Future searches for new physics beyond the Standard Model are without doubt in need of a diverse approach and experiments with complementary sensitivities to different types of classes of models. One ...of the directions that should be explored is feebly interacting particles (FIPs) with masses below the electroweak scale. The interest in FIPs has significantly increased in the last ten years. Searches for FIPs at colliders have intrinsic limitations in the region they may probe, significantly restricting exploration of the mass range
m
FIP
<
5
-
10
GeV/c
2
. Beam dump-like experiments, characterized by the possibility of extremely high luminosity at relatively high energies and the effective coverage of the production and decay acceptance, are the perfect option to generically explore the “coupling frontier” of the light FIPs. Several proposals for beam-dump detectors are currently being considered by CERN for implementation at the SPS ECN3 beam facility. In this paper, we analyse in depth how the characteristic geometric parameters of a beam dump experiment influence the signal yield. We apply an inclusive approach by considering the phenomenology of different types of FIPs. From the various production modes and kinematics, we demonstrate that the optimal layout that maximises the production and decay acceptance consists of a detector located on the beam-axis, at the shortest possible distance from the target defined by the systems required to suppress the beam-induced backgrounds.
The Search for Hidden Particles (SHiP) experiment is a new purpose fixed target facility proposed for the CERN Super Proton Synchrotron accelerator to search for long-lived exotic particles ...associated with Hidden Sectors and Dark Matter. This paper reports on the development of BIM integrated design for the SHiP experiment, applied initially to the Decay Volume, a >2000 m3 conical steel vessel under a vacuum hosting several large particle physics detector systems. A BIM methodology is used to address all the design phases of the Decay Volume of the SHiP experiment from the conceptual planning to the constructive drawings production. This proposed workflow is a basic plan to be repeated for each sub-component of the SHiP experiment in order to have a full and overall integration of the experiment. In particular, the Decay Volume’s geometrical and structural design and the simulation of its assembly process, both in factory and on site, are proposed. Moreover, the use of collaborative platforms to speed up the ideas exchange, as the basis of a highly multidisciplinary and complex project, is discussed. The complexity, multidisciplinary nature, and size of the SHiP project severely challenge design information management. The final plan to solve this issue is to have a BIM integrated design of each experiment sub-component, such as that demonstrated in this work for the Decay Volume, in order to have a full and multidisciplinary integration of the overall project.
The LHCb Upgrade Jacobsson, Richard
EPJ Web of conferences,
2013, Volume:
60
Journal Article
Peer reviewed
Open access
With the demonstration that LHCb can successfully perform forward precision measurements with event pileup, the operation and trigger strategy evolved significantly during the LHC Run 1 allowing LHCb ...to collect over 3fbsup -1 at centre-of-mass energies of 7TeV and 8TeV. Increased bandwidth opened the door for LHCb to extend the physics program. LHCb will therefore undergo a major upgrade in LS 2 ( 2018-2019) aimed at collecting an order of magnitude more data by 2028. The upgrade consists of a full readout at the LHC bunch crossing rate (40 MHz) with the ultimate flexibility of only a software trigger. In order to increase the instantaneous luminosity up to 2x10sup 33cmsup -2ssup -1, several sub-detector upgrades are also underway to cope with the higher occupancies and radiation dose.
The LHCb experiment at CERN has proposed an upgrade towards a full 40 MHz readout system in order to run between five and ten times its initial design luminosity. The various subsystems in the ...readout architecture will be upgraded to cope with higher subdetector occupancies, higher rate, and higher readout load. We introduce here the new architecture, the new functionalities, and the first hardware implementation of the new LHCb Fast Readout Control system (S-TFC) for the upgraded LHCb experiment. Moreover, in this particular paper we focus our attention in describing solutions for the distribution of clock and timing information to control the entire upgraded readout architecture by profiting of a bidirectional optical network and powerful FPGAs, including a real-time mechanism to synchronize the entire system. Protocols and FPGA logic are also described, together with first results on the simulation and the validation of the system. This paper is a public excerpt of the technical documentation for the LHCb upgrade.
The Search for Hidden Particles (SHiP) experiment is a new general-purpose fixed target facility proposed at the CERN Super Proton Synchrotron (SPS) accelerator to search for long-lived exotic ...particles associated with Hidden Sectors and Dark Matter. This paper reports on the structural design of SHiP’s decay volume,
a
> 2000 m
3
conical vessel under vacuum that should host several large particle physics detector systems. In the field of structural and seismic engineering, the design study in a very multidisciplinary international collaboration has represented a stimulating research challenge. The goal of the design of the decay is to produce a structure as light and as slim as possible to stay within the geometrical envelop determined in the physics simulations. A complete study has been performed with all the steps from the conceptual design, including the interaction with other components and the plant systems, to the assembly procedures for the decay volume realization. The complexity of the case study has been driven by the need of finding the appropriate compromise between the physics performance, the structural aspects, the executive, constructive and operational issues, and the economical constraints. The assembly strategy, the welding techniques, and the expected construction time are discussed in view of the extremely complex installation phase. Building Integrated Model (BIM) methodology is also proposed as an essential tool to coordinate the entire process of designing and managing not only the decay volume but the entire project.
The readout strategy of the LHCb experiment is based on complete event readout at 1MHz. A set of 320 sub-detector readout boards transmit event fragments at total rate of 24.6MHz at a bandwidth usage ...of up to 70GB/s over a commercial switching network based on Gigabit Ethernet to a distributed event building and high-level trigger processing farm with 1470 individual multi-core computer nodes. In the original specifications, the readout was based on a pure push protocol. This paper describes the proposal, implementation, and experience of a non-conventional mixture of a push and a pull protocol, akin to credit-based flow control. An FPGA-based central master module, partly operating at the LHC bunch clock frequency of 40.08MHz and partly at a double clock speed, is in charge of the entire trigger and readout control from the front-end electronics up to the high-level trigger farm. One FPGA is dedicated to controlling the event fragment packing in the readout boards, the assignment of the farm node destination for each event, and controls the farm load based on an asynchronous pull mechanism from each farm node. This dynamic readout scheme relies on generic event requests and the concept of node credit allowing load control and trigger rate regulation as a function of the global farm load. It also allows the vital task of fast central monitoring and automatic recovery in-flight of failing nodes while maintaining dead-time and event loss at a minimum.
This paper demonstrates the strength and suitability of implementing this real-time task for a very large distributed system in an FPGA where no random delays are introduced, and where extreme reliability and accurate event accounting are fundamental requirements. It was in use during the entire commissioning phase of LHCb and has been in faultless operation during the first two years of physics luminosity data taking.
The LHCb experiment at CERN's Large Hadron Collider (LHC) searches for New Physics through precision measurements in the domain of heavy flavour physics, exploiting in particular the large B hadron ...production. After a short introduction to the requirements of the LHCb detector, this paper reviews the operational strategy during the first three years of data taking. The focus is on the detector performance together with a description of several fundamental system developments which emerged in this period and which allowed LHCb to venture well beyond its design parameters and to extend the physics program. With the inclusion of a solid charm physics program and electroweak and soft QCD measurements in the forward direction, LHCb has established itself as an excellent forward general purpose detector at the LHC. Running at twice the design luminosity, LHCb has been able to collect an integrated luminosity of more than 3 fb-! at an operational inefficiency of less than 4% in the first three years.
This paper addresses several aspects of implementing a remote control system for a large number of electronics boards in order to perform remote Field Programmable Gate Array (FPGA) programming, ...hardware configuration, data register access, and monitoring, as well as interfacing it to an expert system. The paper presents a common strategy for the representation of the boards in the abstraction layer of the control system, and generic communication protocols for the access to the board resources. In addition, an implementation is proposed in which the mapping between the functional parameters and the physical registers of the different boards is represented by descriptors in the board representation such that the translation can be handled automatically by a generic translation manager. Using the Distributed Information Management (DIM) package for the control communication with the boards, and the industry SCADA system PVSS II from ETM, a complete control system has been built for the Timing and Fast Control (TFC) system of the LHCb experiment at CERN. It has been in use during the entire prototyping of the TFC system and the developments of the LHCb sub-detector electronics, and is now installed in the online system of the final experiment.
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