Field stability in two-stem drift-tube linacs

Conference · Fri Jan 01 04:00:00 EST 1988

OSTI ID:6771830

Billen, J H; Spalek, G; Shapiro, A H

Drift tubes supported by two stems have been considered for cryogenic drift-tube linacs (DTLs) to reduce vibrations and to minimize drift-tube deflections upon cool down. We investigated rf properties of two-stem DTL structures at room temperature and low power. Even apart is inherently more stable against tuning errors than a similar structure with single stems. The increased stability is higher for DTLs with shorter drift tubes. Ordinary quarter-wavelength-long post couplers actually destabilize the two-stem DTL fields; the extra stem raises the post coupler frequency compared to the frequency of the same post coupler extended beyond the tank wall into coaxial stub tuners. Adjustment of the stub lengths tunes the post-coupler frequencies, but post-coupler lengths in the tank have no effect, which suggests a field pattern different from traditional post couplers. The stabilized DTL resembles multiple-stem DTLs in which the angle between stems is varied to achieve stabilization. Adjusting the coaxial stub length is mechanically simpler than changing the stem azimuth angle. 5 refs., 6 figs., 1 tab.

• Research Organization: Los Alamos National Lab., NM (USA)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 6771830
• Report Number(s): LA-UR-88-3262; CONF-881049-26; ON: DE89000334
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
430100* -- Particle Accelerators-- Design
Development
& Operation
ACCELERATORS
DESIGN
DRIFT TUBES
LINEAR ACCELERATORS
MAGNETIC FIELDS
RF SYSTEMS
STABILIZATION