Speaker
Description
The High Luminosity LHC (HL-LHC) requires 2.3e11 protons per bunch (ppb) at LHC injection. For the SPS, the injector to the LHC, this goal requires a doubling of the injected intensity to 2.6e11 ppb. Longitudinal instabilities were observed in the SPS for intensities below the required 2.6e11 ppb. Identifying, and ultimately mitigating, the impedance sources driving the instabilities requires an accurate impedance model.
Here, we report on measurements of the synchronous phase shift and corresponding energy loss. Using the loss factor to compute the energy loss from the measured bunch spectrum and the SPS impedance model leads to significant disagreements with measurements. This disagreement is investigated for the simplified case of a single resonator. However, simulating matched bunches using the SPS impedance model yields better agreement with measurements.
