| Co-Investigator(Kenkyū-buntansha) |
OHISHI Mikiko Tohoku University, School of Medicine, Professor, 医学部, 教授 (20004921)
ZUGUCHI Masayuki Tohoku University, School of Medicine, Professor, 医学部, 教授 (20172075)
MARUOKA Shin Tohoku University, School of Medicine, Professor, 医学部, 教授 (90173947)
HONMA Noriyasu Tohoku University, School of Medicine, Associate Professor, 医学部, 助教授 (30282023)
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| Research Abstract |
The x-ray tube used in the conventional medical x-ray generator is a hot cathode diode using thermionic emission, while we have developed a flash x-ray generator with a cold cathode diode driven by field emission. Flash x ray equipment by the high energy discharge is composed of a DC high-voltage power supply, a high voltage condenser, a cold cathode x-ray tube, an air gap switch, a trigger pulse generator, and a turbo-molecular pump, and a cold cathode x-ray tube is composed of an anode, negative electrode, trigger electrodes. Many characteristics of a flash x-ray generator occurring under a cold cathode diode are different by materials of an electrode (an anode, the cathode), distance between the anode-cathodes, distance between cathode-trigger electrodes, four factor of a turbo-molecular pump. For examination of materials of an electrode (Ce, Yb, W), but W compared it with other, under charge voltage 90kV, the condition of a pressure of 6.65×10^<-3>Pa, x-ray intensity of 1.3 time was provided. X-ray output pulse was detected using a combination of a plastic scintillator and a photomultiplier, and the pulse width and the maximum tube current were approximately 1.0 μ sec and 40 kA, respectively, with a charging voltage of 90 kV. In order to measure the dimensions of the focal spot, we employed a pinhole camera, and the dimension varied with changes in the electrode angles and the spaces between electrodes. But the spots had size of 2.0 X 2.3mm. In high speed radiography, we obtained stop motion images of various objects including plastic bullets and water flows. In summary, the flash x-ray generator developed in the research is useful to perform high speed radiographies of children, spinal cord injury or disabled persons, because the generator produces extremely short x-ray pulses.
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