ALICE

The ALICE detector
(Credit: CERN)

(A Large Ion Collider Experiment)

Hosted at CERN, ALICE is dedicated to the physics of matter at an infinitely small scale and has made crucial new observations and measurements in the quest to understand excited hadronic matter. ALICE studies the physics of strongly interacting matter at extreme energy densities, where a phase of matter called Quark-Gluon Plasma (QGP) forms.

ALICE uses a highly sensitive detector which takes measurements of hadrons, electrons, muons and photons produced in the collision of nuclei. ALICE has confirmed the basic picture of QGP as an almost-perfect liquid. This success has paved the future of ALICE where it is now important to upgrade the instrument to produce high precision measurements. Further information on ALICE at CERN can be found here.

Quick facts

Quick Facts about the ALICE Detector
Size 26m long, 16m in diameter
Weight 10,000 tonnes
Design Central barrel with a single arm forward muon spectrometer
Quick Facts about the ALICE People
Collaboration More than 1500 physicists, engineers technicians, students and support staff
Number of countries 37
Number of institutes 154
Number of UK institutes 4

Flying over ALICE
(Credit: CERN on behalf of the ALICE experiment)

ALICE Upgrade

ALICE official schematics
(Credit: CERN)

Currently, ALICE is undergoing an upgrade to coincide with the long shutdown (LS2) at CERN. This upgrade encompasses a number of detector, trigger, software and computing developments that will be required to take high precision measurements and continue the exploitation of ALICE through the next decade. Upgrading ALICE will help to determine the precise properties of QGP and go a long way towards a better understanding of Quantum Chromodynamics.

The UK is playing a leading role in the ALICE upgrade, in particular the upgrades to the Central Trigger Processor and the Inner Tracking System.

Science Challenges

The ALICE research programme is key to achieving STFC’s science challenges and hopes to help answer the following questions:

  • What is the physics of the early Universe?
  • How do galaxies evolve?
  • What are the fundamental particles?
  • What is the nature of nuclear and hadronic matter?
  • How do the laws of physics work when driven to the extremes?
  • What can high energy particles tell us about the extreme Universe?

The UKs involvement

Lead collisions

One of the first events from lead-lead collisions at a centre-of-mass energy
(Credit: CERN)

The ALICE-UK Collaboration plays a leading role in the ALICE Upgrade at the LHC. ALICE-UK is developing upgrades for the Central Trigger Processor (CTP) and the Inner Tracking System (ITS). Due to the University of Birmingham’s knowledge and responsibility of operating the current CTP at CERN, Birmingham has been given the responsibility of designing, building and commissioning the CTP Upgrade. The CTP must be designed with the capability of managing a system of detectors with very different properties.

The University of Liverpool and Daresbury Laboratory are highly experienced in R&D, design and construction of silicon detectors, and in collaboration with France, Italy and the Netherlands, have been given the responsibility of designing, building and commissioning the outer layers of the outer barrel of the ITS upgrade. Both of these projects are funded by STFC over a 4 year period from 2015 to 2019, and are fundamental to the ALICE Upgrade.

Impact

There have been a variety of technological advancements resulting from the ambition of understanding matter. Monolithic Active Pixel Sensors (MAPS), which will be developed as part of the ALICE Upgrade, has important consequences for medical imaging. The increased speed of MAPS, compared to more traditional charged coupled devices, will potentially allow diagnosis using lower radiation doses of, for example x-rays.

PhD students and Postdoctoral Research Assistants are also at the heart of the ALICE Upgrade. Investing in the next generation of scientists is key to the future development of state-of-the-art technology.

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