Abstract
Radiation monitoring using ionisation chambers spans a wide spectrum of radiation fields from environmental monitors to ambient dose monitors near particle accelerators. Hence the output ...generated by these sensors can vary from few femtoamperes to microamperes. They require specific front-end electronics that can accurately measure the generated current across a wide dynamic range. This work presents the design of an ASIC that can measure currents from −6 fA to −20 μA without any band switching. By employing two different current measurement methodologies — direct slope measurement method and charge balancing based current to frequency converter method, an accuracy of ±6% is achieved across the entire measurement range. The ASIC was fabricated in the 8 inch fab of TSMC 130 nm technology. The designed ASIC aims to replace the front end electronics of radiation monitors at CERN.
The W-MON project aims to improve and automatize the control of the presence of radioactive material in conventional waste containers at CERN using a distributed network of interconnected low-power ...radiation sensors. The key development is the integration of a lightweight but sensitive radiation sensor in a powerful network that allows continuous data recording, transfer and storage in a database for alarm triggering and subsequent data analysis. The Chiyoda D-shuttle personal dosimeter was used as proof-of-concept. Extensive tests performed with the commercial version of the D-shuttle showed that its robustness, stability under variable thermal conditions, high sensitivity and hourly dose logging capabilities make it a strong candidate for the project. To comply with the requirements of remote operation and wireless data transmission to a central server, a customized version of the D-shuttle has been developed. Two additional radiation sensors are also currently being considered. The sensors have been coupled to a custom-made communication board allowing for long-range low-power LoRa wireless data transmission. A centralized IoT (Internet of Things) end-to-end data architecture has been developed for real-time monitoring and visualization of the radiation level in waste containers before the final integration into REMUS, the overall CERN Radiation and Environment Monitoring Unified Supervision service.
•Environmental radiological monitoring for conventional waste.•Lightweight and smart radiation sensors for real-time monitoring of the radiation level in waste containers.•Distributed network of interconnected low-power radiation sensors with LoRa wireless data transmission.
CERN's new generation of radiation monitoring devices for radiation protection, CROME (CERN RadiatiOn Monitoring Electronics) uses a fully reconfigurable 28 nm Xilinx Zynq SoC (System on Chip) for ...high-end embedded calculations, communication and data storage. In order to meet stringent safety requirements applicable for radiation protection instrumentation, CROME uses the FPGA section of the SoC for all safety critical functions. Whereas the SoC's dual core ARM processor is running an embedded operating system which is used both for communication with the CERN supervisory system and for data management. Due to the use of an embedded Linux OS without a virtualisation layer, the functional reliability of the SoC's FPGA section is considered much greater than the ARM processing system which can be subject to software crashes due to data corruption. This assumption had a central role in CROME's calculation architecture. In order to confirm the assumption and therefore the reliability and robustness of our design, random faults have been voluntarily induced in the SoC by exposing it to ionising radiation of sufficient energy in the CHARM facility, creating Single Event Upsets (SEU). CROME is the first known radiation monitoring system using the FPGA section of a SoC in a safety application. This paper presents the characterisation results of the system in the CHARM facility during a testing campaign of 6 months under an average dose rate of ≥0.1 Gy/day. The tests have provided valuable information on the suitability of this architecture for similar applications.
•It has been confirmed that it is possible to use an Xilinx Zynq SoC for ionising radiation monitoring equipment•With the adequate hardening mechanism, we have proven that a crash of the Linux operating system doesn’t interfere in any way with the safety critical functions implemented into the FPGA•Under mixed radiation fields, we have observed into the Xilinx Zynq SoC 7020: 117 more crashes of the PS than the PL
A reliable and highly scalable Internet of Things (IoT) end-to-end data infrastructure has been developed for environmental radiation monitoring at the European Organization for Nuclear Research ...(CERN) based on a low-power wide-area network (LPWAN). The proposed system, called Waste radiation MONitoring (W-MON), consists of an interconnected network of thousands of highly sensitive and ultralow-power gamma radiation sensors acting as long range (LoRa) transceivers. The aim of the system is to improve and automatize the radiological controls of conventional waste containers. The end devices measure the radiation levels in the waste containers on a continuous basis and send the data periodically to the LoRaWAN network server. The network has been deployed in an outdoor environment covering hundreds of hectares. A set of web-based user applications for real-time monitoring, data visualization, and status control of the devices have been designed based on open-source tools. The data pipeline infrastructure has been designed to allow an easy integration into the overall CERN Radiation and Environment Monitoring Unified Supervision service (REMUS).
Ultra-high dose rate radiation therapy is gaining momentum in the treatment of cancer. Many recent studies have shown promising results with great potential. The instrumentation required for ...commercial, reliable therapy facilities is continuously evolving. Such facilities however face the challenge of developing radiation monitors with a wide dynamic range to ensure the safe operation and protection of the personnel. There is a shortage of reported work in this domain. The main challenge for radiation monitoring in such environments comes from the complex nature of the generated pulses. The dose delivered could be of the order of 5 Gy per pulse with a very short pulse width in the range of microseconds and a period of less than a second. The pulses could also be accompanied by pre and post-pulses which could be orders of magnitude less than the main pulse. The accurate measurement of the generated doses at different locations of a facility is paramount from a radiation protection perspective. This contribution summarizes the characterization performed recently at a FLASH radiation facility where gas-filled ionization chambers were used as radiation sensors. The specifically designed front-end electronics for these chambers is also detailed. The front-end utilizes a custom-designed ASIC which enables accurate measurements of the charges generated by the ionization chamber. It was seen that using the ionization chamber-based radiation monitor, the dose rates at different points in a treatment room could be measured and the time structure of the pre and post-pulses be recorded. The first results obtained on the linearity of the device and the saturation behaviour were encouraging. We will continue to investigate ionization chambers for pulsed radiation monitoring in FLASH therapy applications in the future with a focus on the dose calibration and the accuracy of the measurements.
Damage detection in composite laminates aeronautics structures through accelerometers network Over the past twenty years, the increase of use of structural materials in Aerospace is due to many ...reasons. While the properties of metallic materials are mastered, the risk behavior of composite materials requires monitoring of the structure. That's why many methods of non-destructive testing (NDT) have been implemented and applied for the evaluation of defects in composites. The purpose of our research is the development of a new NDT tool for detecting delamination damages in aircraft's structures. The principle diagnostic is based on the application of a reproducible impact wave on a composite panel and its propagation trough an accelerometer sensor network. The presence of defects will be identified by the temporal and frequency response change compared to calibrated reference recorded before the damage. Therefore, in this paper an experimental study of impact behavior of a composite laminate structure will be presented. The panel is made from a guarded composite long carbon fiber laminate. In the study, the shock propagation wave induced in the materials will take into account the fiber orientation (0°, 45°, 90°, -45°) and plies arrangement (plies stacking sequence of tilt-up). First results of this new NDT for detecting damages of an aircraft structure composite demonstrate the wide possibilities of this technique.
The work reported on this paper describes a new methodology implementation for active structural health monitoring of recent aircraft parts made from carbon-fiber-reinforced polymer. This diagnosis ...is based on a new embedded method that is capable of measuring the local high frequency impedance spectrum of the structure through the calculation of the electro-mechanical impedance of a piezoelectric patch pasted non-permanently onto its surface. This paper involves both the laboratory based E/M impedance method development, its implementation into a CPU with limited resources as well as a comparison with experimental testing data needed to demonstrate the feasibility of flaw detection on composite materials and answer the question of the method reliability. The different development steps are presented and the integration issues are discussed. Furthermore, we present the unique advantages that the reconfigurable electronics through System-on-Chip (SoC) technology brings to the system scaling and flexibility. At the end of this article, we demonstrate the capability of a basic network of sensors mounted onto a real composite aircraft part specimen to capture its local impedance spectrum signature and to diagnosis different delamination sizes using a comparison with a baseline.
With the aim of controlling the risk of releasing radioactive material together with ordinary waste, the Radiation Protection (RP) group at CERN is developing a fully automated network of wireless ...radiation sensors to provide remote and real- time monitoring of the radiation level of hundreds of waste containers located on the CERN sites. The system, based on the Internet of Things (IoT) paradigm, will be included in the existing CERN RP supervisory system, allowing online monitoring and continuous supervision. As proof of concept, a complete IoT architecture was successfully developed. A fully operational monitoring system was installed in a waste container equipped with eight wireless radiation sensors, which record and transmit the radiation measurements every hour to a dedicated custom server.
Structural health monitoring for aeronautics manufacturer is one of the biggest challenge that they face during this decade. Our work in this field focuses on the development and the system ...integration of micrometric piezoelectric sensor/actuator to generate and measure Lamb waves. The aim of the application is to detect mechanical flaws on aeronautics structures to quantify the global structure's reliability. The study begins by a physical and analytical analysis of piezoelectric patch before focusing on acoustic wave generation into the tested structure. This paper brings examples of application on aircraft structures specimens and the feasibility of the system is therefore demonstrated.
Microsystems as attractive as they are in terms of multi-functionality must also be able to perform their mission profile and to have a predictive reliability. However, it appears that the complexity ...of microsystems, their multi-disciplinarity, the heterogeneity of materials and interfaces with the external environment are new unknowns in assessing their reliability. The objective of this work is to propose a methodology to predict lifetime (Time To Failure) of microsystems. The approach that we explored is based on the intensive use of modeling and simulation, assuming real operating and environmental conditions. The achievement of our objective consists to combine the functional and failure (drift) models using the VHDL-AMS language in order to determine the TTF. To support our work, we applied this approach for predicting the reliability of two types of Microsystems: Electro-thermal micro-actuators and capacitive RF MEMS switches.
PDF
