Final focus system tuning studies towards Compact Linear Collider feasibility

E Marin,R Tomás,D Schulte,A Latina

doi:10.1103/physrevaccelbeams.21.011003

E Marin, R Tomás + Show 2 more

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https://doi.org/10.1103/physrevaccelbeams.21.011003

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Abstract

In this paper we present the latest results regarding the tuning study of the baseline design of the final focus system of the Compact Linear Collider (CLIC-FFS). CLIC aims to provide collisions to the experiments at a luminosity above ${10}^{34}\text{ }\text{ }\mathrm{c}{\mathrm{m}}^{\ensuremath{-}2}\text{ }{\mathrm{s}}^{\ensuremath{-}1}$. In order to deliver such luminosity in a single pass machine, the vertical beam size at the interaction point (IP) is reduced to about 1 nm, which imposes unprecedented tuning difficulties to the system. In previous studies, 90% of the machines reached 90% of the nominal luminosity at the expense of 18 000 luminosity measurements, when considering beam position monitor errors and transverse misalignments of magnets for a single beam case. In the present study, additional static imperfections such as roll misalignments and strength errors are included. Moreover both ${e}^{\ensuremath{-}}$ and ${e}^{+}$ beamlines are properly simulated. A new tuning procedure based on linear and nonlinear knobs is implemented to effectively cure the most relevant beam size aberrations at the IP. The obtained results for single and double beam studies under solely static imperfections are presented.

Highlights

The Compact Linear Collider (CLIC) [1] aims to collide e− and eþ at the interaction point (IP), at center-of-mass energy of 3 TeV, delivering a nominal luminosity (L0) of 5.9 × 1034 cm−2 s−1 to the experiments
The results presented in the CLIC Conceptual Design Report (CDR) [7] showed that for the single beam case, 90% of the machines reach equal or larger 90% of L0 after 18 000 luminosity measurements, when beam position monitor and transverse misalignments of the magnets, were assumed in simulations
We report on the tuning feasibility of the CLIC-FFS, assuming a more realistic tuning scenario by considering additional static imperfections in both single and double beam cases, while keeping the number of luminosity measurements as low as possible

Summary

Introduction

The Compact Linear Collider (CLIC) [1] aims to collide e− and eþ at the interaction point (IP), at center-of-mass energy of 3 TeV, delivering a nominal luminosity (L0) of 5.9 × 1034 cm−2 s−1 to the experiments. The required transverse beam sizes at the IP (σÃx;y), of the CLIC baseline design, are 40 nm and 1 nm in the horizontal and vertical planes, respectively. These nano-beam sizes impose challenging tuning difficulties to the CLIC final focus system (CLIC-FFS). The local scheme, which has been experimentally demonstrated [6], offers a cost reduction against the non-local scheme, or so-called traditional system, while delivering sufficient luminosity to the experiments.

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