Document type:
Title:
Revision date:
Revision:
User's Manual (MUT)
Mod. N957 8k Multi-Channel Analyzer
28/05/2012
6
NPO:
Filename:
Number of pages:
Page:
00105/04:N957x.MUTx/06 N957_REV6
35
6
1. General description
1.1 Overview
The Mod. N957 is a 8k Multi-Channel (MCA) with USB port, housed in a 1-unit wide
standard NIM module. The multichannel analyzer performs the essential function of
collecting the data and producing output, in the form of converted value of input peaks.
The input pulses can be those produced by a standard spectroscopy ampli
fi
er. They can
be Gaussian, semi-Gaussian or square waves, unipolar (positive) or bipolar, in a range
from 0 to 10 V, with a rise time greater than 0.1 µs.
The trigger can be made “on signal” (Auto Gate mode) or “external” (External Gate
mode). In the
fi
rst case a discriminator, with a settable threshold, enables the conversion.
In the second case, an external gate is fed to the module, via front panel GATE In
connector.
The input channel has one peak amplitude stretcher, the output of which is digitised by a
13 bit fast (0.8
s) ADC featuring a sliding scale technique, to improve the differential
non-linearity. Converted waveforms are stored into a 64 KSamples buffer memory.
The unit hosts an USB2.0 port (also compatible with USB 1.1), which permits a simple
control and data-acquisition via PC.
Software Libraries, available for both Windows and Linux platforms, are described in § 5.
Future firmware upgrade is possible via USB; only tools developed by CAEN must be
used for the firmware upgrade.
N957 CONTROLLER
(ALTERA CYCLONE EP1C6)
CHANNEL
CONTROLLER
(MAX7032S)
ANALOG FRONT-END
(TRACK-HOLD/PULSE
STRETCHER)
USB
PERIPHERAL
CONTROLLER
ACQUISITION
MEMORY
(SRAM 64Kx16)
USB
CONV
PUR
BUSY
OUTP
ANALOG
IN
GATE
IN
Fig. 1.1: Mod. N957 Block Diagram
