One-Dimensional Position-Sensitive LGAD With a DC Coupled and Resistive Charge Division Mechanism

Abstract

Low-gain avalanche detectors (LGADs) are promising candidates for four-dimensional (4D) tracking detectors in future high-energy physics (HEP) experiments, offering high position and time resolution. However, conventional pixel array LGADs suffer from large dead areas between pixels and require a large number of readout channels, resulting in a poor spatial resolution and high cost. In this paper, we present a one-dimensional position-sensitive LGAD (1D PS-LGAD) based on DC coupling and a resistive charge division mechanism. The 1D PS-LGAD features two cathodes and one anode, with two-dimensional position coordinates obtained by cross-placing two 1D PS-LGADs. With an active thickness of 50 μm and an active area of 2.7 mm × 2.7 mm, a 1D PS-LGAD demonstrated an average position measurement error (PME) of 32.2 ±35.4 μm, accounting for 1.2% of the side length of the active area with a 100% fill factor. The coincidence time resolution and position resolution were 8.8 ps and 22.5 μm, respectively, at the center of the device for incident 532 nm light with a spot diameter of approximately 25 μm and a mean photoelectron number (MPEN) of 6000 when the reverse voltage was 620 V.