ISMP-50-R-V01
Light Reflectance Measurement Instrument with 8/d Geometry per DIN 5036-T3

The ISMP-50-R-V01 is designed to perform total reflectance as well as the diffuse reflectance component measurement of flat surface test samples. The regular reflectance component can be calculated by the difference between the measured values. Its principal design follows the recommendations found in DIN 5036 T3 for 8/d measurement geometry with 8° sample illumination and integrating sphere to measure re-reflected light with an almost hemispherical acceptance angle. Measurement errors caused by the self absorption effect of the test sample can be compensated using the substitution correction port.
The instrument is composed of an integrating sphere with accessory components, light source and supporting electronics. The integrating sphere and the light source are mounted to a stable bench top stand to avoid misalignment during transportation and in use. The sphere itself is 50cm in diameter and includes a measurement port, auxiliary port, illumination port (+8° orientated to sample) and regular reflectance output port (-8° orientated to the sample). The sphere diameter to port size relation is in accordance with DIN 5036 T3 for traceable measurement results. A collimated light source employing a halogen tungsten lamp operated at the color temperature of 2896 K (standard illuminant A) is used for precise sample illumination. The lamp is operated in constant current mode for best stability. Both, the measurement and auxiliary port include a spring load sample holder for positioning the test sample at the reference plane on the port. The electronics include a sophisticated lightmeter/controller with photometric detector mounted onto the sphere and light source power supply. The meter/controller supports the substitution correction measurement routine, the calibration routine and displays the light reflectance measurement values in percent as well as remote control of the power supply.
For measurement applications involving samples with diffuse reflection characteristics Gigahertz-Optik offers a diffuse reflection calibration standard model BN-R98-D2C-PP. Calibration of the diffuse calibration standard is traceable to NRC. For non-diffuse test samples (flat surface mirrors) the BN-RM95-50C-PP mirror type reflectance calibration standard is available with calibration traceable to PTB. Both standards are supplied in a housing with orientation pins on their back side which fit into holes on the sample holder.
To monitor instrument calibration consider keeping one standard as a transfer standard between Gigahertz-Optik and the end-user. This standard should be re-calibrated annually by Gigahertz-Optik and then used for recalibration of the working by the end-user. This way the end-user has a traceable in-house reference standard for periodical check of its measurement device.
ISMP-50-R-V01 measurements should be done under dimmed lighting conditions to avoid ambient light influence on the readings. Ambient light levels can be checked by making a dark signal measurement with the light meter.