Features

Greatly Improves Arc Lamp Drift

Electrode erosion and gas absorption are standard effects of an arc lamp aging with usage. Mercury arc lamps in particular are sensitive to changes in ambient temperature. Both the broadband output intensity and output intensity of a mercury arc lamp's unique spectral lines can change with temperature. Variations in the output power of the lamp with time and even a pronounced frequency dependence may be observed. The plot to the right shows the normalized output current from a photodetector placed at a fixed distance from an arc lamp housing. A 75 W Xe arc lamp was operated in Constant Power Mode and Constant Intensity Mode (with LIK-LMP feedback). The 71582 Si Detector Head was cooled to a temperature of 5°C. As expected, the output intensity of the Xe arc lamp decreased due to the factors discussed above. After 80 hours of operation, an approximate 20% decrease in output intensity is observed. However, with the LIK-LMP providing constant light feedback to the OPS-A Series Power Supply, the power supply is able to adjust its voltage and current supply to the Xe arc lamp to counteract the effects of aging and maintain a constant output intensity.

Greatly Improves QTH Lamp Drift

As a QTH lamp is being operated, the filament slowly evaporates. Evaporation and halogen cycle redisposition of this tungsten filament constantly occurs and changes the microstructure of the filament while the lamp is being operated. As a result, light intensity of the QTH lamp actually increases when used in Constant Power Mode. As seen in the plot to the left, the output intensity of a QTH lamp operated in Constant Power Mode does not change with a consistent trend as seen with a DC Arc Lamp. However, drift improvement as great as 3% was observed from the QTH lamp over a 30 hour operating period when the LIK-LMP was used to operate the OPS-Q Series Power Supply in Intensity Mode. Unfortunately QTH lamps have a much slower response than arc lamps in response to changes in input voltage/current. As a result, the LIK-LMP provides no improvement in light ripple or short term light stability for QTH lamps. However, a definite advantage of consistent output intensity can be observed for applications that require longer term operation of a QTH lamp.

Easy Coupling to Oriel Q Series Housings

The LIK-LMP includes all the necessary components to interface with an OPS Series Power Supply and couple to Oriel's Q Series Housings. The 70062 TE cable for temperature control and 70018 low noise BNC cable for signal feedback allow the 71582 Si Detector Head to interface with an OPS Series Power Supply. The 68954 mounting adapter allows for quick and easy coupling of the 71582 to a Q Series Housing, as shown in the photo to the left.

Easy Coupling to Oriel Research Lamp Housings

The LIK-LMP includes all the necessary components to interface with an OPS Series Power Supply and couple to Oriel's Research Lamp Housings. The 70062 TE cable for temperature control and 70018 low noise BNC cable for signal feedback allow the 71582 Si Detector Head to interface with an OPS Series Power Supply. The 68952 mounting adapter allows for quick and easy coupling of the 71582 to a Research Lamp Housing, as shown in the photo to the right.

Reduces Arc Lamp Ripple

For shorter periods of lamp operation, drift may not be a problem. However, ripple, or output intensity fluctuation associated with shorter periods of lamp operation, may be a problem. The LIK-LMP also improves light ripple characteristics for short term operation periods of an arc lamp. A 0.35% improvement in light ripple has been observed by using the LIK-LMP.

TE Cooled Detector for Low Noise Detection of Intensity Fluctuation

The 71582 TE cooled detector head of the LIK-LMP Light Intensity Controller Kit utilizes a 1-stage TE cooled detector. When used with an OPS Series Power Supply, the temperature of the Si detector can be adjusted from 0 to 25 °C. Cooling the detector below 0°C as shown in the plot to the right is not recommended. In order to cool the Si detector greater than 25 °C below ambient temperature, specialized heatsink requirements not built into the 71582 must be utilized due to the current consumption of the TE cooler at those temperatures.

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