L3377 TDC

The LeCroy CAMAC Model 3377 is a 32-channel Multi-hit 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.

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 ORed 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).

For more information, please see the manual.