Modular Ring Imaging Cherenkov Detector (mRICH)

The modular aerogel RICH is designed for hadron identification covering a momentum range of 3-10 GeV/c. Silica aerogel has been used for decades in threshold Cherenkov counters for high energy physics experiment and has recently been used as radiator material for RICH detectors for the HERMES, LHCb, AMS, Belle experiments [1-4], and for the CLAS12 experiment. This R&D has been benefiting from having in house expertise acquired from CLAS12 RICH [5]. The optical properties of aerogel are crucial parameters for the performance of mRICH. For instance, any angular dispersion of the emitted photons affects the precision of the Cherenkov angle measurements. In addition, a high transparency (transmittance) and a proper refractive index are required in order to collect a sufficient number of photons for a reliable ring reconstruction. The design features of the mRICH are shown in Figure 2.3.1. The main components of the modular design include: (a) the aerogel block at the front (characteristic dimension: 10cm x 10cm x 3cm and n = 1.01 - 1.05), (b) focusing Fresnel lens (for projecting Cherenkov ring image toward the central region of the photosensor plane), (c) high quality mirror set on the side walls, and (d) the photosensor plane. The focus of this particular R&D is to systematically study the mRICH performance through simulation with realistic material properties of the aerogel block, fresnel lens and mirror configuration (i.e. tilting angle) and to verify the simulation results through prototyping and beam test. The performance of the mRICH in the EIC detector will also been studied.