I am looking for a specific type of integrating sphere that can be used to capture diffuse reflectance measurements, and I would appreciate help with locating a commercially availably version of this sphere. The diagram below illustrates the type of sphere I am looking for . Two ports are located at equal an opposite angles from the sample normal so that light that is specularly reflected from the sample can be eliminated by a light trap placed in the non-source port.
I have looked online in attempt to find a commercially available integrating sphere with this design; however, I have only come across general purpose integrating spheres (such as this Edmund Optics one) that have ports located directly across or 90 degrees from each other. Any help locating this specific type of integrating sphere would be much appreciated.