Beam measurement characterization and optics tolerance analysis of a 900 GHz HEB receiver for the ASTE telescope

The optics of a 900 GHz HEB receiver for the ASTE telescope have been characterized using ALMA band 10 facilities at NAOJ. Comparison of measurement results and Physical Optics simulations show important differences. The receiver beams are distorted, which degrades the aperture efficiency and, in turn, the sensitivity of astronomical observations. Several tolerance analysis using Monte Carlo methods and Physical Optics simulations with different tolerance conditions have been performed. Results have been used to identify a defective component in the optical path. Conclusions have been confirmed by additional beam and mechanical measurements.