Precise luminosity measurements for the OLYMPUS two-photon exchange experiment at DESY were performed by counting scattering events with alternating beams of electrons and positrons incident on atomic electrons in a gaseous hydrogen target. Final products of Møller, Bhabha, and pair annihilation interactions were observed using a pair of lead fluoride Cherenkov calorimeters with custom housings and electronics, adapted from a system used by the A4 parity violation experiment at MAMI. This paper describes the design, calibration, and operation of these detectors. An explanation of the Monte Carlo methods used to simulate the physical processes involved both at the scattering vertices and in the detector apparatus is also included.
Fast Beam Condition Monitor for CMS: performance and upgrade
CMS束流和辐射监测子系统BCM1F（快速束流状态监测器）由8个独立的金刚石传感器组成，位于像素探测器体积内的束管周围，用于快速逐束流监测束流背景和碰撞产物。此外，正在努力将BCM1F用作在线光度监测器。BCM1F将在LHC中有束流时运行，其数据采集独立于CMS探测器的数据采集，因此即使CMS没有采集数据，它也会提供亮度。报告给出了在LHC运行I期间BCM1F的性能，包括2012年完成的van der Meer扫描和在线光度监测的结果。为了满足更高亮度和25 ns聚束间距的要求，在即将到来的关机期间必须对系统进行几项更改，包括升级电子设备和精确的增益监控。显示了运行II制备的第一批结果。
A network of 16 Medipix-2 (MPX) silicon pixel devices was installed in the ATLAS detector cavern at CERN. It was designed to measure the composition and spectral characteristics of the radiation field in the ATLAS experiment and its surroundings. This study demonstrates that the MPX network can also be used as a self-sufficient luminosity monitoring system. The MPX detectors collect data independently of the ATLAS data-recording chain, and thus they provide independent measurements of the bunch-integrated ATLAS/LHC luminosity. In particular, the MPX detectors located close enough to the primar…
For cross section measurements, an accurate knowledge of the integrated luminosity is required. The FCC-ee Z lineshape programme sets the ambitious precision goal of $10^{-4}$ on the \emph{absolute} luminosity measurement and one order of magnitude better on the \emph{relative} measurement between energy-scan points. The luminosity is determined from the rate of small-angle Bhabha scattering, $\mathrm{e^+e^- \to e^+e^-}$, where the final state electrons and positrons are detected in dedicated monitors covering small angles from the outgoing beam directions. The constraints on the luminosity mo…
ATLAS-MPX探测器基于欧洲核子研究中心设计的Medipix 2硅器件，用于探测多种类型的辐射。2008年至2013年，16个这样的探测器在LHC的ATLAS探测器中成功运行，并独立于ATLAS数据记录链收集数据。每个ATLAS-MPX探测器提供单独的测量聚束集成LHC光度。亮度监测的内部一致性约为2%。此外，靠近光束的MPX设备足够灵敏，可以在van der Meer校准扫描期间提供相对光度测量，其低光度范围低于基于ATLAS热量计的聚束积分光度计的灵敏度。这些光度研究的初步结果是针对2012年在sqrt（s）=8 TeV质子-质子碰撞中获得的数据。
New front-end electronics including ASICs and FPGA boards are under development for the ATLAS Monitored Drift Tube (MDT) detector to handle the large data rates and harsh environment expected at high-luminosity LHC runs. A mobile Data Acquisition (miniDAQ) system is designed to perform integration tests of these front-end electronics. In addition, it will be used for surface commissioning of 96 small-radius MDT (sMDT) chambers and for integration and commissioning of new front-end electronics on the present ATLAS MDT chambers. Details of the miniDAQ hardware and firmware are described in this …
The Belle II detector is currently under construction at the SuperKEKB electron-positron high-luminosity collider, that will provide an instantaneous luminosity 40 times higher than that of KEKB. There- fore the Belle-II VerteX Detector (VXD) will operate in a very harsh environment. A radiation monitoring and beam abort system is needed to safely operate the VXD detector in these conditions. This system is based on 20 single crystal CVD diamond sensors placed in 20 key positions in the vicinity of the VXD and interaction region. In this contribution we describe the system design and we presen…
A luminosity monitor, based on plastic scintillator detectors, has been developed for the SIDDHARTA-2 experiment aiming to perform high precision measurements of kaonic atoms and was installed in 2020 on the DAFNE $e^+e^-$ collider at LNF (Laboratori Nazionali di Frascati, INFN). The main goal of this system is to provide the~instantaneous and integrated luminosity of the DAFNE facility by measuring the rate of $K^+K^-$ correlated pairs emitted by the phi meson decay. This task requires an accurate timing of the DAQ signals, as well as timing resolution below 1ns, in order to disentangle the $…
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 (Beam RAte of Neutrals) 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 de…
At high luminosity areas, beam loss monitor with fast response and high radiation resistance is crucial for accelerator operation. In this article, we report the design and test results of a fast response and radiation-resistant scintillator detector as the beam loss monitor for high luminosity colliders, especially at low energy regions such as RFQ. The detector consists of a 2 cm*2 cm 0.5 cm LYSO crystal readout by a 6 mm*6 mm Silicon photomultiplier. Test results from various radioactive sources show that the detector has good sensitivity to photons from tens of keV to several MeV with good…
The OLYMPUS experiment measured the cross-section ratio of positron-proton elastic scattering relative to electron-proton elastic scattering to look for evidence of hard two-photon exchange. To make this measurement, the experiment alternated between electron beam and positron beam running modes, with the relative integrated luminosities of the two running modes providing the crucial normalization. For this reason, OLYMPUS had several redundant luminosity monitoring systems, including a pair of electromagnetic calorimeters positioned downstream from the target to detect symmetric Mø ller and B…
Design and performance of the Fast Beam Condition Monitor for luminosity and background measurement at the CMS Experiment in LHC Run 3
Deutsches Elektronen-Synchrotron（德国电子同步辐射中心）；Ghent University（根特大学）；Universidade Estadual Paulista（圣保罗州立大学）；Assiut University（艾斯尤特大学）；National and Kapodistrian University of Athens（雅典国立卡波季斯特里安大学）；HUN-REN Wigner Research Centre for Physics（匈牙利研究与教育网络维格纳物理研究中心）；Tata Institute of Fundamental Research（塔塔基础研究所）；Sharif University of Technology（谢里夫理工大学）；Ecole Polytechnique Fédérale Lausanne（洛桑联邦理工学院）；University of Oxford（牛津大学）；Massachusetts Institute of Technology（麻省理工学院）
The Compact Muon Solenoid (CMS) is a large and complex general purpose experiment at the CERN Large Hadron Collider (LHC), built and maintained by many collaborators from around the world. Efficient operation of the detector requires widespread and timely access to a broad range of monitoring and status information. To this end the Web Based Monitoring (WBM) system was developed to present data to users located anywhere from many underlying heterogeneous sources, from real time messaging systems to relational databases. This system provides the power to combine and correlate data in both graph…
Development of a Silicon-Based Ultra-Fast X-Ray Beam Size Monitor for SuperKEKB
University of Hawaii（夏威夷大学）；High Energy Accelerator Research Organization (KEK)（高能加速器研究机构）；Department of Physics, University of Tokyo（东京大学物理系）；The Graduate University for Advanced Studies (SOKENDAI)（综合研究大学院大学）；SLAC National Accelerator Laboratory（SLAC国家加速器实验室）；Graduate School of Science, Nagoya University（名古屋大学理学研究科）
The upgrade of the ATLAS muon spectrometer for high-luminosity LHC requires new trigger and readout electronics for the various elements of the detector. We present the design of a time-to-digital converter (TDC) ASIC prototype for the ATLAS Monitored Drift Tube (MDT) detector. The chip was fabricated in a GlobalFoundries 130 nm CMOS technology. Studies indicate that its timing and power consumption characteristics meet the design specifications, with a timing bin variation of 40 ps for all 48 channels with a power consumption of about 6.5 mW per channel.
The Belle II experiment has just started, searching for physics beyond the Standard Model in $B$, charm and $τ$ decays using data with the integrated luminosity goal of $50 ~\mathrm{ab}^{-1}$. Before the physics run with full detector system being installed, Belle II Phase 2 run is on-going at the time of the conference, until July 2018. In this presentation, we describe the environmental monitoring system with an emphasis on the software tools to help the experts and the non-expert shifters who operate the experiment. The monitoring tools are prepared on the control room especially for the sh…
We present the second prototype of a time-to-digital (TDC) ASIC for the upgrade of the ATLAS Monitored Drift Tube (MDT) detector for High-Luminosity LHC operations. Compared to the first prototype, triple modular redundancy has been implemented for the configuration and flow control logic. The total power consumption is increased by less than 10 mW while achieving the same time resolution and channel uniformity. A mini-DAQ system has been built to verify the front-end electronics chain with the new prototype together with other ASICs and boards in triggered mode. Cosmic ray tests with a small-…
We present the prototype of a time-to-digital (TDC) ASIC for the upgrade of the ATLAS Monitored Drift Tube (MDT) detector for high-luminosity LHC operation. This ASIC is based on a previously submitted demonstrator ASIC designed for timing performance evaluation, and includes all features necessary for the various operation modes, as well as the migration to the TSMC 130 nm CMOS technology. We present the TDC design with the emphasis on added features and performance optimization. Tests of the timing performance demonstrate that this ASIC meets the design specifications. The TDC has a bin size…
