Optical multiple sample vacuum integrating sphere

Apparatus for making optical radiometric measurements on a plurality of samples, comprising, in combination:

• integrating sphere means (10) including a spherical cavity (24) having a uniform reflecting surface (76), and input port (42) for coupling optical energy from an optically irradiated sample (136) into said cavity (24), and at least one output port (46) for coupling optical output energy uniformly from said cavity to optical detector means;
• sample transport means (12) secured to said integrating sphere means (10) and having means (90) for being attached to a source of incident optical radiation and including an elongated container housing (74) having a central aperture (92) aligned with said input port (42), said housing having a lengthwise channel (78) formed therein for receiving a movable sample holder (80), said sample holder having a plurality of sample receiving means (118, 120, 122, 124) and respective apertures (128, 130, 132, 134) formed therein which are adapted to be selectively placed in alignment with said central aperture (92) and said input port (42) upon movement of said sample holder (80), and means (82) for translating said sample holder (80) linearly within said channel (78) whereby plural samples (136) respectively positioned in said sample receiving means are placed in the path of incident radiation from said source, one at a time;
• a vacuum seal (72) between said sample transport means (12) and said integrating sphere means (10);
• and
• said output port (46) including an optical output window (56) and a vacuum seal (54) whereby a vacuum tight output port is provided and the entire apparatus may be evacuated and radiometric measurements can be made on said samples (136) under a vacuum by translation of said sample holder (80) without the need to interrupt the vacuum while placing individual samples (136) in the path of incident radiation.