CX-4 – Cryogenic Super Low Noise Amplifier

The new CX-4 is an ultra-low noise FET preamplifier, operating in room temperature down to deep cryogenic environments (T = 4.2 K, liquid helium). It is an improved version of its predecessor NexGen3 KC05.

The setup is easy: simply connect the signal and bias voltages to the controller and you are ready to go. The CX-4 is designed for fully-automated plug-and-play functionality.

Key Features
Ultra low input noise (typ. 0.31 nV/√Hz @ 1 MHz)
Frequency range 1 kHz to 4 MHz or 14 kHz to approx. 30 MHz
Input impedance > 15 MΩ
Small size and tiny thermal load of only 300 μW per channel
Fully-automated plug-and-play room temperature controller included!

An example of the application of CX-4 are measurements of excess noise in the anomalous metallic phase in amorphous indium oxide by André Haug and Dan Shahar at the Weizmann Institute of Science, Israel, published 16 January 2024 in Phys. Rev. B 109, 014514:
DOI:10.1103/PhysRevB.109.014514, pre-print: https://arxiv.org/abs/2305.15931

The development of CX-4 has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 721559.

The 30 MHz version

Illustration of connecting a sample to the amplifier’s inputs. Short silver-plated wires for the electrical signal connection, brass or aluminium screw for tight mechanical GND contact.

Amplification at cryogenic temperature as function of the frequency, expressed in dB relative to the amplification factor at f = 100kHz. The data set comprises the cryogenic amplifier (at 5.6K) including the biasing section with 50 Ohm load.

Input Voltage Noise Density at 300K and at 4.2K in a cryogenic vacuum chamber

The room temperature controller indicates the status of the cryo amplifier and allows for setting the overall amplification factor. (current model subject to changes)

Easy setup by simply connecting signal and bias voltages to the controller

30 MHz version on a turntable

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