• M. Wendt, C.I. Briegel, N. Eddy, B.J. Fellenz, E. Gianfelice-Wendt, P.S. Prieto, R. Rechenmacher, D.C. Voy
  Fermilab, Batavia, Illinois
• N. Terunuma, J. Urakawa
  KEK, Ibaraki

To achieve a low vertical beam emittance at the KEK Accelerator Test Facility (ATF) damping ring, the BPM read-out system is currently upgraded with new high resolution electronics. Based on analog and digital down-conversion techniques, the upgrade includes an automatic gain calibration system to correct for slow drift effects and ensure high reproducable beam position readings. The concept and its technical realization, as well as preliminary beam study results are presented.

• J.L. Crisp, N. Eddy, I. Kourbanis, K. Seiya, R.M. Zwaska
  Fermilab, Batavia
• S. De Santis
  LBNL, Berkeley, California

Electron cloud density in the Fermilab Main Injector was measured by observing microwave transmission along the vacuum tube. Presence of the electron cloud reduces the velocity of the microwave signal. Both frequency and time domain methods reveal relative cloud density and time evolution. The effect of beam time structure is clearly evident. The accelerator magnetic field effects the distribution of electrons making it difficult to estimate density.