Apogee Instruments SI-121-SS 소유자 매뉴얼 - 페이지 4

{카테고리_이름} Apogee Instruments SI-121-SS에 대한 소유자 매뉴얼을 온라인으로 검색하거나 PDF를 다운로드하세요. Apogee Instruments SI-121-SS 20 페이지. Infrared radiometer

INTRODUCTION

All objects with a temperature above absolute zero emit electromagnetic radiation. The wavelengths and intensity

of radiation emitted are related to the temperature of the object. Terrestrial surfaces (e.g., soil, plant canopies,

water, snow) emit radiation in the mid infrared portion of the electromagnetic spectrum (approximately 4-50 µm).

Infrared radiometers are sensors that measure infrared radiation, which is used to determine surface temperature

without touching the surface (when using sensors that must be in contact with the surface, it can be difficult to

maintain thermal equilibrium without altering surface temperature). Infrared radiometers are often called infrared

thermometers because temperature is the desired quantity, even though the sensors detect radiation.

Typical applications of infrared radiometers include plant canopy temperature measurement for use in plant water

status estimation, road surface temperature measurement for determination of icing conditions, and terrestrial

surface (soil, vegetation, water, snow) temperature measurement in energy balance studies.

Apogee Instruments SI series infrared radiometers consist of a thermopile detector, germanium filter, precision

thermistor (for detector reference temperature measurement), and signal processing circuitry mounted in an

anodized aluminum housing, and a cable to connect the sensor to a measurement device. All radiometers also

come with a radiation shield designed to minimize absorbed solar radiation, but still allowing natural ventilation.

The radiation shield insulates the radiometer from rapid temperature changes and keeps the temperature of the

radiometer closer to the target temperature. Sensors are potted solid with no internal air space and are designed

for continuous temperature measurement of terrestrial surfaces in indoor and outdoor environments. SI-100

series sensors output an analog voltage that is directly proportional to the infrared radiation balance of the target

(surface or object the sensor is pointed at) and detector, where the radiation balance between target and detector

is related to the temperature difference between the two.