Speaker
Description
The POEMMA-Balloon with Radio (PBR) mission is a NASA super-pressure balloon experiment designed as a pathfinder for future space-based multi-messenger observatories. A central instrument of PBR is the Cherenkov Camera (CC), a 2048-pixel SiPM array optimized for detecting optical Cherenkov signals from extensive air showers. The CC features a curved focal surface tailored to the telescope optics, a wide field of view (12° × 6°), and high angular resolution (0.2° per pixel). Its bi-focal optical design suppresses false triggers by requiring spatial coincidence, significantly enhancing event identification reliability.
The readout electronics are based on ASICs, notably the MIZAR chip, with ongoing parallel development using the Radioroc ASIC for low-power, dual-gain operation. These ASICs integrate fast front-end amplification, on-chip digitization, and programmable triggering, enabling 10 ns-scale time resolution with minimized dead time. A modular architecture of Photo Detection Modules, each managed by FPGA controllers with real-time trigger logic and SiPM bias regulation, ensures scalability and robustness for balloon-borne operation.
Mechanically, the CC is integrated into a Schmidt-type telescope with UV-transparent optics and a segmented reflective mirror assembly. A precision support structure conforms the SiPM arrays to the spherical focal surface, while thermal regulation and shielding ensure stable performance in stratospheric conditions. Current prototype tests of the SiPM matrices confirm compliance with manufacturer specifications for photon detection efficiency, linearity, and noise characteristics, and Geant4-based simulations predict an energy threshold near 0.5 PeV.
The PBR Cherenkov Camera thus combines advanced photodetectors, custom low-power readout electronics, and innovative optical design into a compact, high-sensitivity instrument. Its successful deployment will validate critical technologies and raise the technical readiness of space-based Cherenkov observatories targeting ultra-high-energy cosmic rays and neutrinos.
| Position | RTDb |
|---|---|
| Affiliation | Università degli Studi di Napoli Federico II & INFN Napoli |
| Country | Italy |