Adjustable structural colors hold significant promise for diverse applications such as anti-counterfeiting, printing, communication, and displays. Among the current methods for structural color modulation, the ion beam technique is a promising green approach, offering controllable and flexible modulation of the optical properties of various materials and nanostructures. The feasibility of achieving significant color changes in all-dielectric photonic crystals (PCs) using high-fluence O+ ion irradiation with large fluence variations were experimentally investigated in this study. The pronounced color contrast between unirradiated and irradiated PCs originated from a notable blue-shift in the photonic bandgap, accompanied by significant changes in the reflectance and transmittance spectral profiles. Furthermore, varying the incident angles on the PCs subjected to various O+ ion irradiation fluences simultaneously modulated the transmission and reflection of two-way structural colors. This study expands the design possibilities for structural color modulation and paves the way for applications in color display and projection technologies.

³ He targets are a valuable tool in nuclear physics, particularly for studying nuclear structure and dynamics via direct reactions in inverse kinematics. However, they are often prone to degradation under intense beam irradiation and have insufficient ³ He content for use with low-intensity exotic beams. In a recent AGATA experiment at LNL, designed to study the astrophysically relevant lifetime of a ¹⁵ O excited state, two types of ³ He targets were tested. One was produced using ion implantation and the other with a novel magnetron sputtering technique, in both cases on Au substrates. Following irradiation with a stable ¹⁶ O beam, they were characterized using Nuclear Reaction Analysis (NRA) and Elastic Recoil Detection Analysis (ERDA). Results demonstrated that, under the here used fabrication conditions, sputtered targets present a higher ³ He content, while implanted ones exhibit thinner profiles. This highlights the possibilities and complementarity of these targets, suggesting their tailored use for future experimental campaigns.

Insulated Gate Bipolar Transistors (IGBTs) power devices require high blocking capability, low on-resistance
as well as adaptable switching behaviour. The technique presented in this work aims to realize continuous
deep (> 40 μm) n-type profiles as field stop structures in high voltage silicon IGBTs (1200 V) to adjust the
switching capability. Hydrogen-related donor (HD) defect complexes perform as n-type dopants in single
crystalline silicon. Up to now, these IGBT field stop profiles are generated using multiple high energy (up
to 2 MeV) implantation steps. In contrast, we achieve continuous deep HD profiles in a single implantation
step by inserting a micro-patterned silicon membrane (energy filter) into the primary ion beam at an energy
of 2.5 MeV to provide a beam with a broad customized energy distribution. In this work, we investigate
how filter structure, implanted fluence Φ (from 10¹³ cm⁻² to 5 × 10¹⁵ cm⁻²) and annealing conditions affect the
depth distribution of HD defect complexes. We found that the electrically active dose divided by the implanted
fluence before the energy filter, depends on the pattern type of the membrane (long grooves or squares), the
implanted fluence and the annealing hold temperature (320 °C to 420 °C).

We experimentally and theoretically studied the optical properties of all-dielectric photonic crystals (PCs) under Cl5+ ion irradiation with high fluences. With increasing Cl5+ irradiation fluences, the refractive indices of two different dielectric layers in PCs gradually increased, while their thicknesses decreased more rapidly. Consequently, the optical thickness of every layer in PCs decreased as the Cl5+ irradiation fluence increased. The refractive index ratio between the two dielectric materials in PCs also decreased at the centre wavelength of the photonic bandgap. These changes led to a significant blue shift in both the photonic bandgap and defect modes of the PCs composed of two different dielectric materials as the Cl5+ irradiation fluence increased. The narrowing of the photonic bandgap was primarily attributed to the reduction in the optical thickness of the PC unit cell, in addition to the decrease in the refractive index ratio. The experimental spectra of the PCs are in excellent agreement with the simulation results under different Cl5+ ion irradiation conditions. These results are crucial for the development of tunable optical devices utilizing Cl5+ ion irradiation technology.

Silicon carbide has been considered a material for use in the construction of advanced hightemperature
nuclear reactors. However, one of the most important design issues for future reactors is
the development of structural defects in SiC under a strong irradiation field at high temperatures. To
understand how high temperatures affect radiation damage, SiC single crystals were irradiated at
room temperature and after being heated to 800 °C with carbon and silicon ions of energies ranging
between 0.5 and 21 MeV. The number of displaced atoms and the disorder parameters have been
estimated by using the channeling Rutherford backscattering spectrometry. The experimentally
determined depth profiles of induced defects at room temperature agree very well with theoretical
calculations assuming its proportionality to the electronic and nuclear-stopping power values. On
the other hand, a significant reduction in the number of crystal defects was observed for irradiations
performed at high temperatures or for samples annealed after irradiation. Additionally, indications
of saturation of the crystal defect concentration were observed for higher fluences and the irradiation
of previously defected samples.

To mimic radiation damage by recoiling nuclei following alpha-decay, ceramics and single crystals of LaPO4 monazite doped with Eu(III) were irradiated with 14 MeV Au5+ ions at three different fluences. The crystallinity, local coordination environments, and topography of the samples were probed using numerous methods including grazing-incidence X-ray diffraction (GIXRD), vertical scanning interferometry (VSI), scanning electron microscopy (SEM), Raman, and luminescence spectroscopy. GIXRD data collected from the irradiated regions of the ceramics revealed fluence dependent amorphization. A similar level of amorphization was detected for samples irradiated with 5×1013 ions/cm2 (fluence, F1) and 1×1014 ions/cm2 (F2), while a slightly lower contribution to the scattering signal from the amorphous part was obtained for the sample irradiated with the highest fluence of 1×1015 ions/cm2 (F3). VSI showed clear swelling of entire grains at the highest ion fluence, while more localized damage to grain boundaries was detected for ceramic samples irradiated at the lowest fluence. Single crystal specimens showed no pronounced topography changes following irradiation. SEM backscattered electron images revealed that the ceramic irradiated at the highest fluence exhibited topological features indicative of grain surface melting or softening and displacement of grains. Finally, Raman and luminescence data showed a different degree of disorder in polycrystalline vs. single crystal samples. While changes to PO4 stretching and bending vibrations could be observed in the ceramics, these changes were more subtle or not present in the single crystals. The opposite was observed when probing the local Ln-O environment using Eu(III) luminescence, where the larger changes in terms of an elongation of the Eu-O (or La-O) bond and an increasing relative disorder with increasing fluence were observed only for the single crystals. The dissimilar trends observed in irradiated single crystals and ceramics indicate that grain boundary chemistry likely plays a significant role in the radiation response.

Ce-doped yttria-stabilized zirconia (YSZ) and pure YSZ phases were subjected to irradiation with 14 MeV Au ions. The irradiation studies were performed to simulate long-term structural and microstructural damage due to self-irradiation in YSZ phases hosting alpha-active radioactive species. It was found that both the Ce-doped YSZ and YSZ phases were rather tolerant to irradiation at high ion fluences and the bulk crystallinity was well preserved. Nevertheless, local microstrain increased in all the studied compounds after the irradiation, with the Ce-doped phases being less affected than pure YSZ. Doping with cerium ions increased the microstructural stability of YSZ phases through a possible reduction in the mobility of oxygen atoms, which limits the formation of structural defects. Doping of YSZ with tetravalent actinide elements is expected to have a similar effect. Thus, YSZ phases are promising for the safe long-term storage of radioactive elements. Using synchrotron radiation diffraction, measurements of the thin irradiated layers of the Ce-YSZ and YSZ samples were performed in grazing incidence (GI) mode. A corresponding module for measurements in GI mode was developed at ROBL and relevant technical details of sample alignment and data collection are also presented.

Ion irradiation is a promising tool to emulate neutron-irradiation effects on reactor pressure vessel (RPV) steels, especially in the situation of limited availability of suitable neu-tron-irradiated material. This approach requires the consideration of ion-neutron transferability issues, which are addressed in the present study by comparing the effect of ions with neu-tron-irradiation effects reported for the same materials. The first part of the study covers a com-prehensive characterization, based on dedicated electron microscopy techniques, of the selected unirradiated RPV materials, namely a base metal and a weld. The results obtained for the grain size, dislocation density and precipitates are put in context in terms of hardening contributions and sink strength. The second part is focused on the depth-dependent characterization of the dislocation loops formed in ion-irradiated samples. This work is based on scanning transmission electron microscopy applied to cross-sectional samples prepared by the focused ion beam tech-nique. A band-like arrangement of loops is observed in the depths range close to the peak of in-jected interstitials. Two levels of displacement damage, 0.1 and 1 dpa (displacements per atom), as well as post-irradiation annealed conditions are included for both RPV materials. Compared with neutron irradiation, ion irradiation creates a similar average size but a higher number density of loops presumably due to the higher dose rate during ion irradiation.

Monazites are rare earth phosphates that are potential host matrices for the immobilization of actinides in high-level radioactive waste streams. This is due to their ability to incorporate various cations through different substitution mechanisms as well as their radiation resistance as observed in natural monazite mineral samples. In this study, LnPO4 monazite ceramics and single crystals doped with 500 ppm EuIII as a luminescent probe were irradiated with heavy ions to simulate the recoil of daughter products that occurs during alpha decay of the actinides. More specifically, irradiation experiments were conducted either with 14 MeV Au ions at fluences ranging from 5×1013 – 1×1015 ions/cm2 or with swift 1.7 GeV Au ions at fluences of 5×1011 – 2×1012 ions/cm2.
Irradiated monazite ceramics were analyzed with electron microscopy (SEM), vertical scanning interferometry (VSI), grazing incidence diffraction (GID), Raman spectroscopy, and luminescence spectroscopy to probe long and short range order of the monazite microstructure.
SEM micrographs and VSI data show clear damage of the irradiated regions of the ceramics, in the form of swollen grains and grain boundaries. GID images and powder patterns reveal diffuse scattering and amorphous contributions in irradiated samples. Solid solution compositions show larger damage than corresponding monazite endmembers, while polycrystalline and single crystal samples show similar level of amorphization. In the local coordination environments, Raman spectra of irradiated samples display a shoulder on the ν1 peak, indicating disruption in the vibrational modes of the phosphate tetrahedra. Confocal measurements of the swift heavy-ion irradiated monazites show full amorphization of the surface layers of the monazites samples, and increasing crystallinity with increasing sample depth. Luminescence data illustrate differences in the local LnO9 polyhedral environment in the monazites with irradiation. Integrated excitation spectra show a difference in the intensity and position of the excitation peak with irradiation. Especially single crystal data show a systematic decrease of the local site symmetry of the Eu3+ cation, and a general broadening of emission spectra, indicative for reduced local order following amorphization.

Ion irradiation and femtosecond laser ablation (FLA) are powerful technologies for micro-/nano-machining of transparent materials. In this work, we demonstrate selective surface engineering of optical crystal surface via ion irradiation and subsequent FLA, namely ion-irradiation-assisted FLA. Based on the material modification effects in the ion-irradiated layers, different types of surface structuring characterized by grooves, nanogratings or sub-micron tracks are selectively induced by FLA. It is revealed that the ion-electron interaction induced localized lattice defects and related property modulation in target crystal play important roles in the formation and evolution of laser ablation regimes. Furthermore, the formation process of high-spatial-frequency nanograting is illustrated with the periodical enhancement of local field through the excitation of surface plasmon polaritons, which is experimentally supported through the measurements of transmission electron microscope and energy-dispersive spectroscopy. Our findings further clarify the ion- and laser-matter interactions and the correlation between these processes and surface modifications. The approach proposed in this work shows potential applications in the rapid fabrication of hybrid and versatile surface structures on crystalline materials.

The modulation of structural color through various methods has attracted considerable attention. Herein, a new modulation method for the structural colors in all-dielectric photonic crystals (PCs) using energetic ion beams is proposed. One type of periodic PC and two different defective PCs were experimentally investigated. Under carbon-ion irradiation, the color variation primarily originated from the blue shift of the optical spectra. The varying degrees of both the reflection and transmission structural colors mainly depended on the carbon-ion fluences. Such nanostructures are promising for tunable color filters and double-sided chromatic displays based on PCs.

In this work, carbon ion irradiation and precise diamond blade dicing are applied for Nd:GdCOB ridge waveguide fabrication. The propagation properties of the fabricated Nd:GdCOB waveguides are investigated through experiments and theoretical analysis. The micro-Raman analysis reveals that the lattice of Nd:GdCOB crystal expands during the irradiation process. The micro-second harmonic spectroscopic analysis suggests that the original nonlinear properties of the Nd:GdCOB crystal are greatly enhanced within the waveguide volume. Under a pulsed 1064-nm laser pumping, second harmonic generation (SHG) at 532 nm have been achieved in the fabricated waveguides. The maximum SHG conversion efficiencies are determined to be ~8.32%W^-1 and ~22.36%W^-1 for planar and ridge waveguides, respectively.

Nanoindentation of ion-irradiated nuclear structural materials and model alloys has received considerable interest in the published literature. In the reported studies, the materials were typically exposed to irradiations using a single ion energy varying from study to study from below 1 MeV to above 10 MeV. However, systematic investigations into the effect of ion energy are still missing, meaning that the possibilities to gain insight from systematic energy variations are not yet exhausted. We have exposed pure Fe, ferritic Fe-9Cr, martensitic Fe-9Cr and the ferritic-martensitic reduced-activation steel Eurofer 97 to ion irradiations at 300 °C using 1 MeV, 2 MeV and 5 MeV Fe2+ ions as well as 8 MeV Fe3+ ions and applied nanoindentation, using a Berkovich diamond indenter, to characterize as-irradiated samples and unirradiated references. The effect of the ion energy on the measured nanoindentation response is discussed for each material. Two versions of a primary-damage-informed model are applied to fit the measured irradiation-induced hardening. The models are critically compared with the experimental results also taking into account reported microstructural evidence. Related ion-neutron transferability issues are addressed.

Quartz and feldspar in end-of-life biological shielding concrete in nuclear power plants exhibit a maximum volume expansion at a neutron fluence of 10⁹ n/cm² of 17.8 % and 7.7 % respectively. [1] To simulate neutron-radiation damage, shallow ion-penetration depths in the order of a few hundred nanometers are optimal for 2D examinations of radiation-induced structural changes in silicate minerals and subsequent hydraulic weathering under aqueous alkaline conditions.

Using vertical scanning interferometry (VSI) we observed an out-of-plane expansion for quartz within concrete equivalent to 18.8 vol. % using Si-ion radiation with a fluence of 5·10¹⁴ ions/cm² and an energy of 300 keV. This agrees well with results recently acquired by Luu et al. (2021), [2] who achieved 18.1 vol. % using a Si-ion fluence and beam energy each an order of magnitude higher (6·10¹⁵ ions/cm², 3000 keV). These irradiation conditions correspond to penetration depths calculated in SRIM [3] of respectively 430 nm and 2000 nm.

By virtue of the resistance to polishing exhibited by feldspars, it is difficult to reduce the inherent surface roughness down to submicron relief required for VSI and even finer for electron backscatter diffraction (EBSD). Furthermore, structural relaxation in feldspar begins further away from the surface than quartz. We polish mineral specimen surfaces using a low-energy and -incident Ar+ broad ion beam (Ar-BIB) prior to Si-ion irradiation. In addition to depth profile changes due to radiation-induced structural relaxation and subsequent aqueous alkaline dissolution using VSI, we examine structural changes using EBSD in conjunction with electron scanning microscopy (SEM).

[1] Le Pape et al. (2018) J. Adv. Conc. Technol. 16 191-209
[2] Luu et al. (2021) J. Nucl. Mat. 545 152734
[3] Ziegler et al. (2010) Nucl. Instrum. Methods Phys. Res. B268 1818-1823 (http://www.SRIM.org)

It is generally accepted that the microstructure of ion-irradiated Fe-based alloys does not only depend on the local level of displacement damage and the initial microstructure. Other factors such as the vicinity of a surface and the injected ions also play a role and may give rise to peculiar depth dependencies of the irradiated microstructure. Some investigators reported a band-like appearance indicating depth ranges of relatively uniform microstructure clearly distinguished from other ranges. Clarification is important for at least two purposes: first, to identify a depth range suitable for gaining meaningful information about the behaviour of materials exposed to neutron irradiation and, second, to correctly interpret results obtained by methods, such as nanoindentation, that integrate over extended depth ranges. A variation of the ion energy is expected to gain additional insight. In this work, two samples of Fe-9%Cr were irradiated at 300 °C with Fe2+ ions, one sample using 1 MeV ions and another sample using 5 MeV ions. Calculations using the binary collision code SRIM indicate displacement damage peaks at depths of 0.3 and 1.3 µm for ion energies of 1 and 5 MeV, respectively. The depth distribution of irradiation-induced dislocation loops was studied by cross-sectional scanning transmission electron microscopy (STEM). Loops visible in the STEM images were found to be arranged within two bands with the positions of these bands depending on the profiles of displacement damage and injected interstitials. The first and second band exhibit noticeably different number densities and mean sizes of the loops. For the 5 MeV irradiation, an extended range between the sample surface and the first band was observed, where decoration of pre¬existing line dislocations with loops is dominant. This microstructure resembles cases reported for neutron irradiation. For the 1 MeV irradiation, such a range does not exist. Estimates characterizing the loop size and number density in the distinct depth ranges are provided.