Design of the compact TPC for a high-precision 3D beam diagnostic system

A compact Time Projection Chamber (TPC) with a gas electron multiplier (GEM) is a good candidate for three-dimensional (3D) beam diagnosis of electron and ion beams. To develop the beam diagnostics, we performed simulation studies to design a compact GEM-TPC with COMSOL and GARFIELD++. The primary purpose of this detector is to measure the 3D beam profile at the medical cancer center, which requires a position resolution of ∼300μm in each coordinate and can accommodate a proton rate of 10⁴ s⁻¹. For the design of the detector that satisfies the requirements, the simulations were done on the electric field homogeneity of the cylindrical field cage, the transport properties, and the amplification of electrons in the argon-based gases. This paper presents the design parameters of the compact TPC for constructing a high-precision 3D beam diagnostic system derived from COMSOL and GARFIELD++ simulations.