Download or read book Analysis of Measured Post-coupler Fields in a Ramped-gradient Drift-tube Linac written by and published by . This book was released on 1988 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Post couplers longitudinally stabilize the axial electric field in a drift-tube linac (DTL) against tuning errors. Displacing the post couplers toward one end of the structure results in a ramped field that increases toward the other end. Such a ramped-gradient DTL is also stable, but some of the cavity power is dissipated on the post couplers to maintain the ramp. This paper reports bead-perturbation measurements of the post-coupler magnetic fields near the tank well. A simple physical model reproduces the measured fields with an accuracy of about 2% and yields current-density distributions on the post couplers in terms of the current density on the cavity wall. The peak power density occurs on the sides of the post couplers where the TM010 magnetic field adds to the post-coupler magnetic field. In the Los Alamos Ramped-Gradient DTL (RGDTL), the peak power densities on post couplers located in the steepest part of the ramp exceed by more than 10 times the maximum power density on the tank wall far from any post couplers. Methods to reduce such power losses to levels comparable to a flat-gradient DTL will be discussed. 2 refs., 6 figs., 1 tab.