Patent ID: 7030976

Claim:
A high-pressure resistant compact precision measurement head for highly exact optical refractive index measurements in liquids and/or gases comprising a refractive index reference prism body cut out of one single circular piece of reference material, mounted on a high-pressure bulkhead fitting, which bulkhead fitting is attachable to a housing of a measurement instrument, which measurement instrument contains a light source for directing a measurement light ray into the reference prism body, which body is composed of optically homogenous material and wherein the reference body has space defining measurement surfaces, on its front portion for defining a probe volume of the medium to be measured of less than 0.5 mm 3 , through which measurement medium a measurement light ray can pass, the measurement light ray being producible in a pressure-protected interior cavity of the measurement instrument and evaluated as an angular deflection of the exiting light ray after passing through the measurement medium.