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February 28 - March 2, 2000

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The production of short, stable bunches is key for linear collider injectors. The papers referenced here illustrate some recent work the topic:

SLC Damping Rings:

The SLAC Damping Ring vacuum chamber was almost entirely replaced in 1992-3 in order to raise the threshold of the microwave instability. The threshold was actually lowered by about 30%, but the amplitude of the instability was also reduced. This paper "High-Intensity Single Bunch Instability Behavior In The New SLC Damping Ring Vacuum Chamber", (SLAC Publication-6894) reports our observations. "Simulations of the Longitudinal Instability in the New SLC Damping Rings"  (SLAC-Publication-6878) reports our attempts to explain the results. "Impedance Calculations for the Improved SLC Damping Rings"( SLAC-Publication-6254 ) outlines the design efforts during the chamber replacement project. Each component was modeled.

More recent observations are reported in:

Accelerator Test Facility (ATF) at KEK:

The ATF damping ring is intended to serve as a prototype linear collider low emittance source. Estimates of the impedance ( ESTIMATION OF THE LONGITUDINAL IMPEDANCE OF THE ATF DAMPING RING. By M. Takao, T. Higo (KEK, Tsukuba), K.L.F. Bane (SLAC). KEK-91-14, Mar 1992. 18pp. Published in Particle Accel.Conf: IEEE 1991:506-508 (QCD183:P3:1991)) did not indicate the observed bunch lengthening: "Impedance Measurement of ATF DR" is a paper that summarizes observations,


CESR data on single bunch lengthening is presented in "Streak Camera Measurements of the Longitudinal Distribution of a Single Bunch in CESR". They report good agreement with a simple broadbad resonator model.

Other Observations:

Paper from PF-AR with some discrepancy between expected and observed instability threshold.

Paper from APS showing some sawtooth behaviour

Paper from NSLS showing turbulent bunch length oscillations

Impedance and instability estimates for DAFNE

Bench Measurements

RF Screening by Thin Resistive Layers

Theoretical Papers

Paper showing a theoretical analysis of evolution of the sawtooth instability

Paper by Mosnier on the theory of sawtooth

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This page created on 11/13/98 and updated on October 02, 2002 by Nixx.
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