Read Noise and Dark Current Stability

Principal: Karl Gordon
Deputy: James Muzerolle, Karl Misselt
Data Monkey(s):
Priority: Desired
Downlink Priority: Normal
Analysis Time: 72
Last Updated:

Objective

The stability of the read noise and dark current measurements as a function of time are measured with this task and the standard IOC Dark tasks (MIPS-910, 911, & 912).

Description

This task should be executed in a campaign with a length longer than 1 day at the beginning of which all three standard IOC Dark tasks have executed (MIPS-910, 911, & 912). This task should be executed about 1 day into this campaign.

Point to the 24µm dark position and take dark measurements using the 10 sec Dark IER and read noise measurements using the 10 sec Read Noise IER.

Point to the primary 70µm dark position (#1) and take dark measurements using the 10 sec Dark IER and read noise measurements using the 10 sec Read Noise IER.

Point to the secondary 70µm dark position (#2) and take dark measurements using the 10 sec Dark IER and read noise measurements using the 10 sec Read Noise IER.

Point to the 160µm dark position and take dark measurements using the 10 sec Dark IER and read noise measurements using the 10 sec Read Noise IER.

Data Collected

Each Ge dark current dataset will contain 35, 10 second DCEs with stim flashes every 11 DCEs. The is will result in 3 such datasets for the Ge arrays.

The read noise datasets will each contain 50, 10 second DCEs with no stim flashes. This will result in 3 such datasets for all three arrays.

Data Reformatting Requirements

Array Data Desired:

All Arrays

Data Reformatting Option:

Special Instructions:
The 35 dark current DCEs should be packed into a single FITS file with extensions. The 50 read noise DCEs should be packed into a single FITS file with extensions.

Task Dependencies

Calibration Dependencies

Output and Deliverable Products

The output of the dark current datasets is a dark current calibration image.

The output of the read noise dataset is a read noise calibration image.

The main output associated with this task (when combined with the standard IOC darks) will be characterization of the variability of the dark current and read noise measurements as a function of time. This task will measure the variability over a 1 day interval and the standard IOC Dark tasks will measure the variability over longer intervals (at least 1 week).

Data Analysis

The dark current datasets will be run through mips_sloper, mips_caler, and mips_enhancer with the appropriate switches. The script 'mips_makedark_ge' will be used to ensure that all the appropriate switches are set to these three programs. The dark calibration image will be created by mips_enhancer and will include uncertainties. The IDL program 'merge_dark70' will be used to merge the two dark positions into a single calibration image.

The read noise dataset will be run through mips_sloper. The resulting output will be used as input to the IDL program 'get_rdnoise.pro'. This program will output the read noise calibration image as well as a suitably averaged read noise measurment (over the entire array).

Software Requirements

Actions Following Analysis

If the level of variability is found to be very high, it might become necessary to take dark and read noise calibrations more often than once a campaign.

Failure Modes and Responses

If this task fails to produce useful data, it should be repeated.

Additional Notes