Miniaturized quasi-monochromatic x-ray tubes based on carbon nanotube field emitters

Abstract

A vacuum sealed miniaturized quasi-monochromatic x-ray tube based on carbon nanotube field emitters has been demonstrated. The key point of miniaturized quasi-monochromatic x-ray tube is miniaturization of quasi-monochromatic x-ray tube and one body system that means collimator and filter of quasi-monochromatic x-ray tube connect to vacuum sealed miniaturized monochromatic x-ray tube body. The diameter of the vacuum sealed miniaturized quasi-monochromatic x-ray tube is 10mm, the total length of the vacuum sealed miniaturized quasi-monochromatic x-ray tube is 48mm, and no extra vacuum pump is required for operating the vacuum sealed miniaturized quasi-monochromatic x-ray tube because getter is used to maintain high level vacuum inside vacuum sealed miniaturized quasi-monochromatic x-ray tube. The energy spectrum of x-ray generated from fabricated vacuum-sealed miniaturized quasi-monochromatic x-ray tube is measured at 40keV, 50keV respectively without Mo filter and with Mo filter that has thickness of 10㎛, 20㎛, 30㎛, 40㎛, 50㎛respectively. The x-ray energy spectrum without Mo filter includes broad bremsstrahlung x-rays with the energies up to 40keV and a few characteristic x-rays at 17.48 and 19.61keV that respectively correspond to Kα1 and Kβ1 of the Mo target. In the case of using Mo filter, bremsstrahlung x-rays below than 20.0keV of Mo k-edge energy is attenuated less than Mo k-edge energy. Bremsstrahlung x-ray above Mo k-edge energy is almost attenuated so ratio of characteristic x-ray(Kα) increase.