An international comparison of absolute radiant power measurement capabilities

An International Comparison of Absolute Radiant Power Measurement Capabilities

We report the results of an intercomparison of monochromatic radiant power measurement capabilities recently completed by 11 national laboratories. The intercomparison radiometers, distributed in pairs, included an amplifier with six decades of precision gain and one of two types of silicon photodiode (pn or np-type construction). Eleven of the laboratories measured the absolute responsivity of...

PicoWatt infrared power measurement using an absolute cryogenic radiometer

We report on initial measurements of the low-temperature thermal properties of a device that is similar to the experimental apparatus used for absolute cryogenic radiometry (ACR) within the Low Background InfraRed (LBIR) facility at NIST. The device consists of a receiver cavity mechanically and thermally connected to a temperature-controlled stage through a thin-walled polyimide tube which ser...

Empirical Measurement of Freeway Oscillation Characteristics: An International Comparison

The objective of this paper is to conduct a country specific analysis of freeway traffic oscillations. Toward this end, loop detector data from sites in the United States, Germany and the United Kingdom was analyzed. By using a method applied in previous work, traffic oscillations were identified in all three countries. Calculation of the cross–correlation coefficient reveals that they travel u...

SLO radiant power and brightness.

Available output in the Scanning Laser Ophthalmoscope (SLO) may be expressed as radiant power at the beam pivot (SLO exit pupil), in units of microwatts (microW). This power corresponds to dimensions of brightness (like luminance and retinal illuminance) and to a range of related measures (like cd/m2, lm/m2, and the troland value) in both free and Maxwellian views. We demonstrate that the conve...

Measurement of Radiant Energy in Light Therapy