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N6781

Dual/Quad Digital Multi Channel Analyzer - NIM

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Features

  • Dual or Quad Independent 16k Digital MCA in 1U NIM module
  • Suited for high resolution digital nuclear Spectroscopy
  • Fully controlled by the MC2 Analyzer and CoMPASS Software
  • Selectable Input Dynamic Range and adjustable Digital Fine Gain
  • Features DPP-PHA firmware for energy and time stamp calculation
  • Digital oscilloscope function for an easy setup and signal monitoring
  • Counting Rate up to 1 Mcps
  • USB and Optical Link communication interfaces
  • Drivers, libraries and API for Windows and Linux 32/64-bit
More info
3 Years Warranty
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Overview

The CAEN Mod.N6781 is a a 1-unit wide standard NIM module integrating 4 Independent 16k Digital MCA for digital nuclear Spectroscopy. A version with 2 independent 16k MCA is also available (N6781A). It is ideally suited for high energy resolution semiconductor detectors, like HPGe and Silicon, connected to a Charge Sensitive Preamplifier (CSP) but it can also properly work directly connected to a PMT with inorganic scintillators (Nal, Csl) and other types of crystal, provided that the pulse shape is exponential and the decay time is long enough (typ. > 200 ns).

The module houses 4x (or 2x) 100 MS/s 14-bit waveform digitizer (based on 724 series) on single-ended inputs with BNC connectors, featuring 4-step software configurable input range and adjustable DC offset via a 16-bit DAC on each input in the full range.

The N6781 is equipped with a FPGA featuring the real-time Digital Pulse Processing for Pulse Height Analysis (DPP-PHA firmware) making the module a spectroscopy acquisition system providing energy (i.e. pulse height) and timing information as well as portions of the waveform and other traces for the fine tuning of the PHA settings.

Thanks to its two independent inputs of simultaneous acquisition, the N6781 is able to manage coincidences and anticoincidences between a pair of detectors, allowing the user, for example, to easily take advantage of background rejection or anti-Compton techniques.
The module has been designed to operate as a scalable multi-input, multi-board acquisition system, offering synchronization capabilities.

The N6781 houses USB 2.0 and Optical Link interfaces. USB 2.0 allows data transfers up to 30 MB/s. The Optical Link supports transfer rate of 80 MB/s and offers Daisy-chain capability. Therefore, it is possible to connect up to 8/32 MCA modules to a single Optical Link Controller (Mod. A5818/A4818).

Operating modes:

  • “Pulse Height Analysis (PHA)”: pulse height histogram (1k-2k-4k-8k-16k) built at software level.
  • “List mode”: pulse height and time stamp for each event.
  • “Oscilloscope” mode: input and internal filters waveforms.

Software available (Windows and Linux):

CAEN provides drivers for all the different types of physical communication channels, a set of C and LabView libraries (CAENComm, CAENDigitizer, CAENDPP), demo applications and utilities:

  • CAENUpgrader: tool that allows the user to update the firmware of the digitizers, change the PLL settings, load, when requested, the license for the pay firmware and other utilities.
  • MC² Analyzer: Digital MCA Data Acquisition and Analysis Software designed for CAEN Digital Multi Channel Analyzers and Digitizers running Pulse Height Analysis (Windows only).
  • CoMPASS: Multiparametric DAQ Software for Physics Applications designer for CAEN Digitizers running Pulse Shape Discrimination and Pulse Height Analysis, CAEN Pulse processors and MCAs.

Technical Specifications

Mechanical

Dimensions: 1-unit wide NIM
Weight: 1000 g (N6781 version)

Analog Input
Input Features

  • BNC connector
  • Single-ended, DC coupled
  • Impedance: 1 kΩ
  • Positive and negative signals accepted
  • Programmable 4-step analog coarse gain (x1, x3, x10, x33) corresponding to 10Vpp-3Vpp-1Vpp-0.3Vpp
  • Bandwidth: DC to 5 MHz
  • Programmable DC offset adjustment on each input in the full scale range
 Number of Inputs

  • 4 inputs: DT5781
  • 2 inputs: DT5781A
ADC

Resolution: 14 bits
Sampling rate: 100 MS/s simultaneously on each channel

Digital Signal Processing
  • Trapezoidal filter for the energy calculation with adjustable rise time in the range 0 – 10µs and flat top in the range 0 – 5µs
  • Manual and automated trigger threshold adjustment
  • Manual and automated Pole-Zero cancellation; decay time up to 6.5 ms
  • Digital decimation in steps of 2-4-8 allows to extend the time parameters range
  • Digital fine gain
  • Pile-up rejection and Live Time correction
  • Baseline restorer with programmable averaging
  • Trigger and Timing filter based on integrative-derivative component
  • Time Stamp: 10 ns resolution, 31 bit and rollover tracking event
  • Adjustable moving average low pass filter to reduce the high frequency noise
Operating Modes
  • Pulse Height Analysis (PHA): pulse height histogram (1k-2k-4k-8k-16k) built at software level
  • List mode: pulse height and time stamp for each event
  • Oscilloscope mode: input and internal filters waveforms
Trigger Modes
  • Uncorrelated: each channel operates independently (based on channel self-trigger)
  • Correlated: coincidence/anticoincidence among channels and/or an external trigger (TRG-IN)
  • External: channels are triggered by external trigger only (TRG-IN)
Front Panel Digital I/O
CLK-IN (AMP Modu II)
AC coupled differential Input Clock: LVDS, ECL, PECL, LVPECL, CML (single ended NIM/TTL available by orderable cable); Jitter<100ppm requested; can be used as external clock reference for single board or to synchronize the clocks of multiple boards, provided through a Fan InGPO (LEMO)
General Purpose Output: NIM/ TTL, Zin = 50 Ω
Can be used to propagate the global trigger in multi-board synchronization (in combination with TRG-IN), as output register or Run ON/OFF status		 GPI (LEMO)
General Purpose Input: NIM/TTL, Zin = 50 Ω
Can be used as SYNC/START in multi-board synchronization or Run ON/OFF Control		 TRG-IN (LEMO)
External Trigger Input: NIM/TTL, Zin = 50 Ω
Can be used to force the event acquisition from all the channels of the board, to gate/veto the individual channel triggers, or to propagate the common trigger in multi-board synchronization (in combination with GPO)
Communication interface
Optical Link

  • CAEN CONET proprietary protocol Up to 80 MB/s transfer rate
  • Daisy chain capability: it is possible to connect up to 8 or 32 ADC modules to a single Optical Link Controller (A2818 or A3818 respectively)
 USB

  • USB 2.0 compliant
  • Up to 30 MB/s transfer rate
Firmware

Firmware can be upgraded via USB/Optical Link

Software

Fully controlled by CoMPASS and the MC² Analyzer spectroscopy Software
For developers: general purpose C libraries with demo samples available

Power Requirements
N6781 (Typ.)
+6 VDC (Typ): 3.3 A
-6 VDC (Typ): 100 mA
+12 VDC (Typ): 280 mA		 N6781A (Typ.)
+6 VDC (Typ): 2.5 A
-6 VDC (Typ): 80 mA
+12 VDC (Typ): 120 mA
Environmental

Operational Conditions
0 – 50°C Temperature Range – EMC compliant

Compare

Compare with Multi Channel Analyzers.

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Accessories

A317
Cable assembly for Clock distribution 3-pin AMPMODU IV female terminations – 18 cm / 25cm
A318
Adapter for Clock signal FISCHER S101A004 male to 3-pin AMPMODU IV female – 10 cm
A386
AC coupler BNC female to BCN male
A387
Input Filter cable BNC female to BNC male – 25 cm
DT4700
Clock Generator and FAN-OUT
A1422
Low Noise Fast Rise Time Charge Sensitive Preamplifiers (Boxed)
A1424
Scintillation Preamplifier

Ordering Options

Code Description
WN6781AXAAAA N6781A - Dual Digital MCA   RoHS
WN6781XAAAAA N6781 - Quad Digital MCA   RoHS

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