Jacob C. Jonsson got his Ph.D, in Solid State Physics at Uppsala University in 2004 under supervision of professor Arne Roos. That work was split on two different fields: Measurement of miniature optical elements and translucent sheets for daylighting applications. In addition to measurement techniques the translucent panels were also studied by ray tracing. After leaving Uppsala he went to work at LBNL with Mike Rubin developing measurement techniques for light scattering glazing products. In parallel to the measurement effort a path through ray tracing was pursued.
In the Windows and Envelope Materials group Jacob is responsible for the fenestration optical properties measurement laboratory where solar spectral transmittance and reflectance is measured as well as complete bi-directional scattering distribution functions.
Since 2011 Jacob has been chair of the optical properties subcommittee at the National Fenestration Rating Council and he is heavily involved in maintaining the integrity and accuracy of the International Glazing Database. In 2012 Jacob joined the ASTM and helped in development of the ASTM E903 standard which has also led to being involved with similar CEN and ISO standards.