Workshop proceedings: Sensor systems for space astrophysics in the 21st century

This proceedings provides a summary of the Astrotech 21 Sensor Technology Workshop. Topics covered include: high energy sensors, ultraviolet and visible sensors, direct infrared sensors, heterodyne submillimeter wave sensors, sensor readout electronics, and sensor cooler technology

Sensor Technology using Fluorescent Dyes

This project is concerned with the application of fluorescent dye technology for leak detection in pulp and paper recovery boiler systems in order to avoid a smelt / water explosion. The dyes’ property to absorb light of short wavelength and emit light of a longer wavelength (fluoresce) is what makes them a quintessential candidate for the desired sensor technology. The projected benefits of this technology pertain to cost-effectiveness and safety of recovery boiler operations. For all purposes, the inert dye pyrenetetrasulfonic acid (PTSA) was used as a tracer agent. Multiple methods of experimental design were attempted to determine the reaction kinetics of the aforementioned dye. These methods involved exposing the dye to a specific temperature and monitoring its decomposition rate manually using a fluorometer. The dye was exposed to elevated temperature and pressure conditions in microwave reactors, such as Biotage and CEM Microwave. A design of experiments protocol was developed and executed, and the data collected was analyzed. It was established that PTSA decomposed on a 1st order reaction rate, and corresponding mathematical models were established using mass and energy balances. MATLAB simulations were developed and compared with actual experimental data conducted in a continuous stirred tanks reactor (CSTR) to simulate the real-time conditions of a leak environment. The data collected was also used to demonstrate the accuracy of the mathematical model. The leak detection system is based on steady-state conditions using the PTSA mass balance model as a reference point for any changes that might occur in the system. The decomposition rate of PTSA was monitored through careful recordings of a fluorometer. The decay rate analysis shows a decrease in the dye concentration in water with respect to time. The MATLAB simulation curve demonstrates the logarithmic relationship per the CSTR method at 150 °C and 200 °C. Further research and experimentation is required to understand the dynamics of these fluorescent dyes and their rate kinetics at elevated conditions to match the 10 MPa and 480 °C recovery boiler conditions. This innovative method of applying such world-class detection technology will ultimately mitigate risk by saving lives of employees in the industrial facility and facilitate the process of maximizing profit and minimizing costs associated with a shut-down in the case of a leak.https://scholarscompass.vcu.edu/capstone/1155/thumbnail.jp

Electron tunnel sensor technology

Researchers designed and constructed a novel electron tunnel sensor which takes advantage of the mechanical properties of micro-machined silicon. For the first time, electrostatic forces are used to control the tunnel electrode separation, thereby avoiding the thermal drift and noise problems associated with piezoelectric actuators. The entire structure is composed of micro-machined silicon single crystals, including a folded cantilever spring and a tip. The application of this sensor to the development of a sensitive accelerometer is described

Security in Wireless Sensor Networks: Issues and Challenges

Wireless Sensor Network (WSN) is an emerging technology that shows great promise for various futuristic applications both for mass public and military. The sensing technology combined with processing power and wireless communication makes it lucrative for being exploited in abundance in future. The inclusion of wireless communication technology also incurs various types of security threats. The intent of this paper is to investigate the security related issues and challenges in wireless sensor networks. We identify the security threats, review proposed security mechanisms for wireless sensor networks. We also discuss the holistic view of security for ensuring layered and robust security in wireless sensor networks.Comment: 6 page

Flip-chip assembly of an integrated optical sensor

For enabling low cost mass production for photonic circuits, the application of flipchip technology creates huge expectations. We report on the results of a project, having the goal to demonstrate standard packaging technology in combination with integrated optics, entailing demands and limitations different from IC technology. Mainly fiber attachment, but also special features as sensor window accessibility at the top-side of the chip are prohibiting the positioning of the optical layer stack and solder pads at the same side of the silicon wafer. Therefore, feed through technology had to be included. Compatibility issues in combining feed through technology with integrated optics processing have been solved and the feasibility of feed-through metallization and flip-chip assembly in combination with an integrated optical sensor has been demonstrated

Design and simulation of a multi-function MEMS sensor for health and usage monitoring.

Health and usage monitoring as a technique for online test, diagnosis or prognosis of structures and systems has evolved as a key technology for future critical systems. The technology, often referred to as HUMS is usually based around sensors that must be more reliable than the system or structure they are monitoring. This paper proposes a fault tolerant sensor architecture and demonstrates the feasibility of realising this architecture through the design of a dual mode humidity/pressure MEMS sensor with an integrated temperature function. The sensor has a simple structure, good linearity and sensitivity, and the potential for implementation of built-in-self-test features. We also propose a re-configurable sensor network based on the multi-functional sensor concept that supports both normal operational and fail safe modes. The architecture has the potential to significantly increase system reliability and supports a reduction in the number of sensors required in future HUMS devices. The technique has potential in a wide range of applications, especially within wireless sensor networks

LADAR vision technology for automated rendezvous and capture

LADAR Vision Technology at Autonomous Technologies Corporation consists of two sensor/processing technology elements: high performance long range multifunction coherent Doppler laser radar (LADAR) technology; and short range integrated CCD camera with direct detection laser ranging sensors. Algorithms and specific signal processing implementations have been simulated for both sensor/processing approaches to position and attitude tracking applicable to AR&C. Experimental data supporting certain sensor measurement accuracies have been generated

Photo sensor array technology development

The development of an improved capability photo sensor array imager for use in a Viking '75 type facsimile camera is presented. This imager consists of silicon photodiodes and lead sulfide detectors to cover a spectral range from 0.4 to 2.7 microns. An optical design specifying filter configurations and convergence angles is described. Three electronics design approaches: AC-chopped light, DC-dual detector, and DC-single detector, are investigated. Experimental and calculated results are compared whenever possible using breadboard testing and tolerance analysis techniques. Results show that any design used must be forgiving of the relative instability of lead sulfide detectors. A final design using lead sulfide detectors and associated electronics is implemented by fabrication of a hybrid prototype device. Test results of this device show a good agreement with calculated values

Development of high-performances monolithic CMOS detectors for space applications

This paper describes the development of a 750x750 pixels CMOS image sensor for star tracker applications. A first demonstrator of such a star tracker called SSM star tracker built around a 512x512 detector has been recently developed and proves the feasibility of such instrument. In order to take fully advantage of the CMOS image sensor step, the 750x750 device called SSM CMOS detector which will take part of the final star tracker, can be considered as a major technical breakthrough that gives a decisive advantage in terms of on satellite implementation cost and flexibility (sensor mass and power consumption minimisation, electronics and architecture flexibility). Indeed, built using the 0.5μm Alcatel Microelectronics standard CMOS technology, the SSM CMOS detector will feature on-chip temperature sensor and on-chip sequencer. In order to evaluate the radiation tolerance of such manufacturing technology, a radiation campaign that contains studies of total dose and latch-up effects has been led on a specific test vehicle