The Large Hadron Collider is running out of disk space

By Jessica Hall on October 3, 2016

The Large Hadron Collider (LHC) has run into an unanticipated problem — it’s running out of disk space. “This year the LHC is stable and reliable,” says Jorg Wenninger, head of operations at the LHC. “It is working like clockwork. We don’t have much downtime.” That’s actually the problem.

When the collider was planned out, as Symmetry reports, scientists expected that it would be running about a third of the time. The rest of the time would be used for maintenance, refilling, rebooting, and other such logistical tasks. But that’s not how it seems to work in practice. This may be the first time in history when technicians have made a bad estimate about uptime and had that result in success. The LHC is actually doing collisions about 70% of the time, more than double its expected rate.

This faster collision rate lets scientists learn more about rare processes and particles like the Higgs boson, which the LHC produces about once per billion collisions. It’s also filling up their data storage.

“The number of hard drives that we buy and store the data on is determined years before we take the data, and it’s based on the projected LHC uptime and luminosity,” said Jim Olsen, a physics professor working on the CMS project, to Symmetry. “Because the LHC is outperforming all estimates and even the best rosy scenarios, we started to run out of disk space. We had to quickly consolidate the old simulations and data to make room for the new collisions.”

One reason for the huge glut of data is the number of different experiments going on at CERN. They all have to jockey for time.

Part of the ATLAS/ALFA experiment apparatus at Point 1 in the LHC tunnel. (Image: Ronaldus Suykerbuyk/CERN)

The most recent experiment taking up collider time is on the ATLAS hardware — and instead of focusing on the maximum number of collisions possible (this is typically referred as “luminosity”), the team is prepping for some low-speed, low-energy collisions. The type of scattering they want to study is known as “elastic scattering,” which occurs when two protons survive their encounter with one another in the detector. Instead of smashing protons together to see what happens when they collide, the goal is to bounce them off each other and measure what happens after that. The long-term goal is to better model cosmic rays and understand why cosmic rays that hit our atmosphere split into an array of secondary particles. By watching what happens to protons when they “bounce,” scientists hope to better understand why cosmic rays split into secondary particles when they strike Earth’s atmosphere.

One of the other goals of these upcoming experiments is to measure the probability that two protons could pass directly through each other without interacting at all. This is only possible because, like other atoms (which are mostly made up of empty space), protons are themselves composed of particles. In theory, it may be possible for one proton to pass through another. How often this happens is what we’re hoping to discover.

As for the low storage problem, maybe CERN should call Backblaze. They’ve got some pretty decent drive pods up and running…

Now read: How does the Large Hadron Collider work?

http://www.extremetech.com/extreme/236694-the-large-hadron-collider-of-all-places-is-running-out-of-disk-space