Collaborative Research: Development of a Particle Tracking System for the Qweak Experiment

俄亥俄大学将为杰斐逊实验室的量子弱实验设计和制造两套触发闪烁体。这一重要的新实验将测量质子的弱电荷，作为对弱混合角运行的精确测试，从而提供一个超越粒子物理标准模型的唯一灵敏的物理探针。触发闪烁体是Q弱粒子跟踪系统的重要组成部分，将在校准和背景测量期间用于启动电子和否决中性粒子。每个闪烁体的大小为225厘米x 16厘米x 1厘米，由BC408或同等产品制造。两端的非UVT光导将提供机械上可靠的光学耦合接头。直径5.1厘米、长5厘米的UVT棒将矩形光导耦合到光电倍增管上。闪烁体的长边将经过钻石研磨，末端将加工成600砂砾的砂光。考虑到厚度与长度的极端比例，闪烁体计数器必须由可安装到后室组件的框架支撑。为了减少辐射损害，在大电流运行模式下，该组件将从光束的直视下移除。探测器的组装和测试将在俄亥俄大学核与粒子物理研究所进行，由一名毕业生和至少一名本科生在奥珀教授的指导下完成。俄亥俄大学的团队还将开发这项实验所需的快速触发系统。当探测器被认为可以安装时，学生们将在杰斐逊实验室参与调试。

Ohio University will design and build two sets of triggerscintillators for the Qweak experiment at Jefferson Lab. Thisimportant new experiment will measure the weak charge of the proton,as a precision test of the running of the weak mixing angle, thusproviding a uniquely sensitive probe of physics beyond the StandardModel of particle physics. The trigger scintillators are an essential component of the Qweakparticle tracking system, and will be used to start the electronicsand to veto neutral particles during the calibration and backgroundmeasurements. Each scintillator will be 225 cm x 16 cm x 1 cm andmade from BC408 or its equivalent. Non-UVT lightguides at each endwill provide a mechanically reliable optical coupling joint. UVT rodsthat are 5.1 cm in diameter and 5 cm long will couple the rectangularlightguide to the photomultiplier tubes. The long edges of thescintillators will be diamond milled and the ends finished to a 600grit sanded finish. Given the extreme ratio of thickness to length,the scintillator counters must be supported by a frame which is thenmountable to the rear chamber package. To reduce radiation damage,this package will be removed from direct view of the beam for the highcurrent running mode. The assembly and testing of the detectors will be done at the OhioUniversity Institute for Nuclear and Particle Physics by a graduatestudent and at least one undergraduate student, under the supervisionof Professor Opper. The Ohio University group will also develop the fast triggering system which is required for this experiment. When the detectors have been deemed ready for installation, the students will participate in their commissioning at Jefferson Lab.