Prototype of RF cavities for the Booster

A prototype r.f. cavity for the 800 MeV Booster; four cavities of this type were to be installed (one in each of the four stacked rings). The cavities were to operate over the frequency range 2.8 to 8.5 MHz with ferrite core tuning (a section of the cores is visible in the upper part of the cavity). Because of the space restrictions when the cavities are stacked one on top of another with only 36 cm between the midplanes, the tuning was done by passing a current (up to about 700 A) through a spiral around the cores. In the left foreground is the r.f. amplifier. The ferrite was kept at low temperature by an air conditioning system via the tube which can be seen perpendicular to the cavity. Tests were scheduled for completion at the end of 1969 and the final versions of the cavities were planned to be ready for 1971.