Logo Caen



Shifter Register and Time Recorder


  • Intended for neutron counting applications with multiple detectors
  • Dedicated to Nuclear Safeguards and nuclear material process monitoring in its life cycle
  • 10 ns time stamp resolution
  • 10 ns of pulse pair resolution and minimum pulse width detection
  • 4 single-ended inputs on BNC connectors (TTL, 1000 Ω)
  • 18 differential inputs on DB37 connector (LVDS, 100 Ω)
  • High power high voltage supply output (+2000 V @1 mA)
  • High power low voltage supply output (+5 V @ 1.5 A)
  • microSD card slot for data logging in unattended operating
  • 10/100T Ethernet and USB 2.0 interfaces
  • Provided with readout software, SDK tool and web interface
  • 19” rack form factor and suited for stand-alone use as well


The R7773 device is a Shift Register and Time Recorder able to acquire neutron detector pulse trains through a total of 22 inputs composed of 4 single‐ended TTL (BNC) and 18 differential LVDS channels (DB37). It may provide the time-stamped list of pulses from neutron detector front-end electronics with 10ns pulse pairs resolution independently per each channel, shift register and multiplicity counter functionalities. The unit sampling clock is 100 MHz and each input has its independent buffer for signals acquisition. 

The device can operate in attended and unattended mode. When in unattended operating, the results of coincidence and multiplicity analysis are automatically stored on a removable microSD card to ASCII files that follow the same format as the INCC data files (Neutron Coincidence Counting Program from Los Alamos*) 

It is provided in mechanics compliant to 19” racks and can operated also stand-alone. The R7773 can connect to external host computers by point‐to‐point direct connection through the USB 2.0 link and by a remote network connection through the Ethernet 10/100T port. The internal CPU manages the board settings, the acquisition and the data transfer of the pulse train from each channel of the board to the host PC. The computational resources and data throughput allow the acquisition of a high total continuous input rate (up to 4∙106 cps in attendend mode by Ethernet). 

The device is equipped with high power outputs for multiple detector operation at once: HV output channel for the detector bias and LV output channel for powering the front-end electronics such as preamplifiers and discriminators. 

The R7773 is fully supported by CAEN ShiftRegister control software which configures the device and handles the data acquisition. In attended mode, the recorded pulse trains can be saved to binary files on the host computer for offline analysis (supported PTR-32 format compatible with the INCC software*). It is also possible to import stored pulse trains and to execute coincidence and multiplicity analysis in post‐processing. Users can take advantage of the provided CAENSR library for custom development. Firmware upgrade, file management and other useful functions are available through the integrated Web Interface. 

*INCC Software Users Manual: http://lib-www.lanl.gov/la-pubs/00326587.pdf 

Technical Specifications

From Factor 

1.25U wide
compatible with 19” rack


2300 g 


4 signal inputs 

Single-ended TTL (Zin = 1000 Ω) 

BNC socket 

Pulse width detected bigger than 10 ns 


18 signal inputs 

Differential LVDS (Zdiff = 100 Ω) 

DB37 socket 


High Voltage output 

SHV plug 


Low voltage output 

BNC jack receptacle 


Memory slot for microSD card 


USB2.0 communication port 

Type-B socket 


10/100T Ethernet port 

RJ45 shielded jack 

Power In 

100 ‐ 240 V 


Sigle channel for the detector power supply:
SHV plug
Output Bias Voltage (Vset) = 0 ÷ +2000 V DC
Output Bias Current (Iset) = 1 mA (max.)
Vset Resolution = 1 V
Vmon Resolution = 1 V
Imon Resolution = 1 μA
Ramp‐Up/Ramp‐Down = 1 ÷ 500 V/s in steps of 1V


Sigle channel for the detector power supply:
Output Bias Voltage (Vset) = 0 ÷ +2000 V DC
Output Bias Current (Iset) = 1 mA (max.)
Vset Resolution = 1 V
Vmon Resolution = 1 V
Imon Resolution = 1 μA
Ramp‐Up/Ramp‐Down = 1 ÷ 500 V/s in steps of 1V


Single channel for the preamplifier power supply:
+5 V @ 1.5 A (max.)


ARM Cortex‐A8 1 GHz (SDRAM Memory 512 MB DDR3L 800 MHz) running Linux Debian system


Attended and unattended


Removable 32GB microSD memory card for unattended operation
Raw data saved to ASCII files compatible with INCC data file format

  • Internal clock: 100 MHz
  • Pulse pair resolution: bigger that 10 ns
  • Power (LED, green)
  • HV ON (LED, red)
  • EXT MODE (LED, yellow)
  • Reset (button)

10/100 Mbps 

Compatible with IEEE 802.3u 100BASE-T standard 

Configuration, operation, and data taking in attended mode 


Version 2.0 

Configuration, operation and data taking in attended mode 

  • Windows® and Linux® support:
  • Drivers for the communication links
  • SDK tool including CAENSR library and demo code for custom development
  • CAEN ShiftRegister control software
  • Compatibility with INCC software
  • Web Interface (Board information retrieval, files management, firmware upgrade)

Integrated primary power supply unit 9-36V DC:
Voltage = 100 ‐ 240 V ∼
Frequency = 50/60 Hz
Current = 0.5 A RMS (max.)
FUSE = 2x T1A 6.3×32 250VAC

Ordering Options

Code Description
WR7773XAAAAA R7773 - Neutron Multiplicity and Time Recorder   RoHS