- H II region
- A cloud of glowing gas and plasma in which star formation is
taking place. Named for the large amount of ionized atomic
hydrogen it contains.
- Hoist and Crane.
- Hoisting and Rigging.
- Hazard Assessment.
- The activity of computer enthusiasts who are challenged by
the practice of breaking security measures designed to prevent
unauthorized access to one or more computer systems. (Hacking
which involves criminal activity is called cracking.)
- Hazardous Atmosphere Detector.
- High Acceptance Di-Electron Spectrometer
- Generic name for members of the largest family of elementary
particles. Hadrons interact strongly with one another, usually
produce additional hadrons in collisions at high energy, and are
- HST Archive Galaxy-scale Gravitational Lens Survey.
- Half Duplex
- Data transmission in either direction, but only one
direction at a time.
- The time required for the elimination of one half a total
dose of radiation from the body.
- The time required for a pollutant to lose half its effect on
the environment. For example, the half-life of DDT in the
environment is 15 years, of radium, 1,580 years.
- The time required for half of the atoms of a radioactive
element to undergo decay.
- Any of a group of five chemically-related nonmetallic
elements that includes bromine, fluorine, chlorine, iodine, and
- Halogenated Hydrocarbons
- A group of organic compounds which include one or more atoms
of a halogen, e.g., chlorine or bromine, in their molecular
- Bromine-containing compounds with long atmospheric lifetimes
whose breakdown in the stratosphere cause depletion of ozone.
Halons are used in fire-fighting.
- The procedures and standards (protocol) used by two
computers or a computer and a peripheral device to establish
- Histogram and display package program. Computer graphics
software used at SLAC.
- Hazardous Air Pollutant.
- Hybrid Avalanche Photo Detector.
- Hall A Proton Parity EXperiment, at the US DOE's Jefferson
- Hazardous Air PollutantS.
- High-Availibility Power Supplies.
- Hydrogeological Assessment Report. (TPCA)
- Hardware Address
- The low level address used by a physical network. Each type
of network hardware has its own addressing scheme. For example,
Ethernet uses 48-bit hardware addresses assigned by the vendor,
while proNET-10 uses small integer hardware addresses assigned
when a connection to the network is installed.
- Hardware Status
- See HSTA.
- House Armed Services Committee. (US)
- The synchrotron radiation laboratory at DESY (Germany)
- Hazard Analysis Working Group.
- A threat to workers, public, environment, or property.
- Hazard Evaluation System and Information Service
- See HESIS.
- Hazardous Air Pollutants
- Air pollutants which are not covered by ambient air quality
standards but which, as defined in the Clean Air Act, may
reasonably be expected to cause or contribute to irreversible
illness or death. Such pollutants include asbestos, beryllium,
mercury, benzene, coke oven emissions, radionuclides, and vinyl
- Hazardous and Solid Waste Amendments
- See HSWA.
- Hazardous Experimental Equipment Committee
- See HEEC.
- Hazardous Ranking System
- The principal screening tool used by EPA to evaluate risks
to public health and the environment associated with abandoned or
uncontrolled hazardous waste sites. The HRS calculates a score
based on the potential of hazardous substances spreading from the
site through the air, surface water, or ground water and on other
factors such as nearby population. This score is the primary
factor in deciding if the site should be on the National
Priorities List, and, if so, what ranking it should have compared
to other sites on the list.
- Hazardous Substance
- Any substance named by EPA to be reported if a designated
quantity of the substance is spilled in the waters of the United
States or if otherwise emitted into the environment.
- Hazardous Substance
- Any material that poses a threat to human health and/or the
environment. Typical hazardous substances are toxic, corrosive,
ignitable, explosive, or chemically reactive.
- Hazardous Substance Account
- See HSA.
- Hazardous Waste
- By-product of society that can pose a substantial or
potential hazard to human health or the environment when
improperly managed. Possesses at least one of four
characteristics (ignitability, corrosivity, reactivity, or
toxicity), or appears on special EPA lists.
- Hazardous Waste Control Account
- State fund derived from fees paid by operators of onsite and
offsite disposal facilities and used to support the hazardous
waste management program of the Department of Health Services.
- Hazards Analysis
- The procedures involved in (a) identifying potential sources
of release of hazardous materials from fixed facilities or
transportation accidents, (b) determining the vulnerability of a
geographical area to a release of hazardous materials, and (c)
comparing hazards to determine which present greater or lesser
risks to a community.
- Hazards Identification
- Providing information on which facilities have extremely
hazardous substances, what those chemicals are, and how much
there is at each facility. The process also provides information
on how the chemicals are stored and whether they are used at high
- HAZard COMmunication. An Occupational Safety and Health
Administra tion (OSHA) standard that requires all employers to
instruct their workers on the hazards associated with the
chemicals they use.
- HAZard and OPerability study.
- HAZardous Waste OPerations and Emergency Response standard.
- The bend in the DRIP where the beams returning from the
rings get injected back into the LINAC.
- Hydrogen bubble chamber.
- Heavy Baryon Chiral Perturbation Theory
- Historically Black Colleges and Universities (US).
- High-energy cut-off BL Lac object.
- Hepatitis B Virus.
- Hadron barrel CALorimeter.
- Human Capital Management.
- Hazard Communication Program. (SLAC)
- Heavily Charged Particles in Biology and Medicine.
- Hazardous Communications Standard. (OSHA)
- Hepatitis C Virus.
- Higher Deriviative.
- Hydrogen and deuterium bubble chambers.
- Hubble deep field.
- Hierarchical Data Format 5.
- How Do I. SLAC Financial and Human Resources gateway.
- Higgs Doublet Model.
- Heidelberg Dark Matter Search (Gran Sasso)
- High Density PolyEthylene.
- Hardware DeSCripter.
- High Density Spiral Projection Chamber.
- |Basic unit of a FITS file consisting of an ASCII header and
a data table.|
Glast Category: SAS, software
- Hybrid Damped structure.
- High Energy Accelerator Conference.
- High-Energy Astrophysics Division (American Astronomical
- The portion of a packet, preceding the actual data,
containing source and destination addresses and error-checking
- |This pixelization produces a subdivision of a spherical
surface in which each pixel covers the same surface area as every
other pixel. The pixel centers occur on a discrete number of
rings of constant latitude, and the number o|
|f constant-latitude rings depends on the resolution of the
Glast Category: SAS, software
- High Energy AStrophysics Science ARChive (Goddard).
- | HEASARC archives data from Gamma-ray, X-ray, and extreme
ultraviolet observations of cosmic (non-solar) sources. The
HEASARC group provides access to analysis software, data, and
documentation. See NASA's HEASARC website.|
Glast Category: astronomy, organization
- Heat Exchanger
- A locked radiation area where radioactive cooling water
coming back from the slits, collimators and beam dumps is cooled
and demineralized. (The heat exchange is with the cooling tower
water.) The radiation levels in the heat exchangers are monitored
- Heavy Metals
- Certain metallic elements having a high density and which
are generally toxic, e.g., lead, silver, mercury, and arsenic.
- High-Energy Beam.
- HElium Bubble Chamber.
- High-Energy Density Science (LCLS).
- High-Energy Density Science. (LCLS)
- High-Energy Extraction.
- Hazardous Experimental Equipment Committee. An ad hoc
committee which reviews and approves certain hazardous systems
such as pressure vessels or large volumes of hazardous gases or
cryogenic liquids for use by experimenters.
- High Energy Equipment Pool. A SLAC organizational group.
Also High Energy Electronics Pool.
- High Energy Focusing Telescope.
- High Energy Gamma Ray Astronomy telescope. Five-telescope
array built in La Palma by a German-Spanish-Armenian
- High Energy physics Latin-american-European Network.
- High-Energy Laser Embodying Neodymium. British laser brought
to LC LS in 2011.
- CERN Super Proton Synchroton detector
- Helmholtz Coil
- A coil in which the first and last winding are separated by
2r where r is the radius of the winding. Used to produce a
uniform solenoid field. Designed by Hermann Helmholtz.
- Helmholz Alliance
- Network of German laboratories and universities involved in
the LH C and the ILC.
- High-Energy North Injection Transport.
- High Energy and Nuclear Physics.
- High Energy Physics.
- High Energy Physics. A major SPIRES database maintained
jointly by the SLAC and DESY libraries which in 1999 contained >
390,000 references to preprints, journal articles, reports,
theses, and conference papers. Used worldwide.
- HeP E-tool
- Hazard Evaluation and Planning Electronic tool. (SLAC ES&H)
This tool is an activity-based questionnaire intended for use by
n on-ESH staff, in particular supervisors, activity planners and
UTR s. The tool identifies SLAC required permits and plans based
on re sponses t the questions. May be accessed from the WPC
- High Efficiency Particulate Air.
- High Energy Physics Advisory Panel.
- High Energy Photon Conference.
- Physics databases maintained at Durham/Raleigh.
- W. W. Hansen Experimental Physics Laboratory, Stanford
University. (Formerly, High Energy Physics Laboratory.)
- High Energy Physics Network. An international network
linking computers of High Energy Physics laboratories.
- High Energy and Particle Physics, a division of the EPS.
- HElium Proportional Tubes.
- High Energy Ring for PEP-II, a 9 GeV storage ring for
- See DESY HERA
- an experiment at DESY.
- See Hz.
- Hadron Emission Reactions With Interfering Gluons.
- Hazard Evaluation System and Information Service. Sponsored
by SDOHS and Cal OSHA. Provides information on chemicals to
employers and employees.
- High Energy Stereoscopic System. A next generation system of
imaging atmospheric Cherenkov telescopes aimed at the study of
cosmic gamma rays. (Namibia) Name honors Viktor Hess, who
received the 1936 Nobel prize for his discovery of cosmic rays.
- Hefei SYnchrotron Radiation Laboratory.
- Hobby-Eberly Telescope.(McDonald Observatory)
- High Energy Transport Code
- High Energy Transport Code
- Hobby-Eberly Telescope Dark Energy Experiment.
- In computing and artificial intelligence, common sense rules
drawn from experience and used to solve problems.
- High Frequency. Allocated band of radio frequencies from
3MHz to 30 MHz.
- Heavy Flavor Averaging Group.
- High-Flux Beam Reactor (Brookhaven)
- Heavy Fermion Formalism
- HyperFine Structure constant
- Haleakala Gamma Ray Observatory.
- High-Gradient Radio-Frequency.
- Heavy Hadron Chiral Perturbation Theory
- Howard Hughes Medical Institute.
- Household Hazardous Waste.
- Heating Hot Water Return.
- Heating Hot Water Supply.
- A troubleshooting technique. The process of increasing a
voltage potential to a specified high level, with respect to
ground, in order to check for failure or ground fault in a
magnet. Used to measure very high resistances, or the voltage at
which an insulator will break down.
- Heavy Ions Collision
- Hierarchical Routing
- Routing that is based on a hierarchical addressing scheme.
Most Internet routing is based on a two-level hierarchy in which
an Internet address is divided into a network portion and a host
portion. Gateways use only the network portion until the datagram
reaches a gateway that can deliver it directly. Subnetting
introduces additional levels of hierarchical routing.
- Heavy Ion induced Fusion. Also, Heavy Ion Fusion.
- Higgs Boson
- the last undiscovered particle of the Standard Model,
predicted by Peter Higgs, a Scottish theorist. The Higgs Boson is
thought to be heavier than any particle as yet observed.
- SUSY partner of the elusive Higgs boson.
- High Energy Equipment Pool
- See HEEP.
- High Energy Physics
- See HEP.
- High Energy Physics Network
- See Hepnet.
- High Frequency
- See HF.
- High Voltage Ready
- See HVR.
- High-Level Radioactive Waste
- See HLW.
- Heavy Ion Linear Accelerator.
- Heavy-Ion Medical Accelerator in Chiba, Japan. Began
operating in 1994.
- A program for symbolic calculation of Feynman diagrams.
- Holding Ion Pump.
- High Intensity Pulsed Proton Injector (CERN).
- A data visualization program for displaying histograms
developed by Paul Kunz (SLAC) and Jeff Gould (Gould Software).
- High Resolution Fly's Eye, an experiment.
- Heidelberg Ion Therapy centre.
- Human Immunodeficiency Virus.
- HANNA Imersive Visualization Environment (Stanford)
- HyperKahler with Torsion
- High-Level (physics) Applications. (LCLS)
- Horizontal LAMbertson. A septum magnet used to extract the
scavenger beam from the LINAC to the positron target. Designed by
Glen Lambertson. See Septum.
- Heavy-Liquid Bubble Chamber.
- Hydrostatic Leveling System.
- High-Level Trigger.
- High-Level Radioactive Waste. Waste generated in the fuel of
a nuclear reactor and found at nuclear reactors or nuclear fuel
reprocessing plants. It is a serious threat to anyone who comes
near the wastes without shielding.
- Hazardous Materials. (DOE)
- Hazardous Material Business Plan.
- Hybrid Monte Carlo
- Hazardous Materials Program. (DOE)
- High Momentum Particle Identification Detector (ALICE).
- Hazardous Materials Storage Facility.
- Hazardous Materials Transportation Act. (49 U.S.C. Sec. 1801
- Halogenated Organic Compound.
- A detector, usually used for triggering and based on
scintillation counters with very short output pulses, which
records the paths of ionizing particles by means of ion counters
in close array. (From the Greek "pathviewer")
- In inertial confinement fusion reaction experiments, a gold-
lined, pencil-eraser-sized chamber that contains the nuclear
energy. Fr om the German for 'small hollow.'
- Higher Order Modes.
- HOMEstake underground scintillation detector (South Dakota)
- Hood Capture Efficiency
- The emissions from a process which are captured by hood and
directed into the control device, expressed as a percent of all
- Horizontal Lambertson
- See HLAM.
- The current computer being used in a network. Also called a
- Host Name Resolution
- A mechanism with static and dynamic elements for resolving
host names into numeric addresses. The Internet Name Server
Protocol accesses an Internet Name Server which provides dynamic
name-to-number translation (this process is specified in IEN
116). The Domain Name Protocol accesses a Domain name Server
which provides dynamic name-to-number translation (this process
is specified in RFCs 1033 and 1034). A static local host table
can also be accessed for name-to-number translation.
- Host Table
- An ASCII text file where each line is an entry consisting of
one numeric address and one or more names associated with that
address. Host tables are used to resolve host names into numeric
- The name given to a machine. See also FQDN.
- Sponsored by SLAC Computing Services, this meeting includes
a review of scheduled power outages, a discussion of identified
problems and outstanding issues, along with a brief recap of the
Accelerator Operations daily meeting. The meeting is open to all
- Health Physics.
- Health Physicist.
- Hectopascal. 100 Pascals.
- High Performance Computing.
- Hybrid PhotoDiode
- High Performance FORTRAN. An evolving industry standard
based on FORTRAN 90 + a FORALL statement + data partition
directives that will be available on IBM's POWERparallel Systems
like the 9076 SP1.
- Human Performance Improvement.
- High-Power RF.
- Hutch Protection System.
- High-Performing Sustainable Building.
- High-Performance Storage Systems.
- Health Physics Technician.
- High Power Target Module.
- Harvard-Pennsylvania-Wisconsin detector.
- High PoWeR.
- High-field Quadrupole.
- DOE HeadQuarters (Washington, DC).
- Heavy Quark Effective Theory.
- Heavy Quark Effective Theory
- Hybrid Quark Hadron.
- Human Resources Department (SLAC).
- High Radiation Area.
- Human Resources Information Systems.
- Human Resources Management System.
- PEP High-Resolution Spectrometer (SLAC).
- Hazard Ranking System. (CERCLA)
- Hoisting and Rigging Saftey Committee.
- Hazardous Substance Account. A California state fund derived
from fees paid by persons who deposit more than 500 pounds per
year of hazardous or extremely hazardous waste to onsite or
offsite hazardous waste disposal facilities. This is the primary
funding source for the State Superfund program. (CH&SC Sec. 25300
- Health and Safety Directive.
- Health, Safety and Security office. (DOE)
- Hubble Space Telescope.
- Hardware STAtus. A VAX database status bit indicating if a
device is on-line or off-line.
- Hazardous and Solid Waste Amendments. The 1984 law which
amended RCRA and created a federal program for underground tanks.
- Hard Thermal Loop
- Hierarchical Triangular Mesh.
- HyperText Markup Language. The standard language used for
creating hypermedia documents within the World Wide Web. It
specifies the layout and linking commands present in the
hypertext documents themselves.
- High Temperature Superconductivity
- Hypertext Transfer Protocol. The standard application-level
protocol for distributed, collaborative, hypermedia information
systems. It describes the way that hypertext documents are
fetched over the Internet and is most commonly associated with
the World Wide Web.
- Hutch User's Panel. (LCLS)
- 't Hooft-Veltman
- High Voltage.
- Heating and Ventilating unit.
- Heating, Ventilation and Air Conditioning.
- High Voltage Ready. A klystron SDS message indicating that a
given klystron is ready for use.
- High Voltage Terminal Cabinet.
- Health and Welfare Agency (California).
- Hazardous Waste Control Law. (CH&SC Sec. 25100 et seq)
- Hazardous Waste and Material Coordinator.
- Hazardous Waste Storage Area.
- Hazardous Waste Storage Yard.
- Hard X Corrector.
- Hard X-Ray Self-Seeding.
- HYBRid: bubble chamber + electronics.
- Hard Y Corrector.
- A large group of organic compounds composed largely of
carbon and hydrogen.
- The geology of ground water, with particular emphasis on the
chemistry and movement of water.
- The science dealing with the properties, distribution, and
circulation of water.
- A kind of programming environment that organizes all forms
of information into what appear as stacks of index cards. The
user then manipulates those stacks to create applications.
- An element in an electronic document that links to another
place in the same document, or to an entirely different document.
Typically, you click on the hyperlink to follow the link.
Hyperlinks are the most essential ingredient of all hypertext
systems, including the World Wide Web.
- A heavy version of a neutron. Hyperons can be made
artificially in accelerators, where they are unstable and decay
- Hertz. The basic unit of frequency measurement that replaced
the former unit of cycles per second (cps). One hertz is equal to
one cycle per second.
- DESY-HERA detector
Send corrections to firstname.lastname@example.org
or propose new terms for SLACspeak.