A high rate and high timing photoelectric detector prototype with RPC structure

To meet the needs of high counting rate and high time resolution in future high energy physics experiments, a prototype of a gas photodetector with a Resistive Plate Chamber (RPC) structure was developed. We simulated the detector’s performance using Garfield++ and utilized an ultraviolet laser to evaluate the single photoelectron performance of various mixed gases. The detector uses a low-resistivity ($\sim$ 1.4 × 10¹⁰ $\Omega \mathrm{cm}$) float glass so that its rate capability is significantly higher than that of ordinary float glass (10¹²–10¹⁴ $\Omega \mathrm{cm}$). The laser test results show that in the MRPC gas mixture (R134a/iC₄H₁₀/SF₆ (85/10/5)), the best single photoelectron time resolution is 20.3 ± 1.0 ps at an induced signal charge of 6 × 10⁶ Qe. Increasing the concentration of iC₄H₁₀ can effectively reduce the probability of photon feedback, without changing the time resolution and maximum gain. In addition to its application in high-precision time measurement scenarios (e.g. T0 and TOF), the detector can also quantitatively evaluate the single photoelectron performance of various gases and will be utilized for identifying eco-friendly RPC gases.