1,721,064 research outputs found
The RD53 effort towards the development of a 65 nm CMOS pixel readout chip for extreme data rates and radiation levels
No full textExperimental Characterization of a Personal Wireless Sensor Network for the Medical X-Ray Dosimetry
No full textWireless sensor networks are an important technology for large-scale monitoring, providing sensor measurements at high temporal and spatial resolution. In healthcare applications, a variety of system prototypes and commercial products have been designed and manufactured with the aim to provide an alternative and more efficient method for real-time operator monitoring during medical procedures. In the framework of the Real-Time Active Pixel Dosimetry project, the attention has been focused on dose monitoring of interventional radiology (IRad) operators. A sensor network has been developed, which consists of several personal sensor nodes (PSNs), monitoring the absorbed dose in different positions of the operator body (e.g., on the head or arms) and providing a measurement of the absorbed dose for each medical procedure. In this paper, we describe the first characterization of the final version of a system by measuring the radiation diagram and exposing the system to a direct X-ray beam showing a linearity of the response up to 3.3 mGy/s of dose rate. The system has been characterized during several IRad procedures when two PSNs have been simultaneously used in the network. The packet error rate of the network has been measured and the absorbed dose has been evaluated for each medical procedure, showing an uncertainty on the dose measurement lower than 10% with respect to the reference dosimetric devices
Vertically integrated CMOS active pixel sensors for tracking applications in HEP experiments
No full textn this work we propose an innovative approach to particle tracking based on CMOS Active Pixel Sensors layers, monolithically integrated in an all-in-one chip featuring multiple, stacked, fully functional detector layers capable to provide momentum measurements (particle impact point and direction) within a single detector. This will results in a very low material detector, thus dramatically reducing multiple scattering issues. A first chip prototype has been fabricated within a multi-project run using a 130nm CMOS 3D Chartered/Tezzaron technology, featuring two layers bonded face-to-face. Tests have been carried out on full 3D structures, providing the functionalities of both tiers and their inter-communications. Actually, laser scans have been carried out using highly focussed spot size, obtaining coincidence responses of the two layers. X-rays sources have been used as well for sensor calibration purposes. Beam tests with 3MeV protons have been carried out at the INFN LABEC laboratories in Florence (Italy) to assess the suitability of the proposed approach for Minimum Ionizing Particle detection
Experimental Characterization of a Wireless Personal Sensor Node for the Dosimetry During Interventional Radiology Procedures
No full textWireless sensor networks featuring portable devices are widely used for healthcare applications such as real-time patient monitoring. For such applications, design constraints are limited in the amount of energy, network capacity (short communication range and low bandwidth), and processing and memory resources in each node. In the framework of the real-time active pixel dosimetry project, the attention has been focused on the design of a dosimetric system for online dose monitoring of interventional radiology (IRad) operators. This paper describes the experimental characterization of the prototype used during several IRad procedures. The wireless link of the prototype has been characterized by measuring the packet error rate of the network in different scenarios: the worst obtained result was lower than 0.4%, which is acceptable for the specific application. The prototype has also been compared with a reference acquisition system to fully validate the system in operating condition. A linear correlation has been observed between the observables for all the working conditions. Moreover, the average pixel response could be used as an indicator of the goodness of the data acquisition for a given procedure showing that it does not depend on the procedure, hence on the particular spectrum of the diffused radiation. Finally, the measurement of absorbed dose (μGy) has been calculated for different IRad procedures
Accurate Analytical Thermal Model of the Heating Element in Micromachined Gas Sensors
No full textIn this paper, a simple analytical model of the steady -state thermal behavior of a Pt microheater for micromachined gas sensors is presented. It is demonstrated that simple resistance vs. power measurements, coupled with a suitable thermal model, are sufficient for a precise determination of the sensor temperature
RAPID: A prototype for personnel dosimetry during interventional radiology procedures
No full textPurpose: We present the tests performed on the prototype of a personal wireless dosimeter for medical staff during Interventional Radiology procedures, developed in the framework of the INFN RAPID Project.
Methods and materials: The prototype is composed by a sensing element (a CMOS silicon pixel device), a real-time data reduction system (a CPLD), a control system, a wireless transmission module, a remote station for prototype configuration, control and data storage.
The prototype has been irradiated in laboratory using monochromatic X-ray photons to calibrate the sensing element, then using the angiography system with a PMMA phantom, to diffuse the direct radiation, in all the working conditions (continuous/pulsed, fluoroscopy/digital radiography acquisition) and with different sensor settings. The prototype has also been exposed to a certified X-ray beam to obtain a relative calibration. Finally the sensing element of the prototype has also been used during medical procedures, mounted over the lead apron dressed by the medical staff.
All the results have been compared with two control systems, a set of TLDs and an UNFORS EDD-30 system.
Results: Two sensor quantities have been used to verify the linearity of the prototype's response:
the number of detected photons and the total detected signal in a frame. The appropriate data reduction strategies have then been implemented in CPLD to obtain a limited amount of data to be transmitted to the remote station with a 1-10 Hz frequency, lowering the needed throughput of the wireless system, and hence the power consumption.
The uncertainty on the dose and dose-rate measurements is below 10%, and the wireless transmission protocol has been found to be adequate also in the capability of establishing the connection through the operating room walls.
Conclusion: The wireless dosimeter prototype, produced in the framework of the RAPID project, for personnel dosimetry of the medical staff during interventional radiology procedures, has been tested and found to be satisfactory from the power consumption, the wireless transmission capability, the precision in dose and dose-rate measurements
The RD53 collaboration’s SystemVerilog-UVM simulation framework and its general applicability to design of advanced pixel readout chips
No full textThe foreseen Phase 2 pixel upgrades at the LHC have very challenging requirements for the design of hybrid pixel readout chips. A versatile pixel simulation platform is as an essential development tool for the design, verification and optimization of both the system architecture and the pixel chip building blocks (Intellectual Properties, IPs). This work is focused on the implemented simulation and verification environment named VEPIX53, built using the SystemVerilog language and the Universal Verification Methodology (UVM) class library in the framework of the RD53 Collaboration. The environment supports pixel chips at different levels of description: its reusable components feature the generation of different classes of parameterized input hits to the pixel matrix, monitoring of pixel chip inputs and outputs, conformity checks between predicted and actual outputs and collection of statistics on system performance. The environment has been tested performing a study of shared architectures of the trigger latency buffering section of pixel chips. A fully shared architecture and a distributed one have been described at behavioral level and simulated; the resulting memory occupancy statistics and hit loss rates have subsequently been compared
A laser test system for characterizing CMOS active pixel sensors
No full textCMOS active pixel sensor suitability for radiation detection purposes has been already demonstrated. In particular, the adoption of a
fully standard deep sub-micron CMOS technology allows to obtain a very compact pixel size, an efficient integration of smart electronics
and ease of porting to future, more advanced, technology nodes. These characteristics potentially enhance the sensor capabilities, in
terms of spatial resolution and energy resolution. In order to verify such hypotheses, test chips have been fabricated, and a dedicated
laser test bench has been devised and implemented. The test bench features a mechanical movement section with sub-micron positioning
capabilities, and an optic axis with a beam-splitter that allows the fine focalization of a near infrared laser stimulus and also to obtain a
visible picture to control the irradiated region. A low-cost comprehensive active pixel sensor characterization can be therefore carried out
as an alternative to more expensive beam test characterizations
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