June 1, 2023
Report

A Radiation-Shielded, Shallow Underground, Long-Coherence Time Quantum Qubit Concept

Abstract

Ionizing radiation from ambient radioactivity has been shown to reduce the coherence time of superconducting qubits. Qubit performance can be improved by shielding the system from external radiation: operating the system underground to reduce cosmic rays, and use of lead shielding to reduce ambient gammas. Here we present a design for a lead shield optimized for a dilution refrigerator operating in PNNL's Shallow Underground Laboratory. The shield reduces the ambient gamma flux by approximately 99.8\%, so that cosmic ray muons dominate the ionizing radiation input to the qubits.

Published: June 1, 2023

Citation

Loer B.M., B.C. Archambault, E.S. Fuller, and B.D. Pierson. 2021. A Radiation-Shielded, Shallow Underground, Long-Coherence Time Quantum Qubit Concept Richland, WA: Pacific Northwest National Laboratory.