STIS Cycle-26 Calibration Phase-1 Last Revised: May 22, 2018 Proposal ID: Title: CCD Hot Pixel Annealing PI: Doug Branton Co-I(s): --------------------------------------------------------------------------- # Orbit estimates are TOTAL for all of cycle-26; assume 13 weeks # 01 October 2018 to 01 October 2019 Total Prime Orbits: 0 External Parallel Orbits: 0 Internals or no-impact orbits: 39 Comments on orbit estimate: 1 anneal will execute every 4th week using 3 orbits. --------------------------------------------------------------------------- # This section should be written with a GO audience in mind -- use # Calibration plans in WFPC-2 handbook as a guide. Purpose: To anneal hot pixels and the effectiveness of the CCD hot pixel annealing is assessed by measuring the dark current behavior before and after annealing. Description: The CCD Thermoelectric cooler will be turned off to allow the CCD detector temperature to rise from ~ -80 C to +5 C. The CCD will be left in the uncooled state for approximately 12 hours. At the end of this period the Thermoelectric cooler is turned back on and the CCD is cooled to its normal operating temperature. Since the CCD on Side-2 does not have thermistor, a 4 hour period, at a minimum, is necessary to ensure that the CCD is cool and stable Accuracy: 1% on hot pixel growth rate if possible Comments on Accuracy: Anneal the CCD and measure the growth rate of hot pixels Products: Hot pixel growth rate, median dark count rate, and a summary in the end of cycle ISR --------------------------------------------------------------------------- # THE REST OF THIS FORM IS FOR INTERNAL USE --------------------------------------------------------------------------- # Target information (copy for each target) Target Name.............................: n/a (internal) RA.............................................: n/a Dec...........................................: n/a Flux (and units)........................: n/a Visibility window (if known or relevant): n/a Comment on choice of target: n/a # Table of exposures (copy for each exposure): Target or lamp..........................: DARK Type of Acquisition.....................: Detector for observation................: STIS/CCD Operating mode .........................: Spectral Element........................: DEF Aperture................................: DEF Central Wavelength......................: Exposure Time...........................: 1100s Number of Iterations ...................: 3 BOP Predicted Local Count Rate for MAMA.: BOP Predicted Global Count Rate for MAMA: ETC PID IDs for Count Rates.............: Special Requirements or options.........: Comments: Take Exposure every 4th week. Target or lamp..........................: BIAS Type of Acquisition.....................: Detector for observation................: STIS/CCD Operating mode .........................: Spectral Element........................: DEF Aperture................................: DEF Central Wavelength......................: Exposure Time...........................: 0 Number of Iterations ...................: 1 BOP Predicted Local Count Rate for MAMA.: BOP Predicted Global Count Rate for MAMA: ETC PID IDs for Count Rates.............: Special Requirements or options.........: Comments: Take exposure every 4th week. Target or lamp..........................: TUNGSTEN Type of Acquisition.....................: FLAT Detector for observation................: STIS/CCD Operating mode .........................: ACCUM Spectral Element........................: MIRROR Aperture................................: 50CCD Central Wavelength......................: Exposure Time...........................: 0.6s Number of Iterations ...................: 3 BOP Predicted Local Count Rate for MAMA.: BOP Predicted Global Count Rate for MAMA: ETC PID IDs for Count Rates.............: Special Requirements or options.........: GAIN=4 Comments: Take exposure every 4th week. Target or lamp..........................: TUNGSTEN Type of Acquisition.....................: FLAT Detector for observation................: STIS/CCD Operating mode .........................: ACCUM Spectral Element........................: G750M Aperture................................: 52X2 Central Wavelength......................: 6768 Exposure Time...........................: 0.1s Number of Iterations ...................: 3 BOP Predicted Local Count Rate for MAMA.: BOP Predicted Global Count Rate for MAMA: ETC PID IDs for Count Rates.............: Special Requirements or options.........: Comments: Take exposure every 4th week. Target or lamp..........................: NONE Type of Acquisition.....................: Detector for observation................: STIS/CCD Operating mode .........................: ANNEAL Spectral Element........................: Aperture................................: Central Wavelength......................: Exposure Time...........................: 0 Number of Iterations ...................: 1 BOP Predicted Local Count Rate for MAMA.: BOP Predicted Global Count Rate for MAMA: ETC PID IDs for Count Rates.............: Special Requirements or options.........: Turn of TED for 12 hours and let cool and stabilize for 3 hours when turning the TEC back on. Comments: Take exposure every 4th week. --------------------------------------------------------------------------- # Special needs of this proposal? Scheduling: Schedule every four weeks. Start on October 01, 2018. Prerequisites: n/a PDB update? no On-board table update? no # Special Requirements: Real time? N Special commanding? N Quick Data turnaround? N Special timing required? N Other? N Describe (& justify) special requirements: ------------------------------------------------------------------------- # Link to Cycle 26 Science Fraction of science programs supported by this calibration: 16% of STIS total exposure time. List categories of science which can't be executed until after this proposal: none why: List categories of science which are best performed contemporaneous with this proposal: none why: --------------------------------------------------------------------------- Expected FTE weeks for analysis: 3 Required turnaround on analysis (weeks): 3 Data volume (Mb needed for analysis): 10.5Mb Special software needed for analysis? (Describe): Anneal_Monitor.py, replaces do_anneals.cl, anneal_darks.cl and common pixels. This script normalizes the darks to the ccd housing temperature and calculates the growth rates, anneal rates, number of hot pixels, and raw mean and median dark current. saa_plot.pro tracks whether a sub-exposure interacted with the SAA. Description of analysis Plans: Data reduction and analysis will be done using calstis and various Python and IRAF scripts. Data reduction will be done using calstis to reduce the raw fits files to cosmic ray rejected fits files. Analysis will determine the location, brightness and number of hot pixels from the pre and post-darks. From this analysis, comparisons of which hot pixels persist, hot pixels that are not affected by the annealing and annealed hot pixels are made. From these results the growth rate of hot pixels, annealed away rate of hot pixels, mean raw dark count rate and median dark count rates can be determined. Furthermore, from these results, linear expressions for mean raw and median count rates per day or year can be determined from linear fit routines. Further analysis will be done on both types of flats to evaluate if any window contamination was acquired during the annealing period.