Did the world end and I didn't notice it?

I'm pretty sure the world has not ended yet, but unfortunately I can explain why that is so.

CERN scientists are being incredibly cautious bringing the ring up this time.  Last week the status was that the ring was half-tested, meaning the protons had been extracted from hydrogen, accelerated by a linear accelerator (LINAC2),  shaped by the PS Booster, then go into the Proton Synchrotron (PS), followed by the Super Proton Synchrotron (SPS), before finally reaching the Large Hadron Collider (LHC) and going half way around. When this thing finally gets all fired up the protons will  circulate in the LHC for 20 minutes before reaching their maximum speed and energy.

The synchrotrons mentioned above are rings, and the Super Proton Synchroton was started in 1976, halfway through my college studies.  Each one of these devices has been a workhorse for experiments, and new discoveries were found when using every single one of them.  In addition, the beauty of CERN is that the design is open-ended, with every stage leading into the next stage - they built what they could, built useful tools, used them, and then added on to them for the next stage.  This last stage, the Large Hadron Collider, is the first stage at CERN that uses superconducting magnets.  That has helped them achieve much higher energies.

At least in theory.  In practice the doggone thing is not yet fully operational, and they expect half-speed collisions before Christmas but not before.  I had to guess about when to come here when I was planning this trip.  I had to guess when the final ring traversal would be made, and when the first collisions would happen, and doggone it but they are only about 90% there, and no farther at this time.  They use the weekends to try the full functional runs, then work like crazy during the week to get everything in order for the next run.

Whew.

Because of the US holidays my travel was the best, and cheapest, this week.  I really wish I could have been here for the first actual collision though.  

Oh well.

I found out many interesting things while here, even though the world did not end.  I'll try to share them here.

The scientists in the control rooms are so YOUNG.  How must it be for them, to be so young and to have such a huge future ahead of you?  They are so fortunate!!  I found out that the beams - they will start with protons - are very carefully shaped.  They are clustered into packets, with short gaps between packets, so that they travel similar to cars in a train.  Because the protons all have the same positive charge they repel each other, so they must be focused and clustered together by special magnets.  In addition, each channel in the tube (there are two channels, one for each direction) can have four beams at the same time!  I did not know this!  In that way the beams can be different - different energies, and even different materials.  They have plans to use lead ions in some of the beams!  Wow.

The physical size of the thing is staggering.  The ring itself just less that 27,000 meters in diameter.  It is 100 meters underground, for a couple reasons.  First, it rests on bedrock, and if the bedrock was at 50 meters they would have built it only 50 meters down.  Second, they did not want to disrupt the countryside.  I am glad that money is not king in every part of the world.  I think the ground helps with insulation against the elements, although that could be done above ground, even for the super conducting magnets.

Speaking of magnets, they have four different sets of magnets running.  The first set curves the beam into a circle.  The second set compress or focuses the beams.  The third set fine tunes the aiming of the beams to a precise X,Y location.  The fourth set accelerates the beams, and it will take about twenty minutes to get the beam to full speed, 7 TeV.

Wait, I think there must be a fifth set of magnets, because to force a collision, once two beams are ready to go, whirling around in opposite directions, they use magnets to push a few of the packets (train cars) into each other to collide.

This is not as easy as it may sound.  The timing is very critical, so the collision happens in one of the four pre-set detector areas - Atlas, CMS,  Alice, or LHCb.  Also, the beams are VERY narrow, and even then there is a large amount of empty space between the protons.

Speaking of empty space, the air is evacuated from the entire ring, including the detector chambers.  The vacuum is ten times greater than the vacuum on the moon.  That is so the protons do not collide with atoms or gas molecules.

And speaking of empty space, I think I hard my guide say something like empty space repels itself?  I need to follow-up on that,  I knew that on the quantum level photons are created and annihilated all the time, and if you put two metal plates near each other the photons created between them will have lower energy, so the plates tend to get pushed together, but I have never heard about the empty space repelling itself thing.

The other mind blowing thing I heard from my guide is that some interpretations of the Heisenberg equations suggest perhaps there is an underlying fabric to space-time, and the interaction of matter with the fabric manifests itself as what we call mass?  I need to check on that, too.  I know they are hoping to find the Higgs boson, the so-called God Particle, the particle that gives the property of mass and transfers the force of gravity.

I think.  Dang it all.  I really wish I was smart enough to understand all this.  It is very frustrating to be curious and to not understand all the possible answers, but perhaps it is also a blessing to have such a puzzle to ponder on?

Some of the engineering challenges were staggering, too, but I must leave those for another post.