Large Scale Production of Photonic Crystals on Scintillators

Knapitsch, A.; Auffray, E.; Barbastathis, George; Chevalier, Céline; Hsieh, Chih-Hung; Kim, Jeong-Gil; Li, Shuai; Marshall, Matthew S. J.; Mazurczyk, Radoslaw; Modrzynski, Pawel; Nagarkar, Vivek V.; Papakonstantinou, Ioannis; Singh, Bipin; Taylor, Alaric; Lecoq, P.

doi:10.1109/tns.2016.2535328

Cited by 7 publications

(5 citation statements)

References 12 publications

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“…As demonstrated by earlier work (Levin 2002), measured light output for side readout of long and narrow scintillation crystals is substantially improved compared to the case where a crystal is coupled to a photosensor on its narrow end (figure 8(a)). For context, consider that in recent years significant effort has been put forth to improve LCE with end-coupled scintillation crystals by exploiting photonic crystal techniques (Knapitsch and Lecoq 2014), and simulated gain in LCE for optimized nanoimprinted structures predict 15%-30% improvement compared to a polished exit coupled to a sensor with an optical glue (Knapitsch et al 2016). In section 3.1 we showed that >50% improvement in LCE can already be achieved with the side readout orientation of a 20 mm length crystal, compared to end readout of a crystal with the same length.…”

Section: Discussionmentioning

confidence: 99%

Evaluation of a clinical TOF-PET detector design that achieves ⩽100 ps coincidence time resolution

Cates

Levin

2018

Phys. Med. Biol.

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Commercially available clinical positron emission tomography (PET) detectors employ scintillation crystals that are long (≥20 mm length) and narrow (4–5 mm width) optically coupled on their narrow end to a photosensor. The aspect ratio of this traditional crystal rod configuration and 511 keV photon attenuation properties yield significant variances in scintillation light collection efficiency and transit time to the photodetector, due to variations in the 511 keV photon interaction depth in the crystal. These variances contribute significant to coincidence time resolution degradation. If instead, crystals are coupled to a photosensor on their long side, near-complete light collection efficiency can be achieved, and scintillation photon transit time jitter is reduced. In this work, we compare the achievable coincidence time resolution (CTR) of LGSO:Ce(0.025 mol%) crystals 3–20 mm in length when optically coupled to silicon photomultipliers (SiPMs) on either their short end or long side face. In this “side readout” configuration, a CTR of 102±2 ps FWHM was measured with 2.9×.2.9×20 mm3 crystals coupled to rows of 3×3 mm2 SensL-J SiPMs using leading edge time pickoff and a single timing channel. This is in contrast to a CTR of 137±3 ps FWHM when the same crystals were coupled to single 3×3 mm2 SiPMs on their narrow ends. We further study the statistical limit on CTR using side readout via the Cramér-Rao lower bound (CRLB), with consideration given to ongoing work to further improve photosensor technologies and exploit fast phenomena to ultimately achieve 10 ps FWHM CTR. Potential design aspects of scalable front-end signal processing readout electronics using this side readout configuration are discussed. Altogether, we demonstrate that the side readout configuration offers an immediate solution for 100 ps CTR clinical PET detectors and mitigates factors prohibiting future efforts to achieve 10 ps FWHM CTR.

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Section: Discussionmentioning

confidence: 99%

Evaluation of a clinical TOF-PET detector design that achieves ⩽100 ps coincidence time resolution

Cates

Levin

2018

Phys. Med. Biol.

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“…Notice that for the lower refractive index, the optimal periodicity is shifted to higher values (up to 1.7 µm). On the same line, our collaboration published a work [64] that identified the hybrid structure as a convenient option for large-scale production of PhC slabs. The expected gain in LY for a PhC slab of hexagonally-placed cones of TiO 2 (RI = 2.5), 700 nm period and 1.5 µm height, applied to an 10 × 10 × 10 mm 3 LYSO Teflon wrapped and optically coupled to the PMT is 1.3.…”

Section: Hybrid Phc Slabs: Diffraction and Index Matchingmentioning

confidence: 99%

“…This is a relatively simple method to obtain a mono-layer of nano-spheres that will arrange themselves in a hexagonal lattice. Afterwards, the layer is treated with a plasma, thereby shrinking the nano-spheres to the desired dimension [64,65].…”

Section: Self-assemblymentioning

confidence: 99%

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Enhancing Light Extraction of Inorganic Scintillators Using Photonic Crystals

et al. 2018

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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.

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“…Lijing Zhang, Jie Wang, Shengyang Tao,* Chong Geng, and Qingfeng Yan DOI: 10.1002/adom.201701344 of light due to the existence of a photonic bandgap (PBG) and have been widely used in ultralow reflection solar cells, [6] LED light output, [7] light extraction from scintillation materials, [8] and FL enhancement. [9][10][11][12][13] Studies have shown that light propagates near the PBG will be at reduced group velocity owing to resonant Bragg scattering, which can enhance optical gain leading to stimulated emission and amplify the excitation of incident light.…”

Section: Universal Fluorescence Enhancement Substrate Based On Multipmentioning

confidence: 99%

Universal Fluorescence Enhancement Substrate Based on Multiple Heterostructure Photonic Crystal with Super‐Wide Stopband and Highly Sensitive Cr(VI) Detecting Performance

Zhang

Wang

Tao

et al. 2018

Advanced Optical Materials

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of light due to the existence of a photonic bandgap (PBG) and have been widely used in ultralow reflection solar cells, [6] LED light output, [7] light extraction from scintillation materials, [8] and FL enhancement. [9][10][11][12][13] Studies have shown that light propagates near the PBG will be at reduced group velocity owing to resonant Bragg scattering, which can enhance optical gain leading to stimulated emission and amplify the excitation of incident light. [14][15][16] Adjusting the bandgap structure to match the maximum excitation and emission wavelengths of a fluorescent dye can enable strong FL signal enhancement. PCs can achieve FL enhancement in two ways: enhancing emission by matching the bandgap position with the fluorophore excitation wavelength (E) and enhancing the emission by blue bandgap matching the emission wavelength (F) or the Bragg mirror effect. [17] Zhou et al. [18] observed a 320-fold luminescence enhancement for [Ru(dpp) 3 ]Cl 2 dispersed on a PMMA PC with stopband matching with the E, and a 71-fold enhancement of rhodamine B (RhB) was observed by Tao et al. [19] Li et al. [20] demonstrated a PC-based light-amplification method for ultrasensitive DNA detection with stopband matching of the donor emission and acceptor absorbance. Song and co-workers [21] reported a 162-fold enhancement of Nile Red based on a heterostructure PC with dual stopbands overlapping the E and F of Nile Red. Eftekhari et al. [22] demonstrated an extraordinary FL amplification of RhB with a 3D E-F-E double heterostructure, which provided higher FL enhancement than monolithic E-PCs and F-PCs. However, the abovementioned PC architectures are effective only for a particular fluorescent medium. For different dyes, the stopband structure and position of the PC must be specifically prepared and regulated. On the one hand, a PC with a broadened stopband can overlap with both the excitation and emission maxima, thereby achieving simultaneous amplification of the excitation of incident light and enhancement of the extraction of light generated by fluorescent media. On the other hand, if this stopband is wide enough to cover the E and F of most dyes, it can serve as a universal FL enhancement substrate. Therefore, novel PC architectures with broadened stopbands should be explored further to obtain more remarkable and extensive FL enhancement. Universal fluorescence (FL) enhancement is achieved based on a multiple heterostructure photonic crystal (MHPC) with a super-wide stopband. This MHPC film is fabricated by layer-by-layer deposition of annealed colloidal crystal monolayers with gradient sizes, and it displays a broadened stopband (from 280 to 650 nm) that can overlap with the excitation wavelength (E) and the emission wavelength (F) of most commonly used fluorescent media.More than 100-fold FL enhancement of [Ru(dpp) 3 Cl 2 ], rhodamine 6G (Rh6G), and rhodamine B (RhB) on the MHPC is observed compared to that on a glass substrate. This super-wide stopband MHPC may find significant applications for augmenting FL intens...

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Large Scale Production of Photonic Crystals on Scintillators

Cited by 7 publications

References 12 publications

Evaluation of a clinical TOF-PET detector design that achieves ⩽100 ps coincidence time resolution

Evaluation of a clinical TOF-PET detector design that achieves ⩽100 ps coincidence time resolution

Enhancing Light Extraction of Inorganic Scintillators Using Photonic Crystals

Universal Fluorescence Enhancement Substrate Based on Multiple Heterostructure Photonic Crystal with Super‐Wide Stopband and Highly Sensitive Cr(VI) Detecting Performance

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