Cavity preparation/assembly techniques and impact on Q, realistic Q-factors in a module, review of modules

This contribution summarizes the surface preparation procedures for niobium cavities presently used both in laboratory experiments and for modules, such as buffered chemical polishing (BCP), electropolishing (EP), high pressure ultrapure water rinsing (HPR), CO2 snow cleaning and high temperature heat treatments for hydrogen degassing or post-purification. The impact of surface treatments and the degree of cleanliness during assembly procedures on cavity performance (Q-value and accelerating gradient Eacc) will be discussed. ition, an attempt will be made to summarize the experiences made in module assemblies in different labs/projects such as DESY (TTF), Jlab (Upgrade) and SNS.