High-Pressure TPC System Based on Micromegas: Technological Breakthroughs and Frontier Applications in Rare Event Detection
In high-energy physics experiments, particularly in the exploration of rare events such as neutrinoless double beta decay and direct dark matter detection, the development of detector systems with high spatial resolution, superior energy resolution, ultra-low radioactive background, and long-term operational stability is critical. The high-pressure time projection chamber (HP-TPC) system based on micromesh gas detectors (Micromegas) has emerged as a pivotal solution in this field due to its unique technical advantages.
PandaX-III-Inspired Low-Background HP-TPC Solution
The low-background high-pressure Micromegas detector solution developed for the PandaX-III neutrinoless double beta decay experiment integrates 52 low-background Micromegas detectors, each with a sensitive area of 194×194 mm², to form the cylindrical TPC readout plane. The system operates at a final working pressure of 10 bar, demonstrating structural robustness and performance stability under extreme conditions.
Key Innovations in Low-Background HP-TPC Detectors
Building upon traditional Micromegas detectors, the following advancements have been implemented:
Material Optimization: Replacement of conventional FR4 anode plates with polyimide-based flexible anode plates combined with high-purity oxygen-free copper backing plates. This modification reduces radioactive background at the material level.
Manufacturing Process: Adoption of a novel printed thermal bonding method to replace traditional hot-rolling lamination. This enhances pressure tolerance and operational stability, enabling stable high-gain operation under high-pressure conditions.
Structural Refinement: Implementation of narrow-edge design and polishing techniques to achieve compact geometry and improved energy resolution.
Applications and Prospects
The Micromegas-based HP-TPC system provides a highly sensitive and reliable solution for rare event detection. Its technological advancements also create new opportunities for cross-disciplinary applications, including nuclear safety monitoring and medical imaging. Continuous optimization of this platform positions it as a vital tool for future high-energy physics research and practical implementations.
Technical Parameter
1. Detector area: 194x194 mm² with 3 mm pitch
2. Low background: 11.98+1.68 uBq/cm² for ²³⁸U, 3.55+1.64 uBq/cm² for ²³²Th
3. Energy resolution: 13.6% (FWHM @5.9 keV) at 1 bar and 19% at 10 bars
4. Long term stability and high gain: ~10⁵ @1 bar or ~10⁴@10 bars
