In the realm of energy and particle detection, a team of researchers from various institutions, including CERN, the University of Texas at Arlington, and the University of Ioannina, among others, has been working on a novel detector concept aimed at achieving unprecedented timing resolution for charged particle detection. Their work, titled “Design, simulation and performance of the resistive-anode PICOSEC Micromegas detector,” was recently published in the Journal of Instrumentation.
The PICOSEC Micromegas detector is a Micro-Pattern Gaseous Detector designed to achieve tens of picosecond timing resolution by combining a Cherenkov radiator with a two-stage Micromegas amplification structure. To enhance operational robustness, the researchers implemented a resistive anode using a diamond-like carbon (DLC) layer deposited on a Kapton substrate. While this design improves detector stability, the resistive layer may influence rate capability, signal formation, and detector capacitance, potentially altering timing performance.
The researchers conducted a comprehensive study of the resistive design, developing an analytical model and finite-element simulations to quantify rate-dependent gain reduction due to ohmic voltage drop on the resistive layer. They derived an analytical solution for the voltage across a finite-size resistive layer and developed a numerical model to evaluate gain suppression under intense particle fluxes. Using time-dependent weighting fields and the Garfield++ simulation framework, they investigated the impact of the resistive layer on signal formation and found that the signal leading edge is preserved for surface resistivities above 100 kohm per square.
Single-channel resistive-anode prototypes were designed, constructed, and experimentally characterized. Laboratory measurements using single photoelectrons and power spectral density analysis confirmed the predicted reduction in signal amplitude while preserving the leading edge. Muon beam tests with CsI and DLC photocathodes demonstrated a time resolution of 11.5 ps for CsI, comparable to 11.9 ps for the metallic-anode device, showcasing the suitability of the resistive design for precision timing applications.
The practical applications of this research for the energy sector include improved particle detection and timing resolution in high-energy physics experiments, which can enhance our understanding of fundamental particles and their interactions. This, in turn, can contribute to advancements in energy production, storage, and management technologies. Additionally, the enhanced stability and precision of the PICOSEC Micromegas detector can benefit various industrial and medical applications that require accurate particle detection and timing measurements.
Source: Djunes Janssens et al., “Design, simulation and performance of the resistive-anode PICOSEC Micromegas detector,” Journal of Instrumentation, 2023.
This article is based on research available at arXiv.