UHF-CNT Pulse Counter

The UHF-CNT Pulse Counter features analysis of up to 4 pulse trains in parallel, enabling event based measurements, e.g. photon detection using photo-multiplier tubes. There are five distinct modes of operation and each channel offers an adjustable discriminator. The maximum count rate is 225 MHz. Measurement results from the pulse counters can be conveniently analyzed with the LabOne® toolset, which features time domain and histogram display. Through the cross-domain trigger engine, branching conditions for the UHF Arbitrary Waveform Generator can be defined based on counter values, enabling ultra-fast feed-forward loops for quantum error correction.

UHF-CNT Key Features

  • 4 counter modules
  • 225 MHz maximum count rate
  • 5 modes: manual, triggered, free, gated and pulse tagging
  • 4 signal inputs with adjustable discriminator level
  • Background subtraction using 2 counter modules
  • Count integration

UHF-CNT Upgrade and Compatibility

  • Option upgradeable in the field
  • Compatible with all other UHF options

UHF-CNT Applications

  • Quantum optics
  • Trapped ion experiments
  • Diamond N/V center experiments
  • Phosphorescence Lifetime Imaging (PLIM)

UHF-CNT Functional Diagram

UHF-CNT Description

The UHF-CNT Pulse Counter enables measurement of randomly distributed pulses and can operate with the following modes:

  • Free running mode: the counter runs in repeated periods defined by the a configurable timer. At the beginning of each period the counter is reset, and at the end, the accumulated number of counts is output.
  • Gated mode: the counter is controlled with the gate input signal. The counter is enabled at the rising edge of the gate input signal and disabled at the falling edge. The accumulated number of counts is output on the falling edge of the Gate Input signal.
  • Gated free running mode: similar to the free running mode, but additionally the Gate Input signal controls when the counter is allowed to run. The counter as well as the timer is reset when the Gate Input signal is low.
  • Time tagging: every single event is counted and transmitted to the host computer along with a time tag. 

All modes feature background subtraction, i.e. taking into account measurement values from two separate counters, and count integration over time. Via the 1GbE or USB interface, the counter data can be streamed to the host PC where they can be analyzed using the LabOne toolset.

In combination with the UHF Arbitrary Waveform Generator the UHF-CNT features advanced cross-triggering functionality for complex pulsed experiments in quantum optics. Counters can be initiated and reset by the UHF AWG, and vice versa, counter values can serve as a trigger or branching conditions for the UHF AWG. 

UHF-CNT Specifications

signal inputs 4 Trigger Inputs, 32 DIO
# counter modules 4
counter value depth 32 bit (4.29 Gcounts)
maximum count rate 225 MHz
time resolution 4.44 ns
run modes manual, triggered, free-running, gated, pulse-tagging
signal input impedance 50 Ω/1 kΩ
dead time between periods <30 ns
signal input (discriminator) range –2.5 V to +2.5 V (50 Ω input impedance)
–5 V to +5 V (1 kΩ input impedance)
signal input (discriminator) resolution <0.2 mV
signal input (discriminator) hysteresis 100 mV


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