CAEN C207 16 Channel Programmable Discriminator

OVERVIEW

The CAEN Model C207 is a 16 Channel Programmable Discriminator housed in a 1-unit wide CAMAC module.

The module accepts 16 negative inputs via 16 front panel LEMO 00 type connectors (INPUTS 0 to 15) and produces 16 differential ECL outputs (with a FAN-OUT of two for each channel) that are available on two front panel flat cable connectors (OUTPUTS 0 to 15 A and B).

Each channel consists of a discriminator on a hybrid circuit and an 8-bit DAC for the threshold setting.

The Timing Stage of the discriminator works in UPDATING mode. It produces an output pulse whose width is independent from the input signal time over threshold and adjustable in two ranges via the front panel common trimmer WDT (16 internal jumpers, one per channel, allow the range setting).

The module's operations can be controlled either via CAMAC or locally. A front panel "LOC" LED indicates when lit that the module is controllable locally. A back panel switch disables the REMOTE operations and sets the module in LOCAL mode ("LOC" LED is ON).

Each channel has its own discriminating threshold programmable via CAMAC, and can be turned on or off via CAMAC by using a mask Register (Pattern of Inhibit). The thresholds can be set in a range from 0 mV to -510 mV (-2 mV step), though for proper functioning a minimum threshold of -6 mV is required.

In LOCAL mode a common threshold can be set and monitored respectively via front panel trimmer and test point. Moreover, the Pattern of Inhibit is disabled (all channels are enabled) and the CAMAC functions are ineffective.

Some operations can be also performed using two external NIM signals (indicated on the back panel connectors with "VETO" and "TEST"):

VETO: an input signal sent through this connector allows vetoing of all channels simultaneously. A veto pulse of width T will veto the input during this time T.
TEST: a pulse sent through this connector triggers all the enabled channels at once (all channels in LOCAL mode). This useful feature allows a complete test of the module without removing any input cable as well as it allows generation of a pattern of pulses suitable to test any following electronics.

These are high impedance inputs and each one is provided with two bridged connectors for daisy chaining.

On the front panel there is also available a Current Sum output that 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 W load) ±10%.

An "OR" output signal on a front panel connector provides a global OR of the Shaped Outputs.

An "OR" LED lights up if at least one of the unmasked channels is over threshold.

CHARACTERISTICS OF THE SIGNALS

Inputs:

INPUT CHANNELS:: negative polarity, 50 W impedance;
maximum absolute ratings: ± 5 Volts;
input offset voltage: ± 5 mV;
reflections < 4% for 2 ns risetime pulses.
THRESHOLD:: -6 mV to -510 mV, 2 mV step in programmable mode,
continuous set in Local mode via front panel trimmer;
monitor test point on front panel with range +6 mV to +510 mV.
VETO(*):: std. NIM level, high impedance;
minimum width: 10 ns;
veto leading edge must precede of at least 7 ns the input leading
edge and overlap completely the input signal.
TEST(*):: std. NIM level, high impedance;
maximum frequency: 125 MHz;
minimum width: 5 ns.
terminated on 50 W
have thus to be properly matched.

(*) These inputs are at high impedance and each one is provided with two bridged connectors for daisy chaining. Note that the high impedance makes these inputs sensitive to noise, so the chains have to be on the last module; the same is needed also if one module only is used, whose inputs

Outputs:

CHANNELS:: differential ECL level into 110 W twisted-pair;
pulse width continuously adjustable via trimmer in two ranges:
· 4 - 40 ns (approx.);
· 40 - 300 ns (approx.);
range selection via internal jumpers;
Input/Output delay: 8 ±1 ns;
Test/Output delay: 13 ns;
Risetimes and Falltimes: < 3 ns.
CURRENT SUM (S):: high impedance current source;
current proportional to the input multiplicity;
rate: -1.0 mA per hit (-50 mV/hit into a 50 W load) ±14%
offset: -60 mV approx. (no channel over threshold).

General

Double pulse resolution: 7.5 ns.
Maximum frequency: 125 MHz.
Interchannel isolation: better than 50 dB.
Time slewing < 400 ps for input amplitudes from 2x to 20x over threshold.
Power Requirements:: - 24 V25 mA; + 12 V15 mA; - 12 V30 mA; + 6 V500 mA; - 6 V3.4 A

CAMAC Commands

X response is generated for each valid function.
Q response is generated in REMOTE Mode only for each valid function unless otherwise specified.

F(0) N A(0-15)	Reads the Discriminator Thresholds on R1..R8 (Q response also in LOCAL mode).
F(1) N	Reads the Pattern of Inhibit on R1..R16 (Q response also in LOCAL mode).
F(2) N	Tests the module activity and clears the Q line. Q response if at least one channel is over threshold.
F(16) N A(0-15)	Writes the Discriminator Thresholds on W1..W8.
F(17) N	Writes the Pattern of Inhibit on W1..W16.
F(25) N	Common Test.
I	Vetoes the channels via CAMAC.
F(9) N, C, Z	Resets the module

The Whole C207 User's Manual:

in PDF

in PS