Superconducting Cloud Chamber

Abstract

We propose a new particle-trajectory detector composed of Josephson junctions, named the superconducting cloud chamber. By measuring the quantum phase difference, this device can detect charged particles with extremely low kinetic energy, providing a new method for detecting slow-moving particles. It can also be utilized to detect millicharged dark matter particles thermalized with the Earth's environment within the mass range of $10^3\sim 10^{10}\,$GeV.

Figures (5)

• Figure 1: Schematic diagram illustrating the detection of moving charged particles by an RF-SQUID. The particle trajectory is at a distance $d$ from the insulator with angle $\theta$.
• Figure 2: A schematic representation of a multiplexed readout module for the superconducting cloud chamber. The module comprises multiple microwave resonators capacitively coupled to a common microwave feedline. Each resonator is modulated by its own RF-SQUID, which serves as the fundamental particle detection unit. The RF-SQUID is inductively coupled to the load impedance of the quarter-wave resonator. The microwave signal transmitted through the feedline is amplified by a HEMT amplifier. A common flux-ramp modulation line is applied to all RF-SQUIDs to linearize their responses.
• Figure 3: The schematic diagram of the superconducting cloud chamber. Each cube represents a basic detection unit shown in Fig.1, forming a 3D array with a spacing of $D$ between adjacent units. When a charged particle passes through the cloud chamber, it excites pulsed signals in JJs surrounding its trajectory.
• Figure 4: A schematic illustration of a particle passing through the superconducting cloud chamber (local view).
• Figure 5: The projected sensitivity of superconducting cloud chamber on millicharged DM assuming the $\text{SNR} = 10$, shown as the different colored shaded region depending on if the DM is thermalized or not. The constraint from collider is the grey shaded region, while the constraints from ion trap experiments are blue solid and green dashed lines depending on the DM fraction. The sensitivity by assuming $\text{SNR}=1$ is also presented as the red dashed line.