| 摘要 |
<p>A polycrystalline scintillator for detecting soft X-rays, which comprises Ce as a light-emitting element and at least Y, Gd, Al, Ga and O, and has a garnet crystal structure, and a composition represented by the general formula of (Y 1-x-z Gd x Ce z ) 3+a (Al 1-u Ga u ) 5-a O 12 , wherein 0 ‰¤ a ‰¤0.1, 0.15 ‰¤ x ‰¤ 0.3, 0.002 ‰¤ z ‰¤ 0.015, and 0.35 ‰¤ u ‰¤ 0.55, with 0.05-1 ppm by mass of Fe and 0.5-10 ppm by mass of Si by outer percentage, a ratio µ 50 /µ 100 of 3 or more, wherein µ 50 is an absorption coefficient of X-rays at 50 keV, and µ 100 is an absorption coefficient of X-rays at 100 keV, and afterglow of 800 ppm or less after 3 ms from the termination of X-ray irradiation.</p> |
