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G. García et al., This paper presents experimental data and analysis of the structural damage caused by swift-heavy ion irradiation of single-crystal diamond. The patterned buried structural damage is shown to generate, via swelling, a mirror-pattern on the sample surface, which remains largely damage-free. While extensive results are available for light ion implantations, this effect is reported here for the first time in the heavy ion regime, where a completely different range of input parameters (in terms of ion species, energy, stopping power, etc.) is available for customized irradiation. The chosen ion species are Au and Br, in the energy range 10-40 MeV. The observed patterns, as characterized by profilometry and atomic force microscopy, are reported in a series of model experiments, which show swelling patterns ranging from a few nm to above 200 nm. Moreover, a systematic phenomenological modelling is presented, in which surface swelling measurements are correlated to buried crystal damage. A comparison is made with data for light ion implantations, showing good compatibility with the proposed models. The modelling presented in this work can be useful for the design and realization of micropatterned surfaces in single crystal diamond, allowing to generate highly customized structures by combining appropriately chosen irradiation parameters and masks., GG acknowledges support from the ALBA synchrotron, W. Schildkamp for inspiring discussions on the behavior of diamond and J. Ferrer for his help in experiment preparation. GG, MD-H, VT-M, OP-R and JO acknowledge the projects MAT-2011-28379-C03-02 of the Spanish Ministry of Economy and Competitiveness, TECHNOFUSION(II)¬CM (S2013/MAE¬2745) of the Community of Madrid, and Moncloa Campus of International Excellence (UCM-UPM) foundation for offering a PICATA postdoctoral fellowship (OP-R). FP is supported by the “DiNaMo” project n° 157660 funded by National Institute of Nuclear Physics. PO is supported by the FIRB “Futuro in Ricerca 2010” project (CUP code: D11J11000450001) funded by MIUR and by the “A.Di.N-Tech.” project (CUP code: D15E13000130003) funded by the University of Torino and “Compagnia di San Paolo”. The MeV ion beam implantations performed at the INFN Legnaro National Laboratories was supported by the “Dia.Fab.” experiment, and those at the INFN LABEC Laboratory by the “FARE” and “CICAS” experiments. NMP is supported by the European Research Council (ERC StG Ideas 2011 BIHSNAM n. 279985, ERC PoC 2013-2 KNOTOUGH n. 632277 and ERC PoC 2015 SILKENE no. 693670), by the European Commission under the Graphene Flagship ("Nanocomposites", n. 604391). FB acknowledges support from BIHSNAM. LL-M and CO acknowledge the Spanish MINECO through the Severo Ochoa Program (SEV-2015-0496) and MAT2013-47869-C4-1-P. CO acknowledges the specific agreement between ICMAB-CSIC and the Synchrotron Light Facility ALBA.

We present experimental results and numerical simulations to investigate the modification of structural-mechanical properties of ion-implanted single-crystal diamond. A phenomenological model is used to derive an analytical expression for the variation of mass density and elastic properties as a function of damage density in the crystal. These relations are applied together with SRIM Monte Carlo simulations to set up Finite Element simulations for the determination of internal strains and surface deformation of MeV-ion-implanted diamond samples. The results are validated through comparison with high resolution X-ray diffraction and white-light interferometric profilometry experiments. The former are carried out on 180 keV B implanted diamond samples, to determine the induced structural variation, in terms of lattice spacing and disorder, whilst the latter are performed on 1.8 MeV He implanted diamond samples to measure surface swelling. The effect of thermal processing on the evolution of the structural-mechanical properties of damaged diamond is also evaluated by performing the same profilometric measurements after annealing at 1000 {\deg}C, and modeling the obtained trends with a suitably modified analytical model. The results allow the development of a coherent model describing the effects of MeV-ion-induced damage on the structural-mechanical properties of single-crystal diamond. In particular, we suggest a more reliable method to determine the so-called diamond "graphitization threshold" for the considered implantation type., Comment: 19 pages, 4 figures

The use of wavelength-shifting interferometry with a He–Ne laser source is presented. The approach is based on the thermal expansion of the laser cavity during the warm-up time, in conjunction with an unequal path interferometric configuration. The optics principles are reviewed, and a demonstrative measurement is presented. The technique extends the capability of phase-shift acquisition and processing to cases where conventional methods with piezoelectric transducers cannot be used, and particularly to external measurement cavities of large diameter.