Study of the electronics architecture for the mechanical stabilisation of the quadrupoles of the CLIC linear accelerator

Abstract

To reach a sufficient luminosity, the transverse beam sizes and emittances in future linear particle accelerators should be reduced to the nanometer level. Mechanical stabilisation of the quadrupole magnets is of the utmost importance for this. The piezo actuators used for this purpose can also be used to make fast incremental orientation adjustments with a nanometer resolution. The main requirements for the CLIC stabilisation electronics is a robust, low noise, low delay, high accuracy and resolution, low band and radiation resistant feedback control loop. Due to the high number of controllers (about 4000) a cost optimization should also be made. Different architectures are evaluated for a magnet stabilisation prototype, including the sensors type and configuration, partition between software and hardware for control algorithms, and optimization of the ADC/DAC converters. The controllers will be distributed along the 50 km long accelerator and a communication bus should allow external control. Furthermore, one might allow for an adaptive method to increase the S/N ratio of vibration measurements by combining seismometer measurements of adjacent magnets. Finally a list of open topics, the current limitations and the plans to overcome them will be presented.

First considerations on the supporting structures of FCC-ee booster and collider in the arc regions

“…As a result of an iterative work involving integration studies, design and simulations, a preliminary version of the supporting system for the FCC-ee booster and collider elements in the arc regions has been defined. The study will be completed by random vibration analyses including a reasonable footprint of the expected ground motion [7], as well as adding the collider to the FEM model, to evaluate the vibrational crosstalk. The oscillation at the level of the beam axis can then be evaluated and compared with the demanding specification, in terms of stability, of the FCC-ee magnets (See table 1).…”

Study of the hybrid controller electronics for the nano-stabilization of mechanical vibrations of CLIC quadrupoles

“…It has been demonstrated in [3] that latency above 80 µs in the control loop negatively affects performance. For this reason a local control strategy was chosen over remote central control, leading to a local controller situated next to each stabilized magnet in the tunnel.…”

Measuring field multipoles in accelerator magnets with small-apertures by an oscillating wire moved on a circular trajectory

“…Magnets with small apertures of about 10 mm in diameter are developed for new linear accelerator studies, such as the Compact Linear Collider (CLIC) at the European Organization for Nuclear Research (CERN) [8]- [9], as well as for the Linac 4 project. For high-precision search coil manufacture, a new printed-circuit board technology is used [10] for the small shafts.…”