70 µm Stim Response

Principal: J Stansberry
Deputy: D. Frayer
Data Monkey(s):
Priority: 1
Downlink Priority: Normal
Analysis Time: 2 Hours
Last Updated:

Objective

To verify operation of every 70 µm stimulator, and that the array responds to light from them. Additionally to get a rough measure of stim brightness vs. DAC setting for comparison with ground-test data. The 160 µm stimulators are also exercised, although telescopee background may be too high for 160 data when this task executes.

Description

The telescope is pointed to the CVZ dark position, and 6 sets of 32 3 second DCEs are taken in order to exercise all 4 70 µm stimulators and to operate the Flood-A stim at 3 different brightness levels. Each of the 6 sets include an initial background DCE, followed by 31 DCEs with a stim flash every 5 DCEs for a total of 6 flahses. The 160 µm stims are also exercised, although telescope background may be too high at the time of execution for the 160 µm data to be useful. The settings for the 6 data sets are:

Set 70 µm
Stim 70 µm Stim
Brightness 160 µm
Stim 160 µm Stim
Brightness

1 Flood A Normal Flood A Normal
2 Flood B Normal Flood B Normal
3 Flat A Normal Flood B Normal
4 Flat B Normal Flood B Normal
5 Flood A 1/2 Flood A Normal
6 Flood A 1/4 Flood A Normal

Set	70 µm Stim	70 µm Stim Brightness	160 µm Stim	160 µm Stim Brightness
1	Flood A	Normal	Flood A	Normal
2	Flood B	Normal	Flood B	Normal
3	Flat A	Normal	Flood B	Normal
4	Flat B	Normal	Flood B	Normal
5	Flood A	1/2	Flood A	Normal
6	Flood A	1/4	Flood A	Normal

The nominal DAC settings for the Flood A stims are 0x33 (70A) and 0x40 (160A). The 1/2 and 1/4 brightness settings for the 70 µm Flood A are 0x2d and 0x27, respectively. These data should be inspected to determine if the signal from the first stim flash in each set is anomalously high or low (the so-called first stim bad effect, see meta-task MIPS-2045). If the 160 µm data are not saturated, they will be particularly suited for this ancillary purpose if they are grouped into a Flood A dataset (32 x 3 DCEs, with 18 stim flashes overall, and 3 stim flashes that fall on the first DCE of an exposure), and a Flood B dataset (same structure).

Data Collected

12 exposure commands are issued to collect the 6 data sets described above. A total of 192 DCEs will be taken on each array.


IER is available here.

Data Reformatting Requirements

Array Data Desired:

70 and 160 µm

Data Reformatting Option:

SPECIAL

Special Instructions:
2 exposures should be packed into a single fits file: the beginning dark DCE and the following 31 DCEs with stims and backgrounds. The result will be 6 70 µm fits extension files, each one containing 32 DCEs pertaining to a particular stimulator or stim/DAC setting combination. The 160 µm data should be repacked similarly. The 24 µm data can be discarded.

Task Dependencies

None beyond the global critical tasks.

Calibration Dependencies

Ground-test plots of

stim brightness vs. DAC setting.

Output and Deliverable Products

6 plots of array-averaged signal and signal on 4 example pixels vs. DCE # for each stimulator or stimulator/DAC setting combination.

Data Analysis

The reformatted fits-extension files will be run through mips_sloper. The reduced data will be run through a standard MIPS IDL script, plot_mcnts.pro, to produce plots of brightness vs. DCE number and a listing of the stim brightness.

The data should be inspected for the "first stim bad" effect, particularly at 160 microns where there are 3 repeats of the 32 DCE cycle on the Flood A stim and 3 more on the Flood B stim. Plot_mcnts.pro can accept multiple files as input and will string them together in a single plot, which is an excellent way to see the first stim bad effect.