A 3.5 m r.f. deflector complete with vacuum system and support structure; the waveguide entry is on the left and the r.f. load on the right. In the final installation the deflector is surrounded by a water jacket to ensure temperature stability. The photograph was taken towards the end of January 1970 just before the performance of the cavity, powered with 20 MW of r.f. power, was tested. The tests confirmed the reliability of the system chosen for the r.f. separator for Serpukhov.