N844

Overview

The CAEN Mod. N844 is an 8 Channel Low Threshold (leading edge type) Discriminator housed in a one unit wide NIM module. The module accepts 8 negative inputs and produces 2×8 NIM outputs (NIM outputs are provided with a fan-out of two) +8 /NIM outputs (negated) on front panel LEMO 00 connectors. The pulse forming stage of the discriminator produces an output pulse whose width is adjustable in a range from 6 to 95 ns. The discriminator thresholds are individually settable in a range from -1 mV to -255 mV (1 mV step), via an 8-bit DAC; a positive input version (Model N844P), with the thresholds settable in the 1 mV to 255 mV range, is also available. The minimum detectable signal is -3 mV. The back panel houses VETO and TEST inputs, the logical OR output (the relevant OR LED lights up if at least one channel is over threshold) and the Current Sum output, which generates a current proportional to the input multiplicity, i. e. to the number of channels over threshold, at a rate of -1.0 mA per hit (-50 mV per hit into a 50 Ω load) ±20%.