scholarly journals Dosimetry with gafchromic films based on a new micro-opto-electro-mechanical system

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
C. Guardiola ◽  
A. Márquez ◽  
M. C. Jiménez-Ramos ◽  
J. García López ◽  
A. Baratto-Roldán ◽  
...  
Keyword(s):  
Mechanical System ◽  
Real Time ◽  
Optical Measurements ◽  
Radiochromic Film ◽  
Light Emitting ◽  
Radiochromic Films ◽  
New Device ◽  
Active Sensor ◽  
Gafchromic Films

AbstractThis work presents the first tests performed with radiochromic films and a new Micro‒Opto‒Electro-Mechanical system (MOEMS) for in situ dosimetry evaluation in radiotherapy in real time. We present a new device and methodology that overcomes the traditional limitation of time-delay in radiochromic film analysis by turning a passive detector into an active sensor. The proposed system consists mainly of an optical sensor based on light emitting diodes and photodetectors controlled by both customized electronic circuit and graphical user interface, which enables optical measurements directly. We show the first trials performed in a low‒energy proton cyclotron with this MOEMS by using gafchromic EBT3 films. Results show the feasibility of using this system for in situ dose evaluations. Further adaptation is ongoing to develop a full real‒time active detector by integrating MOEM multi‒arrays and films in flexible printed circuits. Hence, we point to improve the clinical application of radiochromic films with the aim to optimize radiotherapy treatment verifications.

scholarly journals Absolute calibration for film dosimetry

2020 ◽  
Vol 50 ◽  
pp. 2060012
Author(s):  
Pierluigi Casolaro ◽  
Luigi Campajola ◽  
Giovanni Breglio ◽  
Salvatore Buontempo ◽  
Marco Consales ◽  
...  
Keyword(s):  
Real Time ◽  
Spectral Response ◽  
Logistic Equation ◽  
Radiochromic Film ◽  
Absolute Calibration ◽  
Calibration Function ◽  
Film Dosimetry ◽  
Radiochromic Films ◽  
Film Reading ◽  
Kinetics Of

Recent results in the field of film dosimetry demonstrated that the Green–Saunders equation, a solution of the logistic equation describing phenomena of kinetics of chemical reactions, is the absolute calibration function for all radiochromic film types. Taking advantage of the new opto-electronics-based radiochromic film reading method, which allows real-time measurements of the spectral response of radiochromic films, we confirm that the film darkening is ruled by the Green–Saunders equation independently both from the reading instrument or the choice of the observable used for the calibration. In order to demonstrate it, we exposed an XR-QA2 Gafchromic film to 90Sr/90Y beta rays up to 1400 mGy. Film spectra are recorded in real-time. The calibration is performed by means of two analytic methods: evaluation of the integral under the curves from 500 nm to 645 nm and evaluation of the intensity at 570, 600 and 643 nm. Experimental data fit to the Green–Saunders equation for both methods.

Modeling and Validation of Sensor and Actuator Dynamics for, And Real-Time Feedback Control of Thermal Chlorine Etching of Gallium Arsenide

1999 ◽  
Vol 569 ◽  
Author(s):  
I. G. Rosen ◽  
T. Parent ◽  
R. Mancera ◽  
P. Chen ◽  
A. Madhukar
Keyword(s):  
Gallium Arsenide ◽  
Real Time ◽  
Optical Measurements ◽  
Etch Depth ◽  
Linear Quadratic ◽  
Feedback Controllers ◽  
Actuator Dynamics ◽  
Primary Motivation ◽  
Design And Testing

ABSTRACTA dynamic model for the simulation of thermal chlorine etching of gallium arsenide is developed. The primary motivation for the development of the model is the design and testing of real time feedback controllers which rely upon in-situ optical measurements of etch depth obtained via spectroscopic ellipsometry. Unmeasurable parameters which appear in the model are identified, and the model is validated using experimental data. A linear-quadratic controller based on our model is designed and tested.

Probing the Dynamic Self-Assembly Behaviour of Photoswitchable Wormlike Micelles in Real Time

2018 ◽  
Author(s):  
Elaine A. Kelly ◽  
Judith E. Houston ◽  
Rachel Evans
Keyword(s):  
Real Time ◽  
Absorption Spectroscopy ◽  
Self Assembly ◽  
Uv Light ◽  
Wormlike Micelles ◽  
Tetraethylene Glycol ◽  
Light Illumination ◽  
First Time ◽  
Dependent Processes

Understanding the dynamic self-assembly behaviour of azobenzene photosurfactants (AzoPS) is crucial to advance their use in controlled release applications such as<i></i>drug delivery and micellar catalysis. Currently, their behaviour in the equilibrium <i>cis-</i>and <i>trans</i>-photostationary states is more widely understood than during the photoisomerisation process itself. Here, we investigate the time-dependent self-assembly of the different photoisomers of a model neutral AzoPS, <a>tetraethylene glycol mono(4′,4-octyloxy,octyl-azobenzene) </a>(C<sub>8</sub>AzoOC<sub>8</sub>E<sub>4</sub>) using small-angle neutron scattering (SANS). We show that the incorporation of <i>in-situ</i>UV-Vis absorption spectroscopy with SANS allows the scattering profile, and hence micelle shape, to be correlated with the extent of photoisomerisation in real-time. It was observed that C<sub>8</sub>AzoOC<sub>8</sub>E<sub>4</sub>could switch between wormlike micelles (<i>trans</i>native state) and fractal aggregates (under UV light), with changes in the self-assembled structure arising concurrently with changes in the absorption spectrum. Wormlike micelles could be recovered within 60 seconds of blue light illumination. To the best of our knowledge, this is the first time the degree of AzoPS photoisomerisation has been tracked <i>in</i><i>-situ</i>through combined UV-Vis absorption spectroscopy-SANS measurements. This technique could be widely used to gain mechanistic and kinetic insights into light-dependent processes that are reliant on self-assembly.

Flat Flexible Thin Milli-electrode Array for Real-time in situ Water Quality Monitoring in Distribution Systems

2017 ◽  
Vol 2017 (4) ◽  
pp. 5598-5617
Author(s):  
Zhiheng Xu ◽  
Wangchi Zhou ◽  
Qiuchen Dong ◽  
Yan Li ◽  
Dingyi Cai ◽  
...  
Keyword(s):  
Water Quality ◽  
Real Time ◽  
Distribution Systems ◽  
Electrode Array ◽  
Water Quality Monitoring ◽  
Quality Monitoring

scholarly journals Underground Microseismic Event Monitoring and Localization within Sensor Networks

Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2830
Author(s):  
Sili Wang ◽  
Mark P. Panning ◽  
Steven D. Vance ◽  
Wenzhan Song
Keyword(s):  
Sensor Networks ◽  
Real Time ◽  
Information Needs ◽  
Localization Algorithm ◽  
Distributed Sensors ◽  
Distributed Sensor ◽  
Microseismic Events ◽  
The Stability ◽  
Stability And Accuracy

Locating underground microseismic events is important for monitoring subsurface activity and understanding the planetary subsurface evolution. Due to bandwidth limitations, especially in applications involving planetarily-distributed sensor networks, networks should be designed to perform the localization algorithm in-situ, so that only the source location information needs to be sent out, not the raw data. In this paper, we propose a decentralized Gaussian beam time-reverse imaging (GB-TRI) algorithm that can be incorporated to the distributed sensors to detect and locate underground microseismic events with reduced usage of computational resources and communication bandwidth of the network. After the in-situ distributed computation, the final real-time location result is generated and delivered. We used a real-time simulation platform to test the performance of the system. We also evaluated the stability and accuracy of our proposed GB-TRI localization algorithm using extensive experiments and tests.

scholarly journals An Autonomous Platform for Near Real-Time Surveillance of Harmful Algae and Their Toxins in Dynamic Coastal Shelf Environments

2021 ◽  
Vol 9 (3) ◽  
pp. 336
Author(s):  
Stephanie K. Moore ◽  
John B. Mickett ◽  
Gregory J. Doucette ◽  
Nicolaus G. Adams ◽  
Christina M. Mikulski ◽  
...  
Keyword(s):  
Real Time ◽  
Domoic Acid ◽  
Harmful Algae ◽  
Coastal Trapped Waves ◽  
Resource Managers ◽  
Bloom Formation ◽  
High Concentrations ◽  
Data Gap ◽  
Autonomous Technology

Efforts to identify in situ the mechanisms underpinning the response of harmful algae to climate change demand frequent observations in dynamic and often difficult to access marine and freshwater environments. Increasingly, resource managers and researchers are looking to fill this data gap using unmanned systems. In this study we integrated the Environmental Sample Processor (ESP) into an autonomous platform to provide near real-time surveillance of harmful algae and the toxin domoic acid on the Washington State continental shelf over a three-year period (2016–2018). The ESP mooring design accommodated the necessary subsystems to sustain ESP operations, supporting deployment durations of up to 7.5 weeks. The combination of ESP observations and a suite of contextual measurements from the ESP mooring and a nearby surface buoy permitted an investigation into toxic Pseudo-nitzschia spp. bloom dynamics. Preliminary findings suggest a connection between bloom formation and nutrient availability that is modulated by wind-forced coastal-trapped waves. In addition, high concentrations of Pseudo-nitzschia spp. and elevated levels of domoic acid observed at the ESP mooring location were not necessarily associated with the advection of water from known bloom initiation sites. Such insights, made possible by this autonomous technology, enable the formulation of testable hypotheses on climate-driven changes in HAB dynamics that can be investigated during future deployments.

scholarly journals Dimension control of in situ fabricated CsPbClBr2 nanocrystal films toward efficient blue light-emitting diodes

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Chenhui Wang ◽  
Dengbao Han ◽  
Junhui Wang ◽  
Yingguo Yang ◽  
Xinyue Liu ◽  
...  
Keyword(s):  
Quantum Well ◽  
Light Emitting Diodes ◽  
Blue Emission ◽  
Light Emitting ◽  
Mixed Ligands ◽  
Dimension Control ◽  
Nanocrystal Films ◽  
Width Distribution ◽  
Quantum Well Width

AbstractIn the field of perovskite light-emitting diodes (PeLEDs), the performance of blue emissive electroluminescence devices lags behind the other counterparts due to the lack of fabrication methodology. Herein, we demonstrate the in situ fabrication of CsPbClBr2 nanocrystal films by using mixed ligands of 2-phenylethanamine bromide (PEABr) and 3,3-diphenylpropylamine bromide (DPPABr). PEABr dominates the formation of quasi-two-dimensional perovskites with small-n domains, while DPPABr induces the formation of large-n domains. Strong blue emission at 470 nm with a photoluminescence quantum yield up to 60% was obtained by mixing the two ligands due to the formation of a narrower quantum-well width distribution. Based on such films, efficient blue PeLEDs with a maximum external quantum efficiency of 8.8% were achieved at 473 nm. Furthermore, we illustrate that the use of dual-ligand with respective tendency of forming small-n and large-n domains is a versatile strategy to achieve narrow quantum-well width distribution for photoluminescence enhancement.

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