Diagnostics upgrades for investigations of HOM effects in Tesla-type SCRF cavities

TL;DR

This paper details upgrades to diagnostic tools at Fermilab's FAST accelerator to study high-order mode effects in TESLA-type SCRF cavities, crucial for improving beam quality in advanced accelerators.

Contribution

It introduces new diagnostic capabilities enabling detailed investigation of HOM effects in TESLA-type SCRF cavities.

Findings

Preliminary HOM detector data obtained.

Prototype BPM test results presented.

First high-resolution OTR imaging demonstrated.

Abstract

We describe the upgrades to diagnostic capabilities on the Fermilab Accelerator Science and Technology (FAST) electron linear accelerator that will allow investigations of the effects of high-order modes (HOMs) in SCRF cavities on macropulse-average beam quality. We examine the dipole modes in the first pass-band generally observed in the 1.6-1.9 GHz regime for TESLA-type SCRF cavities due to uniform transverse beam offsets of the electron beam. Such cavities are the basis of the accelerators such as the European XFEL and the proposed MaRIE XFEL facility. Preliminary HOM detector data, prototype BPM test data, and first framing camera OTR data with ~20 micron spatial resolution at 250 pC per bunch will be presented.