This broadband thermopile detector allows for the measurement of total broadband radiation emitted by a light source. It could also be used to measure the light power density on a surface in W/cm², which is particularly useful for uniformity measurements and checking solar simulator performance. This detector has a 19mm diameter sensor and spectral range of 190-20000nm. This detector head requires and external display controller or computer interface (sold separately) to show the measured power. This system includes the detector head, post and post holder.

Difference Between 15W and 30W Model

The two models have identical electronics and sensor. The only difference is that the 30W model has a heat sink such that it can tolerate more heat power. The electronic readout is also the same, there are no additional digits or precision gained using the 15W model over the 30W model.

NIST Calibration Certificate

The detector head comes with a NIST calibration certificate that states that broadband power readings are accurate to NIST standards. This certification is performed on each individual detector unit and hence each unit has a unique parameter value on the certificate that relates its output voltage (in mV) to the actual power measured (in W).

Spectral Wavelength Sensitivity Curve

Since this detector is a broadband detector the NIST calibration certificate only certifies broadband measurements. However, a measured spectral wavelength sensitivity curve for that particular detector unit is available at extra cost.

Total Power and Power Density Readings

The optional external display controller shows both total power in W and power density in W/cm². For power density readings, the user has to enter the beam size as detected by the sensor (up to the maximum 19mm diameter size of the detector sensor). Please note that the software provided in both the display controller and computer interface only displays total power. However, it is possible for the user to calculate the power density within the Labview software that it is available with the computer controller option.

Computer Interface

Both the optional display controller and computer interface allows for either USB or RS-232 connection to a computer. A Labview based software with Windows driver that reads the NIST calibrated power data from the detector head is included. Please note that the software does not calculate power density as it only displays total power. However, being a Labview based software, it is possible for the user to compute the power density values within Labview. Alternatively, the user can also read raw uncalibrated millivolt values from the display controller or computer interface. A manual provides the ASCII RS-232/USB commands used to read in these values. In this case, the user also has to multiply the raw readout values (in millivolts) by a calibration factor that is provided in the NIST Calibration certificate to determine total power in watts.

Connecting Detector Head to Third Party Controllers, Oscilloscopes and Voltmeters

The thermopile head provides a raw output signal in millivolts (mV) that can be connected to a third party controller, oscilloscope or voltmeter. To convert this reading to actual power measured in Watts, the user must multiply the voltage signal by a coefficient that is provided in this NIST calibration certificate. This coefficient value is individual for each unit according to its factory measured calibration. The standard detector head has a DB15 male output connector, in which 2 of the pins are the raw output voltage signal. The other pins provide the calibrated parameter values used by the dedicated display controller or computer interface. If the user has his own third party display controller, oscilloscope or voltmeter, there is an optional BNC adapter that can be ordered. This BNC adapter converts the DB15 male output connector into a BNC connector for convenient interfacing with third party controllers. Please keep in mind that the BNC connector only provides the raw voltage output value and not the calibrated value. This is why the final calibrated power/power density value has to be computed inside the third party controller.

Technical Specifications

• DB15 male output connector from detector head (for connection to dedicated computer interface or display monitor)
• Optional DB15 to BNC adapter available (for connection to third party controllers)
• Outputs raw uncalibrated values in mV, which can be calculated into power/power density by controller
• Detector head dimensions: 50 x 50 x 20.6mm
• Sensor dimension: 19mm diameter
• Integration time: 7s for stable measurement