Progress Report on Modeling CTE in ACS/WFC TIPS May 19, 2011 Jay Anderson CTE in ACS/WFC Brief review Many many ISRs Riess, Mack, Chiaberge Massey et al paper in 2010 Modeled WPs in COSMOS images 50e- background ; assumed mini-channel Anderson/Bedin 2010 correction Modeled WPs in darks Two parameters: (q) - the density of traps at electron level (j;q)-the trail profile for electron level V low background; no mini-channel Implemented into CAL/ACS in Fall. Good job, but 25% 15% 10% Limitations to the Implemented Algorithm 1)1000s Darks are only so dark Could not probe below 30 e ACS team took shorter darks: 33s, 100s, 339s 99% chance of loss! (j;q) trail profile for electron level a surprise Lower e - traps have steeper trails Low trap trails go out to only 19 pixels High trap trails go out to 60 pixels New Model (q) trap density below 10e : >99% chance of loss! (j;q) trail profile for electron level a surprise Lower e - traps have steeper trails Low trap trails go out to only 19 pixels High trap trails go out to 60 pixels New Model (q) trap density below 10e : >99% chance of loss! (j;q) trail profile for electron level a surprise Lower e - traps have steeper trails Low trap trails go out to only 19 pixels High trap trails go out to 60 pixels ACS Team Plans 1) Port to Python / IRAFX 2) How to modify the error array? 3) How best to mitigate readnoise? 4) Column by column fine-tuning? 5) How does CTE impact S/N? (When pathological?) 6) Integrate into pipeline (darks, new products) 7) x-CTE and bias-shift effect de-striping, too 8) Time dependency 9) UDF/HDF comparisons 10) Validation against standard tests: recommendations 11) Optimization within Multi-drizzle NEXT: UVIS Column-by-Column dependency PHYSICAL PRE-SCAN MAGIC SQUARE OVER-SCAN DEEPLY EXPOSED FLAT ACS OVER TIME P1WP ACS OVER TIME P1WP JULY 2006 TEMP CHG BEFORE: 77 C AFTER: 81 C ACS OVER TIME P1WP FAR FROM; UNCORR FAR FROM AMP; CORR NEAR AMP; CORR