SQUID G.A.M.E. – testing quantum devices using multiple techniques
06 Mar 2026
Researchers from the University of Trento, in collaboration with staff from ISIS and Los Alamos National Laboratory, have used multiple irradiation techniques to test the resilience of a fundamental superconducting quantum device.
Superconducting Quantum Interference Devices (SQUIDs) are becoming increasingly popular in the commercial sector as scalable, fast and efficient manipulators of encoded information. However, they have a high susceptibility to noise and radiation. Shielding against noise is already being applied, but their resilience to radiation is not fully understood.
This study, published in IEEE Transactions on Nuclear Science, aimed to address this by exposing a SQUID to Gamma rays, as well as Atmospheric and Mono-Energetic neutrons (hence the abbreviation SQUID G.A.M.E.). The ChipIr instrument at ISIS replicates atmospheric neutron exposure, with NILE able to provide mono-energetic neutrons.
Quantum devices such as SQUIDs measure magnetic fields with high precision and can also be used to encode a superposition of states. These states are physically encoded into two-level quantum systems, which can be built by exploiting different technologies including, as in a SQUID, superconducting circuits. Quantum states implemented using superconducting quantum devices are extremely prone to decoherence by intrinsic or external factors such as radiation.
SQUIDs are the most basic superconducting quantum devices that share the same working principle with the Quantum bits (Qubits) that are actually used in modern quantum computers. Understanding the basic effects of radiation on SQUIDs is, then, the first step to move towards understanding the impact of radiation on qubits.
As a SQUID’s original purpose is to measure magnetic fields with extreme precision, it is highly sensitive to external electromagnetic fields. The team had to develop an experimental setup that could be used to characterise how radiation affects the SQUID in the absence of varying magnetic fields. To provide the full picture of the reliability problem on fundamental quantum devices, the group also used computer simulation to validate their experiments.
Our experiments showed two categories of transient radiation effects: burst-type and peak-type. Burst-type cause a long perturbation of current and voltage, while peak-type effects are a shorter variation of the two channels.
Paolo Rech, from the University of Trento
“Our experiments showed two categories of transient radiation effects: burst-type and peak-type,” explains Paolo Rech, from the University of Trento. “Burst-type cause a long perturbation of current and voltage, while peak-type effects are a shorter variation of the two channels.”
They noticed that these radiation effects occurred at different frequencies, depending on the irradiation environment. At NILE, peak-type faults were rarely recorded but, on the contrary, at ChipIr they represented 60% of the total events.
In addition to neutron radiation, at both NILE and ChipIr, gamma radiation is present. According to the team’s simulations, gamma rays could also induce transient effects in quantum devices. It is then necessary to better distinguish between effects of gamma rays and neutrons. To do so, the researchers took the SQUID to CALLIOPE at ENEA, in Rome, Italy, to irradiate the device with only gamma rays.
“We did not observe any gamma-ray-caused transient effects at CALLIOPE,” adds Gioele Casagranda from the University of Trento. “However, there might have been a long-lasting gamma induced effect since, when we returned to ISIS to repeat our neutron experiments, we found a stark increase in the device’s sensitivity to external stimuli to the extent that even basic measurements became almost impossible.”
Their study shows that neutron facilities such as NILE and ChipIr can be used for testing quantum devices, as well as showing the effect of both neutron and gamma radiation on a SQUID. At the end of March 2026, the team will bring their quantum devices to ISIS for muon experiments and to repeat the neutron test with an improved setup.
In the future, the group aim to develop a setup where a cryostat that lowers the temperature further can be used during the irradiation experiments.
The full paper can be found at DOI: 10.1109/TNS.2026.3657307
