Neutron tomography McClellan Nuclear Radiation Center (MNRC) TRIGA reactor
- SM-ALC/TIR, 5335 Price Ave., McClellan Air Force Base, Sacramento, CA 95652-2504 (United States)
At the MNRC Reactor Facility we are currently in the process of converting one of our real-time radiography bays into a neutron tomography facility. The facility's initial use will be for the determination of the amount of hydrogen in titanium compressor blades. An increase in the amount of hydrogen within the blade can result in embriddlement and later structural failure of the fan blade. The blades are 'baked' (heated to high temperatures to.force the hydrogen from the blade) after a number of flying hours. The goal of the system is to enable the end user to know when blades have reached potentially damaging levels of hydrogen (greater than 125 ppm). The system also needs to be able to process a large number of blades in a short time (i.e. a production mode). To achieve the goal of detecting the hydrogen at the appropriate levels; maxmize through put, and give the system flexibility to be used in other applications several unique features were incorporated. These design features included; a high resolution CCD camera for imaging, multiple high capacity turn tables to minimize system fixturing time, and automatic image analysis for hydrogen content. The high resolution CCD camera was selected based on previous work at the facility done by Dr. Eric McFarlan of University of California at Santa Barbara. He originally used the ST-4 and ST-6 which had small rectangular arrays of 375x242. For the system we chose the Princeton Instruments TE-1024K which has a segmentable (can be partitioned in smaller areas) array of 1024x1024. The camera also has the ability to digitize image information at 16 bit resolution or as low as 8 bit for high speed. Additionally, the CCD camera sensitivity (quantum efficiency) was matched closely to the wavelength of light emitted by the scintillation screen. The turn tables used have a weight capacity of 2000 pounds. This is well above the weight of the fan blade (less than one pound). To increase the through put we placed 3 blades on each turn table. Then the blades are imaged as if they are a single object. There are four tables each sitting on a large aluminum plate. A single AC brushless servo motor drives the tables in unison. The aluminum plate sits on a Aronson positioner which is manually indexed to place individual tables infront of the neutron beam. This enables twelve blades to be imaged without having to stop to fixture more. Finally, the automatic instead of manual interpretation of the images frees the operator and enables off-line processing. Since the image intensity is proportional to the hydrogen content of the imaged blade it is quite easy to develop formula to return some value proportional to the hydrogen content. The application of this algorithm is accomplished through implementation of basic image processing rules. (author)
- Research Organization:
- General Atomics, San Diego, CA (United States)
- OSTI ID:
- 21141168
- Report Number(s):
- INIS-US--09N0001
- Country of Publication:
- United States
- Language:
- English
Similar Records
Design and development of the 3.2 gigapixel camera for the Large Synoptic Survey Telescope
Modified control software for imaging ultracold atomic clouds