Timothee Greffe: Flat Field Forensics
tgreffe@caltech.edu
I go checking out the reports, digging up the dirt
You get to meet all sorts in this line of work
Treachery and treason, there's always an excuse for it
And when I find the reason I still can't get used to it
Bizarre dips observed in variance curves for many e2v CCDs are explained by Tim for the first time. The Downing Dip and the Bilgi Bump each flag different subtle charge transport problems which could have severely impacted ZTF. |
Date:
Wednesday, July 5, 2017
Time:
12:30 pm PST
Location: Caltech, Cahill 126
Communications:
Zoom |
https://zoom.us/j/6966624617 |
Meeting ID |
696 662 4617 |
Phone to Zoom |
+1 646 558-8656 +1 408 638-0968 |
Direct to Cahill 126: |
+1 626 395-8646 +1 626 395-8884 |
Attending: |
COO crew, Alan Uomoto and Jorge fm Carnegie |
Call-in: |
Greg Brethauer and co at STA |
Questions or comments:
- Click "edit" button above-right or below
- Alan U. asks how it is that Bilgi Bump is restricted to a narrow wignal window without affecting lower fluxes. Roger: good question. We don't know.
- Steve Kaye points out that a structural trap may empty when the clock is taken negative. Roger notes that charge could be pushed forwards (fm TG to serial register) or backwards. Coud the direction of travel be signal dependent?
- Tim notes that we are looking into using an InGaAs camera to look at CCD electrodes through a microscope. One needs the near IR since Silicon becomes trasparent beyond 1 µm.
Lyrics from
Private Investigation by Dire Straights (1982)