Cosmic Rays Illuminate CMS!

The third phase of the Cosmic Run at Zero Tesla (CRUZET3) is keeping all CMS collaborators busy this week... From 7th to 14th July this global commissioning activity is expected to yield millions of detector triggers. ~100 TBs of data coming from the detector will be transferred to Tier-1 sites. CMS is located 100 meters underground; although, high energetic cosmic muons are capable to reach and completely cross the CMS detector. These muons are very useful to study and commission different parts of the detector.

The fraction of CMS sub-detectors participating in CRUZET3 has steadily increased and includes from the first time all its components: the DT muon system, RPC barrel, CSC endcap, HCAL and barrel ECAL calorimeters, and the recently installed silicon strip tracker (the biggest tracker detector ever built!).

Last night (9.7.2008), over 1 million cosmic ray events were reconstructed on the tracker system. This is the first time we see triggered cosmic ray tracks in both TIB and TOB at the Tracker level:

Primary datasets are created using the new Tier-0 “repacker” in almost 'real time' and transferred to CAF and Tier-1 sites for prompt analyses. IN2P3 Tier-1 has the custodial responsibility to hold CRUZET3 data, although all Tier-1 sites are constantly receiving the cosmic data. During these two first days, ~3 TBs of data has landed to PIC, being the best Tier-1 site from Rate and Quality p.o.v (curiosly, yesterday we spent the whole day in scheduled downtime!).

Data volumes are expected to grow later this week as systems are better integrated on this commissioning exercise... So, we need to stay tuned! ;)