Ce:LYSO, from scintillator to solid-state lighting as a blue luminescent concentrator

Abstract

Cerium-doped lutetium-yttrium oxyorthosilicate (Ce:LYSO) is a well-known single crystal scintillator used in medical imaging and security scanners. Recent development of high power UV LED, matching its absorption band, questions the possibility to use Ce:LYSO in a new way: as LED-pumped solid-state light source. Since Ce:LYSO is available in large size crystals, we investigate its potential as a luminescent concentrator. This paper reports an extensive study of the performance in close relation to the spectroscopic properties of this crystal. It gives the reasons why the Ce:LYSO crystal tested in this study is less efficient than Ce:YAG for luminescent concentration: limited quantum efficiency and high losses coming from self-absorption and from excited-state absorption are playing key roles. However, we demonstrate that a Ce:LYSO luminescent concentrator is an innovative source for solid-state lighting. Pumped by a peak power of 3400 W in quasi-continuous wave regime (40 µs, 10 Hz), a rectangular (1 × 22 × 105 mm3) Ce:LYSO crystal delivers a broadband spectrum (60 nm FWHM) centered at 430 nm. At full output aperture (20 × 1 mm2), it emits a peak power of 116 W. On a squared output surface (1 × 1 mm2) it emits 16 W corresponding to a brightness of 509 W cm–2 sr–1. This combination of spectrum power and brightness is higher than blue LEDs and opens perspectives for Ce:LYSO in the field of illumination namely for imaging.

Charge Transfer and Charge Trapping Processes in Ca- or Al-Co-doped Lu2SiO5 and Lu2Si2O7 Scintillators Activated by Pr3+ or Ce3+ Ions

“…Among them, a promising family of scintillation crystals is based on Lu 2 SiO 5 (LSO), (Lu,Y) 2 SiO 5 (LYSO) oxyorthosilicates, and Lu 2 Si 2 O 7 (LPS) and recently (Gd,La) 2 Si 2 O 7 pyrosilicates doped by Ce 3+ or Pr 3+ ions (see, e.g., review paper [ 2 ] and refs. [ 3 , 4 , 5 , 6 ]). All the abovementioned materials are excellent candidates for the detection of gamma rays in both positron emission tomography (PET), a very powerful medical imaging method to monitor metabolism, blood flow, or neurotransmission [ 7 ], and high energy calorimetry [ 2 , 8 ].…”