Speaker
Description
The PICOSEC Micromegas detector is a precise-timing gaseous detector based on a Cherenkov radiator, a semi-transparent photocathode and a Micromegas amplification structure, targeting a time resolution of tens of picoseconds for minimum ionising particles (MIPs). Single-pad metallic prototypes with Cesium Iodide (CsI) photocathodes have demonstrated excellent performance, reaching a time resolution of $\sigma \approx$ 12.5 ps. Ongoing developments aim to adapt the concept for physics applications, with the objective of building robust, tileable multi-channel modules for large-area systems requiring precise timing.
Measurements were carried out both under laboratory conditions and with 150 GeV/c muon beams. Resistive Micromegas technology was integrated into the design and the prototypes maintained outstanding time resolution. Further improvements involved exploring metallic and carbon-based photocathodes, including Titanium (Ti), Diamond-Like Carbon (DLC) and Boron Carbide (B$_4$C). Test beam results show that thinner photocathodes systematically enhance time resolution, with Ti achieving a time resolution of $\sigma \approx$ 29 ps and emerging as a promising compromise between performance and robustness. A key milestone was scaling the prototype to a 100-channel module with 10×10 cm² active area, obtaining a time resolution of $\sigma \approx$ 18 ps for events fully contained within individual pads, thereby confirming the successful transfer of single-pad performance to the multi-channel system. To address rate limitations in large-area resistive readouts, a double-DLC-layer layout with vertical charge evacuation was developed. The prototype assembled with a Ti photocathode achieved a spatial resolution of around 2.5 mm over 10×10 mm² channels and a time resolution of $\sigma$ < 50 ps in a 10×10 mm² area shared between four pads. Additionally, a readout chain using RF-pulse amplifiers and a SAMPIC digitiser was validated, confirming the system’s capability for multi-channel operation. Finally, beyond MIP detection, the PICOSEC Micromegas also holds potential for photon detection. A UV-sensitive prototype based on the 10×10 cm² design is currently being developed and characterised.
Efforts to improve prototype robustness and scalability significantly enhance the feasibility of the PICOSEC Micromegas concept for future experiments, ensuring stable performance while maintaining excellent timing precision.
| Position | Post-Doc |
|---|---|
| Affiliation | CERN |
| Country | Switzerland |