In order to investigate the role of Al2O3 in the network of potassium borate glasses, aluminium oxide has been added at the expense of B2O3 keeping the amount of alkali same. Gamma irradiation has been performed at a dose rate of 573 Gy.h–1 with total absorbed dose of 50 KGy. Samples were characterized before and immediately after irradiation by Raman spectrophotometer. The experimental results clearly indicate a significant change in the structure of borate glass matrix after irradiation, and the dependence of irradiation effects on composition of alkali as well as on aluminium oxide content.

Lead borosilicate and bismuth borosilicate glasses with and without aluminium oxide of varying compositions were prepared by conventional melt-quench method. Raman spectroscopy was used to analyze the influence of Al2O3 incorporation in the heavy metal oxide borosilicate glass network. The compositions of glasses were chosen in a way that Al2O3 is added at expenses of PbO and Bi2O3 in lead borosilicate and bismuth borosilicate glasses, respectively.

NMR correlation maps of paper samples suggest a two-site residence model for water in the ultrastructure of cellulose. When cross-linking and degradation of cellulose occur due to γ-irradiation-induced ageing, a significant fraction of water appears confined into low-mobility sites of the cellulose matrix. As the cellulose damage grows more pronounced, the two-site structure turns into a single-site water arrangement.

The Electron Paramagnetic Resonance technique has been used to study the time decay of paramagnetic species induced by gamma irradiation and the radiation hardness of different alkali borate glasses for their application in safe nuclear waste disposal. Glasses with different composition have been prepared by conventional melt-quenching. Glass compositions have been chosen to elucidate the role of different alkali cations and of aluminium oxide on the borate glass network. The paramagnetic states detected in these glasses have been attributed, according to the literature, to the formation of hole centers associated with threefold coordinated boron. The results indicate that the time decay trend of the different glasses is slow and that the constant decay does not appear related to the chemical composition. Moreover, the undesired strong fading of the radiation-induced signal during the first 24 h after irradiation, observable in silicate glasses has not been detected. Although no species detectable by a X band spectrometer have been generated, the interaction of lithium borate glasses with air seem to accelerate the system decay rate. Annealing was finally performed and optimized, investigating the correlation between the chemical composition and the radiation damage recovery.

In this Letter, the 75P 2 O 5 –25SrO phosphate glass co-doped with SnO 2 /Tm 3+ and SnO 2 /Eu 3+ were prepared and their photoluminescence spectra were investigated. Compared with the singly SnO 2 , Tm 3+ ions or Eu 3+ ions doped glasses, the SnO 2 /Tm 3+ co-doped sample exhibit an enhanced Tm 3+ ions emissions at 455 and 698 nm and the constant SnO 2 emission, while for the SnO 2 /Eu 3+ co-doped sample, all emissions of Eu 3+ ions increased at the cost of SnO 2 emission. The different luminescence behaviors of these glasses were discussed and an energy transfer mechanism from SnO 2 to Tm 3+ ions was proposed combined the down-conversion and the sub-up-conversion processes.

Irradiation treatments on glasses in both PbO–B2O3–SiO2 and Bi2O3–B2O3–SiO2 systems were carried out under the 60Co γ-ray radiation at a dose of 5.0 kGy. Ultraviolet and visible (UV–Vis) transmission spectra were used to compare the optical transmittance before and after irradiation in the wavelength range of 300–800 nm. The radiation-induced absorption coefficient (RIAC), the optical mobility gap (E0), and the width of the energy tail above the gap (ΔE) were calculated by optical transmittance. The variation of these parameters indicated that the structure of glasses changed due to irradiation. The differences in the optical properties of the two glass systems were explained from the viewpoint of glass chemistry.

The infrared absorption spectra of PbO–Al2O3–B2O3–SiO2 glasses have been measured in the spectral range 600–4000 cm−1 before and after absorbed dose of 50 Gy, 4 kGy and 50 kGy to investigate the structural change due to irradiation. The structural change due to composition has also been discussed. The experimental results clearly indicate that after irradiation, a significant change in structure of lead alumino borosilicate glass network is observed. It was shown that BO4 groups decreases and BO3 groups increases with the increase of Al2O3.

Glasses in SiO2–ZnO–BaO system with the different ZnO/BaO ratio were studied. In some cases, BaF2 was introduced to substitute for BaO on the equal base. Photoluminescent spectra showed that ZnO in glass matrices behaved somewhat differently from ZnO crystals. Especially, the introduction of fluorine ions led to dramatic shift of UV emission band of glasses closer to that of ZnO crystals. Raman spectral analysis provided consistent results. In particular, Raman bands in the high frequency region are sensitive to effects of different ZnO/BaO or BaF2/BaO ratio on structure of glasses.

The effect of dose variation of γ-irradiation on optical band gap of PbO–B 2 O 3 glasses have been studied in the wavelength region from 200 to 1200 nm. Absorption of glasses in near ultraviolet/visible have been used to calculate the optical mobility gap and width of tail before and after irradiation. The decrease in transmission due to irradiation indicates the formation of colour centers and structural changes in glass matrix. The optical spectrum has been measured before irradiation and in 50 Gy–50 kGy absorbed dose range.

The Mu2e calorimeter is composed by 1400 un-doped CsI crystals coupled to large area UV extended Silicon Photomultipliers arranged in two annular disks. This calorimeter has to provide precise information on energy, timing and position. It should also be fast enough to handle the high rate background and it must operate and survive in a high radiation environment. Simulation studies estimated that, in the hottest regions, each crystal will absorb a dose of 300 Gy and will be exposed to a neutron fluency of 6 x 10^{11} n/cm^2 in 3 years of running. Test of un-doped CsI crystals irradiated up to 900 Gy and to a neutron fluency up to 9 x 10^{11} n/cm^2 have been performed at CALLIOPE and FNG ENEA facilities in Italy. We present our study on the variation of light yield (LY) and longitudinal response uniformity (LRU) of these crystals after irradiation. The ionization dose does not modify LRU while a 20% reduction in LY is observed at 900 Gy. Similarly, the neutron flux causes an acceptable LY deterioration (, Presented at CALOR 2016, 15-20 May. Submitted to Journal of Physics: Conference Series (JPCS)

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.

Irradiation resistance of as-studied scintillating glass samples were tested under the 60Co γ-ray radiation at doses between 60 and 700 Gy. Photoluminescence properties of glasses with and without cerium ions were investigated to show the effect of cerium (III) on the luminescence of ZnO. Ultraviolet and visible optical transmittance spectra were compared before and after irradiation treatment. The so-called radiation-induced absorption coefficient (RIAC) was introduced to compare more effectively the radiation damage on glass samples. The much reduced transmittance change and decreased RIAC value in UV–Vis region indicate that the density of electron centers and hole centers caused by radiation decreased, which helps to confirm that the reduction and oxidation reaction of cerium ions took place in radiation process. From RIAC curves, it can be seen that TiO2 enhances the irradiation resistance of sample in UV region. However, high TiO2 content has negative effect on visible transmittance of glasses after the higher dose irradiation (700 Gy).

Y 2 O 3 :Eu 3+ phosphor is a very attractive material for use as a red phosphor in many fields. SrAl 2 O 4 :Eu 2+ belongs to long lasting phosphor (LLP) and it is a useful bluish-green luminescence material, which can also be a promising candidate as a simple and easy-to-use radiation detection element for visual display of two dimensional radiation distributions. In the present study, both these two kinds of phosphors were synthesized using high temperature solid state reactions. In our work, the influence of gamma-ray irradiation on the properties of these two kinds of phosphors was studied by comparing photoluminescence, brightness and the decay curve of unirradiated and gamma-ray-irradiated samples. Conclusions from the present work can be briefly summarized as follows. In irradiated samples, the brightness is decreased without sensible change in the wavelength distribution of the luminescence spectrum and in the decay kinetic upon gamma exposure. Moreover, the emission due to Eu 3+ →Eu 2+ conversion in Y 2 O 3 :Eu 3+ phosphors was not observed in our sample after irradiation to high exposure. Also the brightness of SrAl 2 O 4 :Eu 2+ phosphor turned out to decrease after the exposition to ionizing radiation while the luminescence wavelength distribution remained unchanged. The reason for the effect of gamma-ray irradiation on the properties of phosphors is also discussed in the paper.

ZnO–SiO2–BaO(BaF2) glasses are studied in the search for a novel scintillating material. Photoluminescence of such glasses was measured within 8–300 K including the decay kinetics and also the XPS spectra were obtained on selected samples to have information about Zn–O–Si bonding in the glass. Glass emission occurs in the violet-blue spectral range and decay kinetics is governed by the decay times of hundreds ns – units μs. XPS measurements reveal the higher binding energy of the Zn 2P electron and the lower kinetic energy of the Auger Zn L 3 M 4 , 5 M 4 , 5 electron, as well as the lower binding energy of the Si 2P electron, which implies the participation of Zn 2 + cations in the glass network to form the Zn–O–Si bond.

The effect of γ-irradiation on the structure of lead borosilicate glasses of varying composition has been probed by FTIR spectroscopy, before and immediately after γ-irradiation. The glasses were irradiated at Calliope 60 Co plant (RC ENEA Casaccia, Rome), and the spectra were recorded after absorbed doses of 50 Gy, 500 Gy, and 4 kGy. The structural analysis have been made considering both the effect of composition and of irradiation. The experimental results clearly indicate that after irradiation a significant change in structure of borosilicate glass network is observed.

Optical components operating in radiation environments, like nuclear facilities, High Energy Physics and space experiments, are exposed to fluxes of energetic particles, which may deteriorate the image quality. In order to avoid undesired failure of such components that is due to changes produced in the material optical properties by the hostile conditions, it is useful to perform a preliminary investigation of the radiation induced damage on each material and on different types of optical components. In this work, coated optical components are investigated. A set of optical coatings were submitted to /spl gamma/ irradiation at the Calliope /sup 60/Co radioisotope source (Research Centre ENEA-Casaccia, Rome) in order to simulate the hostile radiation environment in which they could be employed. The behavior of different substrates, single-layer materials and multilayer optical coatings was investigated by comparing both transmittance and reflectance measurements before and after the /spl gamma/-ray exposure.

In the present work γ-irradiation induced optical band gap variations (ΔEopt) were investigated on Ge–As–Se and Ge–As–Se–Te chalcogenide glasses. Higher doses of γ-irradiation resulted in decreased Eopt, which was composition dependent. Especially, glasses with stoichiometric compositions showed different ΔEopt from nonstoichiometric glasses under the same irradiation conditions. There seemed existence of a threshold Eopt (TE) under the certain dose of irradiation below which ΔEopt hardly occurred. Results were interpreted from viewpoint of glass structure, Chemical Bond Approach (CBA) and localized states density theory. Raman analysis supported well these discussions.

Radiation-induced transmission spectral variations of Ce3+-doped heavy germanate glasses used as scintillating materials are presented. Glass matrix contains mainly GeO2, BaO and Gd2O3 with a density higher than 5 g/cm3. Glasses are melted in the different atmosphere. The transmission spectra of glasses before and after radiation treatments are measured and compared. Unlike exhibiting the monotonous deterioration effect on the glass matrix, radiation plays the radiation protection role, even making enhanced transmission of Ce3+-doped glasses, depending upon glass melting atmosphere and radiation dose. Radiation-induced reducing and oxidizing mechanism is proposed to explain phenomena.

A set of Ce 3+ -doped and undoped YAP and Y-LuAP scintillating crystals were submitted to γ and neutron irradiations to be characterized in terms of radiation hardness. Their radiation-induced response was probed by transmission measurements, by which the radiation-formed colour centres were identified. A recharge mechanism of Ce 3+ ions in the crystals has been detected and a possible way to improve the crystal radiation hardness has been discussed.

Poly(vinyl chloride) powders were submitted to γ irradiation in the dose range 25–150 kGy in vacuum, argon and air atmosphere conditions. The free radicals induced by radiation were investigated by EPR measurements performed at different times from the end of irradiation. Obtained results confirmed that at room temperature the poly(vinyl chloride) degradation process causes the formation of polyenil radicals, which can react with the oxygen diffused into the polymer giving rise to peroxyl radical species. The ratio of polyenil and peroxyl radicals is a function of the experimental condition atmosphere.

A method has been developed, based on thermoluminescent dosimeters and alanine, aimed at measuring the absorbed dose in tissue-equivalent phantoms exposed to an epithermal neutron beam suitable for neutron capture therapy (NCT), separating the contributions due to the various secondary radiations generated by neutrons. Exposures have been made at the TAPIRO nuclear reactor (ENEA, Italy), in the epithermal column properly designed and set up for experiments on boron NCT.

Six heavy germanate glasses containing GeO 2 , Gd 2 O 3 , BaO, SnO 2 and La 2 O 3 are prepared. Ultraviolet and visible transmission spectra are measured and compared. Special attention is paid to the UV absorption edges of these glasses which prove moderate and suitable for hosting scintillating Ce 3+ activators. Red shifts of UV absorption bands assigned to the solute Sn 2+ and Ce 3+ in these glasses are observed. Reasonable explanations are given from the viewpoint of different mechanisms of UV absorption referring to the different types of metal ions existing in the glass network. The relationship between such red shift and compositions of glass matrices is fully discussed in terms of the so-called ‘optical basicity’ of glasses.

A set of Ce3+ activated phosphate glasses is studied. Dependence of the absorption band-edge position on the activator content and glass composition is discussed with respect to variation of the so-called optical basicity. XPS analysis of the samples is performed to get information about the oxidation state of the Ce activator cations in the glasses.

In this work the interaction between the carbon black reinforcement agent and a polymeric rubber matrix is investigated. Chemical activity of carbon black powder samples was enhanced using γ radiation in the dose range 168–1000 kGy and the radiation induced free radical concentration was investigated by EPR measurements. Activated powder samples were mixed with rubber and the bound rubber values of obtained compounds was measured by TG analysis. A comparison between EPR and bound rubber data shows that the greatest filler–polymer chemical interaction corresponds to the highest radiation induced free radical concentration.

In the present work Ce3+-doped germanate glasses containing Gd2O3 and BaO or La2O3 were developed. The UV and VIS transmission spectra of these glasses were measured before and after irradiation at doses ranging between 3 and 277 Gy. The radiation induced absorption coefficient μ was calculated on the basis of the measured transmission spectra. From these results the cerium ions doping turns out to be effective in improving the radiation hardness of glasses with respect to their undoped matrices.

In this work, we studied a set of Tb 3+ (or Eu 3+ ) doped silicate glasses in which some amounts of BaO were added to increase glass density. The irradiation-induced damage was investigated by absorbance measurements performed before and after each irradiation with doses ranging from 3 to 237 Gy. Analysed glasses underwent also light yield measurements investigated in terms of light production. The results showed that radiation damage and light yield depend on glass composition and are very low for the Eu 3+ containing glass and for the Tb 3+ activated glass which contains also lead. A possible explanation could be that lead and europium favour in the glass matrix the formation of a higher concentration of defects with respect to Tb 3+ doping ions.

Gamma-ray (gamma-ray) sensitivity has been studied in Ag-doped and/or AgI-modified Ge-Ga-S glasses. The sensitivity is controllable in terms of silver presence. Compared to the silver-free sample, the AgI-modified glass shows greater sensitivity to gamma-ray irradiation regarding larger change in the transmission spectra (Delta T), whereas improved resistance to gamma-ray irradiation occurs in the silver-doped AgI-modified glass with only 1 mol% silver metal being intentionally added. (C) 2012 Elsevier B.V. All rights reserved.

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.

Emission intensity variation of the leading 542 nm emission line of Tb 3+ centre in Na–Gd phosphate glasses under 308 nm excimer laser line irradiation was studied. Furthermore, induced optical absorption measurements after 308 nm laser, X-ray and γ-ray irradiations were performed. Thermoluminescence (TSL) above room temperature was also studied after 308 nm and X-ray irradiations at 295 K. The observed phenomenology evidences the presence of traps, which compete for carrier capture from the Gd 3+ energy guiding sublattice with Tb 3+ emission centres. The radiation induced optical absorption features are explained as due to both Tb 4+ and host lattice-related hole colour centres.

A set of heavy germanate glasses were presented as the host for scintillating rare earths. The glasses consisted of GeO 2 , Gd 2 O 3 , BaO as the main constituents and Ce 2 O 3 and Tb 2 O 3 for introducing the activating cations Ce 3+ and Tb 3+ . Ultraviolet and visible transmittance spectra were measured on glass samples before and after irradiations at different doses to study the effects of ionising radiation on their transmission properties. Irradiated samples were submitted to annealing treatments and their transmittance spectra were compared with respect to their thermal bleaching behaviours. Extraordinary irradiation resistance of Ce 3+ doped glasses was observed after comparison with their counterparts doped with Tb 3+ , which is of special significance for their applications in high-energy particle experiments. Possible mechanisms causing the positive effect of cerium doping was discussed in terms of its special valence electron orbital configuration.