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.

Remote Measurements of X-Rays Dose Rate Using a Cerium-Doped Air-Clad Optical Fiber

2020 ◽  
Vol 67 (7) ◽  
pp. 1658-1662
Author(s):  
Jessica Bahout ◽  
Youcef Ouerdane ◽  
Hicham El Hamzaoui ◽  
Geraud Bouwmans ◽  
Mohamed Bouazaoui ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Dose Rate ◽  
X Rays ◽  
Remote Measurements

Optically Stimulated Luminescence Analysis Method for High Dose Rate Using an Optical Fiber Type Dosimeter

2016 ◽  
Vol 63 (4) ◽  
pp. 2262-2270 ◽  
Author(s):  
Katsunori Ueno ◽  
Kazuo Tominaga ◽  
Takahiro Tadokoro ◽  
Koji Ishizawa ◽  
Yoshinori Takahashi ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Dose Rate ◽  
Fiber Type ◽  
High Dose Rate ◽  
Optically Stimulated Luminescence ◽  
High Dose ◽  
Analysis Method ◽  
Luminescence Analysis

X-Rays, $\gamma$ -Rays, and Proton Beam Monitoring With Multimode Nitrogen-Doped Optical Fiber

2019 ◽  
Vol 66 (1) ◽  
pp. 306-311 ◽  
Author(s):  
S. Girard ◽  
D. Di Francesca ◽  
A. Morana ◽  
C. Hoehr ◽  
P. Paillet ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Proton Beam ◽  
X Rays ◽  
Nitrogen Doped ◽  
Beam Monitoring

scholarly journals First demonstration of the FLASH effect with ultrahigh dose rate high-energy X-rays

2021 ◽  
Author(s):  
Feng Gao ◽  
Yiwei Yang ◽  
Hongyu Zhu ◽  
JianXin Wang ◽  
Dexin Xiao ◽  
...  
Keyword(s):  
Dose Rate ◽  
High Energy ◽  
X Rays

scholarly journals First demonstration of the FLASH effect with ultrahigh dose-rate high energy X-rays

2020 ◽  
Author(s):  
Feng Gao ◽  
Yiwei Yang ◽  
Hongyu Zhu ◽  
JianXin Wang ◽  
Dexin Xiao ◽  
...  
Keyword(s):  
Dose Rate ◽  
Cellular Response ◽  
High Energy ◽  
Current Transformer ◽  
Radiochromic Film ◽  
Tumor Control ◽  
Deep Penetration ◽  
X Rays ◽  
Preclinical Research

ABSTRACTThe ultrahigh dose-rate (FLASH) radiotherapy, which is efficient in tumor control while sparing healthy tissue, has attracted intensive attention due to its revolutionary application prospect. This so-called FLASH effect has been reported in preclinical experiments with electrons, kilo-voltage X-rays, and protons, thus making FLASH a promising revolutionary radiotherapy modality. High energy X-ray (HEX) should be the ideal radiation type for clinical applications of FLASH due to its advantages in deep penetration, small divergence, and cost-friendly. In this work, we report the first implementation of HEXs with ultrahigh dose-rate (HEX-FLASH) and corresponding application of in vivo study of the FLASH effect produced by a high-current (10 mA), high-energy (6-8 MeV) superconducting linac. Joint measurements using radiochromic film, scintillator and Fast Current Transformer device validated that a maximum dose rate of over 1000 Gy/s was achieved in the mice and the mean value within several square centimeters keeps higher than 50 Gy/s within a depth of over 15 cm. The performance of the present HEX can satisfy the requirement of the FLASH study on animals. Breast cancer (EMT6) inoculated into BAL b/c mice was found efficiently controlled by HEX-FLASH. The radio-protective effect of normal tissue was observed on the C57BL/6 mice after thorax/abdomen irradiation by HEX-FLASH. Theoretical analyses of cellular response following HEX-FLASH irradiation based on the radiolytic oxygen depletion hypothesis were performed to interpret experimental results and future experiment design. This work provided the first demonstration of the FLASH effect triggered by HEX, which paved the way for future preclinical research and clinical application of HEX-FLASH.

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 Comparative intranight optical variability of X-ray and γ-ray-detected narrow-line Seyfert 1 galaxies

2020 ◽  
Vol 493 (3) ◽  
pp. 3642-3655 ◽  
Author(s):  
Vineet Ojha ◽  
Hum Chand ◽  
Gopal Krishna ◽  
Sapna Mishra ◽  
Krishan Chand
Keyword(s):  
Duty Cycle ◽  
High Energy ◽  
Minor Role ◽  
Optical Variability ◽  
X Rays ◽  
Narrow Line ◽  
X Ray ◽  
Γ Rays ◽  
Γ Ray ◽  
A Minor

ABSTRACT In a systematic program to characterize the intranight optical variability (INOV) of different classes of narrow-line Seyfert 1 (NLSy1s) galaxies, we report here the first comparative INOV study of NLSy1 sets detected in the X-ray and γ-ray bands. Our sample consists of 18 sources detected in X-rays but not in γ-rays (hereafter x_NLSy1s) and seven sources detected in γ-rays (hereafter g_NLSy1s), out of which five are detected also in X-rays. We have monitored these two sets of NLSy1s, respectively, in 24 and 21 sessions of a minimum of 3-h duration each. The INOV duty cycles for these two sets are found to be 12 per cent and 53 per cent, respectively (at a 99 per cent confidence level). In the set of 18 x_NLSy1s, INOV duty cycle is found to be zero for the 13 radio-quiet members (monitored in 14 sessions) and 43 per cent for the five radio-loud members (10 sessions). The latter is very similar to the aforementioned duty cycle of 53 per cent found here for the set of g_NLSy1s (all of which are radio-loud). Thus, it appears that the radio-loudness level is the prime factor behind the INOV detection and the pattern of the high-energy radiation plays only a minor role.

The Basic Physical Principles of Ion, Electron, and X-Ray Detectors and Their Application to Microanalysis

1985 ◽  
Vol 43 ◽  
pp. 154-157
Author(s):  
A.J. Tousimis
Keyword(s):  
Ion Beam ◽  
Depth Resolution ◽  
Sample Surface ◽  
High Energy ◽  
X Rays ◽  
X Ray ◽  
Electrons And Ions ◽  
Spatial Depth ◽  
Minimum Surface Area ◽  
Physical Principles

An integral and of prime importance of any microtopography and microanalysis instrument system is its electron, x-ray and ion detector(s). The resolution and sensitivity of the electron microscope (TEM, SEM, STEM) and microanalyzers (SIMS and electron probe x-ray microanalyzers) are closely related to those of the sensing and recording devices incorporated with them.Table I lists characteristic sensitivities, minimum surface area and depth analyzed by various methods. Smaller ion, electron and x-ray beam diameters than those listed, are possible with currently available electromagnetic or electrostatic columns. Therefore, improvements in sensitivity and spatial/depth resolution of microanalysis will follow that of the detectors. In most of these methods, the sample surface is subjected to a stationary, line or raster scanning photon, electron or ion beam. The resultant radiation: photons (low energy) or high energy (x-rays), electrons and ions are detected and analyzed.

scholarly journals Hierarchical Porous, N-Containing Carbon Supports for High Loading Sulfur Cathodes

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 408
Author(s):  
Jae-Woo Park ◽  
Hyun Jin Hwang ◽  
Hui-Ju Kang ◽  
Gazi A. K. M. Rafiqul Bari ◽  
Tae-Gyu Lee ◽  
...  
Keyword(s):  
High Energy ◽  
High Energy Density ◽  
High Loading ◽  
Carbon Supports ◽  
Structure Directing Agent ◽  
Shuttle Effect ◽  
Main Challenge ◽  
Hierarchical Porous ◽  
Hollow Carbon ◽  
A Minor

The lithium-polysulfide (LiPS) dissolution from the cathode to the organic electrolyte is the main challenge for high-energy-density lithium-sulfur batteries (LSBs). Herein, we present a multi-functional porous carbon, melamine cyanurate (MCA)-glucose-derived carbon (MGC), with superior porosity, electrical conductivity, and polysulfide affinity as an efficient sulfur support to mitigate the shuttle effect. MGC is prepared via a reactive templating approach, wherein the organic MCA crystals are utilized as the pore-/micro-structure-directing agent and nitrogen source. The homogeneous coating of spherical MCA crystal particles with glucose followed by carbonization at 600 °C leads to the formation of hierarchical porous hollow carbon spheres with abundant pyridinic N-functional groups without losing their microstructural ordering. Moreover, MGC enables facile penetration and intensive anchoring of LiPS, especially under high loading sulfur conditions. Consequently, the MGC cathode exhibited a high areal capacity of 5.79 mAh cm−2 at 1 mA cm−2 and high loading sulfur of 6.0 mg cm−2 with a minor capacity decay rate of 0.18% per cycle for 100 cycles.

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