Logo Caen

V812

16 Channel Constant Fraction Discriminator

Features

  • Thresholds individually programmable via VME
  • Constant fraction for precise discrimination timing
  • ECL outputs with fan-out of two
  • Programmable output width
  • Global VETO and TEST inputs
  • Mask register for individual channel enable/disable
  • OR, CURRENT SUM and MAJORITY outputs
  • Libraries (C and LabView) and Software tools for Windows and Linux

Overview

The CAEN Mod. V812 is a 1-unit wide VME module housing a 16 channel constant fraction discriminator. The module accepts 16 negative inputs and generates precise ECL pulses when the input signals exceeds a given threshold: constant fraction technique allows to precisely determine the timing of the discrimination. The pulse forming stage of the discriminator produces an output pulse whose width is adjustable in a range from 12 ns to 206 ns (typical values) via VME.

Moreover, in order to protect against multiple pulsing, it is possible to program via VME a dead time, from 118 ns to 1625 µs (typical values) , during which the discriminator is inhibited from retriggering. The discriminator thresholds are individually settable via VME in a range from -1 mV to -255 mV (1 mV step) through an 8-bit DAC. Each channel can be turned on or off via VME by using a mask register. A Current Sum output 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). The module can operate also with small (below 10 mV) input signals. A MAJORITY output provides a NIM signal if the number of input channels over threshold exceeds the MAJORITY programmed value. Several V812 boards can be connected in a daisy chain via the Current Sum output: in this case, by switching the majority logic to External, it is possible to obtain a Majority signal when the number of active channels in the chained modules exceeds a global Majority level. The logic OR of discriminator outputs is available on a front panel NIM signal.

Technical Specifications

Packaging

6U-high, 1U-wide VME unit

Inputs

16 inputs (negative polarity, 50 Ω impedance)

Max input voltage

-5 V

Min detectable signal

-5 mV

Threshold range

-1 mV to -255 mV (1 mV step)

Constant fraction

20%

Delay

20ns full scale with 4 ns steps (8 ÷ 20 ns operating range)
Optional:

  • 5ns full scale with 1ns steps (4 ÷ 5 ns operating range)
  • 50ns full scale with 10ns steps (10 ÷ 50 ns operating range)
  • 100ns full scale with 20ns steps (20 ÷ 100 ns operating range)
Outputs

16 ECL outputs with a fan-out of two

Input/output delay

Set delay + 4.5 ns ± 2 ns

Output width

Programmable from 12 ns to 206 ns (typical value)

Dead Time

Programmable from 118 ns to 1625 ns (typical value)

Max outputs time walk

±400 ps for input signals in the range from -50 mV to – 5 V with 25 ns rise time

Autowalk

Automatic adjustment of input offset and low frequency input noise of ±40 mV

Control inputs

NIM logic signals, high impedance: VETO: allows to veto all channels simultaneously TEST: triggers all the enabled channels at once

Control outputs
  • VETO IN: NIM signal, high impedance, allows vetoing of all channels simultaneously
  • TEST IN: triggers all the enabled channels at once
  • OR OUT: standard NIM signal, 50 Ohm impedance, logic OR of outputs;
  • SUM OUT: current proportional to input multiplicity (-1 mA ±20% per hit), high impedance

Compare

Compare with Discriminators.

Loading...

Accessories

A954
Cable assembly 2.54mm 34 pin female to two 2.54mm 16 pin female - 50 cm
A385
Adapter 2.54mm 34-pin female to 16x LEMO 00 female (or MCX male) – 50 cm / 1 m

Ordering Options

Code Description
WPERS0081201 V812 Customization - Delay 100ns   RoHS
WPERS0081202 V812 Customization - MSU Delay 5ns   RoHS
WPERS0081203 V812 Customization - Delay 50ns   RoHS
WV812XBAAAAA V812B - 16 Channel Constant Frac. Discriminator (No JAUX)   RoHS

Contacts

Great to have you back!