Prototype study of $0.1\%\,X_0$ and $\mathrm{MHz/cm^2}$ tolerant Resistive Plate Chamber with Diamond-Like Carbon electrodes

A novel Resistive Plate Chamber (RPC) was designed with Diamond-Like Carbon (DLC) electrodes and performance studies were carried out for 384$\,\mathrm{\mu m}$ gap configuration with a $2\,\mathrm{cm}\times2\,\mathrm{cm}$ prototype. The use of thin films coated with DLC enables an ultra-low mass design of $< 0.1\%\,X_0$ with up to a four-layer configuration. At the same time, 42% MIP efficiency, and 180 ps timing resolution per layer were achieved in a measurement performed under a $1\,\mathrm{MHz/cm^2}$ non-MIP charged particle beam. In addition, we propose a further improved design for a $20\,\mathrm{cm}$-scale detector that can achieve 90% four-layer efficiency in an even higher $4\,\mathrm{MHz/cm^2}$ beam. In this paper, we describe the detector design, present the results of performance measurements, and characterize the rate capability of the DLC-based RPCs with a performance projection for an improved design.