[Experienced users only] Detector Power Cycling and Re-initialization

If you are an observatory staff member or an experienced user who is familiar with the IGRINS detector system and can confidently identify which detector is causing the problem, you may use the advanced scripts described on this page.

These procedures are not recommended for general observers.

If image acquisition stops unexpectedly in the DTP (Data Taking Package) or SCP (Slit-view Camera Package), or if an image cannot be read out after an exposure has completed, a malfunction of the detector electronics may be suspected.

The recommended recovery procedure is to cycle the detector power and re-initialize the affected detector.

Unlike the standard recovery procedure, the advanced scripts described on this page allow you to select and recover each detector individually.

1. Close both DTP and SCP.

2. Open a terminal and do
   cd ~/igrins_admin

3. Execute the following command to cycle power for the detectors.
   sh run_det_pwr_adv.sh

4. Type the detector whose power you want to cycle, and press Enter.
   For example: k

5. Follow the instructions displayed on the screen. When you are ready to proceed, press Enter.

6. Wait until the script has completed.

7. After the script finishes, wait an additional 10 seconds.

8. In the same directory, run the following command.
   sh run_det_restart_adv.sh

9. Enter the password when prompted.

10. Type the detector you want to re-initialize, and press Enter.
    For example: k

11. Follow the instructions displayed on the screen. When you are ready to proceed, press Enter.

12. Wait until the script has completed.

13. After the script finishes, wait an additional 10 seconds.

14. If another detector also needs to be power-cycled and re-initialized, repeat the procedure above starting from Step 2 for that detector.

15. Restart DTP and SCP.

When the H-band detector is restarted, a bright vertical band appears due to transient charge accumulation. This is a known characteristic of the H-band detector that has been present since IGRINS was commissioned in 2014. Despite efforts to resolve the issue in collaboration with the detector manufacturer, Teledyne, it has not been eliminated.

The bright band fades exponentially over time. Because the IGRINS detectors are continuously reset while idle (i.e., when no exposures are being taken), leaving the detectors idle for a few minutes after re-initialization allows the brightness of the band to decrease to approximately 10–20 counts.

When performing on-slit guiding on a very bright target, a numerical error may accumulate in the SCP guiding algorithm, causing SCP to freeze. This issue is entirely unrelated to the detector control electronics.

If the H- and K-band detectors are operating normally in DTP and you suspect that SCP has frozen due to this issue, try closing and restarting SCP alone before cycling the detector power or re-initializing the detectors.