Speaker
Description
We report on the performance studies of the SHiP Timing Detector using the FASTIC+ front-end ASIC developed at CERN. The system is designed to achieve sub-100 ps time resolution to suppress combinatorial background in the SHiP experiment. Ongoing work includes comparative tests between FASTIC+ and a discrete electronics board, as well as studies with two scintillator types, EJ-204 and EJ-232. Laboratory tests with a picosecond laser and two dedicated beam campaigns in 2025 aim to evaluate time resolution, signal response, and material effects, guiding the final detector design and confirming FASTIC+ suitability for precision timing in high-rate environments.
Summary (500 words)
The SHiP (Search for Hidden Particles) experiment at CERN is a proposed beam-dump facility designed to explore hidden sectors of particle physics through the detection of long-lived particles. A central component of the experiment is the Timing Detector, whose primary role is to provide precise time-of-flight measurements with a target resolution below 100 ps, essential for suppressing combinatorial background and accurately associating tracks to primary interactions.
To meet these stringent timing requirements, a custom front-end ASIC, the FASTIC+, has been developed at CERN. It is designed to provide fast signal shaping and digitization suitable for high-precision timing in large-scale detectors. Our current R&D efforts focus on integrating the FASTIC+ with plastic scintillator-based detector modules and validating its performance in both laboratory and beam test environments.
In 2025, two test beam campaigns are planned at CERN. The first campaign will focus on benchmarking the performance of the FASTIC+ against a previously validated discrete-component readout board. Identical detector modules—comprising scintillator bars coupled to SiPMs—will be read out in parallel by both systems to enable a direct comparison. The objective is to quantify the timing resolution under realistic beam conditions, using high-energy muons and minimum-ionizing particles, and to evaluate signal quality, noise levels, and synchronization behavior.
The second beam campaign will be dedicated to the evaluation of two different plastic scintillator materials: EJ-204 and EJ-232. EJ-204 provides a high light output and good attenuation length, making it a strong candidate for large-area detectors. EJ-232, by contrast, offers a much faster decay time, which can be advantageous for precision timing but at the cost of reduced light yield. By maintaining consistent test conditions—including photodetector type, mechanical configuration, and optical coupling—we aim to isolate the impact of scintillator properties on the timing resolution and overall detector performance.
In parallel, extensive laboratory studies are being conducted using cosmic muons and a calibrated picosecond pulsed laser system. The laser setup enables precise timing calibration of the electronics chain and facilitates the study of time walk and signal shaping effects. Preliminary lab results indicate that the FASTIC+ ASIC is capable of achieving time resolutions in the range of 70–90 ps, comparable or superior to the discrete electronics solution, while offering advantages in compactness, power consumption, and scalability.
The combined results from the two test beam campaigns and laboratory studies will provide a comprehensive assessment of the FASTIC+ ASIC and its integration with various scintillator materials. These findings will inform the final design of the SHiP Timing Detector, ensuring it meets the strict performance requirements of the experiment. Furthermore, this work contributes to the broader development of precision timing systems for next-generation high-intensity experiments.
