CALBLOCK-F-015: VIS Serial Trap Pumping

Observation configuration file

ocf_CALBLOCK-F-015_SERIAL.csv

Scheduling

This block must be executed immediately prior to CALBLOCK-F-008: VIS PSF Calibration and NISP photo nonlinearity, with a cadence of about 6-8 weeks, but not more frequently than every 4 weeks. During ESOP, we allow the RSD to go faster than 4 weeks, and will check whether an impact in the bias level can still be seen several hours later after CALBLOCK-F-008: VIS PSF Calibration and NISP photo nonlinearity.

Must be followed by CALBLOCK-F-008: VIS PSF Calibration and NISP photo nonlinearity. This is because the VIS bias offset, while spatially stable, will settle over the next few hours after running Serial Trap Pumping. Hence this CalBlock must be either (1) the last to run before VIS is switched off, or (2) followed by bias-offset inseisitive measurements, such as PSF calibration (F-008) or Phase Diversity Calibration (PV-008 / F-013).

In case of failure, skip and continue with the plan.

Time-critical

Yes. Must be followed by CALBLOCK-F-008: VIS PSF Calibration and NISP photo nonlinearity. This is because F-008 is expected to be resilient to the VIS bias perturbation caused at the end of F-015.

Dependencies

Although F-008, F-012 and F-015 remain as individual CalBlock instead of merging them into a new one, they should be scheduled one after the other as a set, in the order F-012, F-015, and F-008.

Objective

This type of trap pumping requires a soft ROE reset to bypass the FPGA bug. As a result, the bias level of the subsequent exposures is instable, and needs several readouts to clear. This CalBlock provides three trash biases for that purpose. To be certain that no ill effect propagates to survey data, this observation must be executed immediately prior to CALBLOCK-F-008: VIS PSF Calibration and NISP photo nonlinearity, where 100 VIS exposures are taken for the PSF model, which should be unaffected by a small bias offset.

Observations

One set of all STP frames as defined in CALPRODUCT-VS-025: VIS Trap Pumping.

Full parameter set for serial trap pumping.

Observation instructions 15: Serial trap pumping: The 12 variants of STP constitute a single STP block, which is headed by a reference BIAS. STP references are contained in each execution of a MSTP sequence. 3x throw-away “trash” biases must be executed before resuming any other science sequences, to clear out any bias level perturbation. It is assumed that the STP sequence itself can tolerate the minor (~1 ADU) bias perturbation caused by the soft ROE reset.
BIAS
STP01, 02, 03, 04, dither
STP05, 06, 07, 08, dither
STP09, 10, 11, 12, 3x throw-away BIASes, dither

Fulfilling

CALPRODUCT-VS-025: VIS Trap Pumping

Targets and pointing constraints

Pointing: Straylight suppression as per MOCDA-SYS-003. The calibration should be taken at the same pointing and with the same \(AA\) as the subsequent CALBLOCK-F-008: VIS PSF Calibration and NISP photo nonlinearity.

Table 36: VIS PSF calibration fields CSV file

#ID

R.A.

Dec

ELON

ELAT

GLON

GLAT

Comment

VIS-PSF-1

292.48

53.53

321.00

73.00

85.33

16.16

VIS-PSF-2

285.03

49.83

302.00

71.60

79.93

19.07

VIS-PSF-3

275.78

47.80

282.00

71.00

75.93

24.30

VIS-PSF-4

265.72

48.09

261.00

71.40

74.83

30.97

VIS-PSF-5

254.20

49.37

237.00

71.00

75.94

38.61

VIS-PSF-6

247.27

52.69

220.00

72.20

80.91

42.58

VIS-PSF-7

239.80

56.89

200.00

73.00

88.18

45.55

VIS-PSF-8

235.16

60.85

184.00

73.80

94.79

45.96

VIS-PSF-9

225.35

61.91

172.50

70.50

100.21

49.09

VIS-PSF-10

221.47

67.43

155.00

71.50

107.55

46.13

VIS-PSF-11

215.61

73.55

135.00

71.00

114.45

42.05

VIS-PSF-12

–

–

–

–

–

–

Too far North for EXT

VIS-PSF-13

43.34

-66.36

339.00

-71.80

285.75

-46.49

VIS-PSF-14

45.21

-61.46

353.50

-70.20

279.78

-49.44

VIS-PSF-15

54.60

-58.77

9.00

-72.30

272.38

-47.24

VIS-PSF-16

59.25

-55.16

23.00

-71.50

266.02

-46.46

VIS-PSF-17

65.30

-51.89

38.00

-70.90

260.15

-43.91

VIS-PSF-18

73.52

-49.10

56.00

-70.60

255.62

-39.06

VIS-PSF-19

81.34

-48.10

72.00

-71.00

254.49

-33.88

VIS-PSF-20

63.55

-49.19

39.00

-68.00

256.73

-45.53

VIS-PSF-21

185.90

78.10

119.02

64.98

124.77

38.93

VIS-PSF-22

150.00

78.50

109.74

59.25

132.49

35.23

VIS-PSF-23

87.60

-47.50

85.04

-70.90

254.36

-29.63

VIS-PSF-24

265.07

71.35

108.00

84.90

102.06

31.26

Instrument configuration

Instrument: Wide survey

Inter-operability constraints

None

In-orbit duration

In-orbit Duration: 1.9 h + 3 dithers

  • (77s + 215s) * 4 (BIAS) + (445s + 30s) * 12 frames = 1.9 h

Data volume

12*VM = 4920 MB (STP) [VM = VIS Multi-STP (partial frame) = 410M compressed, linear interinterpolation from S/C TVac data]

4*VB = 1000 MB (BIAS)

Processing input

Ground Processing Input Data: Prerequisites for trap pumping

Data Description: Series of MSTP exposures

Processing method

VIS_CTI_TPCALIBRATE

Processing output

Updated serial register trap populations.

Required accuracy, constraints

Images successfully acquired.

Processing tools

VIS_CTI_TPCALIBRATE

Validation

TBW

Recovery

ROE timeout error is generated for any serial trap pumping (STP) that lasts longer than 78 seconds. This particular error message does not indicate a failure in STP data acquisition. However this feature is retained to signal failure in all other normal readouts (STP is a special type of readout). There is no recovery required for this error.

The relevant limitation is as follows:

VIS-L-010: The readout phase in trap pumping sequences can last longer than the maximum readout time of 78s, which is hardcoded in CPDU FPGA, depending on the settings applied (number of lines, number of shuffles, dwell time, …). When this happens, the CDPU will report a ROE timeout error.

Quality control parameters

DataModel: https://gitlab.euclid-sgs.uk/

Contact person

Calibration Lead