Megajoule Laser

CEA (Atomic Energy and Alternative Energy Commission) is a French government funded research organisation dedicated to the fields of energy, defense and security, information technologies and health technologies. It conducts fundamental and applied research into the design of nuclear reactors and the manufacturing of integrated circuits.

CEA plays a major role in sustaining long term French nuclear deterrent capabilities. Since 1996, when nuclear testing was ended, the operation and safety of weapons in the French deterrent force have been guaranteed by means of computer simulation. A key part of the Simulation program is the Megajoule Laser (LMJ) located on CESTA’s premises (Scientific and Technical Research Centre) near Bordeaux which allows researchers to study, at a very small scale, the behaviour of materials under extreme conditions similar to those reached during the operation of nuclear weapons. Projected to be the highest-energy laser in the world, with only a single equivalent in the United States, the project brought together some 250 multidisciplinary contractors that excelled in the conception, design and manufacturing of state-of-the-art technology to ensure the success of this exceptional research facility.

Thales was identified for its extensive expertise, notably in the fields of vacuum, high power electronics, high precision mechanics and fluid management.

Thales worked on several of the facility’s subassemblies, in particular:

Energy Storage System: Thales developed and supplies the Energy Storage Systems for the Megajoule Laser project. These systems power the flash lamps fitted in the laser’s amplifier section. The light emitted by the lamp is used to pump the laser. Ultimately, Thales will deliver these systems which store 300 MJ and activate the 7040 flash lamps required to operate the Laser at full power. The energy bank includes 352 modules each holding 10 capacitors. The 10 capacitors are charged at 24 kV within 1min30s and discharged into the flash lamps in roughly 1 ms.

Optical Interfaces: The final Opto-Mechanic System is a vacuum vessel attached to the experimental chamber, which allows the laser beam to penetrate the chamber and heat the target. The main capabilities of these sub-assemblies are to ensure tightness between the experimental chambers (under vacuum) and the outside, to act as a nuclear containment barrier and to enable automatic change of optics without a break in nuclear containment between the experimental chamber and the experiment room. Thales successfully assembled and performed tightness tests on the first Final Opto-Mechanic System on the Megajoule Laser (LMJ).

Plasma Diagnostics: Thales equipped the Megajoule Laser with the first Plasma Diagnostics System the ‘X Imager’ and the ‘X Spectrometer’. Plasma diagnostics are measuring instruments used to characterize the behaviour of the target during its operation. Their main function is to acquire and store the signals resulting from measurements on the impact products, and then transmit them to a control command system in order to obtain the physical quantities required.

Equipment for the experimental hall: Thales participated in the installation of the experimental chamber. Specifically it developed critical supporting elements which enable the use and maintenance of the experimental chamber. There structures used 800 tons of steel, 100 tons of aluminium and 2500 tons of concrete.

The first laser operation took place on 23rd October 2014 after almost two decades of R&D including innovative manufacturing methods developed by the project’s industrial partners. Thales collaborated closely with CEA from the start of the project, ensuring progress and success from the first laser shot.

This commercial success has been achieved thanks to the know-how of Thales’s Large Research Infrastructures for Science team. The team was able to offer the customer the development, production, integration and testing capabilities based on the multiple technologies required to produce these complex elements. Some of the specific domains of expertise that enabled Thales to excel in these challenging new systems include:

. Functional analysis based on customer specifications
. Sub-systems interface management
. Technical coordination between sub-systems
. Mechanical infrastructure with high constraints
. Engineering
. Onsite integration
. Onsite training
. System operation assistance
. Maintenance and exploitation support

Working closely with customers Thales develops the solution needed for each research program, from drawing up specifications through production and in-service support.