• O.A. Ivanov, A.M. Gorbachev, V.A. Isaev, A.A. Vikharev, A.L. Vikharev
  IAP/RAS, Nizhny Novgorod
• J.L. Hirshfield
  Yale University, Physics Department, New Haven, CT
• M.A. LaPointe
  Yale University, Beam Physics Laboratory, New Haven, Connecticut

Funding: Research sponsored by US Department of Energy, Office of High Energy Physics

Experimental investigations of an active Ka-band microwave pulse compressor are presented. The compressor is based on a running wave three mirror quasi-optical resonator utilizing a diffraction grating whose channels embody plasma discharge tubes as the active switch. The principle of compression is based on quickly changing the output coupling coefficient (Q-switching) by initiating plasma discharges in the grating channels. Excitation of the resonator was achieved with a few 100 kW of 34.29 GHz microwaves in 700 nS pulses from the magnicon in the Yae Ka-band Test Facility. A power gain of at least 7:1 in the compressed pulse with a duration of 10-15 nS was achieved.

• M.A. LaPointe
  Yale University, Beam Physics Laboratory, New Haven, Connecticut
• J.L. Hirshfield
  Yale University, Physics Department, New Haven, CT
• S. Kazakov
  Omega-P, Inc., New Haven, Connecticut
• V.P. Yakovlev
  Fermilab, Batavia

Funding: Supported by US Department of Energy, Office of High Energy Physics

A detailed analysis is presented of a new concept for a high current, high gradient proton beam accelerator in a normal conducting (i.e. room temperature) structure. The structure consists of a cascade of RF cavities in a nearly uniform magnetic axial field. The proton energy gain mechanism relies upon cyclotron resonance acceleration in each cavity. In order to check the concept and determine its limits, an engineering design is presented of a four cavity electron counterpart test accelerator under construction that will mimic parameters of the multi-cavity proton accelerator.

• N. Solyak, V.P. Yakovlev
  Fermilab, Batavia
• J.L. Hirshfield, G.M. Kazakevich
  Omega-P, Inc., New Haven, Connecticut
• M.A. LaPointe
  Yale University, Physics Department, New Haven, CT

Funding: Sponsored in part by US Department of Energy, Office of High Energy Physics.

A preliminary design is presented for a two-cavity 7th harmonic multiplier, intended as a high-power RF source for use in experiments aimed at developing high-gradient structures for a future collider. The harmonic multiplier is to produce power in K-band using as an RF driver an XK-5 S-band klystron (2.856 GHz). The device is to be built with a TE111 rotating mode input cavity and interchangeable output cavities, a principal example of which is a TE711 mode cavity running at 19.992 GHz. Design of the harmonic multiplier is described that uses a 250 kV, 20 A injected laminar electron beam. With 10 MW of S-band drive power, 4.7 MW of 20-GHz output power is predicted. Details are described of the gun beam optics, beam dynamics in the RF system, and of the magnetic circuit. The theory of an azimuthally distributed coupler for the output cavity is presented, as well as the conceptual design of the entire RF circuit.