Novel techniques for sub-nanosecond time-resolved Ring Image Cherenkov photon detection
The High-Luminosity LHC upgrade brings with it a significant increase in detector occupancy that presents a challenge to the LHCb detector. The Ring-Imaging Cherenkov (RICH) detectors are an integral component in LHCb particle identification that will see a degradation in performance under high luminosity conditions. However, it has been shown that the introduction of time resolution on the order of 100 ps is able to overcome the effects of increased occupancy within the RICH detector. Presented in this thesis is the development of a prototype time resolved readout chain, and it’s application in photon timing measurements. The readout uses a custom designed TDC-in-FPGA with a nominal bin width of 150 ps validated by a detailed calibration process. The performance of the prototype readout chain coupled to a photodetector was evaluated under laboratory conditions by making a measurement of an MaPMT transit time spread (TTS) using a pulsed laser apparatus. Several analysis methodologies that account for known sources of timing jitter were used to obtain measurements of the detector TTS, validating the readout performance. Further measurements as a part of a test beam campaign conducted at the CERN SPS beam facilities are presented with similar analysis methodologies. To support the analysis, a detailed simulation of the test beam environment was developed, integrating the timing effects of the photodetectors and readout electronics. These measurements represent the first application of a time resolved LHCb RICH readout chain and serve as integral preparation for the development and testing of the new front-end FastRICH ASICs for the LHCb RICH detector.
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