The great challenges of today’s science require infrastructures and monstrous investments, among which are the Large Hadron Collider (LHC) – the particle accelerator that started on 10 Sept 2008, the most powerful in the world -, the Pierre Auger Observatory – the largest cosmic ray detector of the moment-, the Cassini Huygens probe – the largest spacecraft currently in operation- and the largest neutrino telescope in the world, AMANDA.
Lately, there has been a lot of talk about CERN and the LHC, but for many years there have been particle accelerators or synchrotrons.
TANDAR Linear particle accelerator CNEA Argentina
The synchrotron particle accelerator
It is a particle accelerator that accelerates initially charged particles in a toroidal container.
Unlike a cyclotron that uses a constant magnetic field (which makes the particles rotate) and a constant electric field (to accelerate the particles), and a synchrocyclotron, which varies one of the two fields, in the synchrotron both fields they are varied to maintain the path of the particles constantly, that is, the radius does not vary too much. The maximum speed at which particles can be accelerated is given by the point at which the emitted synchrotron radiation equals the energy injected.
In the isochronous cyclotron, a magnet is constructed such that the magnetic field is stronger when it is closer to the circumference than in the centre of the circumference, thus generating a total increase and maintaining the revolution at a constant frequency. In this device, a magnet ring surrounds a vacuum ring-shaped tank. The magnetic field increases with the speeds of the proton, the particles must be injected into a synchrotron of another accelerator.
The first proton synchrotron was the cosmotron used at the Brookhaven National Laboratory (New York) and began operating in 1952, achieving energy of 3 GeV. Another that followed was the 500-GeV synchrotron from the American Fermi National Accelerator Laboratory in Batavia, Illinois, built to be the world’s most powerful accelerator in the early 1970s; its ring delineates a circumference of approximately 6 kilometres. This machine was updated in 1983 to accelerate protons and count antiprotons that propagate at speeds so enormous that the impacts that ensue deliver energies of up to 2 trillion electron volts (TeV), which is why the ring has doubled in Tevatron.
The Tevatron is an example of a machine that would be capable of producing lightning strikes, and which is actually a double accelerator that is supercharged by the separation of 2 rays after they collide head-on or at a certain angle of incidence. According to relativistic effects, creating the same reactions with a traditional accelerator will require a single beam that would generate far more than twice the energy emitted by either of the colliding beams when reaching a stationary goal.
Longer-range accelerators are built by expanding the radius and using larger, more powerful microwave compartments to accelerate particle radiation at tangential points. Lighter particles (such as electrons) lose a larger fraction of their energy when turning since they move much faster than a proton of the same energy, so high-energy synchrotrons accelerate larger particles; protons or atomic nuclei.
This is why it is said that electrons can be accelerated using the synchrotron, but it is unsuccessful. The electron-accelerating circular device is the betatron, invented in 1939 by Donald Kerst. The electrons are injected into a vacuum ring-shaped compartment that must be surrounded by a magnetic field.
Among the largest synchrotrons, there is the Bevatron, currently in disuse, built-in 1950 at the Lawrence Berkeley National Laboratory (California, USA) and used to establish the existence of the antiproton. The name of this proton accelerator comes from its energy range of 6.3 GeV (then named BeV for its billion electron volts; this machine produced a large number of heavy elements that were not seen in the natural world).
The high cost seems to be the limiting factor in manufacturing heavy particle accelerators. While there is potential for all kinds of heavy particle cyclic accelerators, it appears that the next stage demands intensifying the acceleration energy of the electron out of the need to avoid losses due to synchrotron radiation.
This will motivate a return to the linear accelerator, but whose devices will be noticeably longer than those currently in use. However, synchrotron radiation is used by many scientists and for them, the production of synchrotron radiation is the sole purpose of it. For a large variety of applications, synchrotron radiation is useful, and many synchrotrons have been specially designed to generate light. SPring-8 in Japan is one of them: its range capacity is the highest in the world in terms of electron acceleration and is 8 GeV.