Pxs on Joe Wiedemann

PXS Microwave Electronics

Sun, 15 Feb 2026 00:00:00 +0000

PXS Electronics Work

As we develop new state-of-the-art amplifier technology for sub-GHz bands, we have needed to develop supporting infrastructure for the auxillary components that make up the rest of our read out chain. Two of the standout infrastructure pieces has been designing room-temperature analog circuitry that controls a cryogenic multi-pole switch, and designing superconducting lumped-element diplexers. This work is complimentary to the effort to develop high quality coaxial cable - see more on that work in PXS Coax Development.

PXS Cryogenic Coax Development

Tue, 20 Jan 2026 00:00:00 +0000

Coaxial Cable and PXS Readout

High-quality cryogenic coaxial cable is critical to sensitive microwave experiments. While the expanding market in support of quantum computing has introduced numerous commericial solutions for bulk and/or high-density cable, these offerings remain expensive and require a priori knowledge of the system design. By developing laboratory methods to fabricate our own cable I was able to reduce lead times and cost, achieve greater freedom in our RF system design, and provide bespoke-level focus that has resulted in leading systematic performance.

Passive pyrolytic graphite heat switch for sub-Kelvin coolers

Fri, 18 Apr 2025 00:00:00 +0000

Abstract

We describe a passive heat switch based on a commercial pyrolytic graphite sheet. Measurements of the thermal conductivity of the graphite are presented, confirming a large difference between room temperature and ≈4 K. The implementation of a graphite heat switch in a cryostat operating a 3He/4He sorption refrigerator is demonstrated.

Achievements

Improved the cooldown time for the 3He stage by 50% with inexpensive graphite sheet
Demonstrated the ‘off’ state of the switch applied only microwatts of heat load
Proved durability through 10+ room temperature-cryogenic cycles
Able to reduce the number of expensive gas-gap heat switches needed to conduct experiment

Links

This publication is based on research conducted in PXS Cryogenics.

PXS Software Development

Mon, 10 Mar 2025 00:00:00 +0000

PXS Software needs

Because the Princeton Axion Search is a new lab at the university, we have had to develop the infrastruture that enables the scientific research. We strongly value flexibility and control, so we opt for open source or homebrew solutions whenever possible. Particularly in the context of a research lab, designing systems that work across various operating systems, integrate with numerous decades of technology, and can are maintainable has proven to be an excellent opportunity to learn about system design.

PXS Cryogenics

Wed, 10 Apr 2024 00:00:00 +0000

PXS Cryogenic Requirements

The haloscope axion experiment model requires superconducting magnet technology, as well as quantum-limited readout. We have had the fortunate ability to develop the sub-systems independently. Each system has unique demands to work cryogenically. The magnet requires hundreds of amps to be delivered at 4 Kelvin, all while being cooled exlcusively through conduction mechanisms. For the readout development, we have had to design and commision a custom cryostat with a base temperature of 270 milli-Kelvin, as well as integrate testing equipment into a Dilution Refrigerator for device testing that requires the 10 milli-Kelvin base temperature.