| 摘要 |
<p>PURPOSE: To reduce both the power consumed by a heater and heater temperature by arranging straps by which a shielding cylinder is supported on a holder, in such a way that one end of each strap is located below a position corresponding to the heating part of a heater on the side face of the shielding cylinder and the other end at the upper end of the holder. CONSTITUTION: A cathode sleeve 2 has a heater 1 built in, has a cup 4 secured to its upper end, and has an emitter-impregnated cathode disk 3 provided therein. A shielding cylinder 7 whose lower end is extended downward past a position corresponding to the lower end of a heating part is placed coaxial with and between the cathode sleeve 2 and a holder 5. The above members are mounted on the upper end of the holder 5 while short straps 6, 9 each of three are alternately interposed between the members at intervals of 60 deg. so that they do not make contact with one another. Therefore at the same cathode temperature, heater temperature can be reduced by about 100 deg.C, and be made lower by about 20 deg.C than if the cylinder 7 is directly provided inside the holder 5.</p> |
