LHCLarge Hadron Collider (LHC) detector upgrades


Prof.dr. Stan Bentvelsen
Science Park 105, 1098 XG Amsterdam
NWO-I Nikhef, Utrecht University, Radboud University, University of Amsterdam, Free University Amsterdam, University of Groningen, Maastricht University

The LHC is the world’s most powerful particle accelerator. In an earlier stage, the LHC experiments already discovered the Higgs particle. They are expected to further clarify some of mankind’s most intriguing mysteries:
• What is the particle content of our Universe,
• How do these particles interact and
• How do the properties of complex matter in our Universe emerge?

Anticipated breakthroughs are: elementary-particle masses (Higgs physics); matter-antimatter asymmetry (CP-violation), the search for Dark Matter (supersymmetry), and Quark-Gluon plasma. This progress report updates the Nikhef activities on the LHC-detector upgrades including the Dutch grid-compute center NL/Tier-1, which secure the present excellent position of Dutch physicists to exploit the full LHC discovery potential during the next decade.

The LHC has been operating at the highest attainable collision energy since 2015; further improvements required to address the above physics questions need to come from a significant increase in beam intensity. This will happen in two phases: preparations are presently ongoing for phase-1 (until 2023), which will double the amount of collisions with respect to today. In phase-2, the total number of collisions will be increased by another factor of ten. Significant upgrades to the detectors are required to maintain optimal exploitation and discovery potential.

The responsibilities taken by Nikhef in view of this roadmap are summarized as
ATLAS (phase-1):
• Implementation of the readout of the New Small Wheel (NSW) detectors as part of the Muon Spectrometer. The NSW improves the granularity of the muon spectrometer, yielding a better detection efficiency for e.g. the Higgs particle. The project includes the production of magnetic field and temperature sensors.
• Development of the Front-End LInk eXchange (FELIX) PC based solution to readout the data from the new detectors installed in preparation for Run 3. Nikhef co-ordinates the firmware and software development efforts and contributes important parts to it.

ATLAS (phase-2):
• The complete Inner Tracker will need to be replaced. Nikhef will design and construct the silicon strip endcap support structures, and assemble one of its two endcaps.
• Further development of the FELIX readout, using new hardware to adapt to higher rate requirements and to deploy the technology to readout all detector subsystems. Nikhef will again co-ordinate the firmware and software development.
• The innermost layer of the Muon Spectrometer will be replaced. Nikhef will contribute the alignment system, and electronics used to monitor the temperature and the magnetic field.

LHCb (phase-1): The Dutch contribution to the LHCb detector upgrade include:
• The production of the silicon detector modules for a new Si micro-vertex pixel detector, the design of the VeloPix ASIC chip and the vacuum encapsulation mechanics of the detector.
• Construction of a large surface scintillating fibre tracker measuring particle tracks in the LHCb dipole magnet field. Contributions include the design and construction of the modules, the cold-boxes housing the Silicon Photomultiplier detectors, the development of Front-End electronics boards and the overall infrastructure of the detector.
• A common contribution of all institutes to the High Level Trigger computing farm as well as the development and commissioning of corresponding Real-Time-Reconstruction algorithms.

ALICE (phase-1):
• Nikhef contributes to the design, electronics and assembly of the new CMOS Monolithic Active Pixel Sensor (MAPS) inner tracking detector. This detector is installed during LS2 and allows for the readout and recording of Pb-Pb minimum bias events at rates of excess of 50 kHz, which is the expected rate the LHC can deliver after LS2. The Dutch contribution is the design of part of the MAPS chip, a common contribution to the acquirement of the chips, the assembly of 25 staves for this detector, producing and testing the read-out boards, and a contribution to the cooling system.

Computing (ALICE, ATLAS, LHCb):
• Provision of ~10% of the global Tier-1 computing needs of the three experiments (each experiment has ~10 Tier-1s world-wide). This relies on the expertise of Nikhef and partners in the Dutch National eInfrastructure (DNeI) for large-scale high-performance computing, storage, and advanced networking. R&D work to follow the increasing capacity requirements are funded partly by the DNeI.

Research at the LHC fits perfectly in the Nationale Wetenschaps Agenda route “Bouwstenen van materie en fundamenten van ruimte en tijd” with corresponding questions NW128 “Kennen we alle elementaire bouwstenen van materie?” and NW130 “Wat is donkere materie en wat is donkere energie?”. The data-intensive, high throughput computing infrastructure fits very well in the Big Data route of the NWA.

Aansluiting bij strategische ontwikkelingen
High Tech Systemen en Materialen
Bouwstenen van materie en fundamenten van ruimte en tijd
Waardecreatie door verantwoorde toegang tot en gebruik van big data