This page summarizes the results of irradiance stability measurements during long-duration illumination for SAN-EI single-lamp AM Solar Simulator models.
In this measurement program, two different methods were used to observe the temporal behavior of irradiance.
- 24-hour continuous measurement (24H measurement)
In this measurement, the pyranometer was installed at the irradiation position and continuously exposed to illumination while irradiance and sensor temperature were recorded over a 24-hour period. - 6-hour measurement (6H measurement)
In this measurement, the pyranometer was placed at the irradiation position only during each measurement, and irradiance was manually read at 30-minute intervals.
During long continuous illumination, the temperature of the pyranometer gradually increases.
Therefore, the results of the 24H measurement may include the influence of the temperature characteristics of the pyranometer.
For this reason, the results of the 6H measurement are used as the primary indicator for evaluating the stability of the light source itself.
The 24H measurement results are used as supplementary information to understand the overall system behavior during long-duration illumination and its relationship with pyranometer temperature.
Measurement Results (6H Stability Comparison)
The table below summarizes the results of the 6H measurements for each model. Irradiance variation is expressed as the percentage deviation relative to the average value during the measurement period.
| Model | Effective irradiation area | Irradiance variation (6H) | Maximum deviation | Drift | IEC class |
| XES-20S1 | 20 × 20 mm | ±0.36 % | 0.36 % | –0.29 % | A+ |
| XES-40S3 | 40 × 40 mm | ±0.86 % | 0.86 % | 1.43 % | A+ |
| XES-50S2 | 50 × 50 mm | ±0.56 % | 0.56 % | 0.86 % | A+ |
| XES-50S3 | 50 × 50 mm | ±0.22 % | 0.22 % | 0.14 % | A+ |
| XES-70S1 | 70 × 70 mm | ±0.22 % | 0.22 % | –0.29 % | A+ |
| XES-100S1 | 100 × 100 mm | ±0.22 % | 0.22 % | 0.29 % | A+ |
| XES-160S1 | 160 × 160 mm | ±0.48 % | 0.48 % | -0.43 % | A+ |
| XES-200S1 | 200 × 200 mm | ±0.57 % | 0.57 % | 1.14 % | A+ |
| XES-250S1 | 250 × 250 mm | ±0.75 % | 0.75 % | 0.95 % | A+ *1 |
| XES-300S1 | 300 × 300 mm | ±0.31％ | 0.31 % | 0.02 % | A+ |
| XES-300S2 | 300 × 300 mm | ||||
| XES-300S3 | 300 × 300 mm | ±0.36 % | 0.36 % | 0.14 % | A+ |
| XES-400S1 | 400 × 400 mm |
The 6-hour measurement results show that all measured models maintained irradiance stability within ±1%, corresponding to IEC Class A+ for long-term temporal stability.
Although some models showed gradual drift during the measurement period,
the results indicate stable irradiance performance across different effective irradiation areas.
In some cases, the measured irradiance variation may include the influence of pyranometer temperature.
Values will be updated as measurement results for additional models become available.
*1 The measured irradiance showed a correlation with pyranometer temperature.
A temperature correction was therefore applied using a linear regression derived from the measurement data.
Observations
For the models measured so far, the irradiance observed in the 6H measurements remains within a limited range around the average value, and no significant temporal variation has been observed during the measurement period.
In contrast, the 24H continuous measurements show a gradual change in irradiance together with the increase in pyranometer temperature.
The results obtained from the Main and Sub pyranometers show generally similar trends, indicating that the observed behavior reflects the characteristics of the measurement system rather than a malfunction of an individual sensor.
Interpretation
The gradual variation observed in the 24H measurement is likely influenced by the temperature change of the pyranometer during long-duration illumination.
Therefore, the results of the 24H measurement do not directly represent the variation of the light source output alone.
In the 6H measurement, the continuous heating of the pyranometer is minimized because the sensor is placed at the irradiation position only during each measurement.
Under this condition, the irradiance remains within a relatively narrow range during the measurement period, indicating that the light source output itself exhibits high stability.
Conclusion
For the SAN-EI single-lamp AM Solar Simulator models measured so far, the results of the 6H measurements confirm that irradiance during operation remains within a narrow range around the average value, indicating stable light source output.
The results of the 24H continuous measurements also provide useful information for understanding the behavior of the system during long-duration illumination and its relationship with pyranometer temperature.
This page will be updated as additional measurement results become available.