Growth of long undoped and Ce-doped LuAG single crystal fibers for dual readout calorimetry

Abstract

The influence of the reducing Ar+CO atmosphere on the stages of starting raw material preparation, growth and post-growth annealing of yttrium aluminium garnet, Y3Al5O12 (YAG) crystals was studied. The chemical reactions involving CO atmosphere and its impact on the raw material, melt, and crystal composition are determined. Modification of YAG optical properties under the reducing annealing is discussed.

Progress in fabrication of long transparent YAG:Ce and YAG:Ce,Mg single crystalline fibers for HEP applications

“…Despite a good transparency and radiation hardness [2] of garnet fibers cut from bulk crystal, micro-pulling-down (µ-PD) is still the only method to produce >20 cm long fibers of needed shape without cutting and additional crystal treatment 3 . Previously we reported the obtaining of LuAG:Ce fibers with the length over 22 cm and excellent transparency (attenuation length Latt of up to 104 cm) 4 . Further efforts have been focused at YAG:Ce fibers as a low-cost alternative to LuAG:Ce due to cheaper starting materials.…”

“…They comprise oxygen and Al 3+ vacancies, as well as various complex defects, for example Lu(Y)Al antisite defects, see for ex., the review 6 ). A high concentration of oxygen vacancies in as-grown garnet fibers has been evidenced by a drastic enhancement of LuAG:Ce fiber transmission after thermal annealing in air 4 . Al and Al-O vacancies in YAG evidenced by positron annihilation spectroscopy 7 may be responsible as well for deterioration of optical and scintillation parameters.…”

Needs, Trends, and Advances in Inorganic Scintillators

“…In this frame, the garnet composition has been identified as the most promising material [156]. During the last few years, much progress has been made in the understanding and optimization of the growing process and the doping conditions to improve the radial segregation of the dopant, the attenuation length, and the radiation hardness [46], [157], [158] in YAG and LuAG fibers. Long fibers of more than 40-cm length can now be produced in a reproducible way with homogeneous quality in term of light yield and attenuation length (Fig.…”

Engineering of bulk and fiber-shaped YAGG:Ce scintillator crystals

“…As fiber-shaped scintillation detectors is one of the possible designs of new high granularity calorimeters in high-energy physics, we attempted to grow YAGG:Ce fibers by the micro-PD method. The fiber growth process was similar to the LuAG and LuAG:Ce growth procedure described in 29 . Ground parts of YGG and YAG:Ce crystals fabricated in ISMA by the Czochralski method were used as raw materials.…”