After a rather quiet period, Sol blasted into action again yesterday.
After 4 M Class Flares, Mr. Sunshine blasted off with an X 2.7 late
last night around 22:00 UTC. All very interesting needless to say, yet
it became much more interesting this morning when I looked into CERN
and what they were up to yesterday.....
http://home.web.cern.ch/about/updates/2015/05/low-energy-collisions-tune-lhc-experiments
http://home.web.cern.ch/about/updates/2015/05/low-energy-collisions-tune-lhc-experiments
Low-energy collisions tune LHC experiments
At about half past nine CET this morning, for the first time since the Large Hadron Collider(LHC)
started up after two years of maintenance and repairs, the accelerator
delivered proton-proton collisions to the LHC experiments ALICE, ATLAS, CMS and LHCb at an energy of 450 gigaelectronvolts (GeV) per beam.
These collisions, which take place with each beam at the so-called
injection energy, that is, the energy at which proton beams are injected
into the LHC from the Super Proton Synchrotron,
enable the LHC experiments to tune their detectors. This process is
also an important step towards readying the accelerator to deliver beams
at 6.5 teraelectronvolts (TeV) for collisions at 13 TeV.
Each low-energy collision sends showers of particles flying through an
experiment's many layers. The experimental teams can use this data to
check their subdetectors and ensure they fire in the correct place at
the precise instant that a particle passes. Reconstructing flight paths
of the particles from many parts of the detector at once helps the
experiments to check the alignment and synchronization of various
subdetector elements.
So just as the LHC team tests each component, system, and algorithm one
after the other, the experiments go through checklists that confirm that
everything is fully functional and no mistakes, bugs or failures are
present when collisions are delivered at 13 TeV.
Meanwhile the LHC Operations team is halfway through its eight weeks of
scheduled beam commissioning, during which the accelerator's many
subsystems are checked to ensure that beams will circulate stably and in
the correct orbit. Sensors and collimators around the accelerator's
full 27 kilometres send information to the CERN Control Centre, from
where the operators can remotely adjust the beam by fine-tuning the
positions and field strengths of hundreds of electromagnets.
Though the first beam at 6.5 TeV circulated successfully in the LHC last
month, there are many more steps before the accelerator will deliver
high-energy collisions for physics to
the LHC experiments. Well before the full physics programme begins, the
LHC operations team will collide beams at 13 TeV to check the beam
orbit, quality and stability.
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