Since the camera electronics (CE) commissioning phase, it is known that CE do suffer from time to time from disturbances or crashes. After more than a year of eROSITA operations, we can conclude that:
For a detailed description of how the eROSITA CEs function, please have a look at Predehl, P., et al. (2021).
The CE disturbances occur randomly on each CE. The major impact that such disturbances have on the CEs health is that the affected CE(s) are out of order for an average of 12 hours, after which the affected CE are reset and returns to nominal operations. For each CE disturbances, the eSASS team places a Bad Time Interval (BTI). This period is obtained from the beginning of the CE disturbance until the affected CE is back into normal operation. This time is added to the corresponding CE calibration file, such that the eSASS pipeline removes the affected data from further processing.
The following table shows the CE disturbances that occurred during the the first eROSITA All-Sky Survey (eRASS1), which spans the eROSITA-DE Data Release 1 (DR1). These ‘bad time intervalls’ (BTIs) are documented in the CALDB (tm[1-7]_badcamt_190701v*) and already accounted for in the pipeline processing of the data:
| Affected CE | Start of BTI [UTC] | End of BTI [UTC] |
|---|---|---|
| TM 4 | 2019-12-18 15:56:19 | 2019-12-18 16:23:00 |
| TM 4 | 2019-12-21 01:45:29 | 2019-12-21 14:55:49 |
| TM 6 | 2020-01-04 14:01:52 | 2020-01-04 14:47:01 |
| TM 4 | 2020-01-09 08:11:19 | 2020-01-09 14:47:33 |
| TM 2 | 2020-01-18 16:32:40 | 2020-01-19 16:02:48 |
| TM 5 | 2020-01-26 14:05:37 | 2020-01-26 14:54:47 |
| TM 6 | 2020-02-05 00:55:20 | 2020-02-05 14:14:38 |
| TM 7 | 2020-02-06 18:47:12 | 2020-02-07 14:47:11 |
| TM 4 | 2020-02-09 16:41:04 | 2020-02-10 12:26:35 |
| TM 1 [1] | 2020-02-10 12:26:35 | 2020-02-12 15:25:16 |
| TM 2 [1] | 2020-02-10 12:26:35 | 2020-02-12 16:04:33 |
| TM 3 [1] | 2020-02-10 12:26:35 | 2020-02-12 16:43:33 |
| TM 4 [1] | 2020-02-10 12:26:35 | 2020-02-12 17:23:45 |
| TM 5 [1] | 2020-02-10 12:26:35 | 2020-02-12 17:59:38 |
| TM 6 [1] | 2020-02-10 12:26:35 | 2020-02-13 15:05:27 |
| TM 7 [1] | 2020-02-10 12:26:35 | 2020-02-13 15:41:57 |
| TM 6 | 2020-02-19 21:51:35 | 2020-02-20 17:16:35 |
| TM 5 | 2020-02-22 17:17:44 | 2020-02-22 17:52:35 |
| TM 5 | 2020-03-06 12:44:00 | 2020-03-06 17:51:00 |
| TM 7 | 2020-03-05 13:39:28 | 2020-03-05 14:31:10 |
| TM 7 | 2020-03-08 17:29:41 | 2020-03-09 17:50:44 |
| TM 2 | 2020-03-24 09:34:00 | 2020-03-24 15:19:00 |
| TM 1 | 2020-03-31 15:27:08 | 2020-03-31 16:23:19 |
| TM 3 | 2020-04-03 07:01:49 | 2020-04-03 15:33:38 |
| TM 7 | 2020-04-06 08:46:39 | 2020-04-06 15:42:18 |
| TM 3 | 2020-04-27 12:02:43 | 2020-04-28 15:44:21 |
| TM 5 | 2020-05-02 03:11:00 | 2020-05-02 16:02:00 |
| TM 4 | 2020-05-04 06:01:00 | 2020-05-04 14:26:16 |
| TM 5 | 2020-05-05 21:22:00 | 2020-05-06 15:58:00 |
| TM 3 | 2020-05-07 09:13:00 | 2020-05-09 15:18:15 |
| TM 6 | 2020-05-10 04:18:15 | 2020-05-10 16:51:35 |
| TM 2 | 2020-05-12 21:14:24 | 2020-05-13 17:56:03 |
| TM 2 | 2020-05-16 17:31:29 | 2020-05-16 18:18:37 |
| TM 2 | 2020-05-28 03:06:35 | 2020-05-28 21:29:55 |
[1] CE reset due to an Interface and Thermal Controller (ITC) malfunction.
The CE disturbances that occurred during the Calibration and Verification phase can be found here.