P

P     Private (computer drive designation).

P Wastes     A federal waste list comprised of substances categorized as acutely hazardous.

P&T     Parking and Transportation or Packaging and Transportation.

P(S)     synchrotron light monitor.

P2/E2 Plan     Pollution Prevention and Energy Efficiency Plan.

P5     Particle Physics Project Prioritization Panel.

PA     Preliminary Assessment.

Pa     Pascal. A unit of pressure.

PA     Project & Activity code. (SLAC)

PAAA     Price-Anderson Amendments Act.

PAB     Physics & Astrophysics Building (Stanford).

PAC     Perturbed Angular Correlation

PAC     Particle Accelerator Conference.

PAC     Physics / Project Advisory Committee.

PAC     Phase and Amplitude Controller.

Packet     The unit of data sent across a packet switching network. The term is used loosely defined. While some Internet literature uses it to refer specifically to data sent across a physical network, other literature views the Internet as a packet switching network and describes IP datagrams as packets.

Packet Internet Groper     See PING.

PACM     Potential Asbestos Containing Material.

PACT     Projects for the Acceleration and Commercialization (DOE)

PAEC     Pakistan's Atomic Energy Commission.

PAESMEM     Presidential Award for Excellence in Science, Mathematics and Engineering Mentoring.

PAFD     Palo Alto Fire Department.

PAH     Polycyclic Aromatic Hydrocarbons.

Pair Production     The creation of an electron and a positron from a high energy photon in a strong electric field such as that surrounding a nucleus. This process is used to create positrons at the positron target.

PAL     Pohang Accelerator Laboratory.(Korea)

Paleoparadoxia     See Neoparadoxia Repenningi entry

PAMELA     Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics.

PAMM     Planned Accessible Machine Maintenance or Planned Access for Maintenance and Modifications. (LCLS)

PANDA     Proton ANtiproton annihilation DArmstadt.

PANIC     Particles And Nuclei International Conference.

Panic Circuit     Part of the linac PPS system that consists of EMERGENCY OFF buttons that will trip off all the VVSs in the LINAC when depressed.

Panofsky Long Ion Chamber     See PLIC.

PAO     Proposal Advancement Office.

PAP     Performance Assurance Plan (GLAST).

PAP     Personnel Access Platform (GLAST).

PAPR     Powered Air-Purifying Respirator.

PARC     Xerox Corporation's Palo Alto Research Center

PARMELA     Phase And Radial Motion in Electron LinAcs. An accelerator simulation program for electron linacs. (CERN) See also PARMILA.

PARMELLA     Phase And Radial Motion in ELectron Linear Accelerators. A modeling and design program for transport line optics that incorporates beam bunching.

PARMILA     Phase And Radial Motion In LinAcs. An accelerator simulation program for linacs. (CERN) See also PARMELA.

PARS     Project Assessment and Reporting System. (DOE)

PARS-II     Project assessment and Reporting System.

PASAG     Particle Astrophysics Scientific Assessment Group.

PASCOS     PArticles, Strings and COSmology (Symposium).

PASHA     Package for Automated Snoop Hardware Analysis.

Pattern Receiver Interrupt Multiplexer     See PRIM.

PAW     Physics Analysis Workstation. A computer program available from CERN, PAW is an interactive utility for visualizing experimental data in a computer graphical display.

PAWS     Parallel Assessment Window System.

PAX     Polarized Antiproton eXperiment.

PB     Performance Baseline

PB     Pep Beamline. (SSRL)

PBGS     Partial Breaking of Global Supersymmetry

PBH     Primordial Black Holes

PBRT     Proton Beam Radio-Therapy.

PBWA     Plasma Beat Wave (laser) Acceleration

PBX     Private Branch eXchange. A private telephone network used within an enterprise. PBX users share a certain number of outside lines for making telephone calls external to the private network.

pc     Parsec. An astronomical unit of measurement equivalent to 3.26 light years' distance, calculated using the PARallax of 1 arc SECond .

PC     Personal Computer.

PC     Protection Collimator.

PCAC     Partially Conserved Axial vector Current

PCAST     President's Council of Advisers on Science and Technology.

PCB     PolyChlorinated Biphenyl. A group of toxic, persistent chemicals used in transformers and capacitors for insulating purposes and in gas pipeline systems as a lubricant. Further sale or new use was banned by law in 1979.

PCB     Printed Circuit Board.

PCD     Power Conversion Department. Engineers, maintains and installs cables for modulators, sub-boosters and all power supplies from the injector through the Research Area.

PCDS     Photon Controls and Data Systems.

PCE     PerChloroEthylene. (aka tetrachloroethylene, or `perc'.)

PCI     Peripheral Component Interconnect

PCI     Phase Contrast Imaging.

PCM     Programmable Control Module.

PCMCIA     Personal Computer Memory Card International Association. This group of manufacturers created the new PCMCIA industry standard adapter. It looks like a credit card and is mounted by pushing it into an external computer slot, similar to an ATM.

PCMS     Project Controls Management System. (FGST)

PCON     Phase CONfiguration. The phase of a klystron taken from a model or a saved configuration.

PCR     Polymerase Chain Reaction.

PCR     Project Closure Review

PCT     Parity Charge conjugation and Time reversal.

PCW     Process Cooling Water.

PD     Project Director.

PDB     Protein Data Bank.

PDE     Partial Differential Equations.

PDES     Phase DESired for a klystron.

PDF     Parton Distribution Function or Pair-Distribution Function.

PDF     Portable Document Format.

PDF     Powder Diffraction File.

PDG     Particle Data Group. The PDG is an international collaboration with affiliations at LBNL, CERN, KEK, INFN, IHEP, SLAC and elsewhere. The PDG reviews the field of particle physics and compiles and analyzes data on particle properties.

PDM     Project or Product Data Management.

PDR     Preliminary Design Review.

PDS     Pole Divergent Subtraction

PDS     Power Density Spectrum.

PE     Plant Engineering. A SLAC organizational group merged under Facilities and renamed the Site Engineering and Maintenance Office (SEM).

PE/BI     Plans Examiner/Building Inspector.

PEA     Personnel Exclusion Area.

PEC     PhotoElectroChemical.

PED     Project Engineering and Design.

PED     Plant Engineering Department.

PEEM     PhotoElEctron Microscopy.

PEG     Polarized Electron Gun. A CID injector gun used to generate a polarized electron beam.

PEL     Permissible Exposure Limit. Maximum exposure levels for workplace chemicals as determined by OSHA.

PEL     Physical ELectronics. Renamed Surface and Materials Science in 2005.

PEMP     Performance Evaluation and Measurement Plan. (DOE)

Pencil Beam     A beam with low energy spread and low emittance: usually tightly collimated by one or more adjustable collimators.

Penetration     The flow of a hazardous chemical through zippers, stitched seams, pinholes, or other imperfections in protective clothing material.

penguin     A type of Feynman diagram describing the weak decay of a quark through an intermediate quark - weak boson loop, in which a gluon (or Z or photon) couples to the quarks in the loop, and then decays to a quark - anti-quark pair.

PENULT     PENULTimate.

PEO     Plant Engineering Operations. (SLAC)

PEP     Project Execution Plan.

PEP-N     Upgrade to PEP-II (proposed).

PEP-X     Synchrotron storage ring project at SLAC utilizing PEP-II. (Proposed)

PER     PERsonnel Department.

PERDPM     PERioDic Permanent Magnet.

Periodic Permanent Magnet Klystron     An advanced generation klystron developed at SLAC, and planned to provide microwave power for the NLC.

Perl     Practical Extraction and Report Language. An interpretive programming language developed by Larry Wall. Because of its strong text-processing abilities, Perl has become one of the most popular languages for writing CGI scripts.

Permeation     An invisible process by which a hazardous chemical moves through a protective clothing material.

Permissible Exposure Limit     See PEL.

Permissive     A pattern gate used to allow the gun to pulse when a set of interlocks is complete. The BCS and some MPS systems remove the permissive in response to interlock trips. Operators also have control of the permissive. This is a `fail-safe' method of killing the beam, in that the gun can only pulse when the permissive gate is present.

Permit     An authorization, license, or equivalent control document issued by EPA or an approved state agency to implement the requirements of an environmental regulation, e.g., a permit to operate a wastewater treatment plant or to operate a facility that may generate harmful emissions.

Persistence     The property of a chemical whereby it tends to remain in the environment in its original molecular form.

Personnel Protection System     See PPS.

PERT     Program/project Evaluation and Review Technique.

PERT     Procurement Evaluation Review Team

PET     Positron Emission Tomography.

PETE     Photon-Enhanced Thermionic Emission.

PETRA     See DESY PETRA

PETS     Power Extraction and Transfer Structure. (CLIC)

PEVATRON     Accelerator of cosmic rays with energies of several PeV.

PF     Photon Factory

PF     Protection Factor. That number which when multiplied by the TLV of a substance yields the maximum permissible concentration in which the respirator in question may be used. Protection factors are assigned to classes of respirators.

PFA     Particle Flow Algorithms.

PFIAB     President's Foreign Intelligence Advisory Board.

PFMON     ProFile MONitor.

PFN     Pulse Forming Network.

PG&E     Pacific Gas and Electric Company

PGB     Pseudo-Goldstone Boson

PGM     Plane Grating Monochromator.

P-Gun or PGUN     Polarized gun. See also PLS.

pH     A measure of corrosivity on a scale from O to 14, with 7 being neutral, acidity increasing toward O and alkalinity increasing toward 14.

Phase Acceptance     See Acceptance.

Phase Advance     The phase change of a betatron oscillation over a certain distance(s) which can be a lattice cell.

Phase and Amplitude Detector     See PAD.

Phase and Amplitude Detector Offset     See PADO.

Phase and Radial Motion in ELectron Linear Accelerators     See PARMELLA.

Phase Configuration     See PCON.

Phase Raw     See PRAW.

Phase Shift Keying     See PSK.

Phase Space    A plot of the beam position versus its phase angle.

Phasing     To adjust the timing of any periodic device less than 360 degrees.

Phasing     To change the timing of a klystron's RF output with respect to the bunch. This will add or subtract energy from the bunch by causing the bunch to see a greater or smaller accelerating voltage.

PHENIX     the Pioneering High Energy Nuclear Interaction eXperiment located at BNL to investigate high energy collisions between heavy ions and protons.

PHENIX    A comprehensive software package for macromolecular structure determination using crystallographic or electron cryo-microscopy data IB-1770

Phishing     The practice of sending false email in an effort to trick the receiver into revealing information that can be used to perpetrate identity theft. Phishers direct the unwary to sites that look legitimate, but are not.

PHM     Klystron summary display indicating that the station mean phase is out of tolerance.

PHM     PHase Mean.

PHMC     Polynomial Hybrid Monte Carlo

PHOBOS     A detector at RHIC.

phonon     wave-like vibration of an atom in a solid.

Photomultiplier     A photon to current transducer amplifier which uses the photoelectric effect and secondary emissions in cascaded diode cells to produce a measurable electric current from a relatively weak light source.

Photon     A particle of light. In 1889, Max Planck postulated that light is not continuous, but comes in bunches, or quanta. Each of these granular quanta of light is made up of photon particles.

photonics     The technology of using particles of light as carriers of information.

PHP     Personal Home Page (original meaning). General purpose scripting language developed by Rasmus Lerdorf.

PHTN     Photon.

Physical Address     A grouping of numbers that identifies a particular piece of computer hardware connected to a local area network or other data communications system. Contrast with logical address.

Physical ELectronics     See PEL.

PHYSTAT     International Conference on Statistical Problems in Particle Physics, Astrophysics and Cosmology.

PIC     Particle-In-Cell

PIC     Port d'Informació Científica. (Scientific Information Harbour)

PIC     Product of Incomplete Combustion.

PIC     Person In Charge. The person in charge of laboratory response to emergencies.

PIC     Pocket Ion Chamber.

PIC     Protection Ion Chamber.

Picobarn     A unit of area equal to 10 to the minus 12 barns. Used to measure cross-sections in nuclear and particle physics.

Picocurie     Measurement of radioactivity. A picocurie is one million millionth, or a trillionth, of a curie, and represents about 2.2 radioactive particle disintegrations per minute.

Picocuries Per Liter     A unit of measure used for expressing levels of radon gas. See also Picocurie.

PICSEL     Physics with Integrated Cmos Sensors and ELectron machines.

Picture Element     See Pixel.

PID     Photo-Ionization Detector.

PID     Particle IDentification.

PIE     Precourt Institute for Energy. (Stanford)

PIE     Process Improvement and Efficiency.

PIER     Promoting Inclusive and Equitable Research (DOE)

Pig     A container, usually lead, used to ship or store radioactive materials.

PII     Personally Identifiable Information.

PILATUS     PIxel ApparaTUs for the Sls project.

Pile     The fuel element in a nuclear reactor.

PIM     Profile Intensity Monitor.

PIMC     Path Integral Monte Carlo

PIMMS     Proton and Ion Medical Machine Study.

PING     Packet INternet Groper. A program which is useful for testing and debugging networks. It sends an ICMP Echo packet to the specified host, and waits for a response. It reports successor failure and statistics about its operation. The term is used as a verb: Ping host X to see if it is up!

PingER     Ping End-to-end Reporting.

PIP      Project Implementation Plan. (ILC)

Piracy     Unauthorized copying of software.

PIS     Primary Instrument Scientist.

PISL     Pi-mode stabilizing loops

PITZ     PhotoInjector Test Facility, Zeuthen. (DESY)

PIV     Personal Identification Verification.

Pixel     Picture element. A dot of video graphics that can be in either an on or off state. The number of pixels determines the resolution. Resolution is the number of pixels on the monitor and is determined by multiplying the number of horizontal pixels by the number of vertical pixels. For example, VGA is 640 x 480 or 307,200 pixels on the monitor.

PJB     Pre-Job Briefing

PJLZ     Parrinello-Jona-Lasinio-Zwanziger.

PKU3     Peking University 3rd. A 1.3 gigahertz TESLA-type nine-cell niobium superconducting cavity.

PL     Pulsed Linac (FEL).

PL/1     Programming Language 1. General-purpose language used for both scientific and business applications.

Plant Engineering     See PE.

PLAS     Plastic detector.

PLC     Programmable Logic Controller.

PLD     Pulsed Laser Deposition.

PLEDGE     PoLicy Enforcement in Data Grid Environments. (NARA)

PLI     Project Leadership Institute. (DOE)

PLIC     Panofsky Long Ion Chamber. A gas filled cable running along the linac housing or primary beam transport line used to detect a mis-steered beam. The point where the beam is lost can be determined from the time of arrival of the ion shower that the lost beam sprays into the cable-chamber. Conceived by Wolfgang K. H. Panofsky, SLAC Director Emeritus.

PLS     Pohang Light Source. (Korea)

Plug Compatibility     Manufactured hardware that is designed to be interchangeable with another vendor's product, even though internal details may differ.

PLUME     Pixelated Ladder with Ultra-Low Material Embedding. (ILC)

PLUT     DESY PLUTO detector.

PM     Peripheral Monitors.

PM     Project Management.

PM     Preventive Maintenance.

PM     Pulsed Magnet.

PM     Performance Measures.

PM     Protection colliMator.

PM     Pulse-bending Magnet.

PMAG     Project Management Assurance Group.

PMAAG     Project Management Advisory and Assurance Group

PMB     Performance Measurement Baseline.

PMC     PCI Mezzanine Card. (GLAST)

PMCS     Project Management Control System

PMD    Photon Multiplicity Detector.

PME     Plant Maintenance Electrical.

PMI     Plant Maintenance Instrumentation.

PMM     Plant Maintenance Mechanics.

PMN     Pre-Manufacture Notification.

PMO     Project Management Office. (SLAC)

PMPS     Photon Machine Protection System

PMS     Program Management System.

PMS     Peripheral Monitoring Stations.

PMS     Plant Maintenance Services.

PMT     PhotoMultiplier Tube. See also Photomultiplier.

PMU     Plant Maintenance and Utilities Building.

PMV     Pulse-bending Magnet Vertical.

PNC     Parity NonConservation, or Parity NonConserving.

PNGB     Pseudo-Nambu-Goldstone Boson.

PNL     An abbreviation for `Panel.'

PNNL     Pacific Northwest National Laboratory.

PNT     Position, Navigation and Time.

PO     Purchase Order.

PO     Pump Out.

POAM     Plan Of Action and Milestones.

POC     Point Of Contact or Point of Connection.

Pockels Cell     A crystal which changes its angle of light polarization when submitted to a high voltage. A Pockels cell is used in the PLS to chop the laser beam and also for polarization and intensity control. It is useful for fast switching and control of polarized light beams.

POD     Print-On-Demand.

POHC     Principal Organic Hazardous Constituent.

POI     Person Of Interest.

Poisson     A modeling program used for calculating magnetic fields.

Poisson     A type of statistical distribution (see also Gaussian) named after the mathematician Simeon Denis Poisson.

Polling     Connecting to another system to check for things like mail or news.

Polychlorinated Biphenyl     See PCB.

POMDP     Partially Observable Markov Decision Process.

Pomeron     A color-neutral collective partonic excitation the aggregate mechanism responsible for elastic scattering.

POMM     Planned Operational Machine Maintenance. (LCLS)

POP     Post Office Protocol. A protocol used to retrieve e-mail from a mail server. Most e-mail applications (sometimes called an e-mail client) use the POP protocol, although some can use the newer IMAP (Internet Message Access Protocol).

POPBCI     POst Processor for Beam Coupling Interfaces.

PosiPol     Polarized positrons.

Positron     A particle with a mass equal to an electron but with opposite charge. First postulated by P.A.M. Dirac in 1929, and experimentally discovered by C.D. Anderson in 1931.

POSS     Palomar Observatory Sky Survey (1950-1955).

Post Telephone and Telegraph Administration     See PTT.

Postmaster     The person responsible for taking care of mail problems, answering queries about users, and other related work at a site.

PostScript     A commonly-used graphics description language designed for use with computer printers. Most modern computer word processors and graphics programs can produce PostScript output.

POTW     Publicly-Owned Treatment Works.

POTW     Plan Of The Week.

POW     Plan Of the Week. (SLAC)

Power Conversion Department     See PCD.

Power Supply Controller     See PSC.

Power Supply Operations Group     See AME.

Power Teks.     See AME.

PPA     Particle Physics and Astrophysics (Directorate-SLAC). Changed in August 2007. Was Particle and Particle Astrophysics (Directorate-SLAC).

PPARC     Particle Physics and Astronomy Research Council (UK).

ppb     Parts per billion.

PPB     Planning and Policy Board. (Stanford University)

PPC     Parallel Plate Chamber

PPDG     Particle Physics Data Grid. Collaboration formed in 1999 to develop a worldwide distributed computing model. 

PPE     Personal Protective Equipment.

PPL     Pervasive Parallelism Laboratory. (Stanford - Computing)

PPL     Pole PLate.

PPM     Piecewise Parabolic Method.

PPM    Periodic Permanent Magnet.

ppm     Parts per million.

PPM Focusing     Periodic permanent magnet focusing. Uses an array of closely spaced magnetic lenses of alternating polarity, driven by ring- shaped, high-energy, rare earth magnets (which provides table fields and require no input current).

PPN     Parametrized PostNewtonian

PPO     Program Planning Office, an ES&H Division Department

PPP     Point to Point Protocol. A protocol that allows a computer to use the TCP/IP protocols and become a full Internet member with a standard phone line and a hi-speed modem. Replaces SLIP.

PPP     Preferred Procurement Products. (DOE)

PPPA     Poison Prevention Packaging Act. (Federal)

PPPL     Princeton Plasma Physics Laboratory.

PPRC     Polarized Photocathode Research Collaboration.

PPS     Pulses Per Second.

PPS     Personnel Protection System. A safety system designed to protect people from radiation hazards. It includes the access control system of radiation areas and the radiation detection systems (BSOIC and BCS).

PPSN     Public Packet Switched Network, e.g., Telnet, Tymnet, Uninet in the U.S., Datapac in Canada, Datexp in Germany.

PQCD     Perturbative QCD

PQFT     Perturbative Quantum Field Theory.

PR     beam position monitor, cherenkov cell, phosphor screen.

PRA     Paperwork Reduction Act. (1995)

PRBs     Permeable Reactive Barriers.

PRC     People's Republic of China.

PRC     PRoperty Control.

PRCS     Permit Required Confined Spaces.

PRD     Physics Requirements Document.

PRD     Pressure Relief Damper.

PREC     Physical Requirements and Exposures Checklist.

Pre-kicker     A small pulsed magnet used on SLC to cancel the kick received by the second bunch on the previous turn of the NDR.

Preprint     A manuscript intended for publication but circulated among peers for comment prior to being submitted for publication.

Preset Buttons     PPS search devices which need to be activated by an operator when searching an accelerator area. These buttons are placed strategically in the beam housing to ensure that the search team does a complete job of searching all the nooks and crannies in the tunnel.

Primary Waste Treatment     The first steps in wastewater treatment. Screens and sedimentation tanks are used to remove most materials that float or will settle. Primary treatment results in the removal of about30 percent of carbonaceous biochemical oxygen demand from domestic sewage.

PRIME     Post-RefInement and MErging. Software program for analyzing data from X-ray laser experiments.

Princeton-Stanford Storage Rings     See Stanford-Princeton Storage Rings.

Print Server     A network server assigned to manage local or remote printers and printer queues. The print server keeps track of print jobs, allows manipulation of print queues, and sends print jobs to various printers.

Priority Pollutants     A list of chemicals selected from the list of toxic pollutants by the EPA as priority toxic pollutants for regulation under the Clean Water Act.

PRISM     Phase-Rotated Intense Slow Muon Source (Osaka).

Private Branch Extension     See PBX.

PRL     Physics Review Letters. PHYSICS

PRL     Phase Reference Line (For PAD).

PRL     Positron Return Line.

Probability     A number between zero and one that represents the chance of occurrence of a given event, wherein a probability of zero means there is no chance of the event occurring, and a probability of one means the event must happen. (A fifty percent chance of occurrence is a probability of one half).

Process     Any autonomous program executed by a computer's CPU is a process. Sometimes called a job.

Profile Monitor     A screen inserted in a beam transport line to view the beam cross section. The visible emission created by the beam exiting the screen's phosphor coating (usually zinc sulfide) is viewed by a video camera and the picture transmitted to the Control Room. Profile monitor screens can usually be inserted and removed remotely by the machine operators.

Program Deputy     The physicist temporarily in charge of the current program. Program deputies usually have the 'duty' for a period of one or two weeks.

Programmable Input/Output Processor     See PIOP.

Programmable Synchronization Unit     See PSU.

Programmable Width Unit     See PWU.

Programmed Data Processor     See PDP-11.

Programming Language 1     See PL/1.

Prop. 65     Safe Drinking Water and Toxic Enforcement Act of 1986, citizen's referendum in California.

PROSCAN     Proton therapy project at the Paul Scherrer Institute (PSI).

Protection Factor     See PF.

Protection System     See PTS.

Protocol     A formal description of message formats and the rules two computers must follow to exchange those messages. A Protocol can describe low-level details of machine-to-machine interfaces(e.g., the order in which bits and bytes are sent across a wire) or high-level exchanges between allocation programs (e.g., the way in which two programs transfer a file across the Internet).

Proxy     The mechanism whereby one system fronts for another system in responding to protocol requests. Proxy systems are used in network management to avoid having to implement full protocol stacks in simple devices, such as modems.

PRP     Potentially Responsible Party.

PRP     Proposal or Program Review Panel.

PRST-AB     Physical Review Special Topics - Accelerators and Beams.

PRT     Participating Research Team (SSRL)

PRV     Pressure Relief Valve

PS     Pico-Second.

ps     A commonly used abbreviation for PostScript. Often used as the extension portion of a computer file specification containing PostScript language commands, as in myletter.ps.

PS     Program Support. (DOE)

PS     Power Supply.

PS     vacuum Pumping (above housing)

PS     Pressure Switch.

PS2     high-energy Photon Science.

PSA     PCB waste Storage Area. SLAC

PSAD     Preliminary Safety Analysis Document.

PSB     Power Supply Board.

PSC     Planar Spark Counter.

PSD     Prevention of Significant Deterioration. (from CAA)

PSD     Pulse Shape Discrimination.

PSE     Power Systems Engineering group (SLAC).

PSES     Pretreatment Standards for Existing Sources. (from CWA)

PSF     Point Spread Function.

PSF     Planetary Systems and Star Formation.

Psi     The Greek letter 'y.' See also Phase Advance.

PSI     Paul Scherrer Institute.(Switzerland)

PSI     A revolutionary long-lived meson discovered simultaneously at SLAC and MIT in 1974. Burton Richter (SLAC) and Sam Ting (MIT) shared the 1976 Nobel Prize in Physics for the discovery of this particle, called J by the MIT team.

PSI     Pounds per Square Inch (unit of pressure).

PSI     Protein Structure Initiative (NIH/NIGMS).

PS-II     PhotoSystem-II

PSK     Phase Shift Keying. Used in the SLED system to add the energy stored in the sled cavity to that being produced by the klystron. The PSK knob moves the envelope of the RF for sector 2-30with respect to the beam. It affects both beams, unlike the phase ramp knob which is used to adjust the e+ and e- beam energies separately.

PSLB     Photon Science Laboratory Building. (Bldg. 057) Renamed Arillaga Science Center in 2017.

PSM     vacuum Pumping (Mech.) (above housing)

PSN    Proper Shipping Name. (from 49 CFR)

PSNM     Power Supply NaMe or serial number.

PSNS     Pretreatment Standards for New Sources. (from CWA)

PSPS     Public Safety Power Shutoff (PG&E)

PSUSY     ParaSUperSYmmetry.

pT     Transverse momentum.

PTA     Projects-Tasks-Awards. (Stanford)

PTE     Potential To Emit.

PTEC     Physics Teacher Education Coalition.

PTFE     PolyTetraFluorEthylene.

PTPS     Pulse To Pulse Stabilizer.

PTS     ProTection System. The SLAC operational group charged with designing and troubleshooting electronics systems used in Beam Containment and PPS.

Public Packet Switched Network     See PPSN.

PUE     Power Usage Effectiveness.

PULSE     Photon Ultrafast Laser Science and Engineering center (SLAC).

Pulsed Amplitude Unit     See PAU.

Pulsed Bend Horizontal     See PBH.

Pulsed Power Output Module     See PPOM.

Pump down     Depressurize.

Pump Probe     A technique developed for the observation of ultra-fast events. A sample of material is 'pumped' at regular intervals to create discrete events, and as the sample is changing, the experimenters 'probe' the response of the system to the created excitation events.

PUR     Purchasing.

PVA     PolyVinyl Alcohol.

PVA

Process Variable Access (Computing)

PVC     PolyVinylChloride.

PVM     Parallel Virtual Machine. A message-passing library and processor daemon for coordinating tasks across processors. Public domain from Oak Ridge National Lab. Like Express and Linda, usage has been growing explosively. Used in conjunction with batch programs like Condor on MPPs or clusters to take better advantage of multiple processors. PVM node programs aren't currently under Condor control.

PVSS     Prozessvisualisierungs und Steuerungs System, an LHC control software.

PWA    Partial-Wave Analysis.

PWC    Proportional Wire Chamber

PWFA    Plasma-based WakeField Acceleration.

PWHA    Pre-Work Hazard Assessment.

PWR    Pressurized Water Reactor.

PWSA    Ports and Waterways Safety Act. (Federal)

PWT    Plane Wave Transformer.

PXE    Preboot eXecution Environment

Pyroehoric    Capable of igniting spontaneously when exposed to dry or moist air at or below 130 degrees F (54.44 C).

Pyrolysis    The destruction of molecular composition through heating, resulting in smaller, simpler, and generally less toxic compounds.