One of the very first particle accelerators of the European Organization for Nuclear Research CERN has recently been “struck” 60 years old, however, this installation still continues to work. Synchrotron Proton Synchrotron (PS) first accelerated protons on November 24, 1959 and at that time it was the most powerful accelerator in the world, accelerating particles to the highest energy. Of course, over time, the PS synchrotron lost this title, but today it continues to deliver accelerated protons and heavy ions to many experiments, including the Large Hadron Collider, which is the bearer of the world’s most powerful particle accelerator to date.
Note that the CERN organization was formed in 1954 to conduct research in the fields of particle physics and nuclear physics, and the PS synchrotron was one of the first projects of this organization. This accelerator was based on an idea developed by scientists from the Brookhaven National Lab to create a synchrotron based on the variable gradient principle to accelerate particles to the highest energies at that time.
The synchrotron captures the particles introduced into it and directs them along a circular path with the help of magnetic fields, the strength of which slowly increases, and which are carefully synchronized with the energy level of the accelerated particles. The principle of a variable gradient is a means of focusing a beam of particles with the help of variable quadrupole magnets, magnets, which can be described as four separate magnets installed in the form of a “” sign, the poles of which alternate in a certain sequence.
As with the construction of any accelerator, scientists encountered a number of problems in the construction of the PS synchrotron, but all the problems that arose were successfully resolved over time. For a very long time they could not get the protons to move strictly along a given trajectory, but a series of small equipment upgrades and adjustments to the operating conditions made the PS accelerator work and reach the calculated energy values of the accelerated particles.
The PS synchrotron receives protons from an appropriate source filled with gaseous hydrogen, which have passed through a preliminary acceleration step with a small linear accelerator. Then the above-mentioned quadrupole magnets “drive” the proton beam in a circle, 628 meters long, accelerating them to an energy of 25 GeV (giga-electronvolt). This is very small energy by today’s standards, which exceeds the mass of a proton by 25 times, but it was enough to start research in the field of high-energy physics. And with the PS synchrotron, in the first five years after its launch, scientists discovered a whole series of new elementary particles.
When scientists built other, more powerful particle accelerators, the PS synchrotron “faded into the background”, becoming an additional and auxiliary tool. It became the source of protons for the next generation Super Proton Synchrotron, which accelerated particles to 400 GeV, which, in turn, supplied these particles to the Large Electron-Positron Collider and now supplies them to the Large Hadron Collider.
The fact that the PS synchrotron works to this day means that this installation was constantly being repaired and modernized. And at this point in time, the PS synchrotron is stopped and 48 of its 100 magnets are being repaired. In parallel with this, the technical staff is cleaning the accelerator structures, changing the pumps and three kilometers of pipelines of its cooling system.
And this, one can say, is a very good gift for the 60th birthday of the accelerator, which has done a lot for the field of particle physics!