TY - JOUR
T1 - Band Gap Variation and Trap Distribution in Transparent Garnet Scintillator Ceramics
AU - Wieczorek, Herfried
AU - Khanin, Vasilii
AU - Ronda, Cees
AU - Boerekamp, Jack
AU - Spoor, Sandra
AU - Steadman, Roger
AU - Venevtsev, Ivan
AU - Chernenko, Kirill
AU - Tukhvatulina, Tansu
AU - Vrubel, Ivan
AU - Meijerink, Andries
AU - Rodnyi, Piotr
PY - 2020/8/8
Y1 - 2020/8/8
N2 - This article outlines the main results of a research and development cooperation between Philips Research Eindhoven; Peter the Great St. Petersburg Polytechnic University; Ioffe Institute, St. Petersburg; Utrecht University; and Philips Healthcare. It reviews the properties of garnet ceramics in the (Lu,Gd)3(Ga,Al)5O12:Ce system for medical imaging, especially time-of-flight positron emission tomography (PET). Thermally stimulated luminescence (TSL) peaks are attributed to impurities, verified by intentional codoping of samples. A lately developed method allows extraction of carrier lifetimes, thermal trap depths, and frequency factors from TSL and afterglow measurements. A detailed analysis reveals the presence of a distribution of trap depths, allowing a more accurate afterglow modeling. Activation energies of thermal ionization and trap depths obtained from TSL show the influence of Ga/Al substitution on thermal quenching and on trap position. The resulting nonmonotonic dependence of the conduction band edge with Ga content in (Lu,Gd) garnets is consistent with earlier predictions. Shallow traps determine both signal decay and short-term afterglow. The impact of signal height, rise, and decay times on coincidence resolving time and further on PET image quality is described by analytical models.
AB - This article outlines the main results of a research and development cooperation between Philips Research Eindhoven; Peter the Great St. Petersburg Polytechnic University; Ioffe Institute, St. Petersburg; Utrecht University; and Philips Healthcare. It reviews the properties of garnet ceramics in the (Lu,Gd)3(Ga,Al)5O12:Ce system for medical imaging, especially time-of-flight positron emission tomography (PET). Thermally stimulated luminescence (TSL) peaks are attributed to impurities, verified by intentional codoping of samples. A lately developed method allows extraction of carrier lifetimes, thermal trap depths, and frequency factors from TSL and afterglow measurements. A detailed analysis reveals the presence of a distribution of trap depths, allowing a more accurate afterglow modeling. Activation energies of thermal ionization and trap depths obtained from TSL show the influence of Ga/Al substitution on thermal quenching and on trap position. The resulting nonmonotonic dependence of the conduction band edge with Ga content in (Lu,Gd) garnets is consistent with earlier predictions. Shallow traps determine both signal decay and short-term afterglow. The impact of signal height, rise, and decay times on coincidence resolving time and further on PET image quality is described by analytical models.
KW - Ceramics
KW - computed tomography (CT)
KW - garnets
KW - positron emission tomography (PET)
KW - scintillators
UR - https://www.mendeley.com/catalogue/762edad8-1a00-39fa-9846-74cf5ec5dddb/
U2 - 10.1109/TNS.2020.3001303
DO - 10.1109/TNS.2020.3001303
M3 - Article
SN - 0018-9499
VL - 67
SP - 1934
EP - 1945
JO - IEEE Transactions on Nuclear Science
JF - IEEE Transactions on Nuclear Science
IS - 8
ER -