Process for treating the internal surface of superconducting cavities (cavity resonators)

摘要

An accelerator unit (1) cavity (7) made up of one or more individual resonators (2) is approximately half-filled with ceramic grinding bodies and with water and slowly rotated at about 9 rev/min. The rotation is maintained for about one week. This smooths the internal surface of the cavity (7) and frees it of defects in such a way that the cavity (7) can be used with appreciably improved properties and without difficulty in the superconducting mode. Specifically, the simple process specified makes possible to increase the longitudinal acceleration field strength achievable in practical operation by at least a factor of 2 or more, i.e. to eliminate at least half the acceleration units (1, 1'). To remove material abraded by the grinding bodies, the cavity (7) is also filled with an acid mixture of about 1 part of HF, 1 part of HNO3 and 6 parts of H3PO4 and thereby cleaned and superficially pickled. <IMAGE>