With its three endstations, FinEstBeAMS is becoming one of MAX IV most prolific beamlines. Recently, three new articles on scintillators are the first studies to be produced using FinEstBeAMS’s photoluminescence endstation.
FinEstBeAMS, the Finnish-Estonian beamline at MAX IV’s 1.5 GeV storage ring, offers research opportunities in the fields of atmospheric and material science. Recently no less than three articles with analysis performed at this beamline have been published. The three new papers represent the first research publications to come out of FinEstBeAMS’s photoluminescence endstation, a setup that currently has no equals in European synchrotron facilities.
Three endstations on two branches represent the rich an diverse setups available to researchers at FinEstBeAMS, with the gas-phase electron spectroscopy endstation and photoluminescence spectroscopy endstation on branch A, and the solid-state electron spectroscopy endstation on branch B. Researchers in Europe were left without a dedicated luminescence spectroscopy endstation after the one at the DESY synchrotron in Hamburg closed its doors in 2012. Experts then found a new home at MAX IV with the photoluminescence spectroscopy endstation at FinEstBeAMS.
As explained by professor Marko Kirm from Tartu University in an article we published in 2019, developing luminescence spectroscopy setups in synchrotron facilities is crucial for scientific research. Taking advantage of synchrotron light, such setups allow to perform experiments at higher energy range and higher time resolution, which in turns means being able to study the material down to its atomic structure.
Scintillators are compounds capable of emitting light in the visible range when excited by an ionizing radiation such as X-rays, gamma-rays, or high energy particles. These materials are widely used in many fields, from high-energy physics to Positron Emission Tomography (PET) for medical imaging. Scintillators are the focus of these three new publications.
Replacing elements for faster scintillation
The Gd2Al2Ga3O12:Ce3+ crystal, also known as GAGG:Ce garnet, is a scintillator drawing much interest among researchers thanks to its high scintillation efficiency. These crystals are very promising scintillators for numerous applications and especially for medical tomography. However, the scintillating performance of this material is hindered by an additional slow decay.
A group of researchers from Moscow State University, the National University of Science and Technology in Moscow, the Skolkovo Institute of Science and Technology, Fomos-Materials, MAX IV Laboratory, and Tartu University attempted to remove the additional slow decay so to refine the GAGG:Ce garnet’s performance. To improve the scintillation properties of the garnet, the researchers modified the crystal’s composition by replacing some of the ions in the lattice, an approach known as “bandgap engineering”.
The team introduced ions of Sc (Scandium), performing partial replacements of Al and Ga ions, and observing how the luminescence properties of the materials changed. At FinEstBeAMS’s photoluminescence endstation they observed that the introduction of Sc (GASGG:Ce) resulted in the enhancement of Ce3+ emission at low temperatures and faster yet less bright Ce3+ emission at 300 K compared to the original GAGG:Ce crystal.
Dopants and co-dopants
In this study, researchers focused on the same mixed oxide crystal, to address the additional slow decay flaw. In GAGG:Ce garnets, the Cerium ion in its 3+ charged state acts as the main dopant. A dopant is an impurity added to the crystal’s lattice that causes the material to express the desired scintillating features.
The team of authors from the National University of Science and Technology in Moscow, Fomos-Materials, MAX IV Laboratory, and University of Latvia tested different co-dopants in the attempt to reduce or eliminate the additional slow decay undermining the performance of these scintillating crystals. Different ions, namely Mg2+, Ca2+, Sc3+, Zr4+, and Mg2+ together with Ti4+, were added to the GAGG:Ce garnet acting as co-dopants.
The results obtained at FinEstBeAMS’s photoluminescence spectroscopy endstation show that the addition of these co-dopants can significantly impact the luminescence emission and excitation spectra of the garnet.
Shifting towards red
In the third article published with analysis from the photoluminescence spectroscopy endstation at MAX IV FinEstBeAMS beamline, researchers from the Vinogradov Institute of Geochemistry, University of Latvia, and MAX IV Laboratory investigated a different scintillating material: the earth halide crystal BaBrI doped by Eu2+ and Sm2+.
The aim of the study is to provide insights into scintillators that can work in the red or near infrared (NIR) spectral range. Most scintillators are developed to function in the visible spectral region close to ultra-violet. However, the development of new technologies requires a new class of scintillator materials that can work in the red or near infrared spectral range.
Based on previous estimations, the researchers studied the earth halide crystal BaBrI co-doped by Sm2+ as a potential successful red-NIR scintillators. Using MAX IV synchrotron light, the team was able to ascertain the energy transfer from intrinsic luminescence centres to the Sm2+ and Eu2+ dopant ions. These results provide important insights for the future development of efficient red emitting scintillators.
Read the articles here
Dmitry Spassky, Nina Kozlova, Evgeniia Zabelina, Valentina Kasimova, Nataliya Krutyak, Alisa Ukhanova, Vladimir A. Morozov, Anatolii V. Morozov, Oleg Buzanov, Kirill Chernenko, Sergey Omelkov and Vitali Nagirnyi
Influence of the Sc cation substituent on the structural properties and energy transfer processes in GAGG:Ce crystals
CrystEngComm, 2020, 22, 2621
Anna P. Kozlova, Valentina M. Kasimova, Oleg A. Buzanov, Kirill Chernenko, Konstantin Klementiev, Vladimir Pankratov
Luminescence and vacuum ultraviolet excitation spectroscopy of cerium doped Gd3Ga3Al2O12 single crystalline scintillators under synchrotron radiation excitations
Results in Physics 16 (2020) 103002
Alexey Shalaev, Roman Shendrik, Anton Rusakov, Alexander Bogdanov, Vladimir Pankratovb, Kirill Chernenkoc, Alexandra Myasnikovaa
Luminescence of divalent lanthanide doped BaBrI single crystal under synchrotron radiation excitations
Nuclear Inst. and Methods in Physics Research B 467 (2020) 17–20
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