Beam loading compensation with variable group velocity
Abstract
Consider a section with linearly variable group velocity and a beam pulse shorter than the section fill time. Choose the current amplitude so that the gradient of the last bunch equals the gradient of the first bunch. For beam pulses less than about 15 percent of fill time, the voltage deviation during the beam pulse is small, but as the pulse width increases the voltage deviation also increases. We show that by decreasing the output to input group velocity ratio, we can reduce the first order voltage deviation, and that we can remove the remaining second-order voltage deviation by linearly decreasing the section input power by a small amount starting at beam injection time. This way we can increase the beam pulse width to more than half the fill time, and thereby increase the RF to beam energy transfer efficiency and the luminosity without increasing the voltage deviation.
- Publication:
-
Presented at the 16th International LINAC Conference
- Pub Date:
- August 1992
- Bibcode:
- 1992lina.confQ..23F
- Keywords:
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- Beam Injection;
- Beams (Radiation);
- Bunching;
- Group Velocity;
- Linear Accelerators;
- Energy Transfer;
- Luminosity;
- Nuclear and High-Energy Physics