With Nagisa Sembo
We conducted the integrating sphere calibration for Pcal-X.
The results are attached. (PDF filer).
Online parameters have not been updated because we found a bug for the update script which is related to the background values.
We will fix it and updayte the online paramters later.
(The influence of this bug is limited, and no significant changes have been detected for Pcal-X calibration factors.)
This report documents the update of EPICS parameters for the ETMX photon calibrator (Pcal-X) on 2025/4/18. The update reflects the results of a calibration conducted on 2025/4/16, including measurements of photodetector background offsets, optical efficiency, power splitting ratio, and Watt-per-Volt (WpV) conversion factors. The update also includes a correction to the way background values are handled in the update script.
During this update, a bug was identified in the online parameter update script. Previously, the script directly wrote the measured background (BG) values to the EPICS parameters. However, the measured BG values are recorded after the existing BG correction has already been subtracted from the sensor signal. Writing them directly would therefore result in incorrect total correction.
To address this issue, the script was modified to compute the updated BG values as the sum of the currently set BG value and the newly measured residual. The parameter update was carried out using the corrected script.
| EPICS Key | Before | After |
|---|---|---|
| K1:CAL-PCAL_EX_1_PD_BG_TX_V_SET | -0.003253 | -0.005059 |
| K1:CAL-PCAL_EX_2_PD_BG_TX_V_SET | 0.003589 | 0.006846 |
| K1:CAL-PCAL_EX_1_PD_BG_RX_V_SET | 0.000312 | 0.000002 |
| K1:CAL-PCAL_EX_1_OE_T_SET | 0.983701 | 0.984207 |
| K1:CAL-PCAL_EX_1_OE_R_SET | 0.983701 | 0.984207 |
| K1:CAL-PCAL_EX_2_OE_T_SET | 0.976668 | 0.976970 |
| K1:CAL-PCAL_EX_2_OE_R_SET | 0.976668 | 0.976970 |
| K1:CAL-PCAL_EX_1_RX_V_R_SET | 0.502888 | 0.502909 |
| K1:CAL-PCAL_EX_2_RX_V_R_SET | 0.497112 | 0.497091 |
| K1:CAL-PCAL_EX_WSK_PER_TX1_SET | 0.526662 | 0.526477 |
| K1:CAL-PCAL_EX_WSK_PER_TX2_SET | 0.387693 | 0.387464 |
| K1:CAL-PCAL_EX_WSK_PER_RX_SET | 1.498458 | 1.496563 |
Compared to previous calibrations, there were no significant changes observed in the calibration factors of the RxPD and TxPDs.
