scholarly journals Investigation of the Incorporation of Cerium Ions in MCVD-Silica Glass Preforms for Remote Optical Fiber Radiation Dosimetry

Sensors ◽  
2021 ◽  
Vol 21 (10) ◽  
pp. 3362
Author(s):  
Monika Cieslikiewicz-Bouet ◽  
Hicham El Hamzaoui ◽  
Youcef Ouerdane ◽  
Rachid Mahiou ◽  
Geneviève Chadeyron ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Dose Rate ◽  
Silica Glass ◽  
Radiation Dosimetry ◽  
Chemical Vapor ◽  
Core Diameter ◽  
X Ray ◽  
Reducing Atmosphere ◽  
Sensing Applications ◽  
Linear Behavior

The incorporation of Ce3+ ions in silicate glasses is a crucial issue for luminescence-based sensing applications. In this article, we report on silica glass preforms doped with cerium ions fabricated by modified chemical vapor deposition (MCVD) under different atmospheres in order to favor the Ce3+ oxidation state. Structural analysis and photophysical investigations are performed on the obtained glass rods. The preform fabricated under reducing atmosphere presents the highest photoluminescence (PL) quantum yield (QY). This preform drawn into a 125 µm-optical fiber, with a Ce-doped core diameter of about 40 µm, is characterized to confirm the presence of Ce3+ ions inside this optical fiber core. The fiber is then tested in an all-fibered X-ray dosimeter configuration. We demonstrate that this fiber allows the remote monitoring of the X-ray dose rate (flux) through a radioluminescence (RL) signal generated around 460 nm. The response dependence of RL versus dose rate exhibits a linear behavior over five decades, at least from 330 µGy(SiO2)/s up to 22.6 Gy(SiO2)/s. These results attest the potentialities of the MCVD-made Ce-doped material, obtained under reducing atmosphere, for real-time remote ionizing radiation dosimetry.

scholarly journals Cu/Ce-co-Doped Silica Glass as Radioluminescent Material for Ionizing Radiation Dosimetry

Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2611
Author(s):  
Jessica Bahout ◽  
Youcef Ouerdane ◽  
Hicham El Hamzaoui ◽  
Géraud Bouwmans ◽  
Mohamed Bouazaoui ◽  
...  
Keyword(s):  
Dose Rate ◽  
Silica Glass ◽  
Energy Levels ◽  
Sol Gel ◽  
Radiation Detection ◽  
Optical Signal ◽  
X Ray ◽  
Dose Rates ◽  
Integrated Intensities ◽  
Co Doped

Optically activated glasses are essential to the development of new radiation detection systems. In this study, a bulk glassy rod co-doped with Cu and Ce ions, was prepared via the sol-gel technique and was drawn at about 2000 °C into a cylindrical capillary rod to evaluate its optical and radioluminescence properties. The sample showed optical absorption and photoluminescence (PL) bands attributed to Cu+ and Ce3+ ions. The presence of these two ions inside the host silica glass matrix was also confirmed using PL kinetics measurements. The X-ray dose rate was remotely monitored via the radioluminescence (RL) signal emitted by the Cu/Ce scintillating sensor. In order to transport the optical signal from the irradiation zone to the detection located in the instrumentation zone, an optical transport fiber was spliced to the sample under test. This RL signal exhibited a linear behavior regarding the dose rate in the range at least between 1.1 mGy(SiO2)/s and 34 Gy(SiO2)/s. In addition, a spectroscopic analysis of this RL signal at different dose rates revealed that the same energy levels attributed to Cu+ and Ce3+ ions are involved in both the RL mechanism and the PL phenomenon. Moreover, integrated intensities of the RL sub-bands related to both Cu+ and Ce3+ ions depend linearly on the dose rate at least in the investigated range from 102 mGy(SiO2)/s up to 4725 mGy(SiO2)/s. The presence of Ce3+ ions also reduces the formation of HC1 color centers after X-ray irradiation.

scholarly journals Optical responses of a copper-activated sol-gel silica glass under low-dose and low-dose rate X-ray exposures

OSA Continuum ◽  
2019 ◽  
Vol 2 (3) ◽  
pp. 563 ◽  
Author(s):  
N. Al Helou ◽  
H. El Hamzaoui ◽  
B. Capoen ◽  
G. Bouwmans ◽  
A. Cassez ◽  
...  
Keyword(s):  
Dose Rate ◽  
Silica Glass ◽  
Low Dose ◽  
Sol Gel ◽  
X Ray ◽  
Low Dose Rate ◽  
Optical Responses

Thermoluminescence of Cu-Doped Li2B4O7 + PTFE Annealed by Graphene Exposed to X-Rays and Gamma Radiation

2020 ◽  
pp. 2050005
Author(s):  
Swarnapriya Thiyagarajan ◽  
M. A. Vallejo ◽  
P. Cerón ◽  
C. Gomez-Solis ◽  
C. Wiechers ◽  
...  
Keyword(s):  
Heating Rate ◽  
X Rays ◽  
X Ray Diffraction ◽  
Medical Field ◽  
X Ray ◽  
Reducing Atmosphere ◽  
Linear Behavior ◽  
Good Potential ◽  
Average Size ◽  
Therapy Treatment

Lithium tetraborate (LTB) was doped with copper (0.1%) to enhance the LTB thermoluminescent (TL) properties. A graphene reducing atmosphere was used to increase the vacancies of oxygen in the crystalline structure. LTB:Cu [Formula: see text] PTFE (polytetrafluoroethylene) pellets were prepared by mixing the Li2B4O7:Cu with PTFE in a 4:1 ratio. The obtained materials were characterized by X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). Crystals of Li2B4O7 with the average size of 134[Formula: see text]nm were obtained. The presence of copper was confirmed by SEM. The TL response of LTB:Cu PTFE pellets was studied with [Formula: see text] radiation by using a [Formula: see text]Co source. TTL response shows a linear behavior depending on the radiation dose. The effect of annealing time on TL glow curve was analyzed from 2[Formula: see text]h to 10[Formula: see text]h by irradiating with X-rays. The effect of mass on the TL response was studied varying the mass of the sample from 10[Formula: see text]mg to 50[Formula: see text]mg. From various heating rate studies, it was observed that the TL intensity increased when heating rate was gradually increased. The kinetic parameters were calculated by using computer deconvolution methods. The dosimetric property results showed that this material could have good potential application in a radiation dosimeter for radiation therapy treatment in the medical field.

scholarly journals Optical Fiber-Based Monitoring of X-ray Pulse Series from a Linear Accelerator

Radiation ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 17-32
Author(s):  
Jeoffray Vidalot ◽  
Adriana Morana ◽  
Hicham El Hamzaoui ◽  
Aziz Boukenter ◽  
Geraud Bouwmans ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Dose Rate ◽  
Fiber Type ◽  
Sol Gel ◽  
High Energy ◽  
Light Transport ◽  
X Rays ◽  
Core Diameter ◽  
A Minor ◽  
Beam Monitoring

We investigated in this work the radioluminescence properties of a Ce-doped multimode silica-based optical fiber (core diameter of 50 µm) manufactured by the sol–gel technique when exposed to the high-energy X-rays (~600 keV) of the ORIATRON facility of CEA. We demonstrated its potential to monitor in real-time the beam characteristics of this facility that can either operate in a pulsed regime (pulse duration of 4.8 µs, maximum repetition rate of 250 Hz) or in a quasi-continuous mode. The radiation-induced emission (radioluminescence and a minor Cerenkov contribution) linearly grew with the dose rate in the 15–130 mGy(SiO2)/s range, and the afterglow measured after each pulse was sufficiently limited to allow a clear measurement of pulse trains. A sensor with ~11 cm of sensitive Ce-doped fiber spliced to rad-hard fluorine-doped optical fiber, for the emitted light transport to the photomultiplier tube, exhibited interesting beam monitoring performance, even if the Cerenkov emission in the transport fiber was also considered (~5% of the signal). The beam monitoring potential of this class of optical fiber was demonstrated for such facilities and the possibilities of extending the dose rate range are discussed based on possible architecture choices such as fiber type, length or size.

Ablation Process of Silica Glass Induced by Laser Plasma Soft X-ray Irradiation

2009 ◽  
Vol 129 (4) ◽  
pp. 595-600
Author(s):  
Tetsuya Makimura ◽  
Takashige Fujimori ◽  
Shuichi Torii ◽  
Hiroyuki Niino ◽  
Kouichi Murakami
Keyword(s):  
Laser Plasma ◽  
Silica Glass ◽  
Ablation Process ◽  
X Ray

Interactions of Ge Atoms with High- ê Oxide Dielectric Surfaces

2005 ◽  
Vol 879 ◽  
Author(s):  
Scott K. Stanley ◽  
John G. Ekerdt
Keyword(s):  
Oxide Layer ◽  
Photoelectron Spectroscopy ◽  
Chemical Vapor ◽  
Temperature Programmed Desorption ◽  
Tungsten Filament ◽  
X Ray ◽  
Dielectric Surfaces ◽  
Temperature Programmed ◽  
The Stability ◽  
Ge Nanocrystals

AbstractGe is deposited on HfO2 surfaces by chemical vapor deposition (CVD) with GeH4. 0.7-1.0 ML GeHx (x = 0-3) is deposited by thermally cracking GeH4 on a hot tungsten filament. Ge oxidation and bonding are studied at 300-1000 K with X-ray photoelectron spectroscopy (XPS). Ge, GeH, GeO, and GeO2 desorption are measured with temperature programmed desorption (TPD) at 400-1000 K. Ge initially reacts with the dielectric forming an oxide layer followed by Ge deposition and formation of nanocrystals in CVD at 870 K. 0.7-1.0 ML GeHx deposited by cracking rapidly forms a contacting oxide layer on HfO2 that is stable from 300-800 K. Ge is fully removed from the HfO2 surface after annealing to 1000 K. These results help explain the stability of Ge nanocrystals in contact with HfO2.

Low Molecular Weight Microfibers with Light Sensing Properties

2017 ◽  
Vol 54 (4) ◽  
pp. 655-658
Author(s):  
Andrei Bejan ◽  
Dragos Peptanariu ◽  
Bogdan Chiricuta ◽  
Elena Bicu ◽  
Dalila Belei
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight ◽  
X Ray Diffraction ◽  
Aromatic Rings ◽  
X Ray ◽  
Force Microscopy ◽  
Light Sensing ◽  
Sensing Applications ◽  
Atomic Force ◽  
Low Molecular Weight Compounds

Microfibers were obtained from organic low molecular weight compounds based on heteroaromatic and aromatic rings connected by aliphatic spacers. The obtaining of microfibers was proved by scanning electron microscopy. The deciphering of the mechanism of microfiber formation has been elucidated by X-ray diffraction, infrared spectroscopy, and atomic force microscopy measurements. By exciting with light of different wavelength, florescence microscopy revealed a specific optical response, recommending these materials for light sensing applications.

Nitrogen (N2) Implantation to Suppress Growth of Interfacial Oxide in Mocvd Bst and Sputtered Bst Films

1999 ◽  
Vol 567 ◽  
Author(s):  
Renee Nieh ◽  
Wen-Jie Qi ◽  
Yongjoo Jeon ◽  
Byoung Hun Lee ◽  
Aaron Lucas ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Interfacial Layer ◽  
Gate Dielectric ◽  
Nitrogen Concentration ◽  
Chemical Vapor ◽  
Future Generation ◽  
Oxide Thickness ◽  
Layer Growth ◽  
X Ray ◽  
Bst Films

ABSTRACTBa0.5Sr0.5TiO3 (BST) is one of the high-k candidates for replacing SiO2 as the gate dielectric in future generation devices. The biggest obstacle to scaling the equivalent oxide thickness (EOT) of BST is an interfacial layer, SixOy, which forms between BST and Si. Nitrogen (N2) implantation into the Si substrate has been proposed to reduce the growth of this interfacial layer. In this study, capacitors (Pt/BST/Si) were fabricated by depositing thin BST films (50Å) onto N2 implanted Si in order to evaluate the effects of implant dose and annealing conditions on EOT. It was found that N2 implantation reduced the EOT of RF magnetron sputtered and Metal Oxide Chemical Vapor Deposition (MOCVD) BST films by ∼20% and ∼33%, respectively. For sputtered BST, an implant dose of 1×1014cm−;2 provided sufficient nitrogen concentration without residual implant damage after annealing. X-ray photoelectron spectroscopy data confirmed that the reduction in EOT is due to a reduction in the interfacial layer growth. X-ray diffraction spectra revealed typical polycrystalline structure with (111) and (200) preferential orientations for both films. Leakage for these 50Å BST films is on the order of 10−8 to 10−5 A/cm2—lower than oxynitrides with comparable EOTs.

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