Large Hadron Collider (LHC) is a phenomenon of technology. It is the most
powerful and the largest particle collider in the world. Also, its facility is
the most complex of all experimental facilities. The LHC is the largest machine
in the world. The collider has been on the used in used for various
revolutionary experiments. The LHC was built and designed by thousands of
people and over 100 countries. The LHC was constructed by the European
Organization for Nuclear Research (CERN). The collaboration among all parties
involved in the building of the LHC occurred between 1998 and 2008. It is
located by the France-Switzerland border, close to Geneva, Switzerland. The
circumference of the LHC is about 17 miles and goes as deep as 574 feet.
Research began in March 2010 and continued till the beginning of 2013. Over
this time the energy that it operated at broke the world record for a collier,
and was 4 times greater than the prior record. From the beginning of 2013 until
2015 the accelerator was improved and updated, and broke its own energy record.
Hadrons include particles that are
made up of quarks and held together by the electromagnetic force. Protons and
neutrons are the most well-known hadrons. A collider refers to an accelerator
of particles with 2 directed beams of particles. The particles are accelerated to
very high velocities, giving them very high amounts of kinetic energy. They
then collide them with other particles.
The LHC is used to allow scientists
and researchers to examine different theories of physics and particles. The
collider is used to measure the properties of the Higgs boson and searched for
the new particles. The collider has seven main detectors, each with a different
purpose, and also has four different crossing points. Mostly protons beams are collided
by the LHC, however it can also collide beams of heavy ions. The LHC also has a
world record for the world’s largest distributed computing grid, which
stretches over 170 facilities and is networked with 36 countries.
Researchers are looking to the Large
Hadron Collider to answer various questions regarding the fundamentals of
physics, including interactions and the forces among elementary objects. They also
look to get a deeper understanding of space and time, and the relationship
between general relativity and quantum mechanics. The data is also used to
figure out which scientific models are more likely right. For example the LHC
looks to choose between the standard Higgs boson model and the Higgsless model.
Other issues explored by the LHC include, a look into the idea of extra
dimensions and the nature of dark matter within the universe.
The world’s largest particle
collider is contained by a circular tunnel. The 12ft tunnel is lined with
concrete and was built between 1983 and 1988, as the tunnel used to be where
the large electron-positron collider was. The majority of the LHC is in France,
however it crosses the border between the countries 4 times. Within the
collider there are two adjacent and parallel beam pipes that travel in opposite
directions. The beams will intersect as four points, and this is where the
collisions occur. In order to keep the beams on their path over 1200 dipole
magnets are used, and in order to keep the beam focused about 400 quadrupole
magnets are used. Overall, there are over 10,000 superconducting magnets within
Map of LHC
When operating the protons each have
an energy of about 6.5 TeV, while the magnets reach 7.7 teslas. The collisions combine
to have an energy of 13 TeV. For a single proton to travel all the way around
the ring once it takes about 90 microseconds, which is about 11,000 revolutions
in a second. In order to space the collisions apart, protons are bunched
together, with about 115 billion protons in each bunch. This way, the
collisions are spread out by about 25 nanoseconds.
particles go through a series of different accelerators before entering the
main ring. Each accelerator increases the energy of the particles successively.
Then after being injected into the last ring the protons are bunched and accelerated
to the maximum energy. These bunches can then circulate from 5 to 24 hours.
While the majority of the collisions tested are proton collisions, sometimes
over a period of about a month collisions with heavy-ions will be tested. The heavy
ions are tested in order to examine quark-gluon plasma, which existed during
the early developments of the universe.
with the LHC there are seven detectors built in caverns near the colliding
points. The two very large and main detectors are the ATLAS experiment and the
Compact Muon Soleniod (CMS). Next there are the ALICE and LHCb detectors that
have more specific tasks, and then the MoEDAL, TOTEM, an LHCf, which are a lot
smaller and have very specialized roles. The ATLAS and the CMS study the Higgs
boson and look for new signs of physics, such as the beginnings of mass and different
dimensions. The ALICE studies the quark-gluon plasma that existed soon after
the Big Bang. The LHCb looks at where the missing antimatter from the Big Bang
The CMS Detector
Along with the design of the LHC was
the construction of the LHC Computing Grid. The grid was made to be able to
process large amounts of data from the collisions. Its network is an
international project that connects 170 computing centers among 36 countries.
CERN designed this network grid to be able to handle a massive volume of data
from the LHC detectors. Within the United State the main computer center for
the LHC is the Open Science Grid. There is a new project called [email protected], which
uses BONIC to gives access to simulations of how the particles would travel in
the beam pipes. Anyone with internet and a computer which contains Mac OS X,
Windows, or Linux, can access this. Using this information it helps decide how
the magnets should be calibrated in order to get the best path for the beams in
The initial testing for the LHC
stated on September 10, 2008, but then was delayed from September 19, 2008
until November 20, 2009, because an incident damaged over 50 of the
superconductor magnets. During its runs from 2010-2013 the LHC was able to
confirm the Higgs boson, discovered the beginning of the quark-gluon plasma,
and was able to validate models of supersymmetry.
Due to the size of the LHC, it
presented many different engineering challenges with many different issues
during it operations. It operates with so much energy that if even one
ten-millionth part of the energy is lost, it can ruin the magnets.
The LHC is one of the most expensive
machines ever used for since, with a budget of approximately $9 billion. The cost
for the accelerator itself is about $4.4 billion, and for the experiments about
$1.1 billion. The budget was approved in 1995, and had an expected completed
date in 2005. However, due reduction in the CERN budget and various other
problems with the cost, the completion date was not until April of 2007. Also
due to the high electricity costs over the winter months, the LHC usually only
runs during the warm months, and usually does not run during winter months.
LHC Superconducting Magnets
In order to avoid quenching of the magnets,
the LHC has to first be run at energies that are below the full operating
energy. It allows the magnets to cool the temperature that they need to operate
while essentially getting rid of any imperfections. Then over time the magnets
will eventually be able to reach the full operating current and energy.
The inaugural circulation of beams
through the collider occurred in 2008 on in the morning of September 10th.
The particles first were sent in the clockwise direction, and took about one
hour to successfully navigate the particles along the circuit. However, 9 days
later is when the magnet quench happened, and faulty electrical problems led
damage of various magnets and the vacuum. The LHC was expected to be operating
fully in September of 2008, however, due to the incident it was not fully
operational until November of 2009. Even though it was not completely
operational yet, on October 21, 2008, the LHC was inaugurated with many world
leaders and scientists attending.
The first operational run occurred
from 2009-2013. In November of 2009, the beams were relatively low energy beams,
with 1.18 TeV per beam. Then in the beginning of 2010 the energy per beam
increased to about 3.5 TeV, with a combined collide energy of 7 TeV. The first
test with lead ions occurred from the beginning of November in 2010, for about
a month to December of 2010. This allowed the ALICE to study what happened to
matter when it was exposed to similar conditions to the Big Bang. It was originally
planned that the CERN would run until the end of 2012, however, as the beam
energy increased to 4 TeV, the Higgs boson was discovered in July 2012. This lead
the CERN to continue operations until the beginning of 2013.
Beginning in February of 2013 the
LHC stopped operations for 2 years in order to complete upgrades. The upgrades
had the goal of being able to create collisions at 14 TeV. Although upgrades
were finished in June 2014, due to the long period of time required to get the
magnets to operating ability, the second operational run did not start until
April 2015. With the upgrades to the completed the LHC began operating again,
however, the beam collision was never able to reach an energy of 14 TeV.
Instead, the magnets were only trained to handle 6.5 TeV per beam, therefore
the collision energy was 13 TeV. Then in 2016, the goal was the increase the
luminosity of the proton-proton collisions. The LHC was able to surpass the
number of collisions from the first operational run, with higher energies each
collision as well. Currently in 2017 the LHC is surpassed the numbers set by
the LHC in 2016. The LHC was recently shut down on December 4, 2017 for its
winter break and will resume operations in 2018.
Originally the focus of the LHC was
to investigate the Higgs boson, and its role in the standard model. It was
believed that if the standard model was true, the LHC would be able to have
collisions with the Higgs boson every minute. Results that pertained to physics
first began the take place in December of 2009. The collisions took place in
the ALICE Detector and the results showed that the proton-proton collisions at
higher energies than the Tevatron proton-antiproton collisions. This then produced
a yield of charged-hadron production, which was much greater than predicted.
Within the first year of data
collection there was no evidence that suggested any new particles. Then in May
2011 quark-gluon plasma was created in the LHC. The LHC continued to search for
the existence of the Higgs boson as well as exotic particles. It was predicted
that the Standard Model would exist in the mass region of 145-466 GeV. However,
this continued to not produce any signals of the Higgs. Then in December of
2011, it was released by CERN that there were spikes of intensity within the
124-125 GeV range, therefore it was believed that the Higgs boson would exist
in the mass range of 115-130 GeV. On December 22, 2011, report of the ?b bottomonium state, a new particle, was observed. It was not
until July 4, 2012 that the CMS and ATLAS confirmed the discovery of a boson around
125 GeV. The results were true to the properties of the Higgs Boson, but scientists
wanted to continue test till it was confirmed as the Higgs boson. In 2014 the
LHCb experiment discovered two new subatomic particles, which were both states
of the Xi baryon. Since 2012 there has been continual results that have
supported the properties of the Higgs boson, however its existence has yet to
be confirmed with 100% confidence.
The CMS Depiction of the Higgs boson
Overall The Large Hadron Collider and
the experiments performed have played a vital role in many ground-breaking discoveries.
It has provided a breakthrough for research of physics. The LHC has allowed for
insight into the existence of the Higgs Boson, as well as the existence of
matter from the Big Bang. As the world’s largest machine, and the most powerful
particle collider, it has been on the front for many different revolutionary
ideas. The LHC is continually researching these collisions and the results from
the experiments. There is still much more to learn from the LHC and in the
future there will likely continue to be discoveries from the LHC.