What the Quark is going on here?

atom smashing in pre-particle acceleration era

You may be asking, why should I care about the Tevatron shutting down? (see last post.) Or about particle accelerators in general? Here’s the thing: large-scale particle accelerators like the Tevatron & Large Hadron Collider are not far off from the microwave in your kitchen or the computer screen from which you’re reading this.

“Microwaves” heat up food by emitting a microwave at a 2500 megahertz frequency (FM radio bandwiths use 88-108 mhz) that is uniquely absorbed and converted into heat by water, fats and sugars. And “atom-smashing” occurs in computer screens every time you power them on: electrons stored in a cathode accelerate through a cathode ray tube, change direction at the pull of electromagnets and smash into the phosphor molecules on the screen, creating a pixel, or light spot.

Particle accelerators produce microwaves on which particles ride. Like computer monitors, they too speed up particles and then very suddenly smash them into targets. The difference between the big-time smashers and those small appliances is that their microwaves are one million times more powerful, and the max speed of their particles is close to the speed of light (approximately 180,000 miles per second).

Thus, the big guys are powerful enough to break down matter into subatomic particles, and we’re not just talking protons, neutrons, electrons here. I personally feel cheated for not having learned about quarks (the smaller components of protons and neutrons) in high school, as well as for not seeing quark as a commonly-used noun in the English language (“the building quarks of matter”, “the little quarky spider”; great opportunities wasted).

After speeding up and smashing particles, particle accelerators use detection devices to analyze the results, including liquid and cloud chambers that track the trail of the scattered bits (similar to cloud trails left by airplanes, which are formed by exhaust condensing in the atmosphere). Some of the subatomic-particles that can be observed include:

-matter including QUARKS (you already know) & different types of LEPTONS (sounds like: leprechaun. similarly speedy. electrons are one type).

-anti-matter including POSITRONS (essentially a positive-charged electron).

-some BOSONS, which are particles that carry forces. The four known forces are strong, weak, electromagnetism and gravity. There is still a lot that scientists hope to discover regarding BOSONS via atom smashing.


Perhaps the biggest aspiration scientists have for atom-smashing is to recreate the Big-Bang theory and understand exactly how the universe formed. The theory is widely-accepted but until it is proven, a theory it shall remain. Other questions left unanswered: what gives particles mass, and what really is the deal with quarks? Who really is that ugly guy from Star Trek? And what DNA manipulation do we need to do to get earlobe/eyebrows like that in the human species?



Quark the bartender from Deep Space Nine


So many questions for Tevatron to answer, and only seven more months to answer them…

Death of a Tevatron

Located beneath the Franco-Swiss border, the Large Hadron Collider (LHC) gained international notoriety in Fall 2008 when its proton beams circulated its 17 mile track for the first time. It was officially the world’s largest particle accelerator—physics enthusiasts across the world cheered at “first beam” all-night pajama parties, calling it the beginning of a new frontier in particle physics.



lookin snazzy there, scientist

Chances are you’ve heard of the LHC, but unless you’re one of those pajama-wearing physics geeks (or a northeastern Illinois resident), you might not have heard of the Tevatron. The Tevatron is a smaller particle accelerator located at the Fermilab center in Batavia, Illinois. Its track is three miles long, which remained the longest in the world until 2008. It ran its first accelerated beam in July 1983. By October 2011 it will have run its last.

The Tevatron is named after the speed at which it is capable of accelerating protons and anti-protons: 1 TeV (see “Breaking it Down”). Though it continues to make significant scientific discoveries since the opening of the LHC (especially in the wake of LHC malfunctions), the larger particle accelerator ultimately renders the smaller obsolete. The Large Hadron Collider is designed to operate at 14TeV. Discover magazine has a great article that chronicles the race between Tevatron & the LHC in more depth (visit http://blogs.discovermagazine.com/cosmicvariance and scroll down to January 11th’s “The End of Tevatron” posted by John).

Researchers at Tevatron still have hope that their track will see the Higgs boson before the LHC does. Higgs boson, aka “the God particle”, is a hypothetical massive particle whose discovery would legitimize the Higgs mechanism, which explains how elementary products become massive. Basically, its discovery would turn theories into laws, giving physics a whole bunch more street cred.

Despite the Tevatron’s contribution to that new frontier in physics, its demise is eminent and far from sudden. Congress voted not to extend funding beyond September 2011 way back during Clinton‘s term. The Director of the Office of Science at the DOE wrote a letter on January 6th confirming that the date has not changed. Even if its scientists were to discover Higgs boson this spring or summer, the Tevatron’s particle beams will still stop beaming come autumn.

Breaking it Down:

Particles in the Tevatron accelerate to near the speed of light (about 180,000 miles per second) but they get there via high voltage. Voltage is analogous to water pressure. The more water pressure there is in a pipe, the faster the water will flow. Electronvolts are thus markers for electron acceleration; an electronvolt is the amount of kinetic energy (energy of motion) gained by one electron when it reaches one volt. A TeV (ie TeV-atron) is defined as one trillion electronvolts. It takes the Tevatron approximately one trillion electronvolts to reach its top speed.

There are two types of particle accelerators: the linear particle accelerator (moves in a straight line) and the circular particle accelerator. Both Tevatron and the LHC are circular particle accelerators.

Both are also synchrotrons, which use synchronized electromagnetism to move particles. The particle beam is what moves; it is synchronized with a magnetic field (it keeps the particles circulating around the track) and an electric field (it accelerates the particles). Synchrotons have the best potential to reach ungodly fast speeds because of this carefully timed synchronization.

Another noteworthy type of circular particle accelerator is the one that paved the way for all other particle accelerators: the cyclotron. Ernest O. Lawrence invented the first in 1929 at 4inches in diameter. Today many cyclotrons are used to treat cancer. The technique is called proton therapy; ion beams are shot into the body to kill tumors without harming healthy tissue on the way. Because they can only move particles at a few percent of the speed of light, however, cyclotrons are not capable of making physics discoveries on the same scale as synchrotons.



rip Tevatron