160 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 both of the 160 µm stimulators, and that the array responds to light from them. Additionally to measure 160 µm stim brightness vs. DAC setting. The 70 µm stimulators are also exercised in this test, and those data will be particularly suitable for looking for the first-stim-bad effect (see meta-task MIPS-2045).

Description

The telescope is pointed to the CVZ dark position, and 4 sets of 32 3 second DCEs are taken in order to exercise both 160 µm stimulators and to operate the Flood-A stim at 3 different brightness levels. Each of the 4 sets includes an initial background DCE, followed by 31 DCEs with a stim flash every 5 DCEs for a total of 6 flahses. The 70 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 4 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
5 Flood A Normal Flood A 1/2
6 Flood A Normal Flood A 1/4

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
5	Flood A	Normal	Flood A	1/2
6	Flood A	Normal	Flood A	1/4

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 160 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). The 70 µm Flood A data will be particularly suited for this ancillary purpose if they are grouped together, resulting in a dataset with 32 x 3 DCEs, with 18 stim flashes overall, and 3 stim flashes that fall on the first DCE of an exposure.

Data Collected

4 pairs of exposure commands are issued, providing a background DCE followed by 31 DCEs with a stim on the first and every 5th thereafter. A total of 128 DCEs will be taken on each array.


IER is available here.

Data Reformatting Requirements

Array Data Desired:

160 and 70 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 4 160 µm fits extension files, each one containing all data pertaining to a particular stimulator or stim/DAC setting combination. The 70 micron data should be repacked similarly.

Task Dependencies

None beyond the global critical tasks.

Calibration Dependencies

Ground-test plots of

stim brightness vs. DAC setting.

Output and Deliverable Products

4 plots of array-averaged signal and signal on 4 example pixels vs. DCE # for each stimulator or stimulator/DAC setting combination for the 160 µm; data.

A single plot showing the brightness vs. DCE number for the 3 datasets taken using the 70 µm Flood A stim should be prepared, to look for the first-stim-bad effect.