N1568A

The CAEN Mod. N1568A is a 16 channel Programmable Spectroscopy Amplifier and Dual 16Ch CFD (30% and 80% constant fraction) implemented in a single-width NIM module.
This module is designed to be used with silicon detectors connected to charge preamplifiers, where the measure of charges collection time allows to obtain the identification in Z of the particles caught by the detector. The rise time is measured via two constant fraction discriminators (30% and 80% of rise time respectively).

Each channel is composed by two sections: Energy section (A) and Timing section (B). The input signal is sent to both sections simultaneously. Section A processes the input signal with a differential circuit, followed by the gain stages (coarse: 2 bit; fine: 8 bit), and finally by the shaping.
Section B processes the signal with a low noise differential stage (500 ns) followed by a 2 bit programmable linear gain stage; the signal is then fed to two low walk and high resolution Constant Fraction Discriminator sections (30% and 80% constant fraction respectively).

The discriminators share a 8 bit common threshold; the discriminators delay is adjustable via PCB jumpers (6 steps from 15 to 150 ns).
The RS485 interface allows to handle most functional parameters such as Shaping Time, Coarse and Fine Gain, Input Polarity, CFD Thresholds, Pole Zero Adjustment etc.