Molybdenum Oxides Coatings for High Demanding Accelerator Components

Abstract

Large electric gradients are required for a variety of new applications, notably including the extreme high brightness electron sources for X-ray free electron lasers (FELs), radio-frequency (RF) photo-injectors, industrial and medical accelerators, and linear accelerators for particle physics colliders. In the framework of the INFN-LNF, SLAC (USA), KEK (Japan), UCLA (Los Angeles) collaboration, the Frascati National Laboratories (LNF) are involved in the modelling, development, and testing of RF structures devoted to particles acceleration by high gradient electric fields of particles through metal devices. In order to improve the maximum sustainable gradients in normal-conducting RF-accelerating structures, both the RF breakdown and dark current should be minimized. To this purpose, studying new materials as well as manufacturing techniques are mandatory to identify better solutions to such extremely requested applications. In this contribution, we discuss the possibility of using a dedicated coating on a solid copper sample (and other metals) with a relatively thick film to improve and optimize breakdown performances and to minimize the dark current. We present here the first characterization of MoO3 films deposited on copper by pulsed-laser deposition (PLD).

Enhanced Thermal Stability of Inverted Polymer Solar Cells Based on Solution‐Processed WOx as an Anode Interlayer

“…As demonstrated, the MoO x layer loss the adhesion to polymers under thermal treatment, [53] thus reducing the electrical contact between active blend and IL. In addition, the mechanical hardness of MoO x layer (H from 1.4 to 2.7 GPa), [54,55] diversely from the relatively softer nanoparticles films, [49] further contribute to BHJ/IL delamination under thermal treatment being relatively brittle and poorly conformable to the morphological variations of the underlying BHJ. [56] Concerning the V OC degradation (not observed for WO x -based devices), we believe that a possible contribution might arise from the MoO x /metal interface.…”

Перспективные Технологии Для Прикладных Резонансных Ускорителей Заряженных Частиц И Примеры Их Использования (Обзор)

“…Также идут работы по разработке структур, не требующих пайки благодаря соединению через острые кромки [80]. Такие методы позволяют достичь более высокой точности изготовления, уменьшить количество составных элементов, избежать спаек в областях, чувствительных для СВЧ-параметров, а в случае использования альтернативных пайке методов соединения получить ускоритель из неотожженой меди, свойства которой более благоприятны для работы на высоких градиентах [81]. Наш опыт работы с разделенными структурами свидетельствует о потенциальном исключении этапа настройки в производстве таких ускорителей [82].…”

Effect of Molybdenum Coatings on the Accelerating Cavity Quality Factor

“…With these goals, a parametric study evaluating the impact of both thickness (within the proved metallic range [16]) and resistivity of MoO 3 metallic coatings on the cavity parameters is here presented. This study is presented as the necessary continuation of the previous studies on the matter [14,15] towards the final implementation of these coatings to validate the usefulness in high-gradient accelerating structures. Formally, the analysis is equivalent to the one presented in [17] regarding superconducting thin-films, for the limit case in which no dielectric substrate is considered between the film and the metallic cover.…”

“…Having this in mind, a straightforward path to reduce the Fowler-Nordheim currents [13] consists in growing coatings characterized by augmented local work function (WF), which may hint at the final cause of breakdowns. This constitutes the main motivation of the previous works [14,15] pursuing the implementation of those coatings in high-gradient accelerating structures.…”