PIP-II: Nitrogen doping and electropolishing

铌腔的表面处理已被证明对大功率超导粒子加速器的效率有显著影响。热处理和表面制备工艺在腔体近表面区域沉积氮气，可以大大提高机器效率，从而降低进行研究的成本。一个国际研究联盟正在推进铌腔表面制备的科学。英国的学术机构和企业目前在这个论坛上并不活跃。因此，不能保证关于粒子加速器效率发展的知识共享。作为支持美国主导的质子改进计划第二阶段（PIP-II）项目的一部分，英国正在开发超导腔的供应链。供应范围不延伸到这些空腔的表面处理。所涉及的组织是达斯伯里实验室（STFC-UKRI）和由焊接研究所（TWI）领导的工业联盟。质子改进计划是一个更大的项目的一部分，该项目旨在创建长基线中微子设施（LBNF），以支持深地下中微子实验（DUNE）。英国参与这一广泛倡议对科学和工业的好处在LBNF-DUNE的概要商业案例中得到了体现。该提案旨在通过在英国开发超导加速腔的加工技术来增加LNBF-DUNE商业案例中引入的科学和经济效益。具体而言，这一建议要求投资于两条科学发展路线：1。氮掺杂;和2。化学抛光，提高空腔效率。在开发化学抛光技术的工作中，将研究替代抛光方法，以减少与当前化学过程相关的危害。

The surface treatment of niobium cavities has been shown to significantly influence the efficiency of high power, superconducting particle accelerators. Heat treatment and surface preparation processes that deposit nitrogen in the near-surface region of cavities can greatly improve machine efficiency and hence drive down the cost of performing research.An international research consortium is advancing the science of surface preparation for niobium cavities. The United Kingdom's academic institutes and businesses are not currently active in this forum. Knowledge sharing on developments in particle accelerator efficiency is therefore not guaranteed.As part of a project to support the US-led Proton Improvement Plan - Phase 2 (PIP-II), the UK is developing a supply chain for superconducting cavities. The scope of supply does not extend to the surface treatment of these cavities. The organisations involved are Daresbury Laboratory (within STFC-UKRI) and an industrial consortium led by The Welding Institute (TWI).The Proton Improvement Plan is part of a larger project to create Long Baseline Neutrino Facility (LBNF) in support of the Deep Underground Neutrino Experiment (DUNE). Benefits to science and industry of the UK's involvement in this broad initiative are captured in the outline business case for LBNF-DUNE.This proposal seeks to augment the scientific and economic benefits introduced in the LNBF-DUNE business case by developing processing techniques in the UK for superconducting accelerating cavities. Specifically, this proposal requests investment in two lines of scientific development:1. nitrogen doping; and 2. chemical polishing to improve cavity efficiency. Within the work to develop chemical polishing techniques, will be the investigation of alternative polishing methods to reduce hazards associated with the current chemical procedures.