Growth of Ce-doped LGSO fiber-shaped crystals by the micro pulling down technique

Luminescence efficiency of (Lu,Gd)2SiO5:Ce (LGSO:Ce) crystals under X-ray radiation

“…Scintillators are used as radiation converting media in various applications, from medical imaging to high energy physics experiments (Kobayashi et al, 2012;Yanagida et al, 2014;Sreebunpeng et al, 2014;Kononets et al, 2015;Nikl and Yoshikawa, 2015). Particularly, in medicine, scintillators have been applied from low energy examinations, such as mammography and general radiography to nuclear medicine and radiotherapy, in powder or crystal form (Valais et al, 2010).…”

“…(Lu,Y) 2 SiO 5 :Ce (LYSO:Ce) is a mixture of LSO with YSO (5e10% Yttrium) which is non-hygroscopic, with high density (7.1 g/cm 3 ), high light output (!25,000 photons/MeV), good energy resolution (~10%) and short decay time (40 ns) (Valais et al, 2007b). Lately a crystal based on a mixture of GSO and LSO orthosilicates (Lu 2x-À Gd 2À2x SiO 5 :Ce e LGSO:Ce) has attracted researcher's attention (Jarý et al, 2014;Kononets et al, 2015). The introduction of Gd 3þ in LGSO reduces the production cost, the crystal has a density of 7 g/ cm 3 , high light output (24,000e34,000 ph/MeV), which is close to LSO and LYSO, energy resolution up to~6.7% (662 keV), which is slightly better than LYSO:Ce and fast scintillation decay time (~40 ns), that can be controlled by changing the Ce 3þ concentration (Moszynski et al, 2007;Sidletskiy et al, 2010;Yamamoto et al, 2010;Kurtsev et al, 2014).…”

“…Cerium concentration also affects LGSO:Ce crystal's light yield. Furthermore, when the crystals are produced with the micro pulling down technique (m-PD), increased Ce 3þ concentration results in reduced afterglow (Kononets et al, 2015). The afterglow can be decreased significantly, compared to LSO:Ce, by choosing the appropriate Lu/Gd ratio and Ce 3þ concentration (Sidletskiy et al, 2010).…”

“…The afterglow can be decreased significantly, compared to LSO:Ce, by choosing the appropriate Lu/Gd ratio and Ce 3þ concentration (Sidletskiy et al, 2010). Depending on the Lu/Gd ratio, the crystals have monoclinic C2/c (LSO) or P2 1/c (GSO) symmetries (Kobayashi et al, 2012;Kononets et al, 2015). A disadvantage of this crystal is the possibility for cracking when the Gd 3þ concentration increase, in an effort to reduce the production cost and to reduce afterglow (Sidletskiy et al, 2010).…”

“…However, Lu concentration can be reduced, to restrict production cost, without degrading crucially crystal parameters (Sidletskiy et al, 2010). Since, it was first patented in 1993 (Akiyama et al, 1993), LGSO has been produced by various methods, such as growth by the Czochralski method , in the form of single crystalline film (SCF) screens (Zorenko et al, 2013), with the micro pulling down technique (Kononets et al, 2015).…”