SUPERKAMIOKANDE ACRONYM DICTIONARY

RJW, updated 2/21/97 [HGB]

AC	Alternating Current. Expression for voltages or currents that alternate with a constant frequency typically provided at an electrical outlet; e.g. common voltages in the US = 110V-120V @ 60Hz, Japan = 100V @ 60Hz/50Hz, Western Europe = 220V @ 50Hz.
ADC	Analog-to-Digital Converter
AGN	Active Galactic Nuclei.
AND	Logical (circuit) function where all (input) bits must be in the TRUE state to set the output to TRUE.
ATM	Analog-to-Time Module, Toshiba front end for ID PMTs
ATMPD	Atmospheric Muon (and Neutrino) Proton Decay.
BCD	Binary-Coded Decimal.
BIP	Buffering In Progress status flag from the TDC modules; a high-level BIP flag indicates the TDC cannot record incoming data (deadtime)
BIPn	BIP signal from Hut n
BIPOR	Combined ("OR"-ed) BIP signal
Bit3	(company name) VMEbus adapter/controller for Sun/Solaris computers.
BTRG	end-of-BIP trigger (trailing edge detector) (See FTRG, LTRG)
CAMAC	A standard system for mounting, controlling and interfacing fast electronics for particle physics applications; historical successor to NIM and predecessor of Fastbus; used for OD trigger system. Provides computer access to individual modules, but lower density and speed than Fastbus.
CD	Central Detector, see ID
Central hut	Electronics hut on the tank top housing VME crates and computers
CPU	Central Processing Unit
DAQ	Data Acquisition system
DBUSY	busy bit of TRG-->FTRG delay circuit, including BIP veto = STRG/FTRG veto
DC	Direct Current; expression for a voltage or current that remains constant (see AC).
DC2	Controller for VME DPMs, mediates transfer of data from Fastbus crates to DPMs.
dECL	differential ECL (see ECL) logic standard, used for transmitting high-speed digital data over long 'twisted-pair' cables. Needs termination of 100-120 Ohms at the receiver.
DPM	Dual-Port Memory, in VME crate in central hut; buffers data between Fastbus crates and Sun host.
dTTL	differential TTL (see TTL) logic standard, used for transmitting medium-speed (<100 MHz) digital data over long 'twisted-pair' cables. 'High' > +0.2V, 'low' < -0.2V between the + and - of the differential pair. Needs 100-120 Ohm termination at receiver and transmitter end.
ECL	Emitter-Coupled Logic: digital logic standard for GHz operations. 'high' = -0.8...-0.9V, 'low' = -1.6...-1.7V.
EMI	ElectroMagnetic Interference.
ENT	Event Number Translator. UW-made custom module for the OD-DAQ.
EPROM	Eraseable and Programmable Read-Only Memory.
Fan-In	A circuit to mix more than one input together for one output. Linear = adds the amplitudes of the input signals together, output equals the algebraic sum of the inputs. Logic/Digital = sets the output to logic high whenever one of the inputs is logic high (logical OR function).
Fan-Out	A circuit to provide multiple identical outputs from an input signal.
Fastbus	A standard system for mounting, controlling and interfacing fast electronics for particle physics applications; historical successor to NIM and CAMAC and providing the highest density of channels per module.
FCM	Fanin/-out and Calibration Module. UW-made custom board for the OD-DAQ.
FDDI	Fiber-optic high rate data bus for local area networks.
FIFO	First-In, First-Out, a pipeline buffer.
FIV	Fastbus Interface to VME; a UW-made custom board for the OD-DAQ.
FRESETn	FSCC reset signal to Hut n.
FSCC	Fastbus Smart Crate Controller.
FTRG	Fastbus trigger (= OD TDC common stop) (see BTRG, LTRG,STRG).
GLB TRG	Global Trigger, generated in the SuperK detector to synchronize data flow at the ID and OD front-end electronics.
GMT	Greenwich Mean Time; international reference time, based on the local time in Greenwich, UK. See UTC.
GPS	Global Positioning System, a satellite system which allows receivers to compute position on earth to a few meters, and absolute UTC (prvided by the USNO Master Clock) to 100 nsec.
HE	High Energy (trigger).
HV	High Voltage; supply voltage for the PMTs, typ. 1.5 ... 3 kVolts.
IC	Integrated Circuit; also commonly called "chip".
ID	Inner Detector (or Central Detector).
IRIG	Standard coding system for clock data, allowing manufacturer-independent transfer of time data.
IRQ	Interrupt Request; commonly used signal in a computer-controlled electronics system for briefly interrupting a running software e.g. for handling a trigger occurence.
Latch	= Register. Circuit to sample and hold digital data at a trigger occurence; similar as FIFO.
LE	Low Energy (trigger).
LED	Light Emitting Diode.
Lemo	(company name) expensive, but commonly used nifty connectors for transfer or fast digital signals (e.g. NIM or TTL levels) over thin coax cables.
LIFO	Last-In, First-Out, a stack buffer.
LINAC	Linear Accelerator.
LSB	Least Significant Bit; lowest-order bit of a grouped binary word, mostly bit 0. Opposite of MSB.
LTC	Local Time Clock, a UW-built 50 MHz (20 nsec count) counter used to generate fine-grained timestamps for events.
LTRG	FIFO Latch (V533) trigger (see BTRG, FTRG, STRG).
MC	Monte Carlo; popular simulation method used in Particle Astrophysics to predict and verify detector performances.
MSB	Most Significant Bit; highest-order bit of a grouped binary word. E.g. bit 15 of a 16-bit word. Opposite of LSB.
ne	electron-neutrino.
NIM	Nuclear Instrumentation Module. An elderly standard for nuclear-physics electronics modules, providing only standard mountings, voltages and crate gating; modified NIM crates are used for the SuperK OD QTCs. Also a logic level definition: 'low' = ~0.0V and 'high' = -0.8...-1.6V. Needs termination of 50 Ohms at the receiver if used over coax cables.
NOVA buffer	Shared memory definition for organized block data transfer in a network computer system; originally developed under OS/9. Widely used in the SuperK workstations for merging and pre-processing raw ID and OD data blocks.
NSM	Net-Shared Memory; used with the NOVA buffers.
nt	tau-neutrino.
nu	muon-neutrino.
OD	Outer Detector (US contribution to Superk); also called "Anti Detector".
OR	Logic (circuit) function where the output is set TRUE whenever one or more (input) bits are TRUE.
PAL	Programmable Array Logic, mostly non-eraseable one-shot programmable logic (TTL) circuit. (See also PLD).
PCB	Printed Circuit Board.
pe	Photoelectron; one photon produces 1 pe in the PMT photocathode with about 25% efficiency.
PLD	Programmable Locic Device: same as PAL, but erasable and re-programmable instead.
PMT	Photomultiplier Tube.
Quadrant hut	One of the four electronics huts on tank top housing front-end electronics and power supplies.
QTC	Charge(Q)-to-Time Converter; part of the BU-built front-end modules (discriminator/QTCs).
RFI	Radio Frequency Interference; electromagnetic noise that occasionally screws up our DAQ system...
RS232	digital data transfer standard with approx. +/- 10V levels; widely used with modems, printers and other lower-speed computer periphals.
RS485	see dTTL.
SK	Super Kamiokande.
SN	Super Nova.
SNP	Solar Neutrino Problem.
SSM	Standard Solar Model.
STRG	Struck latch trigger (See FTRG, LTRG, BTRG).
t0	Reference Global Trigger signal recorded by the TDCs.
TDC	Time-to-Digital Converter.
TKO crate	Toshiba fastbus-like crate for ATMs.
TRG	Commonly refferred to the Global trigger (see GLB TRG).
TTL	Transistor-Transistor Logic: most popular digital logic standard, operating from a single 5V DC supply. 'Low' = 0...+1V, 'high' = +3...+5V.
UNIX	Open, multitasking operating system used by most general purpose workstations and mainframes. Proprietary variants include Xenix, Ultrix and Linux. (Originally developed by AT+T; evolved from MULTICS=MULTiplexed Info. + Computing System).
USNO	United States Naval Observatory; provider of the Master Clock Time for the United States (see GPS and UTC).
UTC	Universal Time (Coordinated), international standard version of GMT commonly used for astronomical event logging. Current time: (updates when you reload this page).
V533	see FIFO; module product name used in the OD-DAQ VME electronics.
VME	Versa Module Europe: international 32-bit (64-bit) parallel computer bus standard. A widely used bus standard which allows interfacing of external equipment to computers.
VSB	A less-widely used bus used for interfacing industrial equipment.
WLS	WaveLength Shifter, a doped acrylic plate which converts UV to longer-wavelength light; used in SuperK to increase the collecting area of the relatively small OD PMTs.
ZEBRA	CERN database system which allows construction and use of pseudo-dynamically allocated tree-structured data under fortran; includes machine-independent data formats so data can be transferred from one CPU to another type.
ZBS	Japanese homebrew database system, ZEBRA-like (but not identical twin).