Multiphysics simulation of a superconducting bolometer working in a portable cryostat

Abstract We present the characterization and the numerical simulation of a high-temperature superconducting bolometer based on an YBa2Cu3O7-x (YBCO) film, which is patterned in serpentine elements and selectively modified by means of micro-collimated high-energy heavy-ion irradiation. The local irradiation of YBCO yields to a controlled reduction of the critical temperature and of the critical current, but the resistance versus temperature slope is preserved near Tc. In this way, only the irradiated part of the YBCO films is used for detecting infrared radiation, while the pristine one serves for electro-thermal feedback. The bolometer has been engineered in a portable cryostat, which is equipped with an optical window for suitably filtering the spectrum of the incoming electromagnetic radiation. The optimization of the cryostat has been performed with modelling by finite element method of the whole apparatus, along with simulations of the bolometer response.