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A research instrument for the exploration of the infinitely small. CSS1 and CSS2 are GANIL's two Separated-Sector Cyclotrons. They can accelerate any ion, from helium to uranium, listed in the Table of Elements.

Particles are accelerated in a second phase of the experiment.
To split the nuclei, a powerful shock between the beam and the target is required. However, it is difficult to produce such a collision because of the repulsion between electrons. And indeed, two atoms never come into contact spontaneously as a result of mutually repulsive magnetic forces, which push them apart.

Therefore, at GANIL, the particles have to be forced to impact each other. For this purpose, a force greater than that which naturally repels two particles must be generated. This is what the accelerator does. Because they are fired at 100 000 km/s, the atoms in a beam have enough power to hit the target's nuclei and even to split as a result of the impact.


The Cyclotron's principle


sh�a cyclotron (400x226)


The GANIL's accelerator assembly comprises several cyclotrons whose magnets maintain the ions in a circular trajectory. After several small electrical accelerations, the ions eventually reach a third of the speed of light, that is, approximately 100 000 km/second.
As the particles accelerate, they describe larger and larger circles through the magnetic field of the cyclotron. The particles then travel in a circle with a maximum radius of 3 m and complete between 100 and 500 revolutions before reaching their maximum velocity.


GANIL's two separated-sector cyclotrons are comprised of four magnets, each weighing approximately 400 tons, and generating a magnetic field of up to 4 Tesla.

They are interconnected by two acceleration cavities.

The incommensurate size difference between these atomic nuclei and the 2000 tons of each of the two cyclotrons in which they are accelerated is stunning.

cycloss (200x210)


Although the GANIL's strongest beam generates thirty thousand billion particles per second, an experiment takes several days to produce a few millions of collisions, including those which may provide new information.

When the accelerators are in use, stringent safety and radiation protection rules are enforced. A team of engineers and operators continuously monitor the accelerator from their control room.


The accelerators operate continuously during periods scheduled in such a way as to enable the experiments to be alternated with periods of maintenance.

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