Molybdenum sputtering film characterization for high gradient accelerating structures

TL;DR

This paper investigates molybdenum sputtering coatings on copper for high-gradient accelerator structures, analyzing their composition, resistivity, and potential to enhance accelerator performance.

Contribution

It provides detailed characterization of molybdenum coatings and demonstrates their application in a three-cell accelerating structure for improved performance.

Findings

Molybdenum coatings exhibit varied resistivity above and below molybdenum dioxide reference.

Chemical and electrical properties characterized by Rutherford backscattering, XANES, and photoemission.

A 500 nm thick molybdenum layer improves X-Band accelerating system performance.

Abstract

Technological advancements are strongly required to fulfill the demands of new accelerator devices with the highest accelerating gradients and operation reliability for the future colliders. To this purpose an extensive R&D regarding molybdenum coatings on copper is in progress. In this contribution we describe chemical composition, deposition quality and resistivity properties of different molybdenum coatings obtained via sputtering. The deposited films are thick metallic disorder layers with different resistivity values above and below the molibdenum dioxide reference value. Chemical and electrical properties of these sputtered coatings have been characterized by Rutherford backscattering, XANES and photoemission spectroscopy. We will also present a three cells standing wave section coated by a molybdenum layer $\sim$ 500 nm thick designed to improve the performance of X-Band accelerating systems.