Wednesday, October 23, 2013

Podcast: RHIC

On this week's podcast, I visit Brookhaven National Lab's Relativistic Heavy Ion Collider, a machine that recreates the conditions of the universe a microsecond after the Big Bang. I got a chance to meet the scientists while they were taking data, and see what they see. However that also meat that I didn't get a chance to see any of the detectors in person because they were busy doing what they were designed to do, detecting particle collisions.

An ariel view of Brookhaven National Labs, with the two-mile-long RHIC accelerator tunnel highlighted and the STAR and PHENIX detectors marked. Inside, there are two beam tubes running parallel to each other but in opposite directions. Ions shoot around the beam tubes and collide with each other at the detectors where the tubes cross. 

Behind this concrete barrier is our first stop, the STAR detector. When the accelerator is turned off and the detector is being serviced, it's rolled out into the high bay for technicians to tune it.

Here's a file photo of what it looks like outside of the tunnel and with technicians all around it. The blue ring are all of the sensors that actually detect the particles flung off of collisions. This photo is from when the detector was first being built in the late '90s. Image: Brookhaven National Labs.

The control room of STAR. From here, the raw data from millions of particle collisions pours in through here.

One of the screens around the room showing the results of a smashing two uranium nuclei together. Each line tracks a single particle that shoots out of the collision. The blue and green lines track particles with lower energy, while yellow and red have more.

There are rows and rows of servers like this leading into the PHENIX detector. Tracking millions of particles every second takes a lot of computing power. 

The door that leads to the PHENIX detector. For a sense of scale, there's an average sized door in the lower right portion of the photo. 

The PHENIX detector after being taken out of its tunnel for maintenance.
Image: Brookhaven National Lab.

A question I couldn't help but wonder was "What's with all the thick slabs of concrete?" It turns out that the particle products of collisions are also extremely dangerous. Radiation is nothing more than subatomic particles flying through the air at tremendous speeds, and that's exactly what these collisions produce. If I were inside ofone of the tunnels while the machine was running, I probably wouldn't make it until tomorrow. These thick slabs of concrete shield everyone from this radiation. The cool thing is that as soon as the accelerator is turned off, and collisions stop, the entire machine is instantly perfectly safe.

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