An experimental test of a microwave inverse Cerenkov accelerator (MICA)

Author

Fang, J.-M. ; Marshall, T.C. ; LaPointe, M.A. ; Hirshfield, J.L.

Author_Institution

Columbia Univ., New York, NY, USA

Volume

5

fYear

2001

fDate

2001

Firstpage

4020

Abstract

We describe first tests of one module of a dielectric-lined vacuum "inverse Cerenkov" accelerator. The module was fabricated by Titan-Beta, based on a design for a smooth-bore, slow wave accelerator powered by S-band microwaves from a SLAC klystron which also produces the injected 6 MeV bunched beam from a thermionic cathode rf gun. The dielectric liner (κ = 9.6) has an outer diameter of 3.14 cm, an inner diameter of 8.9 mm (through which the bunches pass), and a length of 30 cm. Power up to 200 kW was launched into the accelerator in the TM₀₁ mode. The dimensions of the alumina dielectric were chosen so that the phase velocity of the wave is slowed to just below c. Observations are reported for acceleration and deceleration of the injected bunch, as a function of the relative phase of the bunch injection. An energy change up to 2% was found. The energy change scales in proportion to the axial electric field. Maximum acceleration was limited by microwave breakdown most likely caused by deficiencies in design of the input coupler and not by the limiting breakdown strength of alumina

Keywords

Cherenkov radiation; electron accelerators; linear accelerators; 200 kW; 6 MeV; Al₂O₃; S-band microwaves; TM₀₁ mode; alumina dielectric; coupler; dielectric liner; microwave breakdown; microwave inverse Cerenkov accelerator; slow wave accelerator; Acceleration; Cathodes; Charge carrier processes; Dielectrics; Electron emission; Electron traps; Klystrons; Life estimation; Linear particle accelerator; Testing;

fLanguage

English

Publisher

ieee

Conference_Titel

Particle Accelerator Conference, 2001. PAC 2001. Proceedings of the 2001

Conference_Location

Chicago, IL

Print_ISBN

0-7803-7191-7

Type

conf

DOI

10.1109/PAC.2001.988331

Filename

988331