View source for SLAC National Accelerator Laboratory

{{Short description|Research center at Stanford University}}
{{Redirect|SLAC}}
{{Use American English|date=July 2025}}
{{Use mdy dates|date=July 2025}}
{{Infobox laboratory
| logo             = SLAC LogoSD.svg
| logo_size        = 246px
| image            = SLAC aerial.jpg
| caption          = Aerial view of former linear accelerator
| established      = {{Start date and age|1962}} 
| type             = [[Physical sciences]]
| budget           = $383 million (2017)<ref>{{cite web |title=Labs at a glance – SLAC |url=http://science.energy.gov/laboratories/slac-national-accelerator-laboratory/ |website=Science.Energy.gov |publisher=United States Department of Energy |archive-url=https://web.archive.org/web/20140209153921/http://science.energy.gov/laboratories/slac-national-accelerator-laboratory/ |archive-date=February 9, 2014 }}</ref>
| research_field   = [[Accelerator physics]]<br />Photon science
| director         = [[John L. Sarrao]]
| staff            = 1,684
| campus           = {{Cvt|426|acre|ha|order=flip}}
| city             = [[Menlo Park, California]], United States
| address          = 2575 Sand Hill Rd.<br />Menlo Park, California 94025
| coordinates      = {{Coord|37|25|03|N|122|12|09|W|region:US-CA_type:landmark|display=inline,title}}
| location_map     = USA California
| nickname         = SLAC
| affiliations     = [[United States Department of Energy|US Department of Energy]]
| operating_agency = [[Stanford University]]
| nobel_laureates  = {{Ubl|[[Burton Richter]]|[[Richard E. Taylor]]|[[Martin L. Perl]]}}
| website          = {{Official URL}}
}}
{{Infobox particle accelerator
| name        = Stanford Linear Accelerator
| image       = Stanford-linear-accelerator-usgs-ortho-kaminski-5900.jpg
| caption     = 
| type        = [[Linear particle accelerator|Linear accelerator]]
| beam        = [[Electron]]s
| target      = Fixed target
| energy      = 50&nbsp;GeV
| current     = 
| brightness  = 
| luminosity  = 
| length      = {{Cvt|2|mi|km|order=flip}}<ref name="Neal 1968" />{{Rp|55}}
| location    = [[Menlo Park, California]]
| institution = [[Stanford University]], [[United States Department of Energy|US-DOE]]
| dates       = 1966–2006
| preceded    = 
| succeeded   = LCLS
}}

'''SLAC National Accelerator Laboratory''', originally named the '''Stanford Linear Accelerator Center''',<ref name="Stanford Daily 2008">{{cite news |date=October 16, 2008 |title=SLAC renamed to SLAC Natl. Accelerator Laboratory |url=http://archive.stanforddaily.com/?p=556 |archive-url=https://web.archive.org/web/20130605180459/http://archive.stanforddaily.com/?p=556 |archive-date=June 5, 2013 |work=[[The Stanford Daily]] }}</ref><ref>{{cite press release |date=October 15, 2008 |title=Stanford Linear Accelerator Center renamed SLAC National Accelerator Laboratory |url=http://home.slac.stanford.edu/pressreleases/2008/20081015.htm |publisher=SLAC National Accelerator Laboratory |access-date=July 20, 2011 |archive-url=https://web.archive.org/web/20110726095744/http://home.slac.stanford.edu/pressreleases/2008/20081015.htm |archive-date=July 26, 2011 |url-status=live }}</ref> is a [[Federally funded research and development centers|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 {{Cvt|2|mi|km|sp=us|order=flip}} [[linear accelerator]] constructed in 1966 that could accelerate electrons to energies of 50&nbsp;[[GeV]].<ref name="Neal 1968">{{cite book |last=Neal |first=R.B. |date=1968 |title=The Stanford Two-Mile Accelerator |chapter=Chap. 5 |publisher=W.A. Benjamin |location=New York, New York |page=59 |chapter-url=https://www.slac.stanford.edu/spires/hep/HEPPDF/twomile/Chapters_4_5.pdf |archive-date=July 14, 2010 |archive-url=https://web.archive.org/web/20100714021047/http://www.slac.stanford.edu/spires/hep/HEPPDF/twomile/Chapters_4_5.pdf |url-status=live |access-date=July 18, 2025 }}</ref>{{Rp|55}}

Today SLAC research centers on a broad program in [[Atomic physics|atomic]] and [[solid-state physics]], [[chemistry]], [[biology]], and [[medicine]] using X-rays from [[synchrotron radiation]] and a [[free-electron laser]] as well as [[Experimental physics|experimental]] and [[theoretical physics|theoretical]] research in [[elementary particle|elementary]] [[particle physics]], [[accelerator physics]], [[astroparticle physics]], and [[cosmology]]. The laboratory is under the programmatic direction of the United States Department of Energy Office of Science.

==History==
[[File:SLAC Gate Sign.jpg|thumb|alt=A concrete monument sign reads "SLAC National Accelerator Laboratory: Operated by Stanford University for the U.S. Department of Energy".|The entrance to SLAC in [[Menlo Park, California|Menlo Park]]]]

Founded in 1962 as the Stanford Linear Accelerator Center, the facility is located on {{cvt|426|acre|ha|order=flip}} 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 {{cvt|2|mi|km|order=flip|sp=us}} long,<ref name="Neal 1968" />{{Rp|55}} making it the longest linear accelerator in the world,{{Citation needed|date=May 2025}} and has been operational since 1966.

[[File:Nobel Prize.png|thumb|Research at SLAC has produced three [[Nobel Prize in Physics|Nobel Prizes in Physics]]]]

Research at SLAC has produced three [[Nobel Prize in Physics|Nobel Prizes in Physics]]:
* 1976: The [[charm quark]]; see [[J/psi meson|J/ψ meson]]<ref>[http://www.slac.stanford.edu/library/nobel/nobel1976.html Nobel Prize in Physics 1976] {{webarchive |url=https://web.archive.org/web/20051207184709/http://www.slac.stanford.edu/library/nobel/nobel1976.html |date=December 7, 2005 }}.  Half prize awarded to [[Burton Richter]].</ref>
* 1990: [[Quark]] structure inside [[proton]]s and [[neutron]]s<ref>[http://www.slac.stanford.edu/library/nobel/nobel1990.html Nobel Prize in Physics 1990] {{webarchive |url=https://web.archive.org/web/20051126144121/http://www.slac.stanford.edu/library/nobel/nobel1990.html |date=November 26, 2005 }} Award split between [[Jerome I. Friedman]], [[Henry W. Kendall]], and [[Richard E. Taylor]].</ref>
* 1995: The [[tau lepton]]<ref>[http://www.slac.stanford.edu/library/nobel/nobel1995.html Nobel Prize in Physics 1995] {{webarchive |url=https://web.archive.org/web/20051202103410/http://www.slac.stanford.edu/library/nobel/nobel1995.html |date=December 2, 2005 }} Half prize awarded to [[Martin L. Perl]].</ref>

In 1984, the laboratory was named an [[List of Historic Mechanical Engineering Landmarks|ASME National Historic Engineering Landmark]] and an [[List of IEEE milestones|IEEE Milestone]].<ref>{{cite web |url=http://www.ieeeghn.org/wiki/index.php/Milestones:Stanford_Linear_Accelerator_Center,_1962 |title=Milestones:Stanford Linear Accelerator Center, 1962 |work=IEEE Global History Network |publisher=IEEE |access-date=August 3, 2011 |archive-date=March 6, 2012 |archive-url=https://web.archive.org/web/20120306060256/http://www.ieeeghn.org/wiki/index.php/Milestones:Stanford_Linear_Accelerator_Center,_1962 |url-status=live }}</ref>

SLAC developed and, in December 1991, began hosting the first [[World Wide Web]] server outside of Europe.<ref>{{cite web |url=http://www.slac.stanford.edu/history/earlyweb/history.shtml |title=Archives and History Office: Early Chronology and Documents |access-date=December 27, 2016 |archive-date=November 24, 2005 |archive-url=https://web.archive.org/web/20051124035516/http://www.slac.stanford.edu/history/earlyweb/history.shtml |url-status=live }}</ref>

In the early-to-mid 1990s, the Stanford Linear Collider (SLC) investigated the properties of the [[Z boson]] using the Stanford Large Detector.

By 2005, SLAC employed over 1,000 people, some 150 of whom were [[physicist]]s with [[doctorate degree]]s, and served over 3,000 visiting researchers yearly, operating [[particle accelerator]]s for [[high-energy physics]] and the [[Stanford Synchrotron Radiation Laboratory]] (SSRL) for [[synchrotron light]] radiation research, which was "indispensable" in the research leading to the 2006 [[Nobel Prize in Chemistry]] awarded to Stanford Professor [[Roger D. Kornberg]].<ref>{{cite web |date=n.d. |title=2006 Nobel Prize in Chemistry |url=http://www2.slac.stanford.edu/vvc/nobel/2006nobel.html |website=SLAC Virtual Visitor Center |publisher=Stanford University |archive-url=https://web.archive.org/web/20110805135252/http://www2.slac.stanford.edu/vvc/nobel/2006nobel.html |archive-date=August 5, 2011 |access-date=March 19, 2015 }}</ref>

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 the Department of Energy's attempt to trademark "Stanford Linear Accelerator Center".<ref name="Stanford Daily 2008" /><ref>{{cite web |url=http://today.slac.stanford.edu/feature/2008/new-name-for-slac.asp |title=SLAC Today |archive-date=July 30, 2011 |archive-url=https://web.archive.org/web/20110730054445/http://today.slac.stanford.edu/feature/2008/new-name-for-slac.asp |url-status=live |access-date=December 27, 2016 }}</ref>

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.<ref>{{Cite web |url=http://home.slac.stanford.edu/pressreleases/2009/20090323.htm%7Ctitle%3DMarch |title=23, 2009 - SLAC National Accelerator Laboratory to Receive $68.3 Million in Recovery Act Funding |access-date=May 30, 2014 |archive-date=October 20, 2022 |archive-url=https://web.archive.org/web/20221020032922/https://www6.slac.stanford.edu/ |url-status=live }}</ref>

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, the state-owned Chinese electric utility.<ref>{{cite news |last1=Knowles |first1=Hannah |last2=Jin |first2=Berber |title=Chinese Access to Research Questioned: Disagreements Ensue over Inclusion and National Security |publisher=The Stanford Daily |date=May 29, 2019 |volume=255 |issue=66 }}</ref>

In April 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 become operational in 2025.<ref>{{cite news |last=Dorsey |first=Dustin |date=April 12, 2024 |title=World's Largest Digital Camera Now Complete at SLAC National Accelerator Laboratory in Bay Area |url=https://abc7news.com/worlds-largest-digital-camera-complete-at-slac-national-accelerator-laboratory-in-bay-area-after-2-decades/14648141/ |work=[[KGO-TV]] |publisher=[[ABC Owned Television Stations]] |access-date=June 16, 2024 }}</ref><ref>{{Cite web |last=Baron |first=Ethan |date=June 23, 2025 |title=First images unveiled from world's largest camera, built in the Bay Area |url=https://www.mercurynews.com/2025/06/22/first-images-worlds-largest-camera-built-bay-area/ |website=The Mercury News |access-date=July 6, 2025 }}</ref>

== Components ==
[[File:SLAC long view.jpg|thumb|SLAC {{cvt|3|km|mi|0|adj=mid|-long|sp=us}} Klystron Gallery above the [[beamline]] Accelerator]]

=== Accelerator ===
[[File:SLAC tunnel 2.jpg|thumb|left|Part of the SLAC beamline]]

The main accelerator was an [[Linear particle accelerator|RF linear accelerator]] that accelerated [[electron]]s and [[positron]]s up to 50&nbsp;GeV.  At {{cvt|2|mi|km|order=flip}} long,<ref name="Neal 1968" />{{Rp|55}} the [[particle accelerator|accelerator]] was the longest [[linear accelerator]] in the world, and was claimed to be "the world's most straight object."<ref>Saracevic, Alan T. "[http://www.sfgate.com/bayarea/article/Silicon-Valley-It-s-where-brains-meet-bucks-2600193.php Silicon Valley: It's Where Brains Meet Bucks.] {{Webarchive|url=https://web.archive.org/web/20121122075513/http://www.sfgate.com/bayarea/article/Silicon-Valley-It-s-where-brains-meet-bucks-2600193.php |date=22 November 2012 }}" ''[[San Francisco Chronicle]]'' October 23, 2005. p J2. Accessed October 24, 2005.</ref> until 2017 when the [[European x-ray free electron laser]] opened. The main accelerator is buried {{cvt|30|ft|m|0|order=flip}} below ground<ref name="Neal 1968" />{{Rp|59}} and passes underneath [[Interstate 280 (California)|Interstate Highway 280]]. The above-ground [[klystron]] gallery atop the [[beamline]], was the longest building in the United States until 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.<ref>{{Cite web |url=https://opennav.com/waypoint/US/VPSLA |title=VPSLA waypoint &#124; OpenNav |archive-date=August 9, 2019 |archive-url=https://web.archive.org/web/20190809181545/https://opennav.com/waypoint/US/VPSLA |url-status=live |access-date=August 9, 2019 }}</ref>

A portion of the original linear accelerator is now part of the Linac Coherent Light Source.{{Citation needed|date=July 2025}}

=== Stanford Linear Collider ===
[[File:SLAC pit and detector.jpg|thumb|left|SLC pit and detector]]

The Stanford Linear Collider was a [[linear accelerator]] that collided [[electron]]s and [[positron]]s at SLAC.<ref>{{cite conference |last=Loew |first=G.A. |date=1984 |title=The SLAC Linear Collider and a few ideas on Future Linear Colliders |book-title=Proceedings of the 1984 Linear Accelerator Conference |url=http://accelconf.web.cern.ch/accelconf/l84/papers/wed0002.pdf |access-date=June 29, 2013 |archive-date=June 8, 2013 |archive-url=https://web.archive.org/web/20130608004653/https://accelconf.web.cern.ch/AccelConf/l84/papers/wed0002.pdf |url-status=live }}</ref> The [[center of mass]] [[energy]] was about 90&nbsp;GeV, equal to the [[mass]] of the [[W and Z bosons|Z boson]], which the accelerator was designed to study.
Grad student Barrett D. Milliken discovered the first Z [[event (particle physics)|event]] on April 12, 1989, while poring over the previous day's computer data from the Mark II detector.<ref>{{cite journal |last=Rees |first=J. R. |date=1989 |title=The Stanford Linear Collider |journal=Scientific American |volume=261 |issue=4 |pages=36–43 |doi=10.1038/scientificamerican1089-58 |bibcode=1989SciAm.261d..58R}} See also a colleague's logbook at http://www.symmetrymagazine.org/cms/?pid=1000294 {{Webarchive|url=https://web.archive.org/web/20070927224133/http://www.symmetrymagazine.org/cms/?pid=1000294 |date=September 27, 2007 }}.</ref> 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, the highly [[Helicity (particle physics)|polarized]] electron beam at SLC (close to 80%<ref>Ken Baird, Measurements of A<sub>LR</sub> and A<sub>lepton</sub> from SLD http://hepweb.rl.ac.uk/ichep98/talks_1/talk101.pdf {{Webarchive |url=https://web.archive.org/web/20160305040733/http://hepweb.rl.ac.uk/ichep98/talks_1/talk101.pdf |date=March 5, 2016 }}</ref>) made certain unique measurements possible, such as parity violation in Z Boson-b quark coupling.<ref>{{Cite web |last=Wright |first=Thomas R. |date=2002 |url=https://pdfs.semanticscholar.org/22c0/158e9d4f5e1f85484aec7150e44b996dbf1a.pdf |archive-url=https://web.archive.org/web/20201126154003/https://pdfs.semanticscholar.org/22c0/158e9d4f5e1f85484aec7150e44b996dbf1a.pdf |archive-date=November 26, 2020 |s2cid=116959532 |doi=10.2172/801825 |title=Parity Violation in Decays of Z Bosons into Heavy Quarks at SLD |osti=801825 }}</ref>

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.

=== SLAC Large Detector ===
[[File:SLAC detector.jpg|thumb|Inside view of the SLD]]

The SLAC Large Detector (SLD) was the main detector for 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.<ref>{{Cite web |url=https://www.slac.stanford.edu/gen/grad/GradHandbook/slac.html |title=The Stanford Linear Accelerator Center |access-date=October 10, 2020 |archive-date=December 5, 2020 |archive-url=https://web.archive.org/web/20201205153703/https://www.slac.stanford.edu/gen/grad/GradHandbook/slac.html |url-status=live }}</ref>

=== PEP ===
PEP (Positron-Electron Project) began operation in 1980, with center-of-mass energies up to 29&nbsp;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.<ref>{{cite web |url=http://www.slac.stanford.edu/gen/grad/GradHandbook/slac.html |title=The Stanford Linear Accelerator Center |archive-date=April 28, 2016 |archive-url=https://web.archive.org/web/20160428002905/http://www.slac.stanford.edu/gen/grad/GradHandbook/slac.html |url-status=live |access-date=December 27, 2016 }}</ref>

=== PEP-II ===
<!--"PEP-II" redirects here.-->
From 1999 to 2008, 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 {{cvt|2.2|km|mi}} in circumference. PEP-II was host to the [[BaBar experiment]], one of the so-called [[B-Factory]] experiments studying [[CP-symmetry|charge-parity symmetry]].

=== Stanford Synchrotron Radiation Lightsource ===
{{Main|Stanford Synchrotron Radiation Lightsource}}

The Stanford Synchrotron Radiation Lightsource (SSRL) is a [[synchrotron light]] user facility located on the SLAC campus.  Originally built for particle physics, it was used in experiments where the [[J/psi meson|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 the main linear accelerator.

=== Fermi Gamma-ray Space Telescope ===
{{Main|Fermi Gamma-ray Space Telescope}}
[[File:GLAST on the payload attach fitting.jpg|thumb|upright|Fermi Gamma-ray Space Telescope]]

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:
* To understand the mechanisms of particle acceleration in [[Active galactic nucleus|AGNs]], pulsars, and [[Supernova remnant|SNRs]]
* To resolve the gamma-ray sky: unidentified sources and diffuse emission
* To determine the high-energy behavior of gamma-ray bursts and transients
* To probe dark matter and fundamental physics

=== KIPAC ===
{{Main|Kavli Institute for Particle Astrophysics and Cosmology}}

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.

===PULSE===
{{Main|Stanford PULSE Institute}}

The Stanford PULSE Institute (PULSE) 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 [https://scholar.google.com/citations?sortby=pubdate&hl=en&user=cJvCrvsAAAAJ&view_op=list_works here].

=== LCLS ===
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 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.<ref>{{cite web |url=https://lcls.slac.stanford.edu/ |title=SLAC Linac Coherent Light Source |access-date=December 27, 2016 |archive-date=December 6, 2017 |archive-url=https://web.archive.org/web/20171206180107/https://lcls.slac.stanford.edu/ |url-status=live }}</ref>

[[File:Stanford-linear-accelerator-usgs-ortho-kaminski-5900.jpg|thumb|center|750px|Aerial photo of the Stanford Linear Accelerator Center, showing the {{Cvt|2|mi|km|order=flip|sp=us}} building housing the accelerator beamline,<ref name="Neal 1968" />{{Rp|55}} which passes under [[Interstate 280 (California)|Interstate 280]].  The detector complex is visible to the east, on the right side.]]

The laser produces hard X-rays, 10<sup>9</sup> 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 the atomic level before obliterating samples. The laser's wavelength, ranging from 6.2 to 0.13&nbsp;nm (200 to 9500 [[electron volt]]s (eV))<ref name="SXR">{{cite web |title=Soft X-Ray Materials Science (SXR) |url=https://portal.slac.stanford.edu/sites/lcls_public/Instruments/SXR/Pages/Specifications.aspx |archive-date=September 17, 2015 |archive-url=https://web.archive.org/web/20150917114355/https://portal.slac.stanford.edu/sites/lcls_public/instruments/SXR/Pages/Specifications.aspx |url-status=live |access-date=March 22, 2015 }}</ref><ref>{{cite web |title=LCLS status page |url=https://portal.slac.stanford.edu/sites/lcls_public/Pages/status.aspx |archive-date=December 7, 2016 |archive-url=https://web.archive.org/web/20161207031754/https://portal.slac.stanford.edu/sites/lcls_public/Pages/status.aspx |url-status=live |access-date=February 4, 2016 }}</ref> is similar to the width of an atom, providing extremely detailed information that was previously unattainable.<ref>
{{cite journal |last1=Bostedt |first1=C. |display-authors=etal |date=2013 |title=Ultra-fast and ultra-intense x-ray sciences: First results from the Linac Coherent Light Source free-electron laser |journal=Journal of Physics B |volume=46 |issue=16 |article-number=164003 |doi=10.1088/0953-4075/46/16/164003 |bibcode=2013JPhB...46p4003B |s2cid=121297567 }}</ref> Additionally, the laser is capable of capturing images with a "shutter speed" measured in femtoseconds, or million-billionths of a second, necessary because the intensity of the beam is often high enough so that the sample explodes on the femtosecond timescale.<ref>{{cite web |last=Ehrenberg |first=Rachel |url=http://www.sciencenews.org/view/generic/id/69496/title/X-raying_life%E2%80%99s_microscopic_machinery/ |archive-url=https://web.archive.org/web/20111213193448/https://www.sciencenews.org/view/generic/id/69496/title/X-raying_life%E2%80%99s_microscopic_machinery/ |archive-date=December 13, 2011 |title=X-raying life's microscopic machinery / New laser technique promises to make the subcellular visible |publisher=[[Science News]] |website=ScienceNews.org }}</ref><ref name="SXR" />

===LCLS-II===
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 {{cvt|500|m|ft}} of existing tunnel to add a new superconducting accelerator at 4&nbsp;GeV and two new sets of undulators that will increase the available energy range of LCLS. The advancement from the discoveries using this new capabilities may include new drugs, next-generation computers, and new materials.<ref>{{cite news |date=July 8, 2015 |title=LCLS-II Upgrade to Enable Pioneering Research in Many Fields |url=http://www.cryogenicsociety.org/csa_highlights/lcls_ii_upgrade_to_enable_pioneering_research_in_many_fields/ |work=Cryogenic Society of America |archive-date=September 23, 2015 |archive-url=https://web.archive.org/web/20150923211328/http://www.cryogenicsociety.org/csa_highlights/lcls_ii_upgrade_to_enable_pioneering_research_in_many_fields/ }}</ref>

===FACET===
In 2012, the first two-thirds (~2&nbsp;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&nbsp;GeV, 3&nbsp;nC electron (and positron) beams with short bunch lengths and small spot sizes, ideal for beam-driven [[plasma acceleration]] studies.<ref>{{Cite web |url=http://accelconf.web.cern.ch/accelconf/ipac2012/papers/weppp010.pdf |title=FACET: SLAC's new user facility |access-date=August 6, 2014 |archive-date=November 22, 2014 |archive-url=https://web.archive.org/web/20141122165023/http://accelconf.web.cern.ch/AccelConf/IPAC2012/papers/weppp010.pdf |url-status=live }}</ref> The facility ended operations in 2016 for 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.

===NLCTA===
The Next Linear Collider Test Accelerator (NLCTA) is a 60–120&nbsp;MeV high-brightness electron beam linear accelerator used for experiments on advanced beam manipulation and acceleration techniques. It is located at SLAC's end station B.<ref>{{cite web |url=https://portal.slac.stanford.edu/sites/ard_public/tfd/facilities/nlcta/Pages/Recent-Publications.aspx |title=Recent Publications |website=Portal.SLAC.Stanford.edu |archive-url=https://web.archive.org/web/20150915180410/https://portal.slac.stanford.edu/sites/ard_public/tfd/facilities/nlcta/Pages/Recent-Publications.aspx |archive-date=September 15, 2015 }}</ref>

===Theoretical Physics===
{{Main|SLAC Theory Group}}

SLAC also performs theoretical research in elementary particle physics, including in areas of [[quantum field theory]], collider physics, [[astroparticle physics]], and particle phenomenology.

== Other discoveries ==
* SLAC has also been instrumental in the development of the [[klystron]], a high-power [[microwave]] amplification tube.
* There is active research on [[plasma acceleration]] with recent successes such as the doubling of the energy of 42&nbsp;GeV electrons in a meter-scale accelerator.
* There was a ''[[Paleoparadoxia]]'' found at the SLAC site, and its skeleton can be seen at a small museum in the breezeway.<ref>[http://www2.slac.stanford.edu/vvc/paleo.html Stanford's SLAC Paleoparadoxia] {{Webarchive|url=https://web.archive.org/web/20050829115053/http://www2.slac.stanford.edu/vvc/paleo.html |date=August 29, 2005 }} much thanks to Adele Panofsky, Dr. Panofsky's wife, for her reassembly of the bones of the Paleoparadoxia uncovered at SLAC.</ref>
* The SSRL facility was used to reveal hidden text in the [[Archimedes Palimpsest]]. X-rays from the synchrotron radiation lightsource caused the iron in the original ink to glow, allowing the researchers to photograph the original document that a Christian monk had scrubbed off.<ref>{{cite web |last=Bergmann |first=Uwe |url=http://www.slac.stanford.edu/gen/com/images/technical%20summary_final.pdf |title=X-Ray Fluorescence Imaging of the Archimedes Palimpsest: A Technical Summary |publisher=SLAC National Accelerator Laboratory |archive-date=May 18, 2017 |archive-url=https://web.archive.org/web/20170518121622/http://www.slac.stanford.edu/gen/com/images/technical%20summary_final.pdf |url-status=live |access-date=October 4, 2009 }}</ref>

==Directors==
The following persons served as director of SLAC:<ref>{{cite web |url=https://history.aip.org/phn/21609005.html |title=Stanford Linear Accelerator Center |website=History.AIP.org |publisher=[[American Institute of Physics]] |access-date=July 18, 2025 }}</ref>

{| class="wikitable"
|-
! {{abbr|No.|Number}}
! Image
! Director
! Term start
! Term end
! {{abbr|Refs.|References}}
|-
| 1
|
| [[Wolfgang Panofsky]]
| 1961
| 1984
|
|-
| 2
| [[File:Burton Richter NSF crop.jpg|70px]]
| [[Burton Richter]]
| 1984
| August 31, 1999
| <ref>{{cite web |url=https://www6.slac.stanford.edu/news/1998-11-23-burton-richter-step-down-slac-director |title=Burton Richter to Step Down as SLAC Director |date=November 23, 1998 |publisher=SLAC }}</ref>
|-
| 3
| [[File:Jonathan Dorfan (26772816747).jpg|70px]]
| [[Jonathan Dorfan]]
| September 1, 1999
| December 12, 2007
| <ref>{{cite web |url=https://www6.slac.stanford.edu/news/1998-02-22-b-factory-leader-dorfan-named-third-director-slac |title=B Factory Leader Dorfan Named Third Director of SLAC |date=February 22, 1998 |publisher=SLAC }}</ref><ref>{{cite web |url=https://www.interactions.org/press-release/jonathan-dorfan-step-down-slac-director |title=Jonathan Dorfan to Step Down as SLAC Director |date=March 11, 2007 |work=Interactions.org }}</ref>
|- bgcolor="#e6e6aa"
| acting
|rowspan="2" bgcolor="#ffffff"| [[File:Drell Persis.jpg|70px]]
|rowspan="2" bgcolor="#ffffff"| [[Persis Drell]]
| September 9, 2007
| December 12, 2007
| <ref>{{cite web |url=https://www.interactions.org/press-release/drell-appointed-acting-director-slac-dorfan-accepts-new |title=Drell appointed acting director at SLAC as Dorfan accepts new university position |date=September 9, 2007 |work=Interactions.org }}</ref>
|-
| 4
| December 12, 2007
| October 31, 2012
| <ref>{{cite journal |url=https://pubs.aip.org/physicstoday/online/2965/Persis-S-Drell-Named-Fourth-Director-of-the-U-S |title=Persis S. Drell Named Fourth Director of the U.S. Department of Energy's Stanford Linear Accelerator Center |date=December 12, 2007 |journal=[[Physics Today]] |doi=10.1063/PT.4.1453 }}</ref><ref>{{cite journal |url=https://www.science.org/content/article/persis-drell-step-down-director-slac-national-accelerator-laboratory |title=Persis Drell to Step Down as Director of SLAC National Accelerator Laboratory |date=November 2, 2011 |first=Adrian |last=Cho |journal=[[Science (journal)|Science]] |doi=10.1126/article.28132 }}</ref>
|-
| 5
|
| Chi-Chang Kao
| November 1, 2012
| February 3, 2023
| <ref>{{cite web |url=https://www6.slac.stanford.edu/news/2012-10-24-chi-chang-kao-noted-x-ray-scientist-named-slac-director |title=Chi-Chang Kao, Noted X-ray Scientist, Named SLAC Director |date=October 24, 2012 |publisher=SLAC }}</ref><ref>{{cite web |url=https://news.stanford.edu/stories/2023/01/chi-chang-kaos-last-day-serving-lab-director-will-feb-3 |title=Chi-Chang Kao's last day serving as SLAC lab director will be Feb. 3 |date=January 31, 2023 |publisher=Stanford }}</ref>
|- bgcolor="#e6e6aa"
| interim
| [[File:Stephen Streiffer.jpg|70px]]
| [[Stephen Streiffer]]
| February 4, 2023
| October 1, 2023
| <ref>{{cite web |url=https://news.stanford.edu/stories/2023/07/stephen-k-streiffer-named-director-oak-ridge-national-laboratory |title=Stephen K. Streiffer named director of Oak Ridge National Laboratory |date=July 27, 2023 |publisher=Stanford}}</ref>
|-
| 6
| [[File:John L. Sarrao, 2013.jpg|70px]]
| [[John Sarrao]]
| October 2, 2023
| present
| <ref>{{cite web |url=https://news.stanford.edu/stories/2023/07/john-sarrao-named-director-slac-national-accelerator-laboratory |title=John Sarrao named director of SLAC National Accelerator Laboratory |date=July 17, 2023 |publisher=Stanford}}</ref>
|}

==See also==
{{Portal|San Francisco Bay Area}}
* {{Annotated link|Cyclotron}}
* {{Annotated link|Dipole magnet}}
* {{Annotated link|Electromagnetism}}
* [[List of particles]]
* [[List of United States college laboratories conducting basic defense research]]
* {{Annotated link|Particle beam}}
* {{Annotated link|Quadrupole magnet}}
* {{Annotated link|Spallation Neutron Source}}

==References==
{{Reflist}}

==External links==
{{Commons category}}
* {{Official website}}
** [https://www.symmetrymagazine.org/ ''symmetry'' magazine], SLAC's monthly particle physics magazine, with [[Fermilab]]
* [https://slactour.slac.stanford.edu/ SLAC Virtual Tour]—including science, history, photos and more about SLAC
* ''[https://www.pbs.org/wgbh/nova/einstein/ Einstein's Big Idea]'' (''NOVA'' program includes SLAC footage)
* [https://www-sld.slac.stanford.edu/sldwww/sld.html SLD collaboration page]
* [https://www.slac.stanford.edu/library/2MileAccelerator/2mile.htm The Stanford Two-Mile Accelerator]—''The Blue Book'' in [[PDF]]

{{Stanford University}}
{{Menlo Park, California}}
{{U.S. National Labs}}

{{Authority control}}

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