An aluminum alloy quadrupole mass filter with a 120-m-long rf cable

An aluminum alloy quadrupole mass filter and a new transmitting technique for rf power have been developed for the 30‐GeV TRISTAN ring. The aluminum alloy quadrupole electrodes are produced with a special surface treatment by oxygen gas spraying, and the quadrupole is assembled in a new way without screw clamps. The rf amplifier and tank coil wound on a toroidal core can be separated with a 120‐m‐long coaxial cable. Thus, the part fitted on the analyzer is small and simple and is also resistant to radioactive environments and to heat. The newly developed ionizer has a closed hemispherical mesh anode and can be degassed at high temperatures above 1000 °C by electron bombardment of 50 W. This quadrupole mass filter has a high sensitivity of 1.4×10−3 A/Torr at a resolution of 40 and an rf frequency of 2.5 MHz without a secondary electron multiplier.