L

L     Large, Long (abbreviation used in SLAC drawings)

L2SI     LCLS-2 Strategic Initiative or LCLS-II Instruments

L3     Detector at LEP (CERN).

LA     License Application.

LA     Liquid Argon.

LAA     Local Administering Agency. (CH&SC Sec. 25500 et seq)

LAA     Lepton Asymmetry Analyzer.

LABELIT-CCI     Data characterization software for macromolecular crystallography.

LABL     Serial number or other label for a magnet.

LABRADOR     Large Analog Bandwidth Recorder And Digitizer with Ordered Readout .

LAD     License Application Design.

LAER     Lowest Achievable Emission Rate. (from CAA)

LAF     Linac Accelerator Facility. Includes LCLS-SC, FACET, LCLS-Cu linac areas

LAL     Laboratoire de l'Accélérateur Linéaire. (Orsay)

LAM     Look At Me! A Handshaking protocol between digital electronic systems.

LAMA     Library Administration and Management Association.

Lambda CDM     Lambda Cold Dark Matter. The leading modern cosmological model.

Lambertson     A type of septum magnet named after Glen Lambertson of LBNL. It is used to extract the beam from the LINAC to the positron target. See also HLAM.

LAMP     LCLS-ASG-Michigan Project for novel science with the LCLS FEL.

LAMPF     Los Alamos Meson/Proton Factory (1460 MeV/c Plab).

LAN     Local Area Network. Any physical network technology that operates at high speed over short distances (up to a few thousand meters).

Land Ban     Informal name for Land Disposal Restricted (LDR).

Landfarming     A treatment technique which involves spreading waste on land and utilizing evaporation and microbial action to degrade the wastes. Used primarily for crude oil wastes. It is not the same as landfilling.

LANL     Los Alamos National Laboratory

LAPP     Laboratoire d'Annency-L GOV

LAR     Large Adaptive Reflectors.

LAr TPC     Liquid Argonne Time Projection Chamber.

Large Power Supply     See LGPS.

Large Scale Collaboration Center     facility for lab-wide support of science and computing staff with completion planned in FY2024 (SLAC)

LARP     LHC Accelerator Research Program. (US)

Larse     A brand name for a general purpose alarm system chassis used at SLAC for monitoring fire alarms.

Laser     Light Amplification by Stimulated Emission of radiation. A device that uses the principle of amplification of electromagnetic waves by stimulated emission of radiation and operates in the infrared, visible, or ultraviolet region.

Laser Cavity Shutter     See LCS.

Laser Feedback Intensity Control     See LFIC.

Laser Safety Officer     See LSO.

Laser Safety Stopper     See LSS.

LASS     LASer analyzing Station. A B-line apparatus.

LAST     Life, Art, Science, Tech festival

LAT     Large Array Telescope (GLAST --FERMI).

LAT     Local Area Transport.

LATOR     Laser Astrometric Test of Relativity.

Lattice     A repeating pattern of magnets.

Launch Knob     A multiknob using a set of correctors to launch beam in the LTRs, the Rings or other sections of the machine. The knobs are orthogonalized to give independent control of position and angle at a given reference point.

LBL     Low-energy cut-off BL Lac object.

LBL     see LBNL

LBNE     Long-Baseline Neutrino Experiment. (FermiLab)

LBNF     Long-Baseline Neutrino Facility.

LBNL     Lawrence Berkeley National Laboratory, CA. Full name of lab is Ernest Orlando Lawrence Berkeley National Laboratory.

LC     Liquid Crystal.

LC     Linear Collider.

LCA     Labor Condition Application.

LCA     Laser Controlled Area.

LCB     Lat Communications Board.

LCC     Linear Collider Collaboration. A collaboration between SLAC and KEK to define common parameters for a TeV center-of-mass energy linear collider.

LCCA     Life Cycle Cost Analysis.

LCD     Liquid Crystal Display.

LCD     Linear Collider Detector.

LCDG4     GEANT4-based flexible full-detector simulation program.

LCFI     Linear Collider Flavour Identification Project (ILC).

LCFOA     Linear Collider Forum Of America (ILC).

LCFT     Logarithmic Conformal Field Theory.

LCG     LHC Computing Grid.

LCHb     An experiment at the Large Hadron Collider (LHC) to study in detail the physics of the 'b' or 'beauty' quark.

LCID     Linac CID.

LCIO     Linear Collider Input/Output.

LClo     Lethal concentration low. The lowest concentration of a substance in air which has been reported to have caused death in humans or animals.

LCLS     Linac Coherent Light Source. A linac-based X-ray free-electron laser at SLAC.

LCLS-II    Linac Coherent Light Source II. next-generation X-ray laser

LCLS-II HE     LCLS-II High Energy upgrade

LCPC     Laboratory Computer Policy Committee

LCS     Laser Compton Scattering.

LCS     Laser Cavity Shutter. A PPS device used to stop the PLS laser whenever the laser room door is opened.

LCSGA     Linear Collider Steering Group of the Americas.

LCSR     Light Cone Sum Rules.

LCTPC    Linear Collider Time Projection Chamber collaboration.

LCUK     Linear Collider collaboration - United Kingdom (ILC).

LCW     Low Conductivity Water. Used for cooling magnets, electrical cables and other devices where normal water could cause a short under high voltage. LCW is manufactured by deionizing 'house' water at a plant on the SLAC site.

LCWS     Linear Collider WorkShop.

LD50     Lethal Dose Fifty. A calculated dose of a substance which is expected to cause the death of 50 percent of an entire defined experimental animal population.

LDA     Local Density Approximation.

LDA     Large Aperture Dipoles.

LDAP     Lightweight Directory Access Protocol.

LDC     Large Detector Concept for the ILC.

LDlo    Lethal dose low. The lowest dose of a substance introduced by any route other than inhalation which has been reported to have caused death in humans or animals.

LDIP     Laboratory Diversity & Inclusion Plan (SLAC)

LDMX     Light Dark Matter eXperiment (LCLS-II)

LDR     Land Disposal Restricted (Land Ban).

LDRD     Laboratory Directed Research and Development. A program to direct the Laboratory's scientific research capabilities toward vital and emerging scientific challenges that align with the Laboratory's current mission.

LEA     Local Enforcement Agency (for solid waste in California).

Leachate     A solution of contaminants produced by water flowing through materials such as organic matter, soil, or landfills.

Lead (Pb)     Used extensively at accelerator facilities to shield equipment and personnel from electromagnetic radiation. A heavy metal that is hazardous to health if breathed or swallowed. Its use in gasoline, paints, and plumbing compounds has been sharply restricted or eliminated by federal laws and regulations. See also Heavy Metals.

LEAP     Low Energy Antiproton Physics, a biennial international conference .

LEAPS     League of European Accelerator-based Photon Sources.

LEAR     Low Energy Antiproton Ring (CERN)

LEARN     Listen, Engage, Assess, Respond, Notice (SLAC)

LEB     Low Energy Beam.

LEBT     Low-Energy Beam Transport

LeCosPA     Leung center for Cosmology and Particle Astrophysics.(Taiwan)

LECT     Liquid Effluent Cooling Tank.

LED     Light Emitting Diode.

LEE     Low Energy Extraction.

LEED     Low Energy Electron Diffraction, a popular surface-imaging technique.

LEED     Leadership in Energy and Environmental Design (certification from USGBC).

Leed-NC     Leed - New construction.

LEEM     Low-Energy Electron Microscope.

LEET     Large Energy Effective Theory.

LEFF     The effective length of a magnet in meters.

LEI     Low Emittance Injector

LEIR     Low-Energy Ion Ring (CERN), formerly LEAR.

LEL     Lower Explosive Limit or Lower Flammable Limit (LFL). By percentage, the lowest concentration of a substance in air which will ignite. Compare UEL and flammability range.

Lemming     An operator action which consists of adjusting the LINAC quads to the actual energy of the beam using the LEM procedure. The computer ascertains the beam energy at each quadrupole from the phases of the klystrons to that point, and then adjusts the current in each quadrupole for that calculated energy.

LENA     Nonmagnetic lead-glass NaI detector at DORIS.

LENS     A solenoidal focusing magnet.

Lens     Any focusing element.

LEP     Large Electron Positron collider (CERN).

LEPC     Local Emergency Planning Committee. (from EPCRA)

LER     Low Energy Ring in PEP-II, a 3.1 Gev storage ring for positrons.

LESIT     LEistungselektronic, Systemtechnik und Informations Technologie.

LESIT     Low Energy South Injection Transport.

LESR     Laser-Electron Storage Ring

LET     Low Energy Theorem

Lethal Concentration Low     See LClo.

Lethal Dose Fifty     See LD50.

Lethal Dose Low     See LDlo.

LEUTL     Low Energy Undulator Test Line (APS-Argonne).

LFD     Light Front Dynamics

LFD     Linac & FEL Division (within the Accelerator Directorate)

LFIC     Laser Feedback Intensity Control. A feedback system designed to compensate for the loss in laser light intensity of the PLS. SLAC

LFL     See LEL.

LFO     Laboratory Financial Operations.

LFTD     Light Front Tamm-Dancoff

LFV     Lepton-Flavor-Violating/Violation.

LGO     Lunar Geoscience Orbiter.

LGT     Lattice Gauge Theories

LH2     Liquid Hydrogen.

LHC     Large Hadron Collider (CERN).

LHCb     Large Hadron Collider beauty experiment. (CERN)

LHT     Liquid Hydrogen Targets.

LHW     Liquid Hazardous Waste.

LI     Abbreviations for Linac.

LIAR     LInear Accelerator Research code. Accelerator structure design software.

LIARP     LInear Accelerator Research code Parallel. Accelerator structure design software.

LIC     Line Item Construction.

Lichtenberg tree     Or Lichtenberg Diagram. See Beam Tree.

LIDAR     LIght Detection And Ranging

LIGO     Laser Interferometer Gravitational-wave Observatory

LIL     Linac Injecteur de LEP.

LINAC     LINear ACcelerator. A type of particle accelerator in which charged particles are accelerated in a straight line, either by a steady electrical field or by means of radio frequency electric fields. In the latter variety, the passage of the particle is synchronized with the phase of the accelerating field. The SLAC LINAC was built as a two-mile long accelerator, consisting of cylindrical, disc loaded, copper wave-guides placed on concrete girders in a tunnel about 25 feet underground. Rebuilt to power the LCLS-II, in 2023 the linac became a superconducting accelerator.

LINAC Energy Management     See LEM.

Linear Accelerator     See LINAC.

Linear Charge Detector     See LINQ.

Linear Variable Differential Transformer     See LVDT

LINKS     LCLS Information Network for Knowledge Sharing

LINQ     Linear Charge Detector, usually a toroid. `Q' is the physical symbol for electrical charge.

Linux     A freely-distributable implementation of UNIX that runs on a number of hardware platforms. It was originally developed by Linus Torvalds.

LION     Long IONization Chamber

Liouville's Theorem     The mathematical support to the notion that the area in phase space (emittance) occupied by accelerated particles is constant.

Liquid Argon Calorimeter     See LAC.

LISA     Laser Interferometer Space Antenna

LISP     LISt Processor. A high-level programming language popular for artificial intelligence applications. LISP was developed in the early 1960's by John McCarthy at MIT.

List     Shorthand term for EPA list of violating facilities or list of firms debarred from obtaining government contracts because they violated certain sections of the Clean Air or Clean Water Acts. The list is maintained by the Office of Enforcement and Compliance Monitoring.

Listed Waste     Wastes listed as hazardous under RCRA but which have not been subjected to the Toxic Characteristics Listing Process because the dangers they present are considered self-evident.

Little-endian     A format for storage or transmission of binary data in which the least significant byte or bit comes first. See big-endian.

LJE     Liquid Jet End station (LCLS)

LLD     Lower Limit of Detection.

LLL     See LLNL.

LLM     Large Language Model

LLMW     Low Level Mixed Waste.

LLNL     Lawrence Livermore National Laboratory.

LLO     LIGO Livingston Observatory.

LLP     Long-Lead Procurement.

LLR     Lunar Laser Ranging.

LLRF     Low-Level Radio Frequency. Also called low level RF. Pertains to controlling the phase and amplitude of RF signals at low power levels, before they are amplified to high power levels.

LLRW     Low-Level Radioactive Waste (ESH)

LLS     Synchrotron Light Laboratory (Spain).

LLW     Low-Level Waste (ESH)

LMA     Large Mixing Angle.

LMC     Large Magellanic Cloud.

LMP     Lightest Messenger Particle.

LMS     Learning Management System. (SLAC)

LN     Liquid Nitrogen (tank).

LN2     Liquid Nitrogen

LNF     Laboratori Nazionali di Frascati. (INFN)

LNLS     Laboratorio Nacional de Luz Sincrotron (Brazil).

LNS INFN     Laboratori Nazionali del Sud, Italian laboratory located in Catania.

LNTF     Liquid Noble Test Facility

LNW     Lehmann-Newton-Wu

LO     Leading Order.

LOB     Laboratory Operations Board.

LOC     Level of Concern. (related to EPCRA)

Local Area Network     See LAN.

LODCM     Large Offset Double Crystal Monochrometer. Also referred to as LOM (Large Offset Monochrometer).

LOF    LAT Operations Facility. (GLAST- FERMI)

LOFAR     Low Frequency ARray.

LOI     Letters of Intent. (ILC)

LOIS     Loss Of Interim Status.

LOLA     S-band transverse deflecting structures. Named for creators Greg Loew, Rudy Larsen and Otto Altenmueller.

LOM     Large Offset Monochrometer.

Long Ion Chamber     A BCS type beam line device in use in the FFTB tunnel at SLAC. They are gas filled tubes running parallel to the beam line which are able to detect stray beams using the ionization effect.

Look At Me!     See LAM.

LOPA     Layer Of Protection Analysis.

LOREA    angle-resolved photoemission beamline at ALBA.

LOS     Level Of Service.

LOS     LockOut Stop.

LOS     Laboratory, Office and Shops building (SSRL).

LOSB     Laboratory, Office and Shops Building (SSRL).

Lost Phase     See LST.

LOTO     Lock Out / Tag Out.

Low Conductivity Water     See LCW.

Low RF     See LRF.

Lower Explosive Limit     See LEL.

Lower Flammable Limit     See LEL.

LP     Laboratory Protection, department.

LPA     Large Piwinski Angle.

LPC     Laboratory Policy Council.

LPC     LHC Physics Center.(Fermilab)

LPC     Laser Pulse Chopper.

LPG     Liquified Petroleum Gas.

LPHD     Local Parton Hadron Duality

LPL     Lunar and Planetary Laboratory (University of Arizona).

LPM     Landau-Pomeranchuk-Migdal

LPR     License Plate Reader.

LPS     Leading Proton Spectrometer

LPS     Lab Partnering Service (DOE)

LPSPL     Low-Power Superconducting Proton Linac.

LQ     Long Quadrupole.

LQCD     Lattice Quantum ChromoDynamics

LR     Long Racetrack.

LRCA     Limited Radiological Control Assistant.

LRDP     Long-Range Development Plan.

LRF     Low RF, A klystron summary display message indicating that the RF power is lower than its normal tolerance setting.

LRIS     Low Resolution Imaging Spectrograph.

LRS     Local Rotational Symmetry

LRSM     Left-Right Symmetric Model.

LS     Level Switch.

LSA     Low Specific Activity.

LSBK     L-Band Sheet Beam Klystron.

LSC     Laser Safety Committee.

LSCC     Large Scale Collaboration Center.

LSD     Lenses Structure and Dynamics.

LSE     Laser Stabilization Experiment.

LSF     Load-Sharing Facility. (Computing)

LSH     Level Switch High.

LSI     Large-Scale Integration.

LSL     Level Switch Low.

LSND     Liquid Scintillator Neutrino Detector (Los Alamos).

LSO     Laser Safety Officer. A person who has authority to monitor and enforce the control of laser hazards.

LSP     Lightest Supersymmetric Particle.

LSR     Local Standard of Rest. (Astronomy)

LSRA     Life Science Research Associate.

LSS     Lean Six Sigma (process improvement method).

LSS     Laser Safety System. A system of interlocks around a secured enclosure to protect personnel from laser light.

LSS     Large Scale Structure

LSST     Legacy Survey of Space and Time (formerly Large Synoptic Survey Telescope).

LSSTC     Legacy Survey of Space and Time Corporation (formerly Large Synoptic Survey Telescope Corporation).

LST     LoST Phase. A klystron summary status indicating that the PAD is not able to measure the klystron phase.

LST     Laser Science and Technology division (LCLS)

LSZ     Little String theory.

LTB     Lemaitre-Tolman-Bondy

LTB     Linac-To-Booster

LTD     Low-Temperature Detectors.

LTE     Long-Term Exposure (photography)

LTMR     Low Temperature Materials Research Group (SLAC)

LTR     Low Temperature Materials Research.

LTR     Low Temperature Reservoir.

LTS     Long-Term Support

LTU     Linac-To-Undulator.

Lucretia     A physics toolbox for the simulation of high-performance single-pass electron beam transport systems.

LUFT     Leaking Underground Fuel Tank.

Luminosity     A measure of the number of events per second and per unit cross section at the IP.

LUSI     LCLS Ultrafast Science Instrument Project.

LUST     Leaking Underground Storage Tank.

LUX     Large Underground Xenon dark matter experiment.

LVD     Large Volume Detector (Gran Sasso)

LVDT     Linear Variable Differential Transformer. A device for measuring positions relative to a fixed reference, (e.g., for measuring slit positions).

LVV     Limited Visibility Vehicle.

LWBM     Lab-Wide Budget Model

LWC     Lost Work Cases.

LWFA     Laser WakeField Acceleration

LZ     LUX-ZEPLIN detector. (South Dakota)