Physics

CERN's powerful new linear accelerator fires up ahead of LHC upgrade

Linac 4, CERN's latest linear particle accelerator
Andrew Hara/CERN
Linac 4, CERN's latest linear particle accelerator
Andrew Hara/CERN

After an almost two-year shutdown for repairs and upgrades, CERN’s Large Hadron Collider (LHC) is beginning to fire back up for its next phase of probing the mysteries of physics. Its newest particle accelerator, Linac 4, completed its first test run over the past few weeks, with the potential to provide much more energetic beams than ever before.

The LHC paused operations in December 2018, beginning a massive overhaul called the High-Luminosity Large Hadron Collider (HL-LHC). When it’s fully finished and finally fired up in 2026, the upgraded facility will be seven times more powerful and will collect around 10 times more data in the following decade than it did during the previous run.

And now, the first incremental stage of this upgrade is coming online. The new linear accelerator, called Linac 4, has been installed and tested over the last few weeks. This device is the starting point for accelerating protons, which are then injected into the Proton Synchrotron (PS) Booster and onto the rest of the accelerator complex.

Linac 4 replaces Linac 2, which was in operation at CERN for 40 years. As you might expect the new model is significantly more powerful, injecting particles into the PS Booster at energies up to 160 MeV – much higher than Linac 2’s 50 MeV. By the time these beams are boosted, they’ll reach energies of 2 GeV, compared to the 1.4 GeV that Linac 2 was capable of.

This extra energy is thanks to the fact that scientists can tweak Linac 4’s beams in much more detail than its predecessor.

“With Linac 4, we can adjust additional parameters of the beam so we can feed the Booster in a loss-free process,” says Bettina Mikulec, team leader at the operations group for Linac 4. “We can also adapt the energy spread of the beams to match the Booster’s acceptance, whereas with Linac 2 one practically only adjusted the length of the beam before injection.”

In the three weeks up to mid-August, Linac 4 was tested with low-energy beams of negative hydrogen ions, running only through the first part of the accelerator. On August 20, it was finally cranked right up to maximum energy, with beams accelerated through the whole machine. These were then sent into a “beam dump” at the end, a device that catches and absorbs the particles.

Further testing will take place over the next few weeks and months. In September, the beams will be sent down the injection line towards the PS Booster, but will be caught in a beam dump before they arrive.

Currently, the first beam to be delivered into the PS Booster is scheduled for December 7. After that, the first test beams will be sent into the LHC at the end of September 2021 – representing a four-month delay thanks to the COVID-19 pandemic.

Source: CERN

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3 comments
Chris Coles
When we look at recent observations of the surface of the Sun, we can see the results of very sudden major explosions, covering areas as large as our planet; yet so far, it would seem, no one has offered an explanation. From what I can make of it, the present belief in the science of the LHC is that when the ions hit the target, the resulting dispersal of fragments into the LHC detectors are caused by the atoms experiencing minor damage; not unlike the action of neutrons within a nuclear reactor, where atoms splitting cause the release of a single neutron, which in turn, causes the split of an adjacent atom to release another neutron, and so on.

My concern has already been recorded. It is my belief that the process of nucleosynthesis does not involve high velocity impact; instead is related to local pressure, and as such, the proton, being formed from an inviolable attachment of an electromagnetic force field to a dipole, forms an almost infinite spring, that when compressed alongside another proton, the combined compression forms additional mass relative to the compressed energy; where e=mc2 is reformed to m=e/c2. In which case, all atoms are composed of protons which must therefore be partially collapsed into compressed energy, all simply held in place by the attachments between the adjacent proton dipoles positive and negative poles.

If my new model for the structure of all atoms is correct, then there are very real dangers if the local pressures exerted upon the surface of atoms of the detector of the LHC by impacting ions reaches sufficient level, not to release a neutron; but instead to release all of the attachments between all of the protons forming an atom; which then may add sufficient released energy of compression, to initiate a chain reaction within the structure of the target . . . along the lines we see on the surface of the Sun.

CERN has received two copies of my work. There has to be a point where the energy released by impact will reach a point where they might then set into motion a chain reaction under my rules for the formation of all atoms. Food for thought?
Chris Coles
To gain a better understanding of what I am describing, you need to understand that I have long argued that the standard model for the proton does not conform to the rules for electromagnetism as laid down by James Clerk Maxwell, which states: A positive field seeks the closest negative potential, or extends to infinity. As such, if the proton is seen as positive, then it's internal structure must include a negative potential upon which the positive field must connect within the structure of the proton. If that is correct, then the structure of the proton form a compressible spring formed from an attached electromagnetic force field; which when compressed by an adjacent proton, forms a compressed spring. From that point, I then proposed that if you compress a spring, then you must add energy to the spring, and in which case you must, under the rules set out by Einstein, you must add mass to the spring.
Marco McClean
@Chris Coles

The pressure on atoms at the surface of the sun is less than a thousandth the pressure at the surface of Earth, and we've created temperatures in labs on Earth hundreds of millions of times higher than on the sun. If your overstressed-springs theory is correct, why are we still here? Why doesn't the planet go nova every time they make diamonds in a press or test a nuclear weapon? Not to mention the pressure and temperature at Earth's core. I'm sure I'm not understanding something, and I'd like to understand. Please show a link to your work.