9 February 2018
Europe/Zurich timezone

Measurements of the longitudinal SPS impedance with beam


Alexandre Lasheen (BE-RF)


One requirement for the High Luminosity-LHC project is to double the bunch intensity. However, this target is challenging and the injectors of the LHC are not presently able to provide this intensity due to various limitations, which are tackled by the LHC Injector Upgrade (LIU) project. One of the most critical limitations is the longitudinal beam instability in the SPS, occurring due to the electromagnetic interaction of the beam with its environment (beam-coupling impedance). To study the instability and to find suitable mitigation measures, a reliable SPS impedance model is needed. This model can be built by adding contributions from various machine elements, but the beam itself can also be used to measure the characteristics of the effective impedance.

This talk aims to give a comprehensive introduction into different techniques used to measure the longitudinal impedance with beam, in particular those which were applied in the SPS. These methods revealed critical contributors responsible for the beam instabilities and their impedance will be reduced during the LS2. The present SPS impedance model is also used to evaluate the achievable beam parameters for the HL-LHC and AWAKE run II.

Start time: 2:30 p.m.

Coffee will be served before the seminar, at 2:15 p.m.

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