Conveners
Poster Session 3
- Marco Pizzichemi (CERN)
- Kristof Pauwels (Universita & INFN, Milano-Bicocca (IT))
- Remi Chipaux (CEA/IRFU,Centre d'etude de Saclay Gif-sur-Yvette (FR))
Quantum tunneling between the activator and a nearby trap(s) is a phenomenon not infrequently encountered in scintillating materials. We confirmed its presence both theoretically and experimentally [1] (and references therein). Experimental evidence in a variety of Ce and Pr doped complex oxides was given by the delayed recombination technique, primarily developed to study the activator’s...
Pure crystals of CeBr3 material were initially produced by Schott Lithotec (Mainz) who then transferred production of several types of pure crystals to the enterprise Hellma Materials GmbH (Jena). CeBr3 is a scintillating material which is very suitable for photon spectrometry in the X-ray and gamma-ray range, in particular because of its high quantum yield. When properly coupled with a...
Scintillation crystals with high density and high atomic number coupled with photodetectors are commonly used in X-ray and gamma-ray spectrometry. There is continuous demand for new scintillation materials in such applications as industrial radiography, medical imaging techniques and nuclear and high-energy physics. In the case of modern scintillators, parameters such as high light yield, high...
The European Synchrotron Radiation Facility builds a new ultra-bright synchrotron source, the ESRF-EBS [1] in the period 2015-2022, which will deliver an X-ray beam with performances multiplied by 100 in terms of brightness and coherence. In this context, diffraction and X-ray imaging experiments will benefit from X-ray detectors covering a large dynamic range (above 16 bits), large field of...
The scintillation characteristics of Czochralski – grown GdLu2Al2Ga3O12:Ce and GdY2Al2Ga3O12:Ce single crystals were compared for γ - ray detection. At 662 keV γ - rays, light yield (LY) of 33,900 ph/MeV and energy resolution of 14.3% obtained for GdLu2Al2Ga3O12:Ce are inferior to those of 37,500 ph/MeV and 10.6% obtained for GdY2Al2Ga3O12:Ce. Scintillation decays were measured using the...
Oxide garnet materials are widely used as scintillators and phosphors and are being actively investigated. Composition versatility for this class of materials enables optimizing garnets’ physical properties to specific application requirements in terms of density, light output or afterglow. Many medical and industrial scintillator applications have strict requirements to time performance of...
Co-doping has been demonstrated to improve the light yield and/or energy resolution for compounds activated with Ce [1] and Tl [2]. Limited efforts have been done for co-doping of Eu-activated halides. We report on the screening of co-dopants for the mixed halide BaBrCl:Eu. With a light output of 52,000 photon/MeV and energy resolution of 3.55%, theoretical performance of BaBrCl:Eu has not...
Gadolinium gallium aluminum garnet (Gd$_{3}$Ga$_{3}$Al$_{2}$O$_{12}$, also called GGAG) doped with Cerium (Ce) has shown the best combination of the scintillation characteristics exhibiting high density (6.7 g/cm$^{3}$), effective atomic number (55), light yield of 54,000 ph/MeV and fast decay time of 55 ns [1]. The efficient and fast emission at 550 nm makes these scintillators very...
Scintillators are widely used to detect high-energy photons and particles and applied in the medical imaging and other applications. Among the many kinds of scintillator materials, oxide scintillation materials based on garnet structure like Ce-doped Lu3Al5O12 (Ce:LuAG) are promising candidates for scintillator applications because of well mastered technology developed for laser hosts, and...
For $\gamma$-ray spectroscopy, apart from having high light output, good energy and timing resolution, it is the high efficiency (both detection and photo-peak) of the detector which is of paramount importance. The detection efficiency is a measure of the percentage of radiation that a given detector detects from the overall yield emitted from the source. In the category of inorganic...
Cerium activated lutetium aluminum garnet (LuAG:Ce) is a perspective material for applications in detection of X-rays, gamma radiation or high energy particles. However, the luminescence response of LuAG:Ce suffers from structural defects (mainly anti-site defects) that create unwanted slow microsecond-component in decay characteristics. Concentration of these defects decreases with decreasing...
Multicomponent (Y,Lu,Gd)3(Ga,Al)5O12:Ce garnets are efficient complex oxide scintillators, whose main advantages are achieved owing to the Ga-induced lowering of the conduction band (CB) bottom resulting in burying of shallow electron traps (see, e.g., review [1]). In this work, the (Y,Lu,Gd)3GaxAl5-xO12:Ce single...
LaBr$_3$(Ce)-based detectors, which provide excellent time response together with high gamma detection efficiency and good energy resolution [1, 2], are optimal devices for a wide range of applications. Their scintillation properties are strongly influenced by their size and shape. Consequently, we have designed novel geometries of LaBr$_3$(Ce) crystals aimed at enhancing the light collection,...
Caesium iodides doped by thallium are one of the most popular scintillators used as gamma ray detectors whether in the scientific or application side. Despite such widespread use it is still ongoing work aimed at understanding the mechanism of light emission in these crystals. Some theoretical interpretation supported by experimental measurements have been already done and were presented in...
GdBO3:Ce3+ emitting phosphors as nanopowders were prepared using aqueous sol-gel method. The photoluminescence (PL) and scintillation properties were analyzed as function of the pH value of precursor suspension (pH=2, 5 and 8) and the nominal Ce3+ concentration (0.5%mol) at different annealing temperatures (600, 700, 800, 900, 1000, 1100 and 1200) °C. The crystal structures of the prepared...
The Advanced Mo Based Rare Process Experiment (AMoRE) collaboration is searching for the neutrino less double beta decays (0ν2β) of 100Mo isotopes using CaMoO4 scintillating crystals operating at milli-Kelvin temperatures [1]. Due to the 2ν2β background caused by 48Ca and the limitation of calcium purification within an acceptable level [2], new molybdate-based scintillation crystals for the...
Crystals doped with rare earth ions find numerous applications as scintillators in various fields of technology including nuclear physics, medical imaging, dosimetry, etc. In this paper, we report on luminescence and optical properties of a new class of LiLa9(SiO4)6O2 (LLSO) crystals doped with Ce3+ and Pr3+ ions which we found potentially attractive for scintillator applications.
The LLSO...
Tetravalent Mn ions have a number of properties that makes them interesting candidates for use as activators in luminescent materials, such as phosphors for fluorescent lamps or white LEDs as well as for thermoluminescence dosimeters. They possess strong absorption bands in the blue and UV spectral region due to spin-allowed transitions $-\ $ $^4$A$_2 \rightarrow ^4$T$_2$ and $^4$A$_2...
Garnet structure is a very flexible crystalline platform which allows one to control the luminescence properties by engineering the excitation transfer processes. The ease of material engineering in garnet structures allows designing materials consisting of lighter ions that are preferable for applications in high energy physics experiments in a harsh radiation environment. Meanwhile, two...
Ce and Pr doped Lu3Al5O12 (LuAG) single crystals started to be systematically studied around year 2000 and 2004, respectively, see review [1]. Among their advantages there is stable crystal growth, relatively high density, fast decay due to allowed 5d-4f transitions of Ce3+ and Pr3+, good light yield, mechanical and chemical robustness and radiation hardness. Degradation of figure of merit of...
High-energy-resolution scintillators are demanded for food/environmental gamma-ray monitoring systems in Fukushima or for other applications. Generally, halide scintillators have high light output due to small band-gap energy, and therefore high energy resolutions are expected [1]. However, almost all halide materials have hygroscopic nature, which makes them difficult to...
ZnO:Ga scintillation powder is a promising candidate for detectors with ultrafast timing, thanks to its extremely short decay and practically no rising time [1]. For practical use, the powder needs to be embedded in a suitable optically transparent matrix. However, heat treatment of ZnO:Ga particles is needed to increase the luminescence at the cost of particle agglomeration. This in turn...
Zinc oxide has a variety of practical applications due to its unique properties. In particular, high radiation hardness and the presence of an ultrafast emission component make this material prospective for scintillators [1]. As a rule, various forms of ZnO exhibit two luminescence bands. One of them is a narrow UV band located near the absorption edge of the crystal; therefore it is called...
The rare-earth doped ternary alkali earth-halide systems are promising scintillators showing high efficiency and energy resolution. Some aspects of crystal growth and data on the structural and luminescence properties of BaBrI, BaClI and SrBrI crystals doped with $\mathrm{Eu^{2+}}$ ions are reported. The crystals are grown by the vertical Bridgman method in sealed quartz ampoule.
Emission,...
CsI activated with thallium is one of the most important scintillators in the radiation detection field. Long a standard for medical diagnostics, it has also become particularly attractive for radiographic scanning and active interrogation of cargo in transit via trucks or rail. CsI:Tl has one of the highest conversion efficiencies (60,000 photons/MeV) of all scintillators in current use,...
The response of GAGG:Ce crystals with different Al/Ga ratio [1] to alpha particles, with the energies of 1.5 MeV up to 8.8 MeV, were studied in relation to that of gamma rays. It was done using ThC source and 241Am source with Si absorbers. The alpha-to-gamma (α/γ) ratio, described as a ratio of the pulse amplitudes normalized to the energy unit, determined in relation to 662 keV gamma ray...
This paper aims at an improved understanding of thermoluminescence of (Lu1-xYx)2SiO5:Ce (x=0 at.%, 9 at.%, 26 at.%, 45 at.%, 66 at.% , 88 at.% and 100 at.%). Wavelength-resolved thermally stimulated luminescence (TSL) spectra and vacuum ultraviolet excitation spectra as well as transmittance spectra of (Lu1-xYx)2SiO5:Ce were investigated as a function of yttrium (shortened as Y) content in it....
LuAG:Ce (Lu$_3$Al$_5$O$_1$$_2$:Ce) garnet scintillator is a scintillator of decent light yield and energy resolution, excellent chemical stability, very good mechanical properties, and fast scintillation decay. However, the LuAG:Ce response is negatively affected by traps, mainly related to Lu$_A$$_l$ antisite defects produced at high temperatures. Traps are responsible for very high intensity...
Scintillation properties of Czochralski-grown Gd3(Al5-xGax)O12:Ce; x = 2.3, 2.6, 3.0 single crystals were investigated. The light yield (LY) and energy resolution were measured using an R6231 photomultiplier. LY non-proportionality and intrinsic resolution were evaluated. At 662 keV γ-rays, the LY value of 46,200, 65,800 and 59,400 ph/MeV was obtained, respectively, for Gd3(Al2.7Ga2.3)O12:Ce,...
Scintillation materials based on halide-lanthanide matrix elements are described in terms of material properties and applications. A new embodiment in this group of scintillators is presented, where the matrix material contains a mixture of two halides, namely lanthanum bromide and lanthanum chloride, that form a solid solution in the uranium tri-chloride lattice type. The matrix material also...
Scintillation properties of new TlGd2Cl7 single crystal is presented. Different Ce-doped (0, 0.5, 1 and 5 mol %) single crystals of TlGd2Cl7 are grown by vertical Bridgman technique. All doped samples show typical Ce3+ emission under X-ray excitation between 350 nm and 500 nm. The emission peak positions slightly changed with the increase of Ce-concentration in the host matrix. Excellent light...
It is well known that Barium fluoride (BaF2) crystals have a fast scintillation light peaked at 195 nm and 220 nm with a sub-ns decay time. This ultra-fast scintillation promises its wide application in future HEP experiments requiring extreme fast rate capability, Gigahertz hard X-ray imaging and TOF-PET etc. BaF2 crystals, however, have also a slow scintillation component...
The alkaline earth co-doping by Mg2+ or Ca2+ ions in LYSO:Ce and LuAG:Ce stabilizes tetravalent Ce4+ ions which then participate in the scintillation process. They act as electron traps and result in reduction of afterglow and slow components in the scintillation decay [1, 2]. Excellent scintillation properties have recently been reported in epitaxial garnet films GAGG:Ce,Mg grown by liquid...
Cerium doped mixed oxide garnets are promising luminescent materials to use as LED phosphors or scintillators. Their properties can be adjusted via composition engineering for use in a specific application [1]. The cubic crystal structure allows preparation of highly transparent scintillation ceramics, which is a more cost efficient process than crystal growth.
Every change in the...
The emission centers in YAG crystals grown in various conditions
S. Vasyukov 1, O. Sidletskiy 1, P. Arhipov 1, S. Tkachenko 1, A. Vedda 2, N. Shiran 1, V. Nesterkina 1
1 Institute for scintillation Materials NAS of Ukraine, 60 Nauka avenue, 61001 Kharkov, Ukraine
2 Department of Materials Science, University of Milano-Bicocca, Via Cozzi 53, 20125 Milan, Italy
The energy relaxation in the...
Scintillating optical ceramics (OC) based on garnet structures have been the subject of intense R&D. The interest on this kind of scintillating optical materials spawned from the excellent results obtained on Nd:YAG laser OC, whose production route allowed better control on dopant concentration and spatial distribution in the final laser active element, substantially outperforming the single...
