“…Approaching the light source to the reaction vessel increases the irradiation levels, but compromises uniformity. The problem can be alleviated using multiple light sources, like LED strips and arrays [24] , [33] , [34] , [35] , [36] . It has been shown that illumination uniformity depends critically on the size of the sample, the distribution of light sources in the array and on the array-sample distance [24] , [37] , [38] and it is very poor if light sources are too close to the sample surface.…”