scholarly journals The Effect of Ionising Radiation on the Luminescence Properties of Fluoroperovskites

2021 ◽  
Author(s):  
◽  
Joseph Schuyt
Keyword(s):  
Energy Levels ◽  
Thermal Quenching ◽  
Ionising Radiation ◽  
Luminescence Properties ◽  
Readout System ◽  
Tissue Equivalent ◽  
Potential Applications ◽  
Radiation Induced ◽  
Medical Dosimetry ◽  
Physical Phenomena

<p>The luminescence of crystalline compounds can be used to monitor many physical phenomena, including doses of ionising radiation. Optically stimulated luminescence (OSL), thermoluminescence (TL), and radiophotoluminescence (RPL) have been successfully employed in dosimetry. However, few materials possess both the structural and luminescence properties required for medical dosimetry. This thesis aimed to investigate the luminescence features of the class of compounds known as fluoroperovskites. Emphasis was placed on studying the effects of irradiation on the luminescence properties, such that the compounds could be evaluated regarding potential applications in clinical dosimetry. Samples were primarily characterised using photoluminescence (PL), radioluminescence (RL), OSL, RPL, TL, and transmittance spectroscopy.  OSL was observed in the majority of samples due to the existence of electron trapping F-type centres. F-centre/Mn complexes were observed in all AMgF3:Mn compounds after irradiation and the energy levels of the complexes in each compound were experimentally determined. The most promising potential dosimeter host material was the near tissue-equivalent NaMgF3. When doped with Mn2+, the compound exhibited RPL via the formation of F-centre/Mn complexes and OSL via several trapping centres. The RPL could be probed independently to the OSL such that the compound could function as a hybrid OSL/RPL dosimeter. In the NaMgF3:Ln compounds, RPL occurred via the radiation-induced reduction Ln3+ → Ln2+ for Ln = Sm, Dy, and Yb. The reduction Sm3+ → Sm2+ was highly stable and could be non-destructively probed independently to the OSL. The Sm doped compound also exhibited radiation-induced conductivity that could be coupled with the RL, such that the compound could function as a real-time hybrid optical/electrical dosimeter. Charge kinetics, thermal quenching, and binding energy models were developed and applied to the compounds.   Finally, a two-dimensional readout system was designed and constructed. The capabilities of the system were evaluated using the OSL of NaMgF3:Eu and NaMgF3:Mn. Sensitivities to doses from < 10 mGy to > 1 Gy were obtained along with sub-millimetre spatial resolutions.</p>

scholarly journals The Effect of Ionising Radiation on the Luminescence Properties of Fluoroperovskites

2021 ◽  
Author(s):  
◽  
Joseph Schuyt
Keyword(s):  
Energy Levels ◽  
Thermal Quenching ◽  
Ionising Radiation ◽  
Luminescence Properties ◽  
Readout System ◽  
Tissue Equivalent ◽  
Potential Applications ◽  
Radiation Induced ◽  
Medical Dosimetry ◽  
Physical Phenomena

<p>The luminescence of crystalline compounds can be used to monitor many physical phenomena, including doses of ionising radiation. Optically stimulated luminescence (OSL), thermoluminescence (TL), and radiophotoluminescence (RPL) have been successfully employed in dosimetry. However, few materials possess both the structural and luminescence properties required for medical dosimetry. This thesis aimed to investigate the luminescence features of the class of compounds known as fluoroperovskites. Emphasis was placed on studying the effects of irradiation on the luminescence properties, such that the compounds could be evaluated regarding potential applications in clinical dosimetry. Samples were primarily characterised using photoluminescence (PL), radioluminescence (RL), OSL, RPL, TL, and transmittance spectroscopy.  OSL was observed in the majority of samples due to the existence of electron trapping F-type centres. F-centre/Mn complexes were observed in all AMgF3:Mn compounds after irradiation and the energy levels of the complexes in each compound were experimentally determined. The most promising potential dosimeter host material was the near tissue-equivalent NaMgF3. When doped with Mn2+, the compound exhibited RPL via the formation of F-centre/Mn complexes and OSL via several trapping centres. The RPL could be probed independently to the OSL such that the compound could function as a hybrid OSL/RPL dosimeter. In the NaMgF3:Ln compounds, RPL occurred via the radiation-induced reduction Ln3+ → Ln2+ for Ln = Sm, Dy, and Yb. The reduction Sm3+ → Sm2+ was highly stable and could be non-destructively probed independently to the OSL. The Sm doped compound also exhibited radiation-induced conductivity that could be coupled with the RL, such that the compound could function as a real-time hybrid optical/electrical dosimeter. Charge kinetics, thermal quenching, and binding energy models were developed and applied to the compounds.   Finally, a two-dimensional readout system was designed and constructed. The capabilities of the system were evaluated using the OSL of NaMgF3:Eu and NaMgF3:Mn. Sensitivities to doses from < 10 mGy to > 1 Gy were obtained along with sub-millimetre spatial resolutions.</p>

scholarly journals Development and Characterization of Silver Containing Free Standing Polymer FILMS for Dosimetry Applications

Polymers ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 3925
Author(s):  
Mantvydas Merkis ◽  
Judita Puišo ◽  
Diana Adliene ◽  
Jurgita Laurikaitiene
Keyword(s):  
Silver Nanoparticles ◽  
X Rays ◽  
Free Standing ◽  
Gel Properties ◽  
Spectral Changes ◽  
Radiation Induced ◽  
Medical Dosimetry ◽  
Physical Phenomena ◽  
Environmentally Friendly Method

Polymer gels and films, due to their near equivalence to biological tissue, are amongst the most promising future dosimetry tools for medical applications. The application of polymer dose gels is limited by the sensitivity of dose readout methods and dose gel properties. It is a challenge to find suitable dosimeters for registration of doses delivered to the target by orthovoltage therapy units. The application of metal-particle-enriched polymer composites for dose registration in X-ray therapy might be an elegant solution, especially if recent dose-reading technologies exploring advantages of different physical phenomena are involved. In this work, X-rays from the orthovoltage therapy range were used for the irradiation of experimental samples. In addition, radiation-induced processes of formation of silver nanoparticles in AgNO3–PVA gels and in free standing AgNO3PVA films, also containing some additional solvents, namely glycerol, ethanol, and isopropanol, have been investigated, with the aim to apply the developed composites for medical dosimetry purposes. A simple and environmentally friendly method for the formation of free-standing AgPVA films at room temperature was proposed and realized for preparing AgPVA films for investigation. Radiation-induced synthesis of silver nanoparticles in AgPVA composites was investigated, analyzing LPSR-based UV-VIS spectral changes to the irradiated films with respect to irradiation doses, and dose-related tendencies were also evaluated. It was shown that AgPVA films were more sensitive for detection of doses from the interval 0–1.0 Gy, thus indicating potential application of AgPVA films for dosimetry purposes.

scholarly journals Enhanced luminescence properties of Ca1+xSr2−xAl2O6:Eu3+ (0 ≤ x ≤ 1) red phosphors based on composition modulation

RSC Advances ◽  
2021 ◽  
Vol 11 (21) ◽  
pp. 12981-12989
Author(s):  
Biao Shen ◽  
Jianghang Xu ◽  
Qinan Mao ◽  
Jiasong Zhong
Keyword(s):  
Optical Properties ◽  
Quantum Efficiency ◽  
Luminescence Properties ◽  
Composition Modulation ◽  
Red Phosphors ◽  
Potential Applications ◽  
Enhanced Luminescence

A series of Ca1+xSr2−xAl2O6:Eu3+ (0 ≤ x ≤ 1) red-emitting phosphors with adjustable optical properties and excellent quantum efficiency was developed for potential applications in warm WLEDs.

Radiation-induced enhancement of jasmonic acid levels

1994 ◽  
Vol 102 ◽  
pp. 303-306
Author(s):  
H. Sprinz ◽  
C. von Sonntag ◽  
U. Franck ◽  
O. Miersch ◽  
H. Dahlhelm
Keyword(s):  
Jasmonic Acid ◽  
Plant Hormone ◽  
Positive Stimulus ◽  
Ionising Radiation ◽  
Physiological Effects ◽  
Low Doses ◽  
Metabolic Processes ◽  
Radiation Induced ◽  
Response To Stress

In recent years, some experiments with low doses of ionising radiation have been performed, with reproducible results, which indicate a positive stimulus rather than a deletirious effect (Decker & Degner 1983; Wolff 1989).The aim of our own studies was to establish whether low doses of ionising radiation can influence metabolism by means of a modification of the concentration of a plant hormone, in this particular case jasmonate. The multiple physiological effects caused by the plant bioregulator jasmonate, including response to stress, suggest their essential involvement in central genetic and metabolic processes (Sembdner & Parthier 1993).

Effect of Different Catalysts and Growth Temperature on the Photoluminescence Properties of Zinc Silicate Nanostructures Grown via VLS Method

2021 ◽  
Author(s):  
Ghfoor Muhammad ◽  
Imran Murtaza ◽  
Rehan Abid ◽  
Naeem Ahmad
Keyword(s):  
Energy Levels ◽  
Visible Region ◽  
Wide Bandgap ◽  
Visible Spectral Range ◽  
Zinc Silicate ◽  
Band Spectrum ◽  
Photoluminescence Properties ◽  
Display Devices ◽  
Crystal Growth Kinetics ◽  
Potential Applications

Abstract Herein, we explore the photoluminescence properties of zinc silicate (Zn2SiO4) nanostructures synthesized by vapor-liquid-solid (VLS) mode of growth using three different catalysts (Sn, Ag and Mn). Different catalysts significantly influence the growth rate which in turn has an impact on the structure and hence the photoluminescence of the prepared zinc silicate nanostructures. Zn2SiO4 has a wide bandgap of about 5.5 eV and in its pure form, it does not emit in visible region due to its inner shell electronic transitions between the 3d5 energy levels. However, the incorporation of different catalysts (Sn, Ag and Mn) at different growth temperatures into the Zn2SiO4 crystal growth kinetics provides wide visible spectral range of photoluminescence (PL) emissions. PL analysis shows broad multi-band spectrum in the visible region and distinct colours (red, yellow, green, blue, cyan and violet) are obtained depending on the crystalline structure of the prepared nanostructures. The allowed transitions due to the effect of different catalysts on zinc silicate lattice offer a huge cross-section of absorption that generates strong photoluminescence. The correlation between the structural and optical properties of the synthesized nanostructures is discussed in detail. The synthesized photoluminescent nanostructures have potential applications in solid-state lighting and display devices.

Sensitivity and latency of ionising radiation-induced cataract

2021 ◽  
pp. 108772
Author(s):  
Elizabeth A. Ainsbury ◽  
StephenG.R. Barnard
Keyword(s):  
Ionising Radiation ◽  
Radiation Induced

Engineering Design as Research

2012 ◽  
pp. 1766-1779
Author(s):  
Timothy L.J. Ferris
Keyword(s):  
Decision Making ◽  
Research Projects ◽  
Design Work ◽  
Engineering Research ◽  
Is Research ◽  
New Knowledge ◽  
Potential Applications ◽  
Actual Design ◽  
Physical Phenomena ◽  
The Impact

Research is defined as an activity that creates new knowledge. This is often misunderstood in the engineering community as necessarily requiring a scientific contribution that advances the theory of some matter related to engineering materials or processes. Consequently, typical engineering research projects investigate physical phenomena thought likely to be interesting in potential applications or to describe the characteristics of processes used in engineering work. The results of such projects provide a fragmented, abstracted view of the phenomena investigated, which is difficult to use in engineering decision making related to contextualised situations. This chapter shows how the actual design of engineered artefacts is research because it provides knowledge of the impact of the integration of various elements of existing knowledge, which demonstrates the properties of the designs achieved through the design work and leads to discovery of solutions to the various challenges of integration discovered through the project which attempts to achieve the integration.

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