scale = 0 - 0.02
counts = (7.96 +/- 4.41)X10-3
scale = 0 - 0.02
counts = (15.0 +/- 11.1)X10-3
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This is the routine 70 µm dark and noise measurement. There were two such measurements in Campaign O. The first uses a stim flash DAC of 0x2D, while the second uses a stim flash DAC of 0x2F. The switch between DAC settings was done at the end of MIPS-180 by accident. The 70 µm array was run at 62/50 mV for side A/B in this campaign.
For the first dark measurment, the average dark current was (7.96 +/- 4.41)X10-3 MIPS70 units. The average noise was 1366.4 +/- 332.2 e for 10 MIPS second DCEs on side A with empirical CR rejection. This translates to a noise of 18.35 +/- 4.46 DN/sec on the slope measurement (118.5 +/- 49.3 DN/sec).
For the second dark measurment, the radhits were intense enough to cause saturation for most of the array. Thus, no dark or noise measurement is possible for the 2nd set.
For comparison to other campaign dark/read noise measurements as well as ground test data, see the meta task 2005.
The dark data were reduced using the DAT version 2-41. Sensitive cosmic ray detection (mips_sloper comandline switch -q) was used and the electronic nonlinearity correction was not applied. The read niose input into mips_sloper was 100 electrons. The dark datasets were run through mips_caler. Finally, the dark images for d2a and d2b were created using mips_enhancer. The mips_enhancer was run with the commandline options "-OW -OD -D". The noise was measured from the noise datasets using the get_rdnoise.pro program.
The d2a and d2b dark images were examined. As has already been reported elsewhere, side A has a bad readout (ramps offset below bottom rail) and side B has significant problems. The d2a position is darker than the d2b position, as expected. In fact, the d2a position is darker accross the entire array than the d2b position as has been noted in previous reports.
| 70 Dark A (d2a) | 70 Dark B (d2b) |
|---|---|
| stim DAC = 0x2D |
scale = 0 - 0.02 counts = (7.96 +/- 4.41)X10-3 |
scale = 0 - 0.02 counts = (15.0 +/- 11.1)X10-3 |
The noise were determined for both the d2a and d2b noise datasets. All pixels on side B basically have a cosmic ray detected in each DCE, it is not possible to measure the noise on this side using our standard method. In addition, many of the pixels on side A have many cosmic rays. Thus, both sides are better measured with an empirical cosmic ray rejection. Side A is measured using our standard method for consistancy with ground testing. Our standard method of measuring read noise is to determine the standard deviation of all the slopes of a pixel without detected cosmic rays. We used an empirical iterative sigma rejection of deviant slopes. We present measurements of the noise for sid A and B separately.
The noise measurement given here is the noise in excess of that expected from photon statistics.
Only d2a data is shown, d2b gives very similiar read noise results, expect for a factor of two higher dark current.
| Empirical Sigma Rejection (cut at 3*sigma) Side A |
Empirical Sigma Rejection (cut at 3*sigma) Side B |
|---|---|
| Flight Data (mips_IER_7323648_d2a_rn_A70_P24_10s) | |
| stim DAC = 0x2D | |
 scale = 0 - 2000 e counts = 841.7 +/- 350.2 e/s noise = 1366.4 +/- 332.2 e DCEs used = 48.19 per pixel 468 pixels |
 scale = 0 - 15000 e counts = 1267.6 +/- 1318.2 e/s noise = 10603.1 +/- 4427.1 e DCEs used = 44.64 per pixel 501 pixels |
The dark measured in the d2a position should be used for standard calibrations as it is darker than the d2b position. The noise on side B is much larger than that on side A, probably related to the electronic problems on side B.
The dark calibration image to be used for standard calibrations of campaign O data has been delivered and distributed with the suite of CamO cal files.
No direct actions necessary. Should evaluate if we need to take d2b data regularly at all.