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INTRODUCTION
The LeCroy CAMAC Model 3377 is a 32-channel Multihit Time-to-Digital
Converter (TDC) intended for high rate particle physics experiments.
The 500 picosecond digitizing resolution, 32 microsecond maximum full
scale, and low dead time make the Model 3377 suitable for a wide range
of applications. The Model 3377 can be operated either in Common
Start or Common Stop mode with up to 16 measurements (16 edge
measurements, leading edge only, or leading and trailing edge) recorded
on each channel. The full scale time range is programmable up to
32 microseconds. The eight trigger outputs are programmable, and can
be used in either first or second level triggers. The multi event buffer
allows up to 31 events to be recorded before readout. The readout is
either over the CAMAC dataway, or by a FERA™ compatible high speed
ECL port.
PRODUCT DESCRIPTION
The 32 inputs are differential ECL, with a balanced 120 ohm termination.
Either the leading edge or both leading and trailing edge may be
recorded, with a double hit resolution of less than 10 nanoseconds. The
number of edge measurements recorded per channel is programmable
from 1 to 16.
The 3377 can be programmed to operate in either Common Start or
Common Stop mode with either single or double data word output
format.
The single word format packs 10 data bits (leading edge only, 9 bits if
both edges are recorded) into a 16 bit word, for low dead time drift
chamber applications. The programmable offset and resolution (500 ps
to 4 nsec LSB) allow the time range (255 nanoseconds to 4 microsec-
onds) to be placed as a window anywhere within the 32 microsecond full
scale.
The double word format preserves the full 16 bit time data for wide
dynamic range applications. The full scale time is programmable in
8 nsec steps up to 32.7 microseconds. The resolution is fixed at
500 picoseconds.
Eight dECL trigger outputs are provided at the rear panel. For trigger
purpose only, the input pulses are OR’ed together in groups of four (for
example: output 1 is the or channels 0, 1, 2, 3). In Common Stop
mode, the trigger outputs are programmable in width and delay, and can
be latched at the Stop time. In Common Start mode, the triggers are
latched.
The 3377 may be tested using an internal tester (Common Start mode
only). The number of pulses and the pulse duration are programmable.
At the end of acquisition (Common Stop or Common Start time out) the
data is unloaded from the MTD133s and stored in a multievent FIFO
buffer. The dead time is 1.8 microseconds plus 100 nsec per recorded
hit (200 nsec per hit when in double word mode).
The readout is by standard CAMAC or by the high speed ECL port. This
can occur in background, while the front end is recording data hits. A
PRODUCT DESCRIPTION
