CALBLOCK-REC-003: VIS CTI Charge Injection and Trap Pumping

Observation configuration file

ocf_REC-003_CI-ROS.csv
ocf_REC-003_PARALLEL-CI-HIGH.csv
ocf_REC-003_SERIAL.csv

Scheduling

This CALBLOCK is split into 3 variants: CI-ROS, PARALLEL-CI-HIGH, and SERIAL.

The CI-ROS variant executs Charge Injection Lines (CIL), run once each of ROS-01 through ROS-16 (as defined in CALPRODUCT-VS-005: VIS CTI Charge Injection Lines and CI config).

The PARALLEL-CI-HIGH variant runs Vertical Trap Pumping (VTP) of the subset with “VSH_Mode=234, high CI (IG1=4V)”, corresponding to VTP1 through VTP12 (as defined in CALPRODUCT-VS-025: VIS Trap Pumping and VTP config), which are repeated twice to mitigate for cosmic rays in the image area.

The SERIAL variant runs Serial Trap Pumping (STP) of the set “Serial_Mode_2_3 and IG1=4V” once, corresponding to once each of STP01, STP02 and STP03 (as defined in CALPRODUCT-VS-025: VIS Trap Pumping). This must be followed by 3x throw-away BIAS to mitigate the bias instability after the FPGA reset that happens after each STP execution.

Note on the SERIAL variant: Even after the 3x throw-away bias, the VIS bias offset, while spatially stable, will settle over the next few hours after running the STP. Hence the SERIAL variant must be either (1) the last to run before VIS is switched off, or (2) followed by bias-offset inseisitive measurements, such as CALBLOCK-F-008: VIS PSF Calibration and NISP photo nonlinearity, CALBLOCK-PV-025: VIS PSF Calibration (DEACTIVATED), or CALBLOCK-F-013: Phase Diversity.

In case of failure, repeat as soon as possible.

Time-critical

The 3 variants must be scheduled in close proximity to each other, The STP block should be scheduled either (1) as the last to run before VIS is switched off, or (2) followed by bias-offset inseisitive measurements, such as CALBLOCK-F-008: VIS PSF Calibration and NISP photo nonlinearity, CALBLOCK-PV-025: VIS PSF Calibration (DEACTIVATED), or CALBLOCK-F-013: Phase Diversity.

Dependencies

None

Objective

To acquire a minimal set of CIL/VTP/STP to measure the VIS detector trap density and charge injection levels before and after heating of the VIS detetctors. CTI calibration must be bracketed with the full decontamination segregating the pre- and post-decontamination CTI calibration regions, as heating is expected to change the trap density.

Observations

Charge injection (CI-ROS) followed by charge shuffling sequence (PARALLEL-CI-HIGH and SERIAL).

Observation instructions 59: Charge Injection Line (CI-ROS): A single execution each of ROS-01 through ROS-16, interleaved with BIAS for every 8 CI execution. The BIAS is necessary as a reference in the image area.
BIAS, ROS-01, ROS-02, ROS-03, ROS-04, dither
      ROS-05, ROS-06, ROS-07, ROS-08, dither
BIAS, ROS-09, ROS-10, ROS-11, ROS-12, dither
      ROS-13, ROS-14, ROS-15, ROS-16, dither
Observation instructions 60: Vertical trap pumping (PARALLEL-CI-HIGH): A single VTP-CI-high block is headed by a BIAS; a block consists of VTP01 to VTP12 repeated twice. VTP01 serves as a reference to all VTP with high charge injection. The 2x repeat is necessary to mitigate cosmic rays in the image area. The group of 12 VTP sequences (headed by VTP01) must be executed uninterrupted.
BIAS
VTP01
VTP02, 03, 04, dither
VTP05, 06, 07, 08, dither
VTP09, 10, 11, 12, dither
VTP01
VTP02, 03, 04, dither
VTP05, 06, 07, 08, dither
VTP09, 10, 11, 12, dither
Observation instructions 61: Serial trap pumping (SERIAL): The 3 sets of Multi-STP (MSTP) parameters constitute a single STP block, which is headed by a single reference BIAS. STP references are contained in each execution of a MSTP sequence. The MSTP block must be executed uninterrupted. 3x throw-away “trash” biases must be executed before resuming any other science sequences, to clear out the expected bias level perturbation from the FPGA reset that is executed after each STP. 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
Execute 3x throw-away BIASes, dither

Fulfilling

CALPRODUCT-VS-005: VIS CTI Charge Injection Lines (partial; covers the minimal set to observe differences before and after heating)

CALPRODUCT-VS-025: VIS Trap Pumping (partial; covers the minimal set to observe differences before and after heating)

Targets and pointing constraints

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

Instrument configuration

Instrument: Wide survey

Inter-operability constraints

None

In-orbit duration

In-orbit Duration (total): 5.1 h + dither (x11)

  • CI-ROS duration: 1.6 h + 4x dithers

  • PARALLEL-CI-HIGH duration: 2.8 h + 6x dithers

  • SERIAL duration: 0.7 h (STP) + 1x dithers

Data volume

Data Volume (total): 26,550 MB

CI-ROS: 14,500MB * (1/2) = 7,250 MB

PARALLEL-CI-HIGH: 24*VCH = 16,320 MB (VTP) [VCH = VIS CI high (full frame) = 680MB compressed]

SERIAL: 3*VM = 1,230 MB (STP) [VM = VIS Multi-STP (partial frame) = 410M compressed]

BIAS: 7*VB = 1,750 MB

Processing input

CI-ROS Half of the nominal CI-ROS set (32/2 = 16 settings) – total of 16 VIS (charge injection) image files.

Parallel-CI-high A single VMODE (x1) and CI level (x1) each for a set of 11 TOI_TP values to be used, plus a reference CI frame (zero shuffle), doubled – total of 24 (trap pumping) files.

Serial A single Shuffle MODE (x1) and CI level (x1) each, for 3 sets of configurations – total of 3 (trap pumping) files.

Data Description: CI-ROS: 16 full frames in different CI level configurations

Parallel-CI-high: 24 full frames in 12 different VMODE and CI level configurations

Serial: 3 frames with 1220 lines (full frame = 2086 lines)

Processing method

Binning, Cosmic Ray Flagging, CTI correction tools in VIS_CTI PE

VIS_CTI_TPCALIBRATE

Processing output

Updated parameters on the CTI model for that given observation data (.json of best fit parameters is stored via the DataModel).

Additional information and metadata on the model-fit (e.g. nested sampling samples, summary statistics).

Position, emission time constant and pumping efficiency estimate of each detected trap.

Required accuracy, constraints

R-CAL-B-VS-4351
R-CAL-B-VS-4355
R-CAL-B-VS-4356
R-CAL-B-VS-4357

Processing tools

VIS_CTI PE

VIS_CTI_TPCALIBRATE

Validation

TBW

Recovery

ROE timeout error is generated for any serial trap pumping (STP) that lasts longer than 78 seconds. This error message indicates a failure in STP data acquisition.

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. If the limitation is not respected, the readout will be interrupted issuing the event ROE READOUT TIMEOUT (MIB ID 310152049), the sequences will be stopped with a 1,8 and the acquired data will be lost.

For STP sequences (serial trap pumping is a special form of readout), tt is necessary to make sure that the settings (specifically, the combination of NROWS, SER_DWELL and SHUFFLE) are compatible with the timeouts in the system. For the MSTP sequence, it is the individual STPs in the MSTP that must obey this readout duration upper limit.

Readout time =  4 * toi_image + SER_SHUFFLE *(t_rphi * 6 + SER_DWELL * 0.000000001) + t_rphi * 3 * NoSerialPixels) * NROWS

Where

  • SER_DWELL is in units of [ns]

  • toi_image = 0.000999 [seconds]

  • t_rphi = 0.00000475 [seconds]

  • NoSerialPixels = 2128

Quality control parameters

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

Contact person

VIS instrument scientist