SiC ΔE-E Telescope Based on Free-Standing Epitaxial Film Fabricated by Laser Processing

The 4H-silicon carbide (SiC) detector has been widely used for detecting charged particles in a strong radiation environment due to its resistance to radiation. The $\Delta $ E-E measurement is an important method for particle identification, especially for identifying the atomic number of heavy-ions. However, the existing epitaxial SiC detector has a thick substrate, typically larger than $100~\mu $ m. This dead layer limits the application of SiC in the $\Delta $ E-E telescope. In this work, the 4H-SiC substrate was completely removed using the picosecond laser etching process. Benefiting from the stepwise power modulation strategy, the thin films can be free-standing to complete the subsequent processes. Two substrate-free detectors with thicknesses of ~17 and $90~\mu $ m were assembled into a $\Delta $ E-E telescope. It exhibits a good detection performance. The energy resolution is about 2.1% for 241Am-239Pu-244Cm $\alpha $ source. Besides, it has been successfully used in a proton scattering experiment performed at the China Institute of Atomic Energy (CIAE). This work provides a route to fabricate substrate-free 4H-SiC telescopes for detecting low-energy charged-particles.