Designing A Passive Star Optical Network For The India-Based Neutrino Observatory

The India-based Neutrino Observatory (INO) uses an iron calorimeter (ICAL) as the neutrino detector. The ICAL consist of 28, 800 resistive plate chambers (RPCs) that generate event data at similar to 650 kbps, for an aggregate of 18 Gbps at the backend. Implementation of a triggerless detection scheme will increase this by a factor of 20. We describe a passive star optical network (PSON) and provide a data networking scheme for the ICAL. We discuss the need of a custom designed communication protocol (ICAL-PRO) for PSON and present its 4 layer architecture and data flow. We use a microcontroller based embedded model to demonstrate a 1 X 16 PSON and discuss its packet error rate (PER) analysis. We achieve a PER of < 10(-9) at the operational signal to noise ratio (SNR) value. We implement time synchronization in the 1 X 16 PSON and achieve an accuracy between 200 - 300 ns. We substantiate the operational principle of ICAL-PRO by successfully demonstrating a 1 X 16 PSON.