Accelerating particles—but not just for the LHC

July 10, 2017
Distribution of protons delivered by the accelerator chain to the different installations. Credit: Daniel Dominguez/CERN

This week, the Large Hadron Collider (LHC) was in technical stop, but particles continued to circulate in the other accelerators. This is because the chain of four injectors that feed the LHC also supplies particles to myriad experiments across several experimental areas.

In fact, even when the LHC is running, the other experimental consume almost all the , as the diagram shows. The large collider uses less than 0.1% of the protons prepared by the injector chain. That's primarily because the LHC is a storage ring: the same beams circulate in the ring for hours at a time, producing collisions with every circuit they complete. That's not the case for CERN's other machines, which send beams to fixed targets – an operation that has to be repeated every time data is taken.

All the protons start their journey in the linear accelerator Linac2, before being launched at a third of the speed of light into the Proton Synchrotron Booster (PSB). At that point, their paths diverge.

More than half of the protons are sent to ISOLDE, a research facility. ISOLDE supplies various experimental areas hosting numerous experiments each year in fields ranging from fundamental physics to materials sciences and the production of isotopes for medical applications. Last year, ISOLDE supplied particles to 46 experiments.

Accelerating particles—but not just for the LHC
The journey of protons begins in the linear accelerator Linac 2, where they are boosted to one third of the speed of light. Credit: Maximilien Brice/CERN

The remainder of the particles leaving the PS Booster go to the Proton Synchrotron (PS), which supplies three other experimental areas: the Antiproton Decelerator (AD), used for antimatter experiments, the East Area, which notably is home to the CLOUD experiment dedicated to studying the formation of clouds, and finally n_TOF, another nuclear physics facility.

The PS sends a small portion of its protons to the Super Proton Synchrotron (SPS), which in turn sends most of them to the North Area, where several fixed-target experiments including COMPASS and NA62 take data. Thus, in the end, the LHC receives only a tiny proportion of the particles that started the journey.

In 2016, CERN's accelerator complex accelerated 134 billion billion protons (1.34 x 1020). This number corresponds to a minuscule quantity of matter, roughly equivalent to the number of protons in a grain of sand, but protons are so small that this amount is enough to supply all the experiments.

The LHC will resume operation tonight. After a week-end of tuning, the LHC physics programme should restart on Monday.

Miniball, one of the experimental set-ups of the nuclear research facility ISOLDE. The Isotope Mass Separator On-Line facility (ISOLDE) uses more than a half of the protons prepared in the CERN accelerator complex to carry out numerous experiments in fields ranging from fundamental physics to materials sciences and the production of isotopes for medical applications.  Credit: Julien Ordan / CERN

Accelerating particles—but not just for the LHC
The Super Proton Synchrotron (SPS) is the last link in the accelerators chain before the LHC. It also feeds the North Area where a test hall for future equipment is located and where several experiments take data. Credit: Piotr Traczyk/CERN

Explore further: The LHC racks up records

Related Stories

The LHC racks up records

June 30, 2017

An unprecedented number of particles has been reached in record time. Just five weeks after physics resumed, the Large Hadron Collider (LHC) is already running at full throttle. On Wednesday 28 June 2017 the LHC established ...

Retired MRI scanner gets new life studying the stars

April 4, 2017

A team of researchers has successfully taken a magnet from a decommissioned MRI scanner used by a Brisbane, Australia, hospital for scanning patients, and recycled it for use in an experiment at CERN's ISOLDE facility.

Linac 4 reached its energy goal

November 8, 2016

CERN's new linear accelerator (Linac 4) has now accelerated a beam up to its design energy, 160 MeV. This important milestone of the accelerator's commissioning phase took place on 25 October.

Injector 2—a pre-accelerator for protons

June 22, 2017

As fundamental building blocks of matter, protons are a part of all things that surround us. At the Paul Scherrer Institute PSI, however, they step out of their usual role and are deployed to generate other particles, namely ...

LHC's objective—maximum intensity

June 7, 2017

Protons are jostling for space in the Large Hadron Collider. Since the start of the physics run on 23 May, the operators of the huge accelerator have been increasing the intensity of the beams, injecting more and more protons ...

Recommended for you

Quantum data takes a ride on sound waves

September 22, 2017

Yale scientists have created a simple-to-produce device that uses sound waves to store quantum information and convert it from one form to another, all inside a single, integrated chip.

A way to measure and control phonons

September 22, 2017

(—A team of researchers with the University of Vienna in Austria and Delft University of Technology in the Netherlands has developed a technique using photons for controlling and measuring phonons. In their paper ...

Gravitational waves may oscillate, just like neutrinos

September 21, 2017

(—Using data from the first-ever gravitational waves detected last year, along with a theoretical analysis, physicists have shown that gravitational waves may oscillate between two different forms called "g" and ...

Detecting cosmic rays from a galaxy far, far away

September 21, 2017

In an article published today in the journal Science, the Pierre Auger Collaboration has definitively answered the question of whether cosmic particles from outside the Milky Way Galaxy. The article, titled "Observation of ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.