Recent AWAKE diagnostics development and operational results
Abstract:
The Advanced Wakefield Experiment (AWAKE) at CERN investigates the plasma-wakefield acceleration of electrons driven by a relativistic proton bunch. After successfully demonstrating the acceleration process in Run 1, the experiment has now started Run 2. AWAKE Run 2 consists of several experimental periods that aim to demonstrate the feasibility of the AWAKE concept beyond the acceleration experiment, showing its feasibility as accelerator for particle physics applications. As part of these developments, a dramatic effort in improving the AWAKE instrumentation is sustained. This contribution reports on the current developments of the instrumentation pool upgrade, including the digital camera system for transverse beam profile measurement, the beam halo measurement and the spectrometer upgrade studies. Studies on the development of high-frequency beam position monitors are also described.
Implementation of RF channeling at the CERN PS for spill quality improvements
Abstract:
Resonant slow extraction from synchrotrons aims at providing constant intensity spills over timescales much longer than the revolution period of the machine. However, the extracted intensity is undesirably modulated by noise on the machine’s power converters with a frequency range of between 50 Hz and a few kHz. The impact of power converter noise can be suppressed by exploiting a Radio Frequency (RF) technique known as empty bucket channelling, which increases the speed at which particles cross the tune resonance boundary. In this contribution the implementation of empty bucket channelling in the CERN Proton Synchrotron (PS) is described via simulation and measurement. The technique was tested with both a resonant RF cavity and an inductive Finemet cavity, which can produce non-sinusoidal waveforms, to significantly reduce the low frequency noise observed on the extracted spill.Simulation studies of intra-train, bunch-by-bunch feedback systems at the International Linear Collider
Abstract:
The International Linear Collider (ILC) is a proposed electron-positron collider targeting collision energies from 250 GeV to 1 TeV. With design luminosities of order 1034 cm2s⁻1 a beam-based, intra-train feedback system would be required near the Interaction Point (IP) to provide nanometre-level stabilisation of the beam overlap in the collisions. Here we present results from beam-tracking simulations of the 500 GeV ILC, including the impact of beam-trajectory imperfections on the luminosity, and the capability of the IP feedback system to compensate for them. Effects investigated include the position jitter introduced by the damping ring extraction kicker, short-range and long-range wakefields, and ground motion. The feedback system was shown to be able to correct for beam-beam offsets of up to 200 nm and stabilise the collision overlap to the nanometre level, within a few bunch crossings.