Something else from Cosmic Variance that caught my eye…  Physicists are eagerly awaiting the first collisions from the new Large Hadron Collider…

The Large Hadron Collider (LHC) is a particle accelerator which will probe deeper into matter than ever before. Due to switch on in 2007, it will ultimately collide beams of protons at an energy of 14 TeV . Beams of lead nuclei will be also accelerated, smashing together with a collision energy of 1150 TeV. 

But they need to be a tad careful in turning it on… 

Now for the reality check, as presented last week by the LHC project manager Lyn Evans (insert drumroll here): The machine will be closed in August 2007 and first collisions will occur in November 2007 at center of mass energy 1.8 TeV. The same energy as the previous run (known as Run I) at the Tevatron! It seems that this decision is very prudent. In 2007, only a couple sectors of the LHC will be fully commissioned to handle 7 TeV proton beams. The remaining sectors will not be commissioned until early 2008.

Let’s think about this for a moment. Commissioning (starting) new colliders is frought with numerous unintentional aborts of the beam. And when a beam is aborted, it has to go somewhere (it’s called dumping the beam). Hopefully it aborts as planned, otherwise….much energy is dumped somewhere it should not be! At full throttle (7 TeV beams), the energy stored in the LHC beam is 700 MegaJoules, or 10 TeraWatts. How big is that? Well, 10 TeraWatts is about half of the world’s total energy output. No wonder the accelerator folks are a bit jittery! They don’t want to dump 10 TeraWatts of beam just anywhere…

Here’s a picture (courtesy of Tom LeCompte) to illustrate this point. The kinetic energy of battleship guns is 300 Megajoules, or just less than half that of the full LHC beam. Now we understand why the machine folks want to be a bit cautious…

Yeah…I think I’d be careful with that too.