Tapered Optical Fiber-based Detection of Charged Particle Irradiation in Space Exploration and Nuclear Reactors

In this work, we demonstrate the use of tapered optical fibers (TOF) to detect charged particle (ions), irradiated at various energies, fluences and species. The single mode tapered optical fiber has been used in various sensing applications in recent times. Here, tapered optical fibers have been exposed to two different ion species namely Ar+ and N+ at different energies and different fluences, respectively. The optical spectrum analyzer (OSA) detects the changes in the free spectral range (FSR), period, and transmission power loss from the ion beam irradiated TOFs. The change in the refractive index of the cladding material due to the implanted ions influences the transmission spectra of the TOFs and we could able to detect ions of energy as low as 80 keV. COMSOL simulation results are employed to explain the observed changes in spectra. The ion beams induced surface modification and defect formation as well as the implantation in TOF have been predicted using Monte Carlo based 3D TRI3DYN ion-solid interaction simulation and corroborated with other experimental studies such as scanning electron microscopy and Raman scattering spectroscopy. Such tapered optical fiber-based detection technique will help to develop portable device to detect charged particles in space exploration and in nuclear reactors.