Preliminary site plan for SLAC, 1962

Historic terms:

0-A      B      C      D      E     F      G      H      I      J      K     L      M     N      O    P      Q      R      S     T      U-V-W      X-Y-Z


Legacy SLACspeak P

PA     Public Affairs.

PAC     Physics Analysis Coordinator (BaBar).

PacMan     A concrete shielding structure at each end of the SLD detector between the endcaps and the pit walls. The two huge overlapping sections of each PacMan can be opened for access to the beam pipe.

PAD Phase and Amplitude Detector     An RF measurement module which has been designed to measure the phase difference between two RF inputs: the signal source and the reference source. The PAD data is fed into the database after several adjustments (linearization of pad error, MDL length, upstream sources). The reference signal is usually derived from the MDL on a local reference line called PRL.

PADO     Phase and Amplitude Detector Offset. The time at which the PAD samples.

PAO     Public Affairs Office

Paranoia     A VAX process that handles error messages from micros or from a SCP process that are destined either for a user or a SCP terminal. All error messages are written to the ERRLOG list which can be retrieved at any later time when investigating a fault or other action.

PAU     Pulsed Amplitude Unit. A CAMAC module used to control devices such as pulsed magnets and phase shifters which must change state at the accelerator pulse rate (up to 120 PPS).

PAWN     Producer-Archive Workflow Network (NARA)

PBC     Propane Bubble Chamber.

PBH     Pulsed Bend Horizontal. Refers to the dipole magnet used to switch electron bunches to the North Ring and positrons to the South Ring. Note that this magnet is no longer pulsed.

PCNL     President's Council on the National Laboratories.

PCR     PEP Control Room.

PD     Physics Discussion.

PD     Program Deputy. (MCC)

PDP-11     Programmed Data Processor. A Digital Equipment Corporation machine.

PDU     Programmable Delay Unit. A CAMAC module that contains in memory a beam matrix of 256 beam code possibilities contained in 16 channels and a desired time of output pulses for each of these channels. The PDU receives the beam code from the micro and the fiducial signal from the FIDO. In this way the two data paths (timing and beam codes) meet.

PDU Channel     One of the 16 channels of a PDU.

PE&D     Plant Engineering and Design.

PEG     Physical Electronics Group.

PEGASYS     PEp Gas tArget Spectrometer sYStem.

PEGGY     Polarized Electron Gun (with additional gy to make it affectionate ).

PEP     Positron Electron Project (originally the Positron Electron-Proton Project). A 2.2km circumference storage ring at SLAC with six interaction points, two SSRL beam lines, electron-positron storage and collision capability, 4 - 18 GeV energy range, and 50 mA currents. PEP was upgraded to be the site of the SLAC B Factory. See also PEP-II. SLAC

PEP II     See PEP-II.

PEP OIC     Operator-in-charge of PEP.

PEP2     PEP-II (Use for Spires).

PEP-II     Upgraded SLAC PEP electron-positron collider. Its transformation into an asymmetric B Factory included addition of a second storage ring, as well as new beam power and control systems.

PEP-II Database     The PEP-II Project-wide Oracle-based database. It is envisioned to encompass off-line data for machine configuration and administration, as well as much of the detector counterpart data.

PEPUP     PEP UPgrade.

Phase Bump     The `Phase Bump' is used to change the phase of the RF fill of an accelerator section. The general intent is to change the average phase of the RF seen by one beam, independent of that seen by the other beam. This is achieved by tweaking the phase (plus or minus) 90 degrees in the first or last 60 ns of the fill time. Currently, this method is used to adjust the energy spread of the scavenger beam.

Phase Decker     See Phase Bump.

Phase Jump     A Phase Shifter to compensate for the beam loading effect of the Damping ring RF cavities.

Phase Ramp     Damping Ring RF Facility for varying the phase so that the time of arrival of the extracted beam at the compressor and LI02 will be changed. Phase Ramp is moved in units of S-BAND degrees or 0.973 picosecond. Operators tweak Phase Ramp to adjust the beam spectrum and energy at the end of the LINAC, using X-ray screens in the BSY area.

Phasefix     A system for measuring and correcting the tune of the SLC arcs.

PI Mode     One of the two modes of bunch oscillation caused by the RF in the Damping Rings (the other one is called O MODE). In Pi mode the two bunches in a ring are opposite and oscillate toward each other (they are Pi radians, or 360 degrees out of phase with each other).

PIO     Public Information Officer.

PIOP     Programmable Input/Output Processor. A CAMAC module used for klystron control.

PIP     PEP Injector Project

Pipeline Mode     A PAU mode of operation in which a beam code signals the PAU to act on the following beam code. This mode of operation is often used in dealing with time slot separation problems.

PLO     PLant Office

PLS     Polarized Light Source. The SLC laser Gun.

PLUTO     Detector at the DORIS electron-positron collider (DESY).

PMAG     Pulsed MAGnets. A VAX database primary.

PMOG     Project Management Oversight Group. (Obsolete--See PMAG)

PNE     Peaceful Nuclear Explosions

PNet     Pattern Network Module.

PNPP     Particle-Nuclear Physics Pool.

POC     Publications Oversight Committee (American Physical Society).

Polarized Electron Gun     See PEG.

Polarized Light Source     See PLS.

Poll 0     A VAX process which checks all SLCNET micros for database status changes and errors. If a micro is not talking anymore, it is removed from the poll list and its poll becomes `0.'

POOP     Principles Of OPeration. An SLC control system document.

POPA     Panel on Public Affairs (APS).

Positron Electron Project     See PEP.

Pp Beam #     The higher byte of the PPYY is the PP beam code number used by the T-Matrix to define a certain beam. This number is generated by MP00 and broadcast to all micros.

PPC     PEP Policy Committee. (Obsolete)

PPF     Preprints in Particles and Fields. A weekly list of new preprints received in the SLAC Library and entered in the HEP database. Once available on the web at See also 'Anti-Preprints.' Ceased publication in 1993

PPOM     Pulsed Power Output Module. A CAMAC module.

PPYY     A 16 bit word used by timing software and hardware to select times at which devices should be triggered on an upcoming machine pulse. It is generated at MP00 and broadcast at 360hz on the SLCNET to the various devices. It is received by the CAR in Crate 1 of a typical sector micro. PP is the high order eight bits or `beam code' used to select the time delays for devices such as klystrons and kicker magnets. YY is the low order eight bits, used to synchronize additional devices such as BPMs.

PRAW     Phase RAW. A database secondary. It is the raw phase measured by the PAD.

Preprints in Particles and Fields     See PPF.

PRIF     Peace Research Institute Frankfurt

PRIM     Pattern Receiver Interrupt Multiplexer. A multibus module which receives PPYYs from the CAR and interrupts the micro CPU.

PRIM-9     Interactive computer graphics program for Picturing, Rotation, Isolation, and Masking in up to 9 dimensions. Developed at SLAC in the 1970's by J. W. Tukey with assistance from Maryanne Fisherkeller.

Primary     A class of signal names in the VAX SLC database.

Principles of Operation     See POOP.

PROD     Photon Research and Operations Division.

Production SLAC Web space     Holds all the SLAC Web pages and associated files connected to the SLAC Core Pages except Individual Home Pages. Files in the Production Space are made available to the Web by authorized SLAC WWW server that use the standard port (now 80), for example, files in /afs/slac/www served by the www host.

Production Web Pages     Pages and directories that are linked directly or indirectly from the SLAC Home Page. Production pages are meant to be viewed (i.e., they are in production) by any intended audiences, including people outside of SLAC. See also: Non-Production Web Pages.

PROF     PROFile Monitor. A VAX primary.

Programmable Delay Unit     See PDU.

Project M     The Stanford University project, developed by interested parties in the Hansen Laboratories and Physics Department, for the construction of a 2-mile, multi-BeV linear electron accelerator. Called Project M from 1956 - 1960, the project was renamed Stanford Linear Accelerator Center in 1960. The M stood for Multi-Gev and/or for Monster.

Proton-Electron Project     See PEP.

PS     Photon Science (Directorate-SLAC).

PSAC     Presidential Science Advisory Committee (US)

PSC     Power Supply Controller. A single width CAMAC module used to control large power supplies. The PSC contains both a DAC and/or an ADC plus control and status bits.

PSIS     Photon Science Integration Study. (SLAC)

PSOG     Power Supply Operations Group. Obsolete: was part of EFD.

PSU     Programmable Synchronization Unit. Provides timing for delays longer than the fiducial period, which is about 2.8 milliseconds, or provides multiple pulses per fiducial. Used to synchronize devices to the damping ring beams. The PSU delay, period and pulse width are programmable.

PTT     Post Telephone and Telegraph Administration. A generic term for government-operated common carriers in countries other than the U.S.A. and Canada. Examples of the PTT are British Telecom in the United Kingdom, the Bundespost in Germany, and the Nippon Telephone and Telegraph Public Corporation in Japan.

Public Disk     A Macintosh in the computer center used as a file server for the MAC network.

PVSO     Pressure Vessel Safety Officer. (SLAC)

PWU     Programmable Width Unit. A CAMAC module used for gated pulses such as gun triggers. Triggers are received from the backplane and outputs are pulsed with programmed duration.