The BRAN luminosity detectors for the LHC
The BRAN luminosity detectors for the LHC
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LHC 的 BRAN 光度探测器
DOI：
10.1016/j.nima.2016.12.019
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发表时间：
2016
影响因子：
1.4
通讯作者：
R. Miyamoto
中科院分区：
文献类型：
--
作者：
H. Matis;M. Placidi;A. Ratti;W. Turner;E. Bravin;R. Miyamoto
本文介绍了LHC中BRAN（BeamRAte of Neutrals）相对光度监测器的概念设计、原型制作、建造和束流测试，以及安装和运行的几个阶段。探测器自2009年以来一直在运行，以促进、优化和维持两个高光度相互作用区域（IR）的加速器性能，即IR 1（ATLAS）和IR 5（CMS）。这些装置是安装在中性粒子吸收器内的气体电离室，距离IR 1和IR 5的相互作用点140米，并监测碰撞产生的高能中性粒子产生的电磁簇射所沉积的能量。该探测器有能力解决在40 MHz的聚束率，以及生存的极端水平的辐射在名义上的LHC操作的聚束亮度。自加速器早期调试阶段以来，这些装置已经在广泛的光度范围内运行，达到1.4×1034cm−2s− 1，峰值堆积为每束交叉45个事件。尽管LHC的标称设计光度已被超过，BRAN运行良好。在描述了如何BRAN可以用来监测对撞机的光度后，我们讨论了技术的选择，导致其建设和不同的测试之前进行的安装在两个IR的LHC。给出了性能模拟和在p操作过程中得到的操作结果，包括在40 MHz聚束速率下的操作、Pb操作和p操作。
This paper describes the several phases which led, from the conceptual design, prototyping, construction and tests with beam, to the installation and operation of the BRAN (BeamRAte ofNeutrals) relative luminosity monitors for the LHC. The detectors have been operating since 2009 to contribute, optimize and maintain the accelerator performance in the two high luminosity interaction regions (IR), the IR1 (ATLAS) and the IR5 (CMS). The devices are gas ionization chambers installed inside a neutral particle absorber 140 m away from the Interaction Points in IR1 and IR5 and monitor the energy deposited by electromagnetic showers produced by high-energy neutral particles from the collisions. The detectors have the capability to resolve the bunch-by-bunch luminosity at the 40 MHz bunch rate, as well as to survive the extreme level of radiation during the nominal LHC operation. The devices have operated since the early commissioning phase of the accelerator over a broad range of luminosities reaching 1.4×1034cm−2s−1with a peak pileup of 45 events per bunch crossing. Even though the nominal design luminosity of the LHC has been exceeded, the BRAN is operating well.After describing how the BRAN can be used to monitor the luminosity of the collider, we discuss the technical choices that led to its construction and the different tests performed prior to the installation in two IRs of the LHC. Performance simulations are presented together with operational results obtained duringp-poperations, including runs at 40 MHz bunch rate,Pb-Pboperations andp-Pboperations.