Development of Radiation-Hard Single-Sided Silicon Pixel Detectors using Planar p-type Technology

欧洲核子研究中心（CERN）的大型强子对撞机（LHC）已经需要前所未有的辐射硬度，因为产生罕见的高质量新粒子需要非常高的碰撞率（每秒10亿个质子-质子碰撞），而建造LHC就是为了寻找这些新粒子。探测器离碰撞点越近，辐射水平越差，而最里面的探测器系统，像素探测器，只有几厘米远。在第一阶段运行之后，大型强子对撞机可以升级，通过将碰撞率提高10倍来寻找更罕见或更大质量的新粒子。然后，在最接近碰撞的层中经历的剂量率会恶化10倍。假设标准技术几乎不能满足LHC当前的运行，研究小组一直在寻找这些最内层的奇异替代方案。利物浦小组在研究微型微带探测器时，将其应用于远离实验中心的地方，得到了一个令人惊讶的结果，即它们作为粒子探测器运行的关键参数——电荷收集效率，即使在非常高的剂量下也不会完全消失。事实上，使用p型传感器，但只进行平面处理，看起来有可能用不那么新奇的技术制造探测器，甚至可以在距离主要碰撞点约4厘米的地方工作。建议将该技术转化为这些低半径所需的像素设计，并使用ATLAS的像素读出电子设备演示在预期剂量下的存活。利物浦小组是微带辐射测试方面的世界专家，他们希望利用他们的发现，为在升级光度（超级）大型强子对撞机上运行的ATLAS和CMS的像素探测器展示一种替代技术。如果成功，它将允许世界领先的公司在为粒子物理学提供硅探测器方面建立更简单的技术，这对可靠性和成本都有影响。它还允许以统一的技术构建像素探测器阵列，而不是为最内层使用特殊和不同的技术。这将有助于找到一个更便宜的解决方案，并允许更多的公司（包括英国公司）竞争超级大型强子对撞机像素探测器的硅传感器生产。

The Large Hadron Collider (LHC) at CERN already requires unprecedented radiation hardness because of the very high collision rate (billion proton-proton collisions per second) required to produced the rare high mass new particles for which the LHC was built to search. The radiation levels get worse the closer a detector sits to the collision point with the innermost detector systems, pixel detectors, being only a few cm away. After its first phase of operation, the LHC could be upgraded to search for even rarer or higher mass new particles by increasing this collision rate by a factor of 10. The dose rates then experienced in the layers closest to the collisions get a factor of 10 worse. Given that it is assumed standard technologies can barely serve for current operation at the LHC, groups have been looking to exotic alternatives for these innermost layers. A surprising result from work by the Liverpool Group when studying miniature microstrip detectors, with application further away from the centre of the experiment, was that they key parameter for operation as a particle detector, the charge collection efficiency, does not completely die away even at very high doses. Indeed, with p-type sensors but only planar processing, it looks possible to build detectors in much less exotic technologies that could work even at about 4cm from the primary collision point. It is proposed to translate this technology into the pixel designs needed at these low radii and to demonstrate survival at the doses expected there using pixel read-out electronics from ATLAS. The Liverpool Group are world experts at this sort of radiation testing for microstrips and wish to exploit their findings to demonstrate an alternative technology for the pixel detectors of ATLAS and CMS operating at the upgraded luminosity (Super-) LHC. If successful, it allows simpler technology which can be built by the leading world companies in providing silicon detectors to particle physics, with implications for both reliability and cost. It also allows the pixel detector array to be built in a uniform technology, rather than have special and different technology for the innermost layers. This should both help lead to a cheaper solution and allow many more companies (including UK ones) to compete for the production of silicon sensors for pixel detectors at the Super-LHC.