The iron-based superconductors display interesting superconducting properties for applications, such as their reasonably high superconducting transition temperature Tc, very high upper critical fields Hc2, and relatively small anisotropy [1]. Among them, FeSe superconductor shows exceptional characteristics: Tc above 100 K with monolayer FeSe [2] or 27 K under pressure [3], modification of the properties by adding Te, a very rich phase diagram. It also allows an easy and cheap production of superconducting material and they are rare-earth free. Furthermore, superconducting properties are closely related with the presence of defect and one way to enhance or decrease those properties is to use irradiation process. Few experimentations where already done on single crystal FeSe [4]-[9], but not on polycrystalline FeSe, which is most relevant for applications like, e.g., supermagnets. This project is being carried out in this context. By means of two experimental campaigns, our objective is to add point-like defects (electron irradiation with SIRIUS facility) and columnar tracks (heavy-ion irradiation with GANIL facility). Magnetization loops and critical current densities of FeSe samples after electron irradiation will be compared to the reference one. Some analysis will be done regarding a possible phase transition of the characterized samples. References: [1]A. Gurevich, “Iron-based superconductors at high magnetic fields,” Rep. Prog. Phys., vol. 74, no. 12, p. 124501, Dec. 2011. [2]J.-F. Ge et al., “Superconductivity above 100 K in single-layer FeSe films on doped SrTiO 3,” Nat. Mater., vol. 14, no. 3, pp. 285–289, Mar. 2015. [3]Y. Mizuguchi, F. Tomioka, S. Tsuda, T. Yamaguchi, and Y. Takano, “Superconductivity at 27K in tetrago-nal FeSe under high pressure,” Appl. Phys. Lett., vol. 93, no. 15, p. 152505, Oct. 2008. [4]F. Massee et al., “Imaging atomic-scale effects of high-energy ion irradiation on superconductivity and vortex pinning in Fe(Se,Te),” Sci. Adv., vol. 1, no. 4, p. e1500033, May 2015. [5]Y. Sun, A. Park, S. Pyon, T. Tamegai, T. Kambara, and A. Ichinose, “Effects of heavy-ion irradiation on FeSe,” Phys. Rev. B, vol. 95, no. 10, Mar. 2017. [6]A. E. Kar’kin, T. Wolf, A. N. Vasil’ev, O. S. Volkova, and B. N. Goshchitskii, “Effect of neutron irradiation on the properties of the FeSe compound in the superconducting and normal states,” Phys. Met. Metallogr., vol. 113, no. 5, pp. 455–459, May 2012. [7]Y. Sun et al., “Enhancement of critical current density and mechanism of vortex pinning in H + -irradiated FeSe single crystal,” Appl. Phys. Express, vol. 8, no. 11, p. 113102, Nov. 2015. [8]S. Teknowijoyo et al., “Enhancement of superconducting transition temperature by pointlike disorder and anisotropic energy gap in FeSe single crystals,” Phys. Rev. B, vol. 94, no. 6, Aug. 2016. [9]D. Ahmad et al., “Effect of proton irradiation on the fluctuation-induced magnetoconductivity of FeSe 1− x Te x thin films,” New J. Phys., vol. 19, no. 9, p. 093004, Sep. 2017.