Beam Determination of Quadrupole Misalignments and Beam Position Monitor Biases in the Slc Linac’

Misalignments of magnetic quadrupoles and biases in beam position monitors (BPMs) in the Stanford Linear Collider (SLC) linac can lead to a situation in which the beam is off-center in the-disk-loaded waveguide accelerator structure. The off-center beam produces wakefields which can limit SLC performance by causing unacceptably large emittance growth. We present a general method for determining quadrupole misalignments and BPM biases in the SLC hnac by using beam trajectory measurements. The method utilizes both electron and positron beams on opposite RF cycles in the same linac lattice to determine simultaneously magnetic quadrupole misalignments and BPM biases. The two-beam trajectory data may be acquired without interruptingSbC colliding beam operations.