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76-810: SLAC National Accelerator Laboratory , originally named the Stanford Linear Accelerator Center , is a federally funded research and development center in Menlo Park , California , United States . Founded in 1962, the laboratory is now sponsored by the United States Department of Energy and administrated by Stanford University . It is the site of the Stanford Linear Accelerator , a 3.2 kilometer (2-mile) linear accelerator constructed in 1966 that could accelerate electrons to energies of 50 GeV . Today SLAC research centers on

152-491: A Radio-frequency quadrupole (RFQ) stage from injection at 50kVdC to ~5MeV bunches, a Side Coupled Drift Tube Linac (SCDTL) to accelerate from 5Mev to ~ 40MeV and a Cell Coupled Linac (CCL) stage final, taking the output to 200-230MeV. Each stage is optimised to allow close coupling and synchronous operation during the beam energy build-up. The project aim is to make proton therapy a more accessible mainstream medicine as an alternative to existing radio therapy. The higher

228-545: A Little Linac model kit, containing 82 building blocks, was developed for children undergoing radiotherapy treatment for cancer. The hope is that building the model will alleviate some of the stress experienced by the child before undergoing treatment by helping them to understand what the treatment entails. The kit was developed by Professor David Brettle, Institute of Physics and Engineering in Medicine (IPEM) in collaboration with manufacturers Best-Lock Ltd. The model can be seen at

304-432: A beam line length reduction from some tens of metres to a few cm is quite possible. The LIGHT program (Linac for Image-Guided Hadron Therapy) hopes to create a design capable of accelerating protons to 200MeV or so for medical use over a distance of a few tens of metres, by optimising and nesting existing accelerator techniques The current design (2020) uses the highest practical bunch frequency (currently ~ 3 GHz) for

380-494: A broad program in atomic and solid-state physics , chemistry , biology , and medicine using X-rays from synchrotron radiation and a free-electron laser as well as experimental and theoretical research in elementary particle physics , astroparticle physics , and cosmology . The laboratory is under the programmatic direction of the United States Department of Energy Office of Science. Founded in 1962 as

456-457: A faster speed each time they pass between electrodes; there is little electric field inside the electrodes so the particles travel at a constant speed within each electrode. The particles are injected at the right time so that the oscillating voltage differential between electrodes is maximum as the particles cross each gap. If the peak voltage applied between the electrodes is V p {\displaystyle V_{p}} volts, and

532-419: A few MeV. An advantageous alternative here, however, is a progressive wave, a traveling wave. The phase velocity the traveling wave must be roughly equal to the particle speed. Therefore, this technique is only suitable when the particles are almost at the speed of light, so that their speed only increases very little. The development of high-frequency oscillators and power amplifiers from the 1940s, especially

608-460: A force given by the Lorentz force law: where q {\displaystyle q} is the charge on the particle, E → {\displaystyle {\vec {E}}} is the electric field, v → {\displaystyle {\vec {v}}} is the particle velocity, and B → {\displaystyle {\vec {B}}}

684-415: A group of particles into the first electrode once each cycle of the voltage, when the charge on the electrode is opposite to the charge on the particles. Each time the particle bunch passes through an electrode, the oscillating voltage changes polarity, so when the particles reach the gap between electrodes the electric field is in the correct direction to accelerate them. Therefore, the particles accelerate to

760-488: A horizontal waveguide loaded by a series of discs. The 1947 accelerator had an energy of 6 MeV. Over time, electron acceleration at the SLAC National Accelerator Laboratory would extend to a size of 2 miles (3.2 km) and an output energy of 50 GeV. As linear accelerators were developed with higher beam currents, using magnetic fields to focus proton and heavy ion beams presented difficulties for

836-450: A linac depends on the type of particle that is being accelerated: electrons , protons or ions. Linacs range in size from a cathode-ray tube (which is a type of linac) to the 3.2-kilometre-long (2.0 mi) linac at the SLAC National Accelerator Laboratory in Menlo Park, California . In 1924, Gustav Ising published the first description of a linear particle accelerator using a series of accelerating gaps. Particles would proceed down

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912-439: A precise alignment of their components through the use of servo systems guided by a laser beam. Various new concepts are in development as of 2021. The primary goal is to make linear accelerators cheaper, with better focused beams, higher energy or higher beam current. Induction linear accelerators use the electric field induced by a time-varying magnetic field for acceleration—like the betatron . The particle beam passes through

988-401: A resonant cavity to produce complex electric fields. These fields provide simultaneous acceleration and focusing to injected particle beams. Beginning in the 1960s, scientists at Stanford and elsewhere began to explore the use of superconducting radio frequency cavities for particle acceleration. Superconducting cavities made of niobium alloys allow for much more efficient acceleration, as

1064-469: A result. The development of the strong focusing principle in the early 1950s led to the installation of focusing quadrupole magnets inside the drift tubes, allowing for longer and thus more powerful linacs. Two of the earliest examples of Alvarez linacs with strong focusing magnets were built at CERN and Brookhaven National Laboratory . In 1947, at about the same time that Alvarez was developing his linac concept for protons, William Hansen constructed

1140-410: A series of ring-shaped ferrite cores standing one behind the other, which are magnetized by high-current pulses, and in turn each generate an electrical field strength pulse along the axis of the beam direction. Induction linear accelerators are considered for short high current pulses from electrons but also from heavy ions. The concept goes back to the work of Nicholas Christofilos . Its realization

1216-482: A series of tubes. At a regular frequency, an accelerating voltage would be applied across each gap. As the particles gained speed while the frequency remained constant, the gaps would be spaced farther and farther apart, in order to ensure the particle would see a voltage applied as it reached each gap. Ising never successfully implemented this design. Rolf Wideroe discovered Ising's paper in 1927, and as part of his PhD thesis he built an 88-inch long, two gap version of

1292-583: A substantially higher fraction of the input power could be applied to the beam rather than lost to heat. Some of the earliest superconducting linacs included the Superconducting Linear Accelerator (for electrons) at Stanford and the Argonne Tandem Linear Accelerator System (for protons and heavy ions) at Argonne National Laboratory . When a charged particle is placed in an electromagnetic field it experiences

1368-430: A systematic approach to research, development, and acquisitions—one independent of the ups and downs of the marketplace and free of the restrictions on civil service. From this idea arose the concept of FFRDCs—private entities that would work almost exclusively on behalf of the government—free of organizational conflicts of interest and with a stable workforce of highly trained technical talent. The U.S. Air Force created

1444-604: A venue for the Homebrew Computer Club and other pioneers of the home computer revolution of the late 1970s and early 1980s. In 1984, the laboratory was named an ASME National Historic Engineering Landmark and an IEEE Milestone . SLAC developed and, in December 1991, began hosting the first World Wide Web server outside of Europe. In the early-to-mid 1990s, the Stanford Linear Collider (SLC) investigated

1520-469: Is a Stanford Independent Laboratory located in the Central Laboratory at SLAC. PULSE was created by Stanford in 2005 to help Stanford faculty and SLAC scientists develop ultrafast x-ray research at LCLS. PULSE research publications can be viewed here . The Linac Coherent Light Source (LCLS) is a free electron laser facility located at SLAC. The LCLS is partially a reconstruction of the last 1/3 of

1596-501: Is accelerated. A linear particle accelerator consists of the following parts: As shown in the animation, the oscillating voltage applied to alternate cylindrical electrodes has opposite polarity (180° out of phase ), so adjacent electrodes have opposite voltages. This creates an oscillating electric field (E) in the gap between each pair of electrodes, which exerts force on the particles when they pass through, imparting energy to them by accelerating them. The particle source injects

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1672-402: Is converted into heat. In an energy recovery linac (ERL), the accelerated in resonators and, for example, in undulators . The electrons used are fed back through the accelerator, out of phase by 180 degrees. They therefore pass through the resonators in the decelerating phase and thus return their remaining energy to the field. The concept is comparable to the hybrid drive of motor vehicles, where

1748-402: Is highly dependent on progress in the development of more suitable ferrite materials. With electrons, pulse currents of up to 5 kiloamps at energies up to 5 MeV and pulse durations in the range of 20 to 300 nanoseconds were achieved. In previous electron linear accelerators, the accelerated particles are used only once and then fed into an absorber (beam dump) , in which their residual energy

1824-560: Is located at SLAC's end station B. A list of relevant research publications can be viewed here Archived 15 September 2015 at the Wayback Machine . SLAC also performs theoretical research in elementary particle physics, including in areas of quantum field theory , collider physics, astroparticle physics , and particle phenomenology. Federally funded research and development centers During World War II scientists, engineers, mathematicians, and other specialists became part of

1900-425: Is necessary to use groups of magnets to provide an overall focusing effect in both directions. Focusing along the direction of travel, also known as phase stability , is an inherent property of RF acceleration. If the particles in a bunch all reach the accelerating region during the rising phase of the oscillating field, then particles which arrive early will see slightly less voltage than the "reference" particle at

1976-427: Is the magnetic field. The cross product in the magnetic field term means that static magnetic fields cannot be used for particle acceleration, as the magnetic force acts perpendicularly to the direction of particle motion. As electrostatic breakdown limits the maximum constant voltage which can be applied across a gap to produce an electric field, most accelerators use some form of RF acceleration. In RF acceleration,

2052-481: Is used to drive a series of gaps, those gaps must be placed increasingly far apart as the speed of the particle increases. This is to ensure that the particle "sees" the same phase of the oscillator's cycle as it reaches each gap. As particles asymptotically approach the speed of light, the gap separation becomes constant: additional applied force increases the energy of the particles but does not significantly alter their speed. In order to ensure particles do not escape

2128-674: The Jefferson Lab (US), in the Budker Institute of Nuclear Physics (Russia) and at JAEA (Japan). At the University of Mainz , an ERL called MESA is expected to begin operation in 2024. The concept of the Compact Linear Collider (CLIC) (original name CERN Linear Collider, with the same abbreviation) for electrons and positrons provides a traveling wave accelerator for energies of the order of 1 tera-electron volt (TeV). Instead of

2204-515: The LIGO project's twin interferometers were completed in 1999. It is easily distinguishable from the air and is marked as a visual waypoint on aeronautical charts. A portion of the original linear accelerator is now part of the Linac Coherent Light Source. The Stanford Linear Collider was a linear accelerator that collided electrons and positrons at SLAC. The center of mass energy

2280-457: The Science Museum, London . The expected shortages of Mo-99 , and the technetium-99m medical isotope obtained from it, have also shed light onto linear accelerator technology to produce Mo-99 from non-enriched Uranium through neutron bombardment. This would enable the medical isotope industry to manufacture this crucial isotope by a sub-critical process. The aging facilities, for example

2356-520: The accelerator was the longest linear accelerator in the world, and was claimed to be "the world's most straight object." until 2017 when the European x-ray free electron laser opened. The main accelerator is buried 9 m (30 ft) below ground and passes underneath Interstate Highway 280 . The above-ground klystron gallery atop the beamline , was the longest building in the United States until

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2432-680: The Department of Energy's attempt to trademark "Stanford Linear Accelerator Center". In March 2009, it was announced that the SLAC National Accelerator Laboratory was to receive $ 68.3 million in Recovery Act Funding to be disbursed by Department of Energy's Office of Science. In October 2016, Bits and Watts launched as a collaboration between SLAC and Stanford University to design "better, greener electric grids". SLAC later pulled out over concerns about an industry partner,

2508-453: The RF power creates a standing wave . Some linacs have short, vertically mounted waveguides, while higher energy machines tend to have a horizontal, longer waveguide and a bending magnet to turn the beam vertically towards the patient. Medical linacs use monoenergetic electron beams between 4 and 25 MeV, giving an X-ray output with a spectrum of energies up to and including the electron energy when

2584-548: The SLAC campus. Originally built for particle physics, it was used in experiments where the J/ψ meson was discovered. It is now used exclusively for materials science and biology experiments which take advantage of the high-intensity synchrotron radiation emitted by the stored electron beam to study the structure of molecules. In the early 1990s, an independent electron injector was built for this storage ring, allowing it to operate independently of

2660-649: The Stanford Linear Accelerator Center, the facility is located on 172 ha (426 acres) of Stanford University -owned land on Sand Hill Road in Menlo Park, California, just west of the university's main campus. The main accelerator is 3.2 km (2 mi) long, making it the longest linear accelerator in the world, and has been operational since 1966. Research at SLAC has produced three Nobel Prizes in Physics : SLAC's meeting facilities also provided

2736-567: The Stanford Linear Collider. It was designed primarily to detect Z bosons produced by the accelerator's electron-positron collisions. Built in 1991, the SLD operated from 1992 to 1998. PEP (Positron-Electron Project) began operation in 1980, with center-of-mass energies up to 29 GeV. At its apex, PEP had five large particle detectors in operation, as well as a sixth smaller detector. About 300 researchers made used of PEP. PEP stopped operating in 1990, and PEP-II began construction in 1994. From 1999 to 2008,

2812-411: The accelerator, it is necessary to provide some form of focusing to redirect particles moving away from the central trajectory back towards the intended path. With the discovery of strong focusing , quadrupole magnets are used to actively redirect particles moving away from the reference path. As quadrupole magnets are focusing in one transverse direction and defocusing in the perpendicular direction, it

2888-406: The atomic level before obliterating samples. The laser's wavelength, ranging from 6.2 to 0.13 nm (200 to 9500 electron volts (eV)) is similar to the width of an atom, providing extremely detailed information that was previously unattainable. Additionally, the laser is capable of capturing images with a "shutter speed" measured in femtoseconds, or million-billionths of a second, necessary because

2964-577: The average output current is still limited.) The high density of the output makes the linac particularly attractive for use in loading storage ring facilities with particles in preparation for particle to particle collisions. The high mass output also makes the device practical for the production of antimatter particles, which are generally difficult to obtain, being only a small fraction of a target's collision products. These may then be stored and further used to study matter-antimatter annihilation. Linac-based radiation therapy for cancer treatment began with

3040-427: The center of the bunch. Those particles will therefore receive slightly less acceleration and eventually fall behind the reference particle. Correspondingly, particles which arrive after the reference particle will receive slightly more acceleration, and will catch up to the reference as a result. This automatic correction occurs at each accelerating gap, so the bunch is refocused along the direction of travel each time it

3116-427: The charge on each particle is q {\displaystyle q} elementary charges , the particle gains an equal increment of energy of q V p {\displaystyle qV_{p}} electron volts when passing through each gap. Thus the output energy of the particles is electron volts, where N {\displaystyle N} is the number of accelerating electrodes in

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3192-555: The constructions of LCLS-II which will occupy the first third of the SLAC LINAC. The FACET-II project will re-establish electron and positron beams in the middle third of the LINAC for the continuation of beam-driven plasma acceleration studies in 2019. The Next Linear Collider Test Accelerator (NLCTA) is a 60-120 MeV high-brightness electron beam linear accelerator used for experiments on advanced beam manipulation and acceleration techniques. It

3268-433: The device. Where Ising had proposed a spark gap as the voltage source, Wideroe used a 25kV vacuum tube oscillator. He successfully demonstrated that he had accelerated sodium and potassium ions to an energy of 50,000 electron volts (50 keV), twice the energy they would have received if accelerated only once by the tube. By successfully accelerating a particle multiple times using the same voltage source, Wideroe demonstrated

3344-598: The dielectric strength limits the maximum acceleration that can be achieved within a certain distance. This limit can be circumvented using accelerated waves in plasma to generate the accelerating field in Kielfeld accelerators : A laser or particle beam excites an oscillation in a plasma , which is associated with very strong electric field strengths. This means that significantly (factors of 100s to 1000s ) more compact linear accelerators can possibly be built. Experiments involving high power lasers in metal vapour plasmas suggest that

3420-581: The discoveries using this new capabilities may include new drugs, next-generation computers, and new materials. In 2012, the first two-thirds (~2 km) of the original SLAC LINAC were recommissioned for a new user facility, the Facility for Advanced Accelerator Experimental Tests (FACET). This facility was capable of delivering 20 GeV, 3 nC electron (and positron) beams with short bunch lengths and small spot sizes, ideal for beam-driven plasma acceleration studies. The facility ended operations in 2016 for

3496-438: The electrons are directed at a high-density (such as tungsten ) target. The electrons or X-rays can be used to treat both benign and malignant disease. The LINAC produces a reliable, flexible and accurate radiation beam. The versatility of LINAC is a potential advantage over cobalt therapy as a treatment tool. In addition, the device can simply be powered off when not in use; there is no source requiring heavy shielding – although

3572-711: The first FFRDC, the RAND Corporation , in 1947. Others grew directly out of their wartime roles. For example, MIT Lincoln Laboratory , founded in 1951, originated as the Radiation Laboratory at MIT, and the Navy's Operation Research Group evolved into the Center for Naval Analyses. The first FFRDCs served the Department of Defense . Since then, other government organizations have sponsored FFRDCs to meet their specific needs. In 1969,

3648-504: The first machine that worked was constructed by Rolf Widerøe in 1928 at the RWTH Aachen University . Linacs have many applications: they generate X-rays and high energy electrons for medicinal purposes in radiation therapy , serve as particle injectors for higher-energy accelerators, and are used directly to achieve the highest kinetic energy for light particles (electrons and positrons) for particle physics . The design of

3724-566: The first patient treated in 1953 in London, UK, at the Hammersmith Hospital , with an 8 MV machine built by Metropolitan-Vickers and installed in 1952, as the first dedicated medical linac. A short while later in 1954, a 6 MV linac was installed in Stanford, USA, which began treatments in 1956. Medical linear accelerators accelerate electrons using a tuned-cavity waveguide, in which

3800-421: The first travelling-wave electron accelerator at Stanford University. Electrons are sufficiently lighter than protons that they achieve speeds close to the speed of light early in the acceleration process. As a result, "accelerating" electrons increase in energy but can be treated as having a constant velocity from an accelerator design standpoint. This allowed Hansen to use an accelerating structure consisting of

3876-489: The frequency of the acceleration voltage selected, the more individual acceleration thrusts per path length a particle of a given speed experiences, and the shorter the accelerator can therefore be overall. That is why accelerator technology developed in the pursuit of higher particle energies, especially towards higher frequencies. The linear accelerator concepts (often called accelerator structures in technical terms) that have been used since around 1950 work with frequencies in

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3952-511: The highly polarized electron beam at SLC (close to 80%) made certain unique measurements possible, such as parity violation in Z Boson-b quark coupling. Presently no beam enters the south and north arcs in the machine, which leads to the Final Focus, therefore this section is mothballed to run beam into the PEP2 section from the beam switchyard. The SLAC Large Detector (SLD) was the main detector for

4028-437: The initial stages of the accelerator. Because the magnetic force is dependent on the particle velocity, it was desirable to create a type of accelerator which could simultaneously accelerate and focus low-to-mid energy hadrons . In 1970, Soviet physicists I. M. Kapchinsky and Vladimir Teplyakov proposed the radio-frequency quadrupole (RFQ) type of accelerating structure. RFQs use vanes or rods with precisely designed shapes in

4104-441: The intensity of the beam is often high enough so that the sample explodes on the femtosecond timescale. The LCLS-II project is to provide a major upgrade to LCLS by adding two new X-ray laser beams. The new system will utilize the 500 m (1,600 ft) of existing tunnel to add a new superconducting accelerator at 4 GeV and two new sets of undulators that will increase the available energy range of LCLS. The advancement from

4180-490: The kinetic energy released during braking is made available for the next acceleration by charging a battery. The Brookhaven National Laboratory and the Helmholtz-Zentrum Berlin with the project "bERLinPro" reported on corresponding development work. The Berlin experimental accelerator uses superconducting niobium cavity resonators. In 2014, three free-electron lasers based on ERLs were in operation worldwide: in

4256-538: The klystron, was essential for these two acceleration techniques . The first larger linear accelerator with standing waves - for protons - was built in 1945/46 in the Lawrence Berkeley National Laboratory under the direction of Luis W. Alvarez . The frequency used was 200 MHz .  The first electron accelerator with traveling waves of around 2 GHz was developed a little later at Stanford University by W.W. Hansen and colleagues. In

4332-455: The machine. At speeds near the speed of light, the incremental velocity increase will be small, with the energy appearing as an increase in the mass of the particles. In portions of the accelerator where this occurs, the tubular electrode lengths will be almost constant. Additional magnetic or electrostatic lens elements may be included to ensure that the beam remains in the center of the pipe and its electrodes. Very long accelerators may maintain

4408-540: The main linear accelerator. SLAC plays a primary role in the mission and operation of the Fermi Gamma-ray Space Telescope, launched in August 2008. The principal scientific objectives of this mission are: The Kavli Institute for Particle Astrophysics and Cosmology (KIPAC) is partially housed on the grounds of SLAC, in addition to its presence on the main Stanford campus. The Stanford PULSE Institute (PULSE)

4484-537: The main purpose of the linear accelerator was to inject electrons and positrons into the PEP-II accelerator, an electron-positron collider with a pair of storage rings 2.2 km (1.4 mi) in circumference. PEP-II was host to the BaBar experiment , one of the so-called B-Factory experiments studying charge-parity symmetry . The Stanford Synchrotron Radiation Lightsource (SSRL) is a synchrotron light user facility located on

4560-518: The massive United States war effort—leading to evolutions in radar, aircraft, computing and, most famously, the development of nuclear weapons through the Manhattan Project . The end of armed conflict did not end the need for organized research and development in support of the government. As the Cold War became the new reality, government officials and their scientific advisors advanced the idea of

4636-409: The maximum power that can be imparted to electrons in a synchrotron of given size. Linacs are also capable of prodigious output, producing a nearly continuous stream of particles, whereas a synchrotron will only periodically raise the particles to sufficient energy to merit a "shot" at the target. (The burst can be held or stored in the ring at energy to give the experimental electronics time to work, but

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4712-475: The number of FFRDCs peaked at 74. The following list includes all current FFRDCs: Linear particle accelerator A linear particle accelerator (often shortened to linac ) is a type of particle accelerator that accelerates charged subatomic particles or ions to a high speed by subjecting them to a series of oscillating electric potentials along a linear beamline . The principles for such machines were proposed by Gustav Ising in 1924, while

4788-527: The original linear accelerator at SLAC, and can deliver extremely intense x-ray radiation for research in a number of areas. It achieved first lasing in April 2009. The laser produces hard X-rays, 10 times the relative brightness of traditional synchrotron sources and is the most powerful x-ray source in the world. LCLS enables a variety of new experiments and provides enhancements for existing experimental methods. Often, x-rays are used to take "snapshots" of objects at

4864-485: The other hand, with ions of this energy range, the speed also increases significantly due to further acceleration. The acceleration concepts used today for ions are always based on electromagnetic standing waves that are formed in suitable resonators . Depending on the type of particle, energy range and other parameters, very different types of resonators are used; the following sections only cover some of them. Electrons can also be accelerated with standing waves above

4940-461: The otherwise necessary numerous klystron amplifiers to generate the acceleration power, a second parallel electron linear accelerator of lower energy is to be used, which works with superconducting cavities in which standing waves are formed. High-frequency power is extracted from it at regular intervals and transmitted to the main accelerator. In this way, the very high acceleration field strength of 80 MV / m should be achieved. In cavity resonators,

5016-447: The particle travels, and the central tubes are only used to shield the particles during the decelerating portion of the oscillator's phase. Using this approach to acceleration meant that Alvarez's first linac was able to achieve proton energies of 31.5 MeV in 1947, the highest that had ever been reached at the time. The initial Alvarez type linacs had no strong mechanism for keeping the beam focused and were limited in length and energy as

5092-426: The particle traverses a series of accelerating regions, driven by a source of voltage in such a way that the particle sees an accelerating field as it crosses each region. In this type of acceleration, particles must necessarily travel in "bunches" corresponding to the portion of the oscillator's cycle where the electric field is pointing in the intended direction of acceleration. If a single oscillating voltage source

5168-566: The properties of the Z boson using the Stanford Large Detector. As of 2005, SLAC employed over 1,000 people, some 150 of whom were physicists with doctorate degrees , and served over 3,000 visiting researchers yearly, operating particle accelerators for high-energy physics and the Stanford Synchrotron Radiation Laboratory (SSRL) for synchrotron light radiation research, which was "indispensable" in

5244-523: The range from around 100 MHz to a few gigahertz (GHz) and use the electric field component of electromagnetic waves. When it comes to energies of more than a few MeV, accelerators for ions are different from those for electrons. The reason for this is the large mass difference between the particles. Electrons are already close to the speed of light , the absolute speed limit, at a few MeV; with further acceleration, as described by relativistic mechanics , almost only their energy and momentum increase. On

5320-471: The research leading to the 2006 Nobel Prize in Chemistry awarded to Stanford Professor Roger D. Kornberg . In October 2008, the Department of Energy announced that the center's name would be changed to SLAC National Accelerator Laboratory. The reasons given include a better representation of the new direction of the lab and the ability to trademark the laboratory's name. Stanford University had legally opposed

5396-653: The state-owned Chinese electric utility. In April of 2024, SLAC completed two decades of work constructing the world's largest digital camera for the Legacy Survey of Space and Time (LSST) project at the Vera C. Rubin Observatory in Chile. The camera is expected to become operational in 2025. The main accelerator was an RF linear accelerator that accelerated electrons and positrons up to 50 GeV . At 3.2 km (2.0 mi) long,

5472-423: The treatment room itself requires considerable shielding of the walls, doors, ceiling etc. to prevent escape of scattered radiation. Prolonged use of high powered (>18 MeV) machines can induce a significant amount of radiation within the metal parts of the head of the machine after power to the machine has been removed (i.e. they become an active source and the necessary precautions must be observed). In 2019

5548-576: The two diagrams, the curve and arrows indicate the force acting on the particles. Only at the points with the correct direction of the electric field vector, i.e. the correct direction of force, can particles absorb energy from the wave. (An increase in speed cannot be seen in the scale of these images.) The linear accelerator could produce higher particle energies than the previous electrostatic particle accelerators (the Cockcroft–Walton accelerator and Van de Graaff generator ) that were in use when it

5624-492: The utility of radio frequency (RF) acceleration. This type of linac was limited by the voltage sources that were available at the time, and it was not until after World War II that Luis Alvarez was able to use newly developed high frequency oscillators to design the first resonant cavity drift tube linac. An Alvarez linac differs from the Wideroe type in that the RF power is applied to the entire resonant chamber through which

5700-651: Was about 90 GeV , equal to the mass of the Z boson , which the accelerator was designed to study. Grad student Barrett D. Milliken discovered the first Z event on 12 April 1989 while poring over the previous day's computer data from the Mark II detector . The bulk of the data was collected by the SLAC Large Detector , which came online in 1991. Although largely overshadowed by the Large Electron–Positron Collider at CERN , which began running in 1989,

5776-620: Was invented. In these machines, the particles were only accelerated once by the applied voltage, so the particle energy in electron volts was equal to the accelerating voltage on the machine, which was limited to a few million volts by insulation breakdown. In the linac, the particles are accelerated multiple times by the applied voltage, so the particle energy is not limited by the accelerating voltage. High power linacs are also being developed for production of electrons at relativistic speeds, required since fast electrons traveling in an arc will lose energy through synchrotron radiation ; this limits

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