ASTM E824–10 Transfer of Calibration from Reference to Field Radiometers

Scope:

ASTM E824-10 is highly significant for the calibration of field radiometers employing standard reference radiometers. It is also useful for cosine and azimuth correction analyses. Traceability shall have been established if a parent instrument in the calibration chain participated in an international Pyrheliometric Comparison (IPC) was conducted at the World Radiation Center (WRC) in Davos, Switzerland for this method. Therefore, it is of great significance.

Procedure:

ASTM E824-10 reference radiometer and field radiometer are mounted for horizontal calibration. Then the height of the photoreceptor, or radiation receptor, of all instruments is elevated to a common point. Transfer of calibration to a field instrument must be oriented at the tilt angle and facing the equator. The voltage signal from each radiometer is measured and stored using calibrated data. A minimum of fifteen measurement sequences are obtained, each sequence comprising a minimum of 21 instantaneous readings.

Specimen Size:

This test method is limited to radiometers having approximately 180° (2π Steradian), field angles.

Result:

Therefore, by performing ASTM E-824-10 carefully, calibrations can be easily transferred from reference to field radiometers