The Development of Low-Q Cavity Type Beam Position Monitor with a Position Resolution of Nanometer for Future Colliders

TL;DR

This paper presents the development and testing of a low-Q C-band beam position monitor achieving nanometer-level resolution, suitable for future collider applications like ILC and ATF2.

Contribution

The paper introduces a novel low-Q C-band BPM with nanometer resolution and demonstrates its effectiveness through beam tests at KEK, advancing high-precision beam diagnostics.

Findings

Achieved 10.1 nm average position resolution at KEK

Projected beam position resolution of 8.8 nm and 4.4 nm for different beam charges

Validated the BPM's capability for nanometer-level precision in collider environments

Abstract

The nano-meter beam size in future linear colliders requires very high resolution beam position monitor since higher resolution allows more accurate position measurement in the interaction point. We developed and tested a low-Q C-band beam position monitor with position resolution of nanometer. The C-band BPM was tested for the fast beam feedback system at the interaction point of ATF2 in KEK, in which C-band beam position monitor is called to IPBPM (Interaction Point Beam Position Monitor). The average position resolution of the developed IPBPMs was measured to be 10.1 nm at a nominal beam charge of $87\%$ of ATF2. From the measured beam position resolution, we can expect beam position resolution of around 8.8 nm and 4.4 nm with nominal ATF2 and ILC beam charge conditions, respectively, in which the position resolution is below the vertical beam size in ILC. In this paper, we describe the development of the IPBPM and the beam test results at the nanometer level in beam position resolution