The Berkeley Lab Laser Accelerator or BELLA is a
laser
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The word "laser" is an acronym for "light amplification by stimulated emission of radiation". The fi ...
built by the
Thales Group
Thales Group () is a French multinational company that designs, develops and manufactures electrical systems as well as devices and equipment for the aerospace, defence, transportation and security sectors. The company is headquartered in Paris' ...
and owned and operated by the
Lawrence Berkeley National Laboratory.
On 20 July 2012 BELLA fired a 40
femtosecond laser
pulse
In medicine, a pulse represents the tactile arterial palpation of the cardiac cycle (heartbeat) by trained fingertips. The pulse may be palpated in any place that allows an artery to be compressed near the surface of the body, such as at the n ...
, establishing a
world record
A world record is usually the best global and most important performance that is ever recorded and officially verified in a specific skill, sport, or other kind of activity. The book ''Guinness World Records'' and other world records organization ...
for most powerful laser.
BELLA was designed and built by Thales as part of the Laser and Optical Accelerator Systems Integrated Studies (LOASIS) program at LBNL. The LOASIS group studies the application of high-powered lasers to build compact
particle accelerator
A particle accelerator is a machine that uses electromagnetic fields to propel charged particles to very high speeds and energies, and to contain them in well-defined beams.
Large accelerators are used for fundamental research in particle ...
s. The BELLA laser was developed for the purposes of studying this principle.
The idea is that a laser which delivers a large amount of
power
Power most often refers to:
* Power (physics), meaning "rate of doing work"
** Engine power, the power put out by an engine
** Electric power
* Power (social and political), the ability to influence people or events
** Abusive power
Power may a ...
in a very short pulse can cause
ionization
Ionization, or Ionisation is the process by which an atom or a molecule acquires a negative or positive charge by gaining or losing electrons, often in conjunction with other chemical changes. The resulting electrically charged atom or molecul ...
in a gas followed by
plasma oscillation Plasma oscillations, also known as Langmuir waves (after Irving Langmuir), are rapid oscillations of the electron density in conducting media such as plasmas or metals in the ultraviolet region. The oscillations can be described as an instability ...
.
As a result the gas will emit
electron
The electron ( or ) is a subatomic particle with a negative one elementary electric charge. Electrons belong to the first generation of the lepton particle family,
and are generally thought to be elementary particles because they have no ...
bundles which can be used for
medical imaging or
materials research.
On 20 July 2012, BELLA fired a laser pulse with a duration of 40 femtoseconds and a repetition frequency of 1
hertz
The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), equivalent to one event (or cycle) per second. The hertz is an SI derived unit whose expression in terms of SI base units is s−1, meaning that o ...
. The pulses had a compressed output
energy
In physics, energy (from Ancient Greek: ἐνέργεια, ''enérgeia'', “activity”) is the quantitative property that is transferred to a body or to a physical system, recognizable in the performance of work and in the form of hea ...
of 42.2
joule
The joule ( , ; symbol: J) is the unit of energy in the International System of Units (SI). It is equal to the amount of work done when a force of 1 newton displaces a mass through a distance of 1 metre in the direction of the force applie ...
, making the power output of the laser 1
petawatt
The watt (symbol: W) is the unit of power or radiant flux in the International System of Units (SI), equal to 1 joule per second or 1 kg⋅m2⋅s−3. It is used to quantify the rate of energy transfer. The watt is named after James Wat ...
:
This result established BELLA as the highest peak power laser in the world (at a 1 Hz repetition rate).
In December, 2014, a team of researchers accelerated electrons using BELLA up to an energy of 4.25 GeV—the absolute highest energies recorded to date using a compact accelerator.
References
Research lasers
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