Noise cancellation by cross–triggering Scintillating Fiber Beam Monitors in the CERN Experimental Areas

In the CERN Experimental Areas, the Beam Instrumentation Group (BEAMS-BI) is working on a new particle detector for low-intensity secondary beams, including the beam line to the novel CERN Neutrino Platform. This XBPF Scintillating Fiber (SciFi) particle detector can detect individual particles and create a beam profile within an active area of 192 x 192 mm. The scintillation is detected by Silicon Photomultipliers (SiPM), connected to application specific readout electronics. The reverse-biased SiPM additionally output false signals generated from thermal noise (Dark Count Events, DCE), which need to be filtered. The detected Dark Count Rate (DCR) can be lowered by increasing the detection threshold, with a reduction of detection efficiency. By creating a logical AND coincidence between two detectors, the detector planes can cross-trigger, which significantly reduces the DCR thermal noise. To create the AND coincidence, both XBPF Frontend and VFC Back-end FPGAs need to be reprogrammed and tested. The resulting particle detector is evaluated and compared to existing systems.