Plasma wakefield acceleration - bridging fund

请求在2014年10月1日至2015年9月30日期间衔接Awag-UK，限制为建议的固定现金续期。这使我们能够在目前得到资助的领域保持我们的努力，尽管为了交付和继续领导，将在加速器审查结果公布后申请更大的赠款。在过渡期间，目前在岗的PDRA将被保留，其他资源将用于基本消耗品和差旅，主要是参加协作会议和访问CERN。Imperial将致力于WP4：等离子放电源。目标摘要如下：2.4WP4：放电等离子体源与金属蒸汽源和螺旋体源一起，放电等离子体电池是设计报告中描述的唤醒技术选项之一。与其他两种电池相比，放电电池具有显著的优势。它可以扩展到远距离(即几十米甚至更远)，这不是金属蒸气电池的情况，虽然Helcon也是类似的可扩展，但由于需要大量的RF来产生Helcon波，这是一个比放电源昂贵得多的选择。放电电池的简单玻璃管结构还应使其更易于使用可利用放电电池的开放结构的诊断设备(例如WP2)。这项工作由帝国理工学院领导，纳尔逊·洛佩斯是苏醒任务的负责人，与里斯本合作。在目前的资助期间，已经建立了原型，一个直径10 mm的1.5米长的电池在1.6微秒的脉冲放电的基础上以~0.3赫兹的频率运行，在2千伏时提供~300A的电流。电力供应是基于帝国理工学院内部制造的原型。目前正在使用干涉测量法对密度均匀度进行测量，完成后将证明这些放电在接近唤醒所需配置的情况下是可行的。更长的电池也在准备中。明年需要解决的关键问题是：*获得玻璃管中的气体压力稳定性；*获得所需的等离子体均匀度；*测量所需的等离子体密度；*确保高压设置的可靠性；*符合欧洲核子研究中心的标准；*开发更长(长达10米)的原型。

A request is made for bridging AWAKE-UK for the period 1 October 2014 - 30 September 2015, restricting to a flat-cash continuation as recommended. This allows us to maintain our effort in the currently funded areas although for delivery and continued leadership, a more significant grant will be requested after the outcome of the accelerator review is known. During the bridging period, PDRAs currently in post will be retained, with other resources used for essential consumables and travel to attend Collaboration Meetings and visits primarily to CERN.Imperial will work on WP4: Plasma Discharge Source. A summary of the objectives are given below:2.4 WP4 : Discharge plasma sourceAlong with the metal vapour and helicon sources, the discharge plasma cell is one of the tech- nology options for AWAKE as described in the Design Report. The discharge cell has significant advantages over the other two, viz. it is scalable to long distances (i.e. tens of metres and beyond) which is not the case for the metal vapour cell, and although the helicon is similarly scalable, this is a far more expensive option than the discharge source due to the large amounts of RF needed to generate the helicon waves. The simple, glass-tube structure of the discharge cell should also make it more amenable to diagnostic devices (e.g. WP2) which can utilise the open structure of the discharge cell. The work is led by Imperial, with Nelson Lopes the AWAKE task leader, in collaboration with Lisbon. During the current grant, prototypes have been built, with a 10mm diameter 1.5m long cell operated at ~0.3Hz based on a 1.6 microsecond pulsed electrical discharge that provides ~300 A at 2 kV. The power supply is based on a prototype built in-house at Imperial. Measurements of the density uniformity using interferometry are now underway which after completion should demonstrate the feasibility of these discharges in a configuration close to the that needed for AWAKE. Longer cells are also in preparation.The key issues to be worked on during the next year are:* Obtain gas pressure stability in the glass tube; * Obtain the required plasma uniformity;* Measure the required plasma density;* Ensure HV setup reliability;* Comply with CERN standards;* Development of longer (up to 10 m) prototypes.