Compensation of detector solenoid effects on the beam size in a linear collider

Yuri Nosochkov,Andrei Seryi

doi:10.1103/physrevstab.8.021001

Abstract

In this paper, the authors discuss the optics effects of the realistic detector solenoid field on beam size at the Interaction Point (IP) of a future Linear Collider and their compensation. It is shown that most of the adverse effects on the IP beam size arise only from the part of the solenoid field which overlaps and extends beyond the final focusing quadrupoles. It is demonstrated that the most efficient and local compensation can be achieved using weak antisolenoids near the IP, while a correction scheme which employs only skew quadrupoles is less efficient, and compensation with strong antisolenoids is not appropriate. One of the advantages of the proposed antisolenoid scheme is that this compensation works well over a large range of the beam energy

Highlights

A linear collider (LC) must collide nanometer scale flat beams at the interaction point (IP) in order to reach the desired luminosity
This paper evaluates the effects of the detector solenoid field on the beam size and orbit at the IP of the Linear
According to Eqs. (5) and (6), the vertical beam size growth in a solenoid is caused by the hyxi coupling term, and the rotation angle at IP is equal to B‘=2B, which is on the order of 0.01 in the NLC for 250 GeV beam

Summary

INTRODUCTION

A linear collider (LC) must collide nanometer scale flat beams at the interaction point (IP) in order to reach the desired luminosity. The standard methods of compensating for the detector solenoid include antisolenoids or skew quadrupoles or their combination. This is automatically achieved if there are no other magnets inside the solenoid The advantage of this scheme is that it is completely local and corrects all energies at once, but the drawback is that the antisolenoids do not permit the interaction region (IR) quadrupoles to be placed close to the IP. This limits the strength of the final beam focusing and the luminosity.

HARD EDGE SOLENOID MODEL

SOLENOID EFFECTS WITH REALISTIC

ANALYTIC DESCRIPTION OF EFFECTS OF

COMPENSATION OF IP BEAM SIZE USING

Findings

CONCLUSION