Abstract
Inorganic scintillators are commonly used as sensors for ionizing radiation detectors in a variety of applications, ranging from particle and nuclear physics detectors, medical imaging, nuclear installations radiation control, homeland security, well oil logging and a number of industrial non-destructive investigations. For all these applications, the scintillation light produced by the energy deposited in the scintillator allows the determination of the position, the energy and the time of the event. However, the performance of these detectors is often limited by the amount of light collected on the photodetector. A major limitation comes from the fact that inorganic scintillators are generally characterized by a high refractive index, as a consequence of the required high density to provide the necessary stopping power for ionizing radiation. The index mismatch between the crystal and the surrounding medium (air or optical grease) strongly limits the light extraction efficiency because of total internal reflection (TIR), increasing the travel path and the absorption probability through multiple bouncings of the photons in the crystal. Photonic crystals can overcome this problem and produce a controllable index matching between the crystal and the output medium through an interface made of a thin nano-structured layer of optically-transparent high index material. This review presents a summary of the works aiming at improving the light collection efficiency of scintillators using photonic crystals since this idea was introduced 10 years ago.
Highlights
Since 1990, photonic crystals (PhCs) have been identified to be a versatile method to modify the way optical photons travel through a medium
The very first contribution to the underlying idea of PhCs was published by Yablonovitch [1], who formulated the theoretical basis of a forbidden band gap created by using a Fabry–Perot three-dimensional resonator with periodicity λ/2
The push for better performing scintillator-based ionizing radiation detectors, in terms of energy and time resolution, has shed light on the potential of photonic crystals to overcome the severe limitation of light extraction efficiency because of the refractive index mismatch between the scintillation crystal and the surrounding medium
Summary
Since 1990, photonic crystals (PhCs) have been identified to be a versatile method to modify the way optical photons travel through a medium. The band structure was recorded performing a scan over different angles of incidence and frequencies impinging on the sample, and a band gap of unallowed wave vectors was observed. This knowledge opened the way toward a wide number of applications in the years to come:. At the end of the process, six crystals of 1.2 × 2.6 × 5 mm were cut and re-polished from the original LSO, together with three other identical reference samples, non-patterned The results of this characterization are shown, for the unwrapped configuration without any optical coupling. All the samples tested showed a gain as compared to the reference crystals, going from 1.15–1.56
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call