PURPOSE: To avoid an increase in the quantity of parts so as to suppress a rise in costs and to prevent X rays from leaking by using a liquid, in which a material with X-ray absorptivity is dissolved, as a cooling liquid.
CONSTITUTION: X-ray absorptivity is given to a cooling transparent liquid 10 which is sealed in a gap formed between a front panel 2 of a cathode-ray tube and a concave lens 4. Because the X-ray absorptivity increases in proportion to four powers of an atomic number of a material and in proportion to the quantity (concentration, thickness) of atoms, the atom of large atomic number is selected in the range in which characteristics required for a cooling liquid 10 do not disappear, and the amount enough to obtain desired absorptivity is dissolved. A simple substance or mixture of ethylene glycol, diethylene glycol, and the like is used as the cooling liquid 10. Hence, since the front of the front panel is screened wholly, reliability in safety of X rays can be upgraded.
MORI SHIGERU
YOSHIZAKI ISAO
WADA KIYOSHI
TAKESHITA MASAMICHI
