CHIMERA: A wide Reynolds number range Taylor-Couette facility
We present a Taylor-Couette facility designed to investigate angular momentum transport over a wide range of Reynolds numbers, from moderate regimes in gases to extreme and potentially quantum regimes in cryogenic helium. The apparatus features a novel torque measurement technique in which the outer cylinder is suspended as a torsion pendulum, allowing direct inference of the fluid-induced torque from its angular deflection. This approach eliminates the need for rotating torque transducers and is particularly well suited for operation in cryogenic environments. Angular deflections are measured optically using a two-dimensional position-sensitive device, providing high sensitivity while enabling detection of spurious motions. An eddy-current damping system ensures rapid stabilization of the pendulum, allowing for steady-state measurements. A dedicated calibration procedure based on the measurement of the natural oscillation frequency yields the torsion constant. Measurements performed in helium, nitrogen, and C4F8 gases at room temperature and variable pressure, as well as in liquid helium between 1.6 K and 3.6 K, cover more than five decades in Reynolds number, up to Re ~ 10^6. The measured dimensionless torque is consistent with established scaling laws in the classical regime. The ability to operate across the classical and superfluid phases of helium provides a unique platform to investigate how quantum effects such as quantized vortices and mutual friction may influence turbulent transport. The apparatus thus offers a versatile and precise experimental framework for studying the turbulent Taylor-Couette flow across an unprecedented range of physical regimes.