The optical multichannel transducer array (OMTA) is a fiber optic-based sensor designed to measure pressure profiles with high time and spatial resolution for wind tunnel applications. The OMTA is an integration of various state-of-the-art technologies and consists of two interchangeable sensor array heads (10 channels, 32 channels) and the associated fiber optics, a filter spectrometer with a 64-element detector array, diode lasers and their controllers, and a LabView-based software control system. The sensor head arrays are produced by anisotropic etching of masked silicon wafers to produce multiple independent elements. These arrays, having 10 and 32 individual, 0.81-mm 2 elements and 1.1-mm center-to-center spacing, are designed for flush mounting in a hypersonic wind tunnel model. Laboratory calibration using dc and low-frequency pressure ramps showed that the measurable displacement resolution was approximately 0.01 , which corresponds in this configuration to 0.1 psi. The frequency response is approximately 50 kHz for 32 channels. The entire system is mounted on one laboratory rack for installation near a wind tunnel facility. © 1996 Society of Photo-Optical Instrumentation Engineers.Subject terms: silicon pressure sensing; fiber optic interferometry; wind tunnel instrumentation.
As part of a fiber optic, interferometric pressure sensing array system for hypersonic wind tunnel studies, a 64 channel spectrometer has been developed to separate the return signals by both position and wavelength. The spectrometer is designed to optically separate the quadrature signals from the interferometer. A ribbon of single-mode fibers carrying the dual wavelengths (811.7 and 813.3 nm) from the sensing surface array forms the entrance slit to the spectrometer. This spectrometer uses a unique optical layout consisting of a 32 element microlens array, narrow passband interference filter and concave mirror to separate and focus the optical signals onto the photosensitive surface of a 1×64 photodiode array. The microlens array collimates the emerging beams from the single-mode fibers to minimize cross talk between channels. The detector array and its control electronics are an integral part of the spectrometer and are mounted on the same baseplate as the other optical components. Fast scanning and digitizing electronics produce an effective data rate of 160 kHz for 64 channels. Details of the construction and results of the calibration are presented.
The use of bio/chemiluminescence immunoassay (BL/CLI) technology for molecular and cellular characterization is rapidly evolving. The excellent selectivity of this method can be exploited to identify the presence and distribution of specific cells. Current work involves the advancement of the required methods and technologies for application to the analysis of vascular wall surfaces. In this effort, various enzymelinked antibodies are being explored which can be directed to cell surface antigens producing a luminogenic reaction. To aid in the analysis of this light emission, a custom high resolution digital imaging system which couples a multi-megapixel CCD with a specially designed image intensifier is under development. This intensifier system has high spatial resolution and excellent sensitivity in the wavelength region of the candidate BL/CL emissions. The application of this imaging system to BL/CLI requires unique performance characteristics and specialized optical design. Component level electro-optical tests of the imaging system will be presented along with design considerations for an eventual catheter based instrument. Initial in vitro experiments focused on the performance limits of the optical system in discriminating candidate luminogenic reactions. The main objective of these tests is the identification of suitable enzyme catalyzed systems for ultimate application to in vivo vascular tissue and cell diagnosis.
4BSTRACTThe steady development of megapixel detector arrays with decreasing pixel size has improved the performance of present imaging systems. These high spatial resolution detectors have been incorporated into a variety of scientific experiments. The sensitivity of the diode arrays has allowed significant progress in instrumentation development and application. However, full application of these detectors to low light level measurements has been hampered by the lack of image intensifiers which can fully exploit the available spatial resolution of the diode arrays. Current architecture of image intensifiers allows significant room for improvement.We are involved in a project to design, develop and characterize an 1 8 mm GEN II image intensifier with improved spatial resolution. Recent advances in microchannel plate production and fiber optic architecture have been exploited to produce a series of image intensifiers. A production run of a series of tubes with reduced cathode to MCP spacing, reduced microchannel diameter and pitch, reduced MCP to phosphor screen spacing and an integral fiber optic taper has been carried out. This intensifier output will be visually examined and coupled to a megapixel array for digital characterization. The goal is to produce a significantly higher limiting spatial resolution to allow for improved measurements in scientific, commercial and military applications. First results from this production run will be discussed and compared to physical performance models.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.