{"id":530,"date":"2026-04-14T20:41:48","date_gmt":"2026-04-14T11:41:48","guid":{"rendered":"https:\/\/www.san-eielectric.co.jp\/am\/?page_id=530"},"modified":"2026-04-28T11:55:32","modified_gmt":"2026-04-28T02:55:32","slug":"irradiance-stability-test-xes-100s1","status":"publish","type":"page","link":"https:\/\/www.san-eielectric.co.jp\/am\/en\/measurement-reports-index\/irradiance-stability-test-24h-6h\/irradiance-stability-test-xes-100s1\/","title":{"rendered":"Irradiance Stability Test XES-100S1"},"content":{"rendered":"\n

Abstract<\/h2>\n\n\n\n

This report evaluates the irradiance stability of the Solar Simulator model XES-100S1 during long-duration continuous operation using two measurements: a 24-hour continuous measurement and a 6-hour manual measurement.<\/p>\n\n\n\n

In the 24-hour measurement, gradual irradiance variation was observed together with an increase in pyranometer temperature. In contrast, the 6-hour measurement showed relatively stable irradiance behavior.<\/p>\n\n\n\n

These results indicate that the long-term variation observed in the continuous measurement is likely influenced by the temperature characteristics of the pyranometer rather than instability of the light source output.<\/p>\n\n\n\n

1. Purpose and Overview of the Measurement<\/h2>\n\n\n\n

This measurement was conducted to observe how irradiance changes over time when a Solar Simulator is operated continuously for an extended period.<\/p>\n\n\n\n

In long-duration illumination tests and light-induced degradation experiments, illumination is often maintained for several hours to several tens of hours. Therefore, it is important to understand the time behavior of irradiance during long continuous operation.<\/p>\n\n\n\n

The purpose of this measurement was to obtain actual measurement data describing the temporal behavior of irradiance during long-duration illumination.<\/p>\n\n\n\n

Two types of measurements were performed.<\/p>\n\n\n\n

\u2022 24-hour continuous measurement (24H measurement)
The pyranometer was installed at the irradiation position and irradiance and sensor temperature were logged continuously for 24 hours.<\/p>\n\n\n\n

\u2022 6-hour measurement (6H measurement)
The pyranometer was placed at the irradiation position only at each measurement time, and irradiance was manually measured and recorded by the operator.<\/p>\n\n\n\n

By comparing these two measurement results, the stability of irradiance during long-duration illumination was evaluated.<\/p>\n\n\n\n

2. Measurement Conditions<\/h2>\n\n\n\n

Solar Simulator: SAN-EI XES-100S1<\/p>\n\n\n\n

Reference Irradiance: 1 SUN (AM1.5G equivalent)
Irradiance Sensor: Pyranometer (Main \/ Sub)
Measurement Environment: Laboratory<\/p>\n\n\n\n

Measurement Date: March 27, 2026
Operator: Shinobu Ito<\/p>\n\n\n\n

3. Behavior Observed in the 24H Measurement<\/h2>\n\n\n\n

In the 24H measurement, both irradiance and pyranometer temperature exhibited characteristic time-dependent behavior (Fig. 1-1, Fig. 2).<\/p>\n\n\n\n

Immediately after lamp ignition, relatively large changes were observed. Afterward, gradual changes continued for several hours, and the values eventually converged toward a nearly constant state after a long period of operation (Fig. 1-1).<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

Two pyranometers, Main and Sub, were used in this measurement. Both sensors showed nearly identical temporal behavior.<\/p>\n\n\n\n

This indicates that the observed variation is not caused by a malfunction of a single sensor but represents behavior common to the overall measurement system.<\/p>\n\n\n\n

Observation of the pyranometer temperature and surrounding temperature shows that the temperature gradually increases over a long period after lamp ignition (Fig. 2).<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

At this stage, several possible causes of the observed behavior can be considered.<\/p>\n\n\n\n

    \n
  • Thermal equilibrium of the light source and power supply<\/li>\n\n\n\n
  • Thermal stabilization of the internal structure and optical system<\/li>\n\n\n\n
  • Temperature characteristics of the pyranometer<\/li>\n<\/ul>\n\n\n\n

    However, it is not possible at this stage to determine which factor is dominant.<\/p>\n\n\n\n

    4. Classification of Time Behavior<\/h2>\n\n\n\n

    The time behavior observed in the 24H measurement can be interpreted by dividing it into three characteristic periods (Fig. 1-2).<\/p>\n\n\n\n

    \"\"<\/figure>\n\n\n\n