STATUS OF BEAM TRANSPORT WITH THE ETA AND ATA ACCELERATORS.

Efforts are now underway to improve both the production of electron beams and their transport through the Experimental Test Accelerator (ETA) and the Advanced Test Accelerator (ATA). These efforts are focused on lowering the emittance and reducing the transverse motion of these beams. There are many possible sources and solutions to these problems. In this paper authors discuss a limited subset of these: namely, (1) phase-mixed damping of transverse motions with a wire zone, (2) efforts to find and correct possible magnetic focusing misalignments or errors, (3) azimuthal drift of the beam caused by the image displacement effect in the accelerator gaps, and (4) growth of the beam breakup instability through the accelerators. These problems are common to both machines. However, because of its much longer length, they become more apparent with the ATA. Therefore, much of the discussion will be on ATA results, even though the problems and solutions apply equally well to the ETA.