CALBLOCK-PV-031: VIS Blooming threshold and persistence

Observation configuration file

ocf_CALBLOCK-PV-031.csv

Scheduling

Once, during PV phase.

In case of failure, repeat at next possible opportunity.

Time-critical

No

Dependencies

VS-CU commissioned

Objective

Obtain pairs of flat field images at high fluence. Detect the onset of blooming in the difference images of the pairs (drop in variance, i.e. the PTC curve). Intersperse darks to check for persistence.

Observations

It is mandatory to take pairs of flat fields at the same dither position. Several pairs at different fluence can be taken at the same dither, before introducing a dither slew to allow for antenna repointing. Flat field pairs cannot be accommodated in the ROS, and must therefore be taken on their own. Darks are interspersed to check for the onset of any persistence effects. Short science (SS) exposures are needed to mask bright sources. Very high fluence flats that will saturate the central detectors are taken at the end; this is because VI-CU has a 40% lower flux at the corners of the FPA, and we need to get high fluxes for them as well.

These calibrations are independent of wavelength and thus use LED3 with a current of 3 mA. At this current, the LED intensity corresponds to 6500 ADU/s:

LED3 signal [ADU/pixel/s] = -9557 + 5353 * I [mA] for I>= 3 mA

Observation instructions 48: Dithered flat field pairs to detect the onset of blooming. The SS image has the same integration time as the one in the ROS. A reference Dark must be taken at the beginning prior to high illumination to heck for persistence. All darks in this sequence have 300 s integration time. Dithers are random in a 3’ box.
BIAS, DARK, dither
SS, 2 flats each at fluences: 41.0, 42.5 kADU, DARK, dither
SS, 2 flats each at fluences: 44.0, 45.5 kADU, DARK, dither
SS, 2 flats each at fluences: 47.0, 48.5 kADU, DARK, dither
SS, 2 flats each at fluences: 50.0, 51.5 kADU, DARK, dither
SS, 2 flats each at fluences: 53.0, 54.5 kADU, DARK, dither
SS, 2 flats each at fluences: 56.0, 57.5 kADU, DARK, dither
SS, 2 flats each at fluences: 59.0, 60.5 kADU, DARK, dither
SS, 2 flats each at fluences: 62.0, 65.0 kADU, DARK, dither
SS, 2 flats each at fluences: 75.0, 85.0 kADU, dither
DARK 5x, dither

Fulfilling

CALPRODUCT-VS-020: VIS Blooming threshold

CALPRODUCT-VS-027: VIS Persistence

CALPRODUCT-VS-018: VIS Extended Pixel Edge Response (CTI-EPER) (partially, high fluence end)

CALPRODUCT-VS-011: VIS Photon Transfer Curve (PTC) (partially, high fluence end)

CALPRODUCT-VS-004: VIS Brighter-fatter Effect (BFE) (partially, high fluence end)

Targets and pointing constraints

Pointing: Straylight suppression as per MOCDA-SYS-003.

Table 66: SELFCAL-FAINT CSV file

# ID

R.A.

Dec

SELFCAL-FAINT

268.51

65.09

Instrument configuration

Instrument: VS-CU LED3 on

Inter-operability constraints

None.

In-orbit duration

In-orbit Duration: 6.9 h + dither (x11)

Assuming execution, readout and processing (including 20s buffer) times of:

5s + 72s + 215s for biases,

305s + 72s + 215s for darks,

102s + 72s + 250s for SS,

15s + 72s + 385s for the high fluence flats.

If TC is executed directly after the previous TC’s readout, a 3s buffer is applied between the end-of-RO and the TC.

Note that 66s of CDPU processing time has been absorbed into each dither/slew.

Data volume

38883 MB

Single [SS, FF pair, FF pair, Dark] pointing block: 4*835MB (VF) + 450MB (VS) + 323MB (VD) = 4113 MB

Note that a single pointing cannot generate data larger than 0xFF000000=4278MB (base-10)

Total: 36*835MB (VF) + 9*450MB (VS) + 14*323MB (VD) + 250MB (VB) = 38883 MB

Processing input

Ground Processing Input Data: BPM, nonlinearity calibration correction, ground-based QE

Data Description: 1 VIS bias for monitoring, 2 VIS flats per LED fluence; 1 SS per dither for bright source masking, and 1 dark per dither for persistence. Total: 36 flats, 9 SS, 14 darks, 1 bias.

Processing output

PTC curves, gain and CTI EPER for each detector.

Required accuracy, constraints

N/A

Processing tools

L1 small scale flat pipeline, trending statistics

Quality control parameters

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

Contact person

VIS instrument scientist