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SLACspeak Terms

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G
Giga, meaning 10to the 9th power, or billions of . . .(e.g.: gigabits).
G&A
General and Administrative.
G&A
General and Administrative.
GA
GAuge / GAge.
GAAP
Generally Approved Accounting Practices.
GaAs
Gallium Arsenide. A compound used in light emitting diodes and very fast semiconductors. It is used in SLC fast clock chips for fiducializing and synchonizing the LINAC with PEP, and is also the basis for cathodes in the polarized guns.
GAC
Granular Activated Carbon.
GADC
Gated Analog to Digital Converter. A circuit that selectively converts analog signals to a format readable by the computer. A SLC database primary.
GADZOOKS
Gadolinium Antineutrino Detector Zealously Outperforming Old Kamio kande Super.
GAFE
12 FREE boards, each mounting 18 GAFE analog ASICs and one GARC digital ASIC, are required read out the 216 channels of data from the ACD photomultiplier tubes.__Each GAFE provides for the charge collection, amplification, shap ing, and discrimination of the analog input from one PMT.
  Glast Category: hardware
galaxy
A massive, gravitationally bound system consisting of stars, interstellar gas and dust, and dark matter, all typically orbiting a common center of mass.
  Glast Category: ASTRONOMY
Galaxy Zoo
A crowd-sourcing project to allow interested members of the public to classify by type the galaxies imaged by the Hubble Space Teles cope.
GALEX
GALaxy Evolution eXplorer/
Gallery
The two-mile-long building where the LINAC klystrons and LINAC magnet power supplies are housed. The actual LINAC beam pipe is approximately 25 feet underground below the gallery.
Gallium Arsenide
See GaAs.
GALPROP
Numerical model of particle propagation in the Galaxy incorporatin g as much realistic input as possible.
Gamma
One of the Twiss parameters, which relates alpha and beta: beta gamma = 1 + alpha(exp 2). It is also the relativistic factor used in acceleration calculations.
Gamma Ray
A high energy photon.
Gamma-ray burst
A short-lived, localized, and intense burst of gamma radiation that originates outside the solar system from an unknown source. These bursts last from milliseconds to many minutes, and are often followed by 'af terglow' emission at longer wavelengths such as X-ray, UV, optical, IR, and radio.
  Glast Category: astronomy
Gamma, Electron, and Muon Experiment
See GEM.
GAM2
IHEP hodoscope Cherenkov gamma calorimeter GAMS-2000.
GAM4
CERN hodoscope Cherenkov gamma calorimeter GAMS-4000.
GAN
Global Accelerator Network (proposed).
GAN
GAlactic Neighborhood.
GANIL
Gran Accélérateur National d'Ions Lourds.
GAO
General Accounting Office.
Gap Monitor
see GAPM.
Gap Voltage
The electrical field between the 2 irises of an RF cavity.
GAPM
GAP Monitor. A break in the conductive beam pipe which is bridged by a ring of ceramic in parallel with a resistance that provides the proper impedance. The beam induces a voltage drop across the resistance, which may be measured and displayed on an oscilloscope. Also called wall current monitor, since it measures the voltage induced by interrupting the current traveling through the beampipe due to the passing of the beam.
GARC
12 FREE boards, each mounting 18 GAFE analog ASICs and one GARC digital ASIC, are required read out the 216 channels of data from the ACD photomultiplier tubes. The GARC provides the interface to the 18 GAFEs and contains th e digital logic and interface circuitry required to prepare event data for transfer to the ACD Electronics Module (AEM).
  Glast Category: hardware
Gargamelle
CERN Bubble Chamber commissioned in 1971.
GASU
Global trigger, Acd interface, and Signal distribution Unit.
GASU
|The GASU contains the central data acquisition hardware of the LAT, including circuitry necessary for control of the detector front-end electronics, including the tower electronics modules (TEMs), and the anti-coincidence detec| |tor (ACD) FREE boards. Powered by the PDU and distributing power to the ACD, the GASU collects instrument data and forwards it to the event processing unit (EPU) and to the spacecraft interface unit (SIU).|
  Glast Category: hardware
GATE
Geant4 Application for Tomographic Emission.
Gated Analog to Digital Converter
See GADC.
Gateway
A special-purpose dedicated computer that attaches to two or more networks and routes packets from one network to the other. In particular, an Internet gateway routes IP diagrams among the networks it connects. Gateways route packets to other gateways until they can be delivered to the final destination directly across one physical network.
Gateway to Gateway Protocol
See GGP.
Gauss
A unit of magnetic flux density, symbol G. Named after the mathematician Karl Friedrich Gauss (1777-1855)
Gaussian
A statistical distribution of particles or objects which is `bell shaped' and can be approximated by the Gauss distribution law. Named after the mathematician Karl Friedrich Gauss (1777- 1855).
GB
See Gigabyte.
GBFEL
Ground-Based Free Electron Laser.
GBM
GLAST Burst Monitor experiment.
GBM
See GBM Instrument Description.
  Glast Category: hardware
  URL: http://www.batse.msfc.nasa.gov/gbm/instrument/description/
GBT
Green Bank Telescope (NRAO-West Virginia).
GC/MS
Gas Chromatography/Mass Spectroscopy.
GCEP
Global Climate and Energy Project. A long-term collaborative effort to conduct fundamental research on a global energy system that would significantly reduce greenhouse emissions. (Stanford)
GCFE
There are 4 AFEE boards per tower: each board has 48 GCFE analog ASICs in 4 layers of 12 each: each layer is controlled by one GCRC ASIC. The GCFE amplifies signals from 2 diodes per crystal end: a large area diode for the low-energy range, and a small diode for the high-energy range.
  Glast Category: hardware
GCM
Generator Coordinate Method
GCM
|The GCM is the backup facility for the MOC, located in a different building at the GSFC. The GCM can command and receive telemetry from GLAST, but is otherwise very limited. For example, no Level 0 or other data products are pr| |ovided to the ISOC while the GCM is active. Instead, the data is saved and forwarded only after the MOC again becomes operational.|
  Glast Category: operations
GCN
See GCN: The Gamma-ray bursts Coordinates Network website.
  Glast Category: operations
  URL: http://gcn.gsfc.nasa.gov/
GCP
General Cascade Program
GCR
Galactic Cosmic Rays
GCRC
Each tower has 4 GCRC digital ASICs on each of 4 AFEE boards. Each GCRC processes the high- and low-energy inputs from each of 12 GCFE ASICs co-located on the same AFEE board. The GCRC outputs High- and Low-Energy Trigger Requests to the Tower Electronics Module (TEM).
  Glast Category: hardware
GCT
Galaxies across Cosmic Time.
GD
|Manufacturer of the GLAST spacecraft.|
  Glast Category: organization
GD&T
Geometric Dimensioning & Tolerancing.
GD&T
Geometric Dimensioning and Tolerancing.
GDE
Global Design Effort.(ILC)
GDH
Gerasimov-Drell-Hearn
GDP
General Development Plan.
GDR
Giant Dipole Resonance
GDS
Global Directory Service. For global namespace, which starts from a global root and divides into a hierarchical tree at country, organization, locality, cell, and other points. XDS from X/Open is the general purpose API for standard applications.
GEANT
A pan-European research and education network and the corresponding four-year project set up by a Consortium of 27 National Research and Education Networks (NRENs) across Europe.
GEANT2
Successor to GEANT, see GEANT.
GEANT3
A computer program for detector description and simulation.
Geant3
Monte Carlo simulation package (CERN).
Geant3
Monte Carlo simulation package (CERN).
GEM
Gamma, Electron, and Muon experiment. An SSC experiment which featured the `GEM' detector.
GEM
Gas-Electron Multiplier.
GEM
Graduate Engineering for Minorities.
GEM
Processes inputs from the ACD and all 16 towers to decide whether or not to trigger a readout of detector data. The sum of all the information read out of the detector electronics when triggered is called an event.
  Glast Category: hardware
GEMS
Graduate degrEes for Minorities in Engineering and Sciences. (Nati onal consortium)
GEMS
Galaxy Evolution from Morphology and Spectral energy distributions .
General Purpose Interface Bus
See GPIB.
Generator
The person or facility who, by nature or ownership, management, or control, is responsible for causing or allowing to be caused, the creation of hazardous waste.
GENI
GENeral Interface.
GENIUS
GErmanium in NItrogen Underground Setup. A proposal to use a ton or more of naked enriched germanium-76 detectors in a shielding of liquid nitrogen to probe neutrino mass.
GEONET
A program for alignment of SLC.
GERT
General Employee Radiological Training.
GES
Geological and Environmental Sciences.(Stanford)
GeV
Giga(billion) electron Volt. An electron volt is the unit of energy equal to the work done by moving an electron across a potential difference of one volt.
GFCI
Ground Fault Circuit Interrupter.
GFEP
GLAST Front-End Processor
  Glast Category: data processing
  URL:
GFP
Government-Furnished Property.
GGF
Global Grid Forum. A community-initiated forum of individual resea rchers and practitioners working on distributed computing, or "grid" technologies. Particle Physics Data Grid (PPDG) is a part of this forum.
GGM
(CERN) GarGaMelle bubble chamber.
GGP
Gateway to Gateway Protocol. The protocol core gateways use to exchange routing information. GGP implements a distributed shortest path routing computation. Under normal circumstances, all GGP participants will reach a steady state in which the routing information at all gateways agrees.
GG1
Global Group 1 (Parameters). (ILC)
GG2
Global Group 2 (Instrumentation and Controls). (ILC)
GG3
Global Group 3 (Operations and Availability). (ILC)
GG4
Global Group 4 (Conventional Facilities and Siting). (ILC)
GG5
Global Group 5 (Cost and Engineering) (ILC)
GG6
Global Group 6 (Options). (ILC)
GHG
GreenHouse Gas.
GHP
Geroch-Held-Penrose
GHS
Garfinkle-Horowitz-Strominger
GHZ
Greenberger-Horne-Zerlinger
GHZ
GigaHertZ. (Written GHZ on drawings, or GHz in text.)
GIAT
Get-It-All-Together (SLC Group).
GIC
Gauge Invariant and Covariant
gif
Graphics Interchange Format. Pronounced jiff or giff (hard g). A bit-mapped graphics file format used by the World Wide Web, CompuServe and many BBSs. GIF supports color and various resolutions. It also includes data compression, making it especially effective for scanned photos.
GIFT
Goldstones Instead of Fine Tuning
Giga
see G
Gigabyte
2 to the 30th power (1,073,741,824) bytes. One gigabyte is equal to 1,024 megabytes. Abbreviated G or GB.
GIM
Glashow-Iliopoulos-Maiani
GIMGOM
|The GIMGOM group meets 4-8 times per year to discuss all aspects of operations relevant to the mission operations center and the instrument teams. Topics include observation strategies, and the operating modes and interactions | |between the spacecraft, the GBM, and the LAT, as well as effective coordination between teams during burst alerts. The GIMGOM also addresses planning of launch and early orbit (LEO) activities, and the transition from LEO to normal operati| |ons. Other topics addressed include data flow, file formats, L0 processing, transfer protocols, and operations data products.|
  Glast Category: operations
GIOC
|Located at Huntsville, Alabama, the GBM Instrument Operations Center is responsible for maximizing the GLAST Burst Monitor's (GBM's) science performance, and for creating and delivering the GBM science data products to the GSSC| | on a daily basis. See GBM Data Products.|
  Glast Category: operations
  URL: http://glast.gsfc.nasa.gov/ssc/data/access/gbm.html
Girder
A support structure for the Accelerator. In the LINAC most girders are 40 feet long. Note that the SLC component numbering system is referenced to girder numbers.
GISO
General Industry Safety Order. (Cal/OSHA)
GIXS
Grazing Incidence X-ray Scattering.
GKS
Graphic Kernal System. (Obsolete)
GKZ
Gelfand-Kapranov-Zelevinski
GLAD
Gev Laser Accelerator Developments (Japan).
GLAM
Geballe Laboratory for Advanced Materials (Stanford).
GLARE
Gemini Lyman-Alpha at Reionization Era.
GLAST
Gamma-ray Large Area Space Telescope. A large aperture, space-based, gamma-ray detector. Also, an international collaboration involving SLAC, Stanford, NASA, and groups in Japan Italy, France and Sweden. Renamed Fermi Gamma-ray Space Telescope (FGST) in August 2008.
GLAST
See Goddard Space Flight Center's GLAST Science web page.
  Glast Category: organization
  URL: http://glast.gsfc.nasa.gov/science/
glast
||
GlastRelease
Primary Science Analysis Systems (SAS) software package consisting of a toolkit of different application software packages with a wrapper bundling them into a single package.
  Glast Category: software, SAS, package
GLC
Global Linear Collider group. (KEK)
GLC
Global Linear Collider.
GLD
Concept detector for the ILC (Global Large Detector).
GLEAM
GLAST Event Analysis Machine.
GLEAM
The top-level GlastRelease package whose basic function is to take the 'raw', Level 0 data delivered to it in LAT Data Format (LDF data) and convert it to Level 1 data ready for analysis using Science Tools software.
  Glast Category: software, SAS, package, data processing
GLIF
Global Lambda Integrated Facility.
GLIMPSE
Galactic Legacy Infrared Mid-Plane Survey Extraorinaire.
Glow discharge
A luminous electrical discharge without sparks through a gas.
GLT
|The GLT is a function of the Global Trigger Electronics Module (GEM). In real time, and at the highest level, the GLT accepts L1 Trigger Request input signals from the TKR, ACD, and CAL detector modules and decides whether to g| |enerate a Global L1 Trigger Acknowledge (TACK). __A TACK response causes information in the detector modules to be latched. The TACK also includes generation of a Trigger Acknowledge Message (TAM), which causes a readout of the raw data.| | At this point, the raw data for the probable L1 event is transferred to the Event Builder Module. |
  Glast Category: hardware
Gluino
In models of supersymmetry, the partner of the gluon.
GM
General Motors.
GMO
Gell-Mann-Okubo
GMOR
Gell-Mann-Oakes-Renner
GMP
Ground water Monitoring Plan.
GMR
Giant MagnetoResistance.
GMRES
Generalized Minimum RESidual.
GMSB
Gauge Mediated Supersymmetry Breaking
GNAT
Global Network of Astronomical Telescopes.
Go Around Frequency
In a storage ring, the number of circumnavigations of the ring made by any given bunch in one second (expressed in Hertz).
GOCO
Government Owned, Contractor Operated (DOE).
Gold Phase
The phase of a klystron with maximum efficiency (if the bunch is riding near the crest of the RF wave). The gold phase is the phase for the maximum energy transfer.
GOLI
CERN GOLIath bubble chamber.
Gopher
A menu-based system for exploring Internet resources that pre-dates the World Wide Web. Requires a gopher server, which presents its contents as a hierarchically-structured list of files.
GOSIP
Government Open Systems Interconnection Profile. A government specification (a collection of protocols referred to as a profile) designed to ensure that communications and networking software used by the government is indeed OSI- compliant when OSI compliance is required.
GOSSIP
Gas On Slimmed SIlicon Pixel.
Government Open Systems Interconnection Profile
See GOSIP.
GP
Guiding Principle (ES&H)
GPD
Generalized Parton Distributions.
GPDF
Generalized Parton Distribution Function.
GPIB
General Purpose Interface Bus. A communication protocol for small computers like PCs or MACs to interface with peripherals, instruments, or other devices. If you want your PC to start your coffee before you wake up in the morning, you will need a GPIB.
GPMP
Ground water Protection Management Program.
GPMPP
Ground water Protection Measurement Program Plan.
GPO
Group Policy Objects (computing). Policies that are defined for ea ch computer or user.
GPP
General Plant Project.
GPR
Gaussian Process Regression.
GPS
Global Positioning of Spin
GPU
Graphics Processing Unit.
GR
General Relativity
GR
Gamma Ray.
GRACE
An automatic scattering amplitude generator that enables theoretic al calculations to match the required high-presicion data analyses required by high-energy physics experiments.
Gray
The International System (SI) unit of absorbed dose. One gray is equal to an absorbed dose of 1 Joule per kilogram (100 RADS).
Gray Water
The term given to domestic wastewater composed of washwater from sinks, kitchen sinks, bathroom sinks and tubs, and laundry tubs.
GRB
Gamma-Ray Burst.
GRB
A short-lived, localized, and intense burst of gamma radiation that originates outside the solar system from an unknown source. These bursts last from milliseconds to many minutes, and are often followed by 'afterglow' em ission at longer wavelengths such as X-ray, UV, optical, IR, and radio.
  Glast Category: astronomy
Greening
The action of trimming a phase, a feedback or a BACT to a nominal value or set-point. The new value as displayed by the VAX on its color monitors will be green (in tolerance) as opposed to red or yellow (out of tolerance).
Grid
see GGF.
GRIDCC
Grid-enabled Remote Instrumentation with Distributed Control and Computation.
GridKA
Grid computing centre KArlsruhe. (Germany)
Gridpix
Detector building block combining the timepix chip with InGrid.
Grinnel
A graphic video display system using the PICT imaging system. Used with the VAX to generate graphics. (The machine is made by Grinnel Systems Corporation).
GriPhyN
Grid Physics Network (pronounced griffin). A system for handling vast amounts of physics data. Participants include the Sloan Digital Sky Survey, the Laser Interferometer Gravitational- Wave Observatory, and two HEP experiments at CERN's LHC.
GROG
General Relativistic Overturn of Gravity.
Gross Alpha Particle Activity
Total activity due to emission of alpha particles. Used as the screening measurement for radioactivity generally due to naturally-occurring radionuclides. Activity is commonly measured in picocuries.
Gross Beta Particle Activity
Total activity due to emission of beta particles. Used as the screening measurement for radioactivity from manufactured radionuclides since the decay products of fission are beta particles and gamma ray emitters. Activity is commonly measured in picocuries.
Ground Water
Water below the land surface in a zone of saturation.
Growler
A small damping ring dipole magnet used to generate an oscillation for tune measurement purposes. When energized, it will excite the beam to oscillate at its natural resonant frequencies.
GRR
Gravitational Radiation Reactions
GRS
Gregory-Rubakov-Sibiryakov
GRT
General Relativity Theory.
GS
Green-Schwarz
GSA
General Services Administration. (US)
GSB
General Services Building. (SLAC)
GSF
Gross Square Feet.
GSFC
Goddard Space Flight Center.
GSFC
Established in 1959 as NASA's first space flight center, the GSFC is located in a Maryland suburb outside of Washington, D.C. and is home to the nation's largest organization of scientists and engineers dedicated to learning and sharing knowledge of the Earth, Sun, Solar System, and Universe.
  Glast Category: organization
  URL: http://www.nasa.gov/centers/goddard/home/index.html
GSG
Graphic Study Group (SCS).
GSH
Graduate Student Handbook. (SLAC)
GSI
Grid Security Infrastructure.
GSI
Gesellschaft für Schwerionenforschung. (Germany)
GSS
Government Scientific Source.
GSSC
GLAST Science Support Center.
GTF
Gun Test Facility. A research project at SSRL aimed at developing the high-brightness electron source that will be needed for future linac-based X-ray free-electron lasers (FELs) such as SLAC's proposed Linac Coherent Light Source (LCLS). GTF is a photocathode gun that uses polarized laser light to generate polarized electrons by means of the photoelectric effect on a gallium arsenide cathode.
GTFE
Each of the 36 Tracker silicon layers consists of 1536 strips managed by 24 GTFE ASICs. These GTFEs are read out by 2 GTRC ASICs. Each GTFE amplifies signals from 64 strips, shapes the signals, and converts them to digital outp ut. The final discriminated signals are used to form a trigger request.
  Glast Category: hardware
GTI
Good Time Intervals.
GTL
Gun-To-Linac. (LCLS)
GTRC
Each tower has 72 GTRC ASICs mounted on 36 Multi-Chip Modules. Two GTRCs read out the signals from 24 GTFEs on each silicon layer - there is one GTRC for the 'right' end of the layer and one for the 'left' end of the la yer. Each GTRC forms a trigger primitive signal, which it sends to the TEM.
  Glast Category: hardware
GUC
German University in Cairo.
GUG
|The GUG represents the interests of the scientific community that will use GLAST. To view their charter, membership list, and presentations made at GUG meetings, see the GSSCs GLAST Users Group web page.|
  Glast Category: organization
  URL: http://glast.gsfc.nasa.gov/ssc/resources/gug/
GUI
Graphical User Interface. Sometimes called windowing systems, GUIs are software interfaces which allow mouse and icon actions in place of typed commands.
GUST
Grand Unified Superstring Theories
GUT
Grand Unified Theories
GVDM
Generalized Vector Dominance Model
GVMD
Generalized Vector Meson Dominance Model.
GW
Ginsparg-Wilson
GWL
Ginsparg-Wilson-Luscher
GWP
Ground Warfare Panel.
GWT
Google Web Toolkit.
GZK
Greisen-Zatsepin-Kuzmin.
G4
GEANT4.

Send corrections to jmdeken@slac.stanford.edu or propose new terms for SLACspeak.

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