The Linear Accelerator Laboratory: furthering fundamental physics

The Linear Accelerator Laboratory: furthering fundamental physics

Achille Stocchi outlines the Linear Accelerator Laboratory’s contributions to various areas of the physics landscapes and introduces a new laboratory.

The Linear Accelerator Laboratory is a fundamental research laboratory focused on the physics of ‘the two infinites’: on the one hand, the study of the ultimate components of matter, the elementary particles; and on the other, cosmology with the history, composition and evolution of the Universe. As its name suggests, since it was founded in 1956, LAL (Laboratoire de l’Accélérateur Linéaire) has been closely related to particle accelerators, both in terms of physics and related technological developments.

The Linear Accelerator Laboratory is a joint unit of National Center for Scientific Research (CNRS) and University Paris-Sud. The laboratory’s physicists (of which there are about 120) are either CNRS researchers or teacher-researchers. In general, the Linear Accelerator Laboratory is very involved in teaching activities at all levels – bachelor, masters, engineering schools – and about 15 students start a PhD thesis every year. More than 100 internship students are present each year in the laboratory. Lastly, the LAL has continued and accentuated its vocation of transmitting knowledge via teaching activities to which is added communication towards the general public. The successes of recent years are called the creation of the Review ‘Elementaire’, The Museum/Association Sciences-ACO, the Masterclasses of CERN, the project Passport for Two Infinite or the annual schools TESHEP in the East Europe, WISHEPP in Palestine.

Science and technology

The Linear Accelerator Laboratory’s success is primarily based on high quality technical and administrative services, bringing together a total of 200 engineers and technicians. Electronic, mechanical, computer and accelerator engineers conceive, implement, install and maintain essential elements of the experiments in which the Linear Accelerator Laboratory is engaged, both locally and in the world’s largest laboratories. The administrative, infrastructure and logistics departments allow that all this work is done in the best conditions.

Gravitational waves discovery

The year 2016 was marked by the discovery of gravitational waves. The fusion of two black holes as well as the collapse of neutron starts has been detected (see Fig. 1). The Linear Accelerator Laboratory is the historical laboratory of the French collaboration of Virgo/Ligo Collaboration and played an important role in the direct search of gravitational waves and its detection for the last 25 years.

Particle physics

The Linear Accelerator Laboratory also contributes to the experiments taking place with the Large Hadron Collider (LHC) at CERN. The Linear Accelerator Laboratory has played an important role in the ATLAS experiment and in the discovery and study of the characteristics of the Higgs boson discovered in 2012. LAL also participated to the construction of the detector and is now involved in the upgrade. The LHCb experiment also took data and produced a lot of results, measuring rare decays and processes that violated CP symmetry (in the area of beautiful and charmed hadrons), with the aim of observing disagreements about the Standard Model. The particle physics programme is completed with participation in the ILC programme, the possible future linear collider in Japan and the participation to Belle II experiments, the super B-factory at the KEKB machine in Japan.

Astrophysics and cosmology

In Cosmology, recent years have been marked by the results of the Planck satellite, with the new maps of the CMB (Cosmological Microwave Background). These results tell us that we live in a Universe made up of a lot of dark matter (27%) and dark energy (68%), with only 5% of visible matter. The LAL teams are already actively participating with a strong implication on the future large telescope LSST (Large Synoptic Survey Telescope) for the black energy and black matter characterisation and studies as well as in the BAORadio project in collaboration with China. LAL teams are also contributing to the experiments for the future of CMB activities (QUBIC and LiteBird).

LAL has also an activity on neutrino physics via its participation in the NEMO experiment in the Modane underground laboratory searching for the neutrino-less double beta decay, which can elucidate the nature of the neutrino particle. LAL has also recently joined the Solid experiment at the Mol reactor in Belgium for investigations into the possible existence of extra neutrino (sterile neutrinos).

Another central theme is the direct search of the dark matter, and LAL physicists have recently jointed the XENON experiment, a large detector installed at the Gran Sasso underground laboratory in Italy.

Accelerator experiments

The LAL is also involved in several accelerator experiments, such as XFEL, the fourth generation light source, installed at DESY to produce a very high flux of X-rays. LAL has been responsible for the conditioning and serial supply of 820 1.3 GHz couplers here.
One of the central projects at LAL in is ThomX. ThomX (see Fig. 2) is a compact source of high-flux ‘hard’ (tens of keV) X-rays obtained by Compton backscattering of a 50 MeV electron beam on an amplified laser with a Fabry-Perot cavity. The potential applications of this type of machine are numerous: medical or life sciences, materials study and art conservation, and more. ThomX will be installed at the end of 2018 and will start to operate in 2019.

We are also working on improving the collimation of the LHC through the use of bent crystal (UA9), and we continued to carry out experiments with the ATF2 platform in Japan and in the BEAST collaboration for machine studies and luminosity measurement at KEKB, also in Japan. The LaseriX platform, a UHI laser at 40J and 40fs has been installed at LAL coupled to the electron photoinjector, PHIL. The combination of the two instruments should allow in the coming years to perform laser/plasma acceleration experiments.

Many detectors have been conceived and constructed for all of the above-mentioned experiments. In addition, we are also seeing the emergence of instrumental projects with a strong orientation in medical applications (such as SIPMED and SONIM).

The richness of the research spectrum is completed by other technology platforms: Virtual Data (mass calculations/grid/cloud), Corto (muons telescope for the characterisation of detectors), Captinnov (detector tests). All of these platforms, together with the others already mentioned (LaseriX, PHIL, XFEL), are not only research but also pedagogical platforms.

Unification of the Orsay Laboratories

In the last two years we have started a project to unify five laboratories present in the Paris-Sud Campus le Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), le Laboratoire d’Imagerie et Modélisation en Neurobiologie et Cancérologie (IMNC), l’Institut de Physique Nucléaire d’Orsay (IPNO), le Laboratoires de l’Accélérateur Linéaire (LAL) et le Laboratoire de Physique Théorique (LPT).

A new laboratory (consisting of about 800 people) will be created the 1 January 2020. It will include new fields of investigation and will cover the entire spectrum of the two infinity physics, including also a large element of medical science and of theory. This laboratory will have the capacity and vocation to be a world leader in a wide range of scientific and technical domains. The research themes of the new laboratory are:

  • Nuclear physics;
  • Nuclear astrophysics and astrochemistry;
  • Health physics;
  • Solid-state physics;
  • Particle physics;
  • Hadronic physics;
  • Data science;
  • Theory;
  • Nuclear energy and environment;
  • Neutrinos;
  • Dark matter;
  • Astroparticles and Cosmology;
  • Accelerator physics; and
  • Detector R&D.

This new laboratory aims to be the driving force for several major flagship projects at both the national and international level, with some of its projects coming from the historical disciplines of the participating laboratories, and others coming from emerging themes at their interfaces. One of the force of this new laboratory will be the presence of a strong pole of engineering, grouping about 300 people working on instrumentation, electronics, mechanics and informatics and acceleration techniques and who are capable to design, develop and use the instruments needed for the challenges of the coming decades (accelerators and detectors).

Achille Stocchi
Linear Accelerator Laboratory (LAL)
+33(0)1 64 46 83 02
Tweet @LALOrsay

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