Wire Scanner Assessment of Transverse Beam Size in the Fermilab Side-Coupled Linac

Drawing of three-wire layout for the Fermilab Linac wire scanners.References Beam intensity and size results from biasing in WSs D13 and D53.Two datasets were taken at each tested voltage.If secondary electron emissions were the cause of the coupling, we would predict a more negative voltage would lead to a larger beam size and larger (more negative) amplitude in the X and Y wires.Overview of the Fermilab Side-Coupled Linac 1 Noble, Robert."The Fermilab Linac Upgrade."15th International Linear Accelerator Conference (1991).FERMILAB-LU-172.2 McCrory, Elliott et al. "Beam Diagnostics for the 400 MeV Fermilab Linac."Conf.Proc.C. Volume 910506 1249-1251 (1991).The wire scanners contain three electrically-isolated wires, mounted at different angles to assess the "X", "Y", and 45°(called "U") directions 2.The wires share a frame which is moved transversely across beam to record current in the wire.Schematic of the Fermilab Side-Coupled Linac 1, composed of seven 805 MHz modules (Modules 1-7) and a transition section (Module 0, containing the buncher (B) and Vernier (V) cavities) which accelerate 116 MeV beam to 400 MeV.The red dots represent the locations of the wire scanners (WSs).