A novel approach to qualify the straightness of electrostatic septa for the SPS slow extraction

The quality of slow extraction from the SPS (Super Proton Synchrotron) to the North Area is critically influenced by the straightness tolerance of the electrostatic septum. Past observations have identified a degradation of the anode body straightness, resulting in an increased beam loss during ex- traction. A new metrology bench including optical sensors has been developed to cope with the tolerance requirements while also allowing process automation. Two distinct mea- surement procedures are currently employed: one for the anode noses and another for the individual wire metrology. A control system was developed to automate the metrology and analysis process, allowing operator and time-independent measurements and increasing process accuracy. The find- ings from these investigations provide accurate information in case corrective machining of the anode body is required. The metrology method and the described nose scan approach will further reduce beam loss during the slow extraction pro- cess.