On low-temperature luminescence quenching in Gd3(Ga,Al)5O12:Ce crystals

The work was supported by the ERDF funding in Estonia granted to the Center of Excellence TK141 “Advanced materials and high-technology devices for sustainable energetics, sensorics and nanoelec-tronics“ (project No. 2014-2020.4.01.15-0011). Partial support of the projects from the Ministry of Education, Youth and Sports of the Czech Republic no. LO1409, LM2015088 and CZ.02.1.01/0.0/0.0/16 013/ 0001406 is also gratefully acknowledged.

High resolution luminescence spectroscopy and thermoluminescence of different size LaPO4:Eu3+ nanoparticles

T. G. acknowledges the ERDF PostDoc project No. 1.1.1.2/VIAA/1/16/215 (1.1.1.2/16/I/001). K. S. and K. L. acknowledge the Latvian National Research Program IMIS2. The authors from Vinča Institute of Nuclear Sciences acknowledge the financial support of the Ministry of Education, Science and Technological Development of the Republic of Serbia (Project No: 45020 and 172056 ).

Towards metal chalcogenide nanowire-based colour-sensitive photodetectors

Financial support provided by Scientific Research Project for Students and Young Researchers Nr. SJZ/2016/6 realized at the Institute of Solid State Physics, University of Latvia is greatly acknowledged. Authors are grateful to Reinis Ignatans for XRD measurements.

Excitation Transfer Engineering in Ce-Doped Oxide Crystalline Scintillators by Codoping with Alkali-Earth Ions

This work has been supported by the European Social Fund Measure No. 09.3.3-LMT-K-712 activity Improvement of Researchers Qualification by Implementing the World-Class R&D Projects, and by grant #14.W03.31.0004 of the Russian Federation Government. Authors are grateful to CERN Crystal Clear Collaboration and COST Action TD1401 "Fast Advanced Scintillator Timing (FAST)" for support of collaboration.

TSL un frakcionētās izspīdināšanas metodes defektu stāvokļu izpētei oksīdu materiālos

Darbā apskatītas termostimulētās un frakcionētās termoizspīdināšanas luminiscences metodes un to pielietojums oksīdu materiālu ķērājcentru izpētē. Izveidota iekārta un programmatūra termostimulētās luminiscence procesu praktiskai izpētei. Izstrādātā programmatūra nodrošina eksperimentālās iekārtas moduļu vadību, izvēlēto algoritmu realizēšanu un iegūto datu apstrādi. Veikta iekārtas un metodikas pārbaude eksperimentos ar ģermāniju aktivētā α-kvarca (SiO2:Ge) paraugiem. Paraugam novēroti divi TSL maksimumi pie 50K un 75K, kuriem iegūtās aktivācijas enerģijas ir 0,06eV un 0,123eV. Papildus tika aplūkota Ge koncentrācijas, ierosmes avota un apstarošanas laika ietekme uz termostimulētās luminis…

Radioluminescence, thermoluminescence and dosimetric properties of ZnO ceramics

The authors gratefully acknowledge the financial support for this work from research grant ERA.NET RUS Plus Nr.609556 and from the SFERA II project Transnational Access activities (EU 7th Framework Programme Grant Agreement no 312643) for supporting ZnO nanopowders preparation.

Nanoscale X-ray detectors based on individual CdS, SnO2 and ZnO nanowires

Abstract The development of nanoscale X-ray sensors is of crucial importance to achieve higher spatial resolution in many X-ray-based techniques playing a key role in materials science, healthcare, and security. Here, we demonstrate X-ray detection using individual CdS, SnO 2 , and ZnO nanowires (NWs). The NWs were produced via vapor–liquid–solid technique and characterized using X-ray diffraction, scanning, and transmission electron microscopy . Electrical measurements were performed under ambient conditions while exposing two-terminal NW-based devices to X-rays generated by a conventional tungsten anode X-ray tube. Fast and stable nanoampere-range X-ray beam induced current (XBIC) in resp…

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment

Financial support provided by Scientific Research Project for Students and Young Researchers, Latvia Nr. SJZ/2018/7 realized at the Institute of Solid State Physics, University of Latvia is greatly acknowledged. Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART2.

Behaviour of advanced tritium breeder pebbles under simultaneous action of accelerated electrons and high temperature

The authors greatly acknowledge the technical and experimen-tal support of O. Valtenbergs and L. Avotina (Institute of Chemical Physics, University of Latvia). The work is performed in the frames of the University of Latvia financed project No. Y9-B044-ZF-N-300, “Nano, Quantum Technologies, and Innovative Materials for Eco-nomics”.

Luminescent PEO Coatings on Aluminum

Novel method of phosphorescent strontium aluminate coating preparation on aluminum

This work was supported by the ERDF , European-Union Project No. 1.1.1.1/16/A/182 .

Gas sensitive luminescence of ZnO coatings obtained by plazma electrolytic oxidation

Abstract The ZnO coatings on Zn substrate were obtained using plasma electrolytic oxidation method. The XRD and SEM methods were used for structural and morphological characterization of obtained coatings. The luminescence of ZnO coatings were studied and compared with luminescence characteristics of ZnO single crystal. It is shown that luminescence intensity in ZnO defect band depends on oxygen concentration in ambient atmosphere. The effect is of interest for oxygen sensing based on ZnO coating luminescence.

The boron effect on low temperature luminescence of SrAl2O4:Eu, Dy

V.V. acknowledges the financial support of ERDF PostDoc project No. 1.1.1.2/VIAA/3/19/440 (University of Latvia Institute of Solid State Physics, Latvia) and K.S., I.B., A.Z., D.M. and K.L. acknowledge the financial support of ERDF, European-Union Project No. 1.1.1.1/16/A/182 (University of Latvia Institute of Solid State Physics, Latvia).

Electronic processes in doped ZnO nanopowders

The financial support of research grants ERA.NET RUS_ST20170-051 and SFERA II project “Transnational Access activities” (EU 7th Framework Programme Grant Agreement N312643). This work was partly supported by the Russian Foundation for Basic Research, project no. 18-52-76002.

The search for defects in undoped SrAl2O4 material

This research project was supported financially by ERDF Project No: Nr.1.1.1.1/16/A/182 .

ZnO and ZnO:Ga Ceramics for Advanced Scintillators

The undoped ZnO reveals narrow luminescence bands located close to fundamental absorption edge, known as near band luminescence (NBL) and defects related wide luminescence band within visible range of spectrum. NBL decay is in sub-nanosecond range and it is promising for fast scintillator development. However, the defects luminescence decay is in microsecond range and it is disturbing for fast scintillators. Dopants strongly change the luminescence properties, mainly the intensity and decay time and that is the cause for intense study of doped ZnO luminescence properties. Thus the study of luminescent properties of undoped ZnO and doped ZnO:Ga ceramics was carried out. The dependence of the…

Recombination luminescence of X-ray induced paramagnetic defects in BaY2F8

This research is funded by the Latvian Council of Science , project “Novel transparent nanocomposite oxyfluoride materials for optical applications”, project No. LZP-2018/1–0335 . The crystal growth research was funded by the CNPq (Brazil), project NO 421581/2016–6 .

Flame-Retardant and Tensile Properties of Polyamide 12 Processed by Selective Laser Sintering

This research was funded by the European Regional Development Fund within Measure 1.1.1.1 “Industry-Driven Research” of the Specific aid objective 1.1.1 “To increase the research and innovation capacity of scientific institutions of Latvia and their ability to attract external funding by investing in human resources and infrastructure” of the Operational Program “Growth and Employment” (Project No. 1.1.1.1/19/A/143). A.S. and A.Z. are grateful to funding received from the European Union Horizon 2020 Framework programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART2.

Nanoengineered Gd3Al2Ga3O12 Scintillation Materials with Disordered Garnet Structure for Novel Detectors of Ionizing Radiation

The authors are grateful to Baker Hughes a GE Company for support of this activity. This work has also been supported by grant N14.W03.31.0004 from the Government of the Russian Federation.

Ar plazmas elektrolītiskās oksidēšanas metodi iegūto modificēto alumīnija oksīdu pārklājumu luminiscences īpašību izpēte

Ar plazmas elektrolītisko oksidēšanu (PEO) iegūtie pārklājumi uz metālu virsmām ir cieti, biezi keramiskie pārklājumi, kuriem ir liels pielietojumu klāsts un daudz priekšrocības salīdzinot ar citiem pārklājumu veidiem. Pārklājumu ar jaunām īpašībām ražošanai ir nepieciešams veids pārklājuma leģēšanai. Darbā tiks apskatīta metode alumīnija oksīda pārklājumu leģēšanai ar Eu joniem izmantojot poru iepildīšanas metodi. Izveidojot ar Eu joniem leģētu alumīnija oksīda pārklājumu uz tehniskā alumīnija sakausējuma virsmas un izpētot iegūtā pārklājuma luminiscences īpašības bija novērota Eu jona stāvokļa maiņa no Eu3+ uz Eu2+ ar fotoluminiscences intensitātes pieaugumu līdz 10 reizēm. Izmantotas lum…

Effect of Ga content on luminescence and defects formation processes in Gd3(Ga,Al)5O12:Ce single crystals

The work was supported by the Institutional Research Funding IUT02-26 of the Estonian Ministry of Education and Research and the project 16-15569S of the Czech Science Foundation.

Thermostimulated luminescence of plasma electrolytic oxidation coatings on 6082 aluminium surface

Financial support provided by Scientific Research Project for Students and Young Researchers Nr. SJZ/2016/12 realized at the Institute of Solid State Physics, University of Latvia is greatly acknowledged. Authors are grateful to R. Ignatans for measurements and analysis of XRD spectra and ElGoo Tech ltd. for providing PEO equipment.

Luminescence of Eu ion in alumina prepared by plasma electrolytic oxidation

Abstract Eu ion luminescence in aluminium oxide nanocrystals and layers prepared by plasma electrolytic oxidation (PEO) are investigated in this study. The Eu ion in PEO coatings has intense luminescence allowing such material to be used for preparation of various phosphor materials. In this study, Eu ion doped coatings were prepared with two methods: anodization and pulsed bipolar plasma electrolytic oxidation. Also, for comparative studies, alumina nanocrystals with the same amount of Eu ions were prepared using Sol Gel and molten salts methods. Obtained Eu-doped coatings were studied using luminescence methods. Typical Eu ion luminescence bands were observed, however intensity and spectr…

Re-Evaluation of Chromium Doped Alumina for Dosimetric Applications

Financial support provided by Scientific Research “Luminescence Mechanisms and Dosimeter Properties in Prospective Nitrides and Oxides Using TL and OSL Methods” LZP FLPP No. LZP-2018/1-0361 implemented at the Institute of Solid State Physics, University of Latvia is greatly acknowledged. The Institute of Solid State Physics, University of Latvia as the Centre of Excellence has received funding from the European Union’s Horizon 2020 Framework Program H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART².

Studies of radiation defects in cerium, europium and terbium activated oxyfluoride glasses and glass ceramics

Abstract Terbium, cerium and europium activated oxyfluoride glasses and glass ceramics have been studied by thermally stimulated luminescence (TSL) and optical absorption techniques after the X-ray irradiation. A creation of colour centres in oxyfluoride glass matrix and TSL peaks depending on the activator type were observed. LaF 3 and rare earth activators were analysed by SEM–EDS.

Sub-nanosecond excitonic luminescence in ZnO:In nanocrystals

The financial support of research European Union ERA.NET RUS_ST20170-51 . This work was partly supported by Russian Foundation for Basic Research, Russia , project No. 18-52-76002 . The sample preparation was carried out as part of SFERA II project -Transnational Access activities ( European Union 7th Framework Programme Grant Agreement N3126430 ).

Pyroelectric activity of LiGaO2, Li2GeO3, Li2B4O7 and LiNbO3 crystals: Pyroelectric luminescence and excitation of cathodoluminescence in scintillator ScPO4

Abstract Basing on results of electric, spectral and kinetic measurements of spontaneous luminescence caused by cooling/heating in pyroelectric crystals LiGaO2, Li2GeO3, Li2B4O7 and LiNbO3 a mechanism of pyroelectric luminescence is proposed. Series of experiments were undertaken attaching a scintillating phosphor ScPO4 to a pyroelectric crystal and subjecting a pair of the bounded crystals to cooling/heating process. Pyroelectric activity causes not only pyroluminescence in pyroelectric crystals but also luminescence in a ScPO4, which is characterized with high intensity and kinetic and spectral properties typical for the intrinsic luminescence of a scintillator.

Synthesis of Eu2+ and Dy3+ Doped Strontium Aluminates and their Properties

Financial support to this project was provided by National Research Programme (IMIS2).

X-ray induced defects in advanced lithium orthosilicate pebbles with additions of lithium metatitanate

Abstract Advanced lithium orthosilicate (Li4SiO4) pebbles with additions of lithium metatitanate (Li2TiO3) as a secondary phase have attracted international attention as an alternative solid-state candidate for the tritium breeding in future nuclear fusion reactors. In this research, the generation of radiation-induced defects in the Li4SiO4 pebbles with various contents of Li2TiO3 was analysed in-situ by X-ray induced luminescence technique. After irradiation with X-rays, the accumulated radiation-induced defects in the Li4SiO4 pebbles were studied by electron spin resonance, thermally stimulated luminescence and absorption spectrometry. On the basis of the obtained results, it is conclude…

Luminescence of X-ray induced radiation defects in modified lithium orthosilicate pebbles with additions of titanium dioxide

The authors greatly acknowledge the technical and experimental support of O. Leys, M. H. H. Kolb, and R. Knitter (Karlsruhe Institute of Technology, Germany). The work is performed in the frames of the University of Latvia financed project No. Y9-B044-ZF-N-300, “Nano, Quantum Technologies, and Innovative Materials for Economics”.

Thermally stimulated luminescence of undoped and Ce3+-doped Gd2SiO5 and (Lu,Gd)2SiO5 single crystals

Abstract Thermally stimulated luminescence (TSL) characteristics (TSL glow curves and TSL spectra) are investigated in the 4–520 K temperature range for the single crystals of gadolinium and lutetium–gadolinium oxyorthosilicates X-ray irradiated at 4 K, 8 K, or 80 K. The nominally undoped Gd2SiO5 and (Lu,Gd)2SiO5 crystals, containing traces of Ce3+, Tb3+, and Eu3+ ions, and Ce3+-doped Gd2SiO5 and (Lu,Gd)2SiO5 crystals are studied. For the first time, the TSL glow curves of these materials are measured separately for the electron (intrinsic, Ce3+- or Tb3+-related) and hole (Eu3+-related) recombination luminescence, and the TSL glow curve peaks, arising from thermal decay of various electron …

Magnetron sputtering fabrication of α-Al2O3:Cr powders and their thermoluminescence properties

The authors gratefully acknowledge the financial support for this work from research grant ERA.NET RUS Plus Nr.609556.

Optical properties of plasma electrolytic oxidation coatings on aluminium alloy surface

Plazmas elektrolītiskā oksidēšana (PEO) ir process biezu (daži desmiti mikronu), cietu un ķīmiski izturīgu oksīdu pārklājumu veidošanai uz metāla virsmām. Šajā darbā pētīti PEO pārklājumu dažādi luminiscences īpašību aspekti. Pētītas gan pārklājumu iegūšanas procesa modificēšanas iespējas, gan iegūto pārklājumu praktiskie pielietojumi, īpašu uzmanību pievēršot korelācijai starp sintēzes parametriem un pārklājumu optiskajām īpašībām. Šajā pētījumā apskatītas trīs galvenās tēmas: 1) PEO pārklājumu aktivēšana ar piejaukumiem to luminiscences īpašību pētīšanai; 2) pārklājumu izgatavošana ar dozimetra īpašībām un to pielietojamības novērtēšana; 3) aktivēta stroncija alumināta kompleksā oksīda si…

Doped zirconia phase and luminescence dependence on the nature of charge compensation

Financial support provided by the Scientific Research Project for Students and Young Researchers Nr. SJZ2015/25 carried out at the Institute of Solid State Physics of the University of Latvia is greatly acknowledged.

Growth and characterization of PbI2-decorated ZnO nanowires for photodetection applications

Financial support provided by Scientific Research Project for Students and Young Researchers Nr. SJZ/2017/1 realized at the Institute of Solid State Physics, University of Latvia is greatly acknowledged. The authors are grateful to Liga Bikse for XRD measurements.

Comparative Study on Micromechanical Properties of ZnO:Ga and ZnO:In Luminiscent Ceramics

The research has been supported by the Project ERANET RUS_ST#2017-051(Latvia) and #18-52-76002 (Russia). The Institute of Solid State Physics, University of Latvia as the Centre of Excellence has received funding from the European Union’s Horizon 2020 Framework, Program H2020-WIDESPREAD-01-2016-2017-Teaming Phase 2 under grant agreement No. 739508, project CAMART2.

Niobium enhanced europium ion luminescence in hafnia nanocrystals

This work was supported by the UL ISSP grant for Scientific Research Projects for Students and Young Researchers SJZ/2016/15 .

Usability of Cr-Doped Alumina in Dosimetry

Dosimetry is a widespread material science field dealing with detection and quantification of ionizing radiation using electronic processes in materials. One of the main aspects that determines the performance of dosimeters is the type of defects the material contains. Crystalline lattice imperfections are formed around impurity ions, which may have a smaller or larger size, or different oxidation states compared to host ions. In this study, we show what effects Cr impurities have on the luminescent properties of alumina. Porous Al 2 O 3 : Cr microceramics synthesized using the sol-gel method showed a higher thermoluminescence response than a single crystal ruby. We have found that Cr 2 O 3…

Production of Phosphorescent Coatings on 6082 Aluminum Using Sr0.95Eu0.02Dy0.03Al2O4-δ Powder and Plasma Electrolytic Oxidation

In this study, a new approach for producing phosphorescent aluminum coatings was studied. Using the plasma electrolytic oxidation (PEO) process, a porous oxide coating was produced on the Al6082 aluminum alloy substrate. Afterwards, activated strontium aluminate (SrAl2O4: Eu2+, Dy3+) powder was filled into the cavities and pores of the PEO coating, which resulted in a surface that exhibits long-lasting luminescence. The structural and optical properties were studied using XRD, SEM, and photoluminescence measurements. It was found that the treatment time affects the morphology of the coating, which influences the amount of strontium aluminate powder that can be incorporated into the coating …

X-ray excited luminescence of SrAl2O4:Eu,Dy at low temperatures

This research project was supported financially by ERDF Project No 1.1.1.1/16/A/182.

Portable low-cost open-source wireless spectrophotometer for fast and reliable measurements

This article is based upon COST Action CA16215 and supported by the ERDF , European-Union Project No.1.1.1.2/16/I/001.

Rare earth doped glass–ceramics containing NaLaF4 nanocrystals

Abstract Oxyfluoride glasses 16Na 2 O–9NaF–5LaF 3 –7Al 2 O 3 –63SiO 2 (mol%) activated with 3% terbium, dysprosium, praseodymium and neodymium fluorides have been prepared and studied by differential thermal analysis, cathodoluminescence, X-ray induced luminescence, X-ray diffraction, scanning electron microscopy and energy dispersive X-ray spectroscopy. We found out that the presence of crystalline phase enhances the X-ray induced luminescence intensity. X-ray induced luminescence is the most intense for the sample activated with terbium and treated at 700 °C, whereas the praseodymium and neodymium activated samples have the fastest decay times.

Effect of Core–Shell Rubber Nanoparticles on the Mechanical Properties of Epoxy and Epoxy-Based CFRP

This research was funded by M-Era.Net project MERF “Matrix for carbon reinforced epoxy laminates with reduced flammability” grant No. 1.1.1.5/ERANET/20/04 from the Latvian State Education Development Agency and M-Era.Net project “EPIC—European Partnership for Improved Composites“ funded by grant No. TH06020001. A.S., K.S. and A.Z. are grateful to funding received from the European Union Horizon 2020 Framework program H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART2.

Synthesis of Eu<sup>2+</sup> and Dy<sup>3+</sup> Doped Strontium Aluminates and their Properties

Strontium aluminate phosphors were synthesized by the solution combustion method using citric acid, urea or glycine as reducing agent and europium and dysprosium as dopants. The content of both dopants was in the range of 1 – 2 mol%. Dependence of phase composition, crystallite size and specific surface area on calcinations temperature, used reducing agents and dopants were determined. Luminescent properties of the calcinated at 1300 °C powders contained SrAl2O4 (90 %) and Sr4Al24O25 (10%) phases with crystallite size of 80 nm were determined.

Effect of Mg 2+ ions co-doping on luminescence and defects formation processes in Gd 3 (Ga,Al) 5 O 12 :Ce single crystals

The work was supported by the Institutional Research Funding IUT02-26 of the Estonian Ministry of Education and Research and the project 16-15569S of the Czech Science Foundation.