Fast Pre-Test Screening Cryogenic Facility for speeding up the Development of Quantum Sensors

Lead Research Organisation: University of Oxford
Department Name: Oxford Physics

Abstract

This proposal seeks support to acquire a fast-screening cryogenic system to speed up the development of quantum sensors for supporting the project "Quantum Sensing for the Hidden Sector" (QSHS, ST/T006277/1), comprising 7 UK research institutes including the University of Oxford.

The development of ultra-sensitive quantum sensors can be benefited hugely from a fast-screening procedure, identifying potential design flaws and fabrication defects quickly, and allowing the researchers to pre-select promising candidate devices to be brought forward for full characterisation measurements. During the fabrication stage, depending on the design of the devices and the complication in the fabrication steps, the yield may not be high, particularly in the exploratory stage. Furthermore, post-fabrication, there are still many delicate steps required before the performance of these quantum devices can be assessed experimentally. These post-fabrication handling stages can be hazardous, potentially causing damage to the devices. As the process of mounting and testing individual devices is time-consuming, it is, therefore, more effective to perform a simple DC and RF screening to identify which of the hundreds of devices on each wafer are most promising for further investigation.

A fast-screening cryogenic system would allow up to 20-50 times faster throughput in sample characterisation, therefore significantly speeding up the developments of cryogenic superconducting quantum devices. In this application, we seek support to acquire a sub-Kelvin system with the wiring setup customised specifically to suit our fast-screening purpose, with the flexibility to host different types of quantum devices. Such a system can be acquired from a commercial supplier, providing fast cooling down time to the sub-Kelvin environment and a long hold time for the screening process. The system will have the capability to DC test up to 40 devices and RF test 12 devices in a single cooldown cycle. It would also be equipped with an additional set of RF cables for in-situ full nonlinear RF characterisation with appropriate microwave and RF components for full device characterisation.

This application applies for funding to cover only the cost of the fast-screening cryogenic system. The build of accompanied electronics and the microwave components required for the in-situ measurement will be covered by the existing grant.

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