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ACIS Bad Pixels and Columns for FP temperature = -120 C

R. Edgar and M. Markevitch  (6/28/01, updated 5/13/03)
cxccal@cfa.harvard.edu
Previous releases: Related:
R. Edgar, 2001 Jun 28:

In the process of making event lists for the ACIS background, Maxim Markevich has identified a number of bad pixels and/or columns on the ACIS chips operating at -120 C. This proposed list has been examined, compared with a similar list based on Bev LaMarr's examination of bias frames, and a final list was agreed to.

The details follow:

Making a bad pixel/bad column list:

[1] Look at Maxim's images by eye and flag bad columns and pixels, grading the columns strong/weak/very weak/node boundary/flight.

[2] make histograms vs. chipx and list columns greater than + 2 sigma. This is the mk_chipx_histo.csh script. Compare in detail. Also compare to Bev's criticisms. Edit list by hand (this procedure doesn't do very well at limited chipy extents, for instance).

[2a] Get everyone to agree on the list (Maxim, Bev, cc: Mark Bautz).

[3] Glenn asked for 1-1024 in chipy instead of 2-1023 as Maxim had.

[4] Turns out the tool adds padding around bad pixels/columns, so remove that from the list. Also add a flag field so I can remember what's going on, include everything, and then strip out only the real bad columns to send to Glenn.

[5] extract using

row < badpix_C_200922_full.rdb Note eq W or Note eq S or Note eq BP

for Glenn. Note column is S (strong) W (weak) VW (very weak), F (Flight), FB (Flight boundary), NB (Node boundary), or BP (bad pixel). This gives only the bad columns (strong or weak) and bad pixels, and no node boundaries and no next-to-bad columns.

The list of flight software excluded bad pixels is then added to this file, called badpix_C_200922.rdb.

Following is the file (in human-readable RDB format) delivered to SDS/Glenn Allen for generation of the CALDB entry:

M. Markevitch, 2003 May 13:

The above list has been made into the CALDB file acisD2000-01-29badpixN0001.fits (and its copies acisD2000-07-04badpixN0001, acisD2000-07-06badpixN0001, acisD2000-08-12badpixN0001).

Since its creation, new bad pixels and columns appeared. From searching grade-filtered event files for permanent bright pixels giving on average >0.1 cts/ks and for obvious permanent bad columns, the following were identified: 

-------------------------
ccd_id chipx chipy
-------------------------
Starting from 2000-11-28:

6      766   501
8      518   1-1024 *
8      630   1-1024
8      874   1-1024
8      878   1-1024
8     1005   1-1024
8     1009   1-1024
(* date of first appearance for these columns is approximate)
-------------------------
Starting from 2002-01-23:

9      150   374
-------------------------
Starting from 2002-10-05:

4      885   460
5      383   586
5      357   303
-------------------------
No other permanent bad pixels or columns are seen as of the long ACIS-I and ACIS-S observations in March 2003. Adding the above new finds to the original -120C list, the following new lists were created, to be included in the CALDB and applied to the data as of the start date in the filename:

For quick reference, below is the list of bad pixels and columns in the latest observations (file acisD2002-10-05badpixN0001). CHIPX0, CHIPX1, CHIPY0, and CHIPY1 are the boundaries of a rectangle defining a region of bad pixels; for a single pixel, CHIPX0=CHIPX1 and CHIPY0=CHIPY1. Notes: F = excluded onboard, S = strong column, W = weak column, BP = bad pixel.

Bad Pixels Table
CCD ID Type Position Note CHIPX0 CHIPX1 CHIPY0 CHIPY1
0 FI I0 F 71 73 1 1024
0 FI I0 W 79 79 1 1024
0 FI I0 S 81 81 1 1024
0 FI I0 S 95 95 1 1024
0 FI I0 W 165 165 1 1024
0 FI I0 W 226 226 1 1024
0 FI I0 W 484 484 1 1024
0 FI I0 W 580 580 1 1024
0 FI I0 S 1010 1010 1 1024
0 FI I0 S 1015 1015 1 1024
0 FI I0 F 303 303 253 253
1 FI I1 W 54 54 1 1024
1 FI I1 W 97 97 1 1024
1 FI I1 F 303 303 1 1024
1 FI I1 F 409 409 1 1024
1 FI I1 W 521 521 1 1024
1 FI I1 W 558 558 1 1024
1 FI I1 W 583 583 1 1024
1 FI I1 W 691 691 1 1024
1 FI I1 W 704 704 1 1024
1 FI I1 S 1008 1008 1 1024
1 FI I1 BP 533 533 33 33
2 FI I2 W 23 23 1 1024
2 FI I2 W 127 127 1 1024
2 FI I2 S 134 134 1 1024
2 FI I2 W 162 162 1 1024
2 FI I2 W 437 437 1 1024
2 FI I2 W 548 548 1 1024
2 FI I2 S 559 559 1 1024
2 FI I2 W 570 572 1 1024
2 FI I2 W 671 671 1 1024
2 FI I2 W 699 699 1 1024
2 FI I2 W 818 818 1 1024
2 FI I2 W 930 930 1 1024
2 FI I2 S 1018 1018 1 1024
3 FI I3 W 474 474 1 1024
3 FI I3 W 492 492 1 1024
4 FI S0 BP 885 885 460 460
4 FI S0 W 9 9 1 1024
4 FI S0 S 39 39 1 1024
4 FI S0 S 107 107 1 1024
4 FI S0 W 162 162 1 1024
4 FI S0 S 197 197 1 1024
4 FI S0 S 363 363 1 1024
4 FI S0 S 488 488 1 1024
4 FI S0 S 507 507 1 1024
4 FI S0 W 544 544 1 1024
4 FI S0 S 586 586 1 1024
4 FI S0 W 601 601 1 1024
4 FI S0 S 628 628 1 1024
4 FI S0 W 839 839 1 1024
4 FI S0 S 862 862 1 1024
4 FI S0 S 876 876 1 1024
4 FI S0 W 890 890 1 1024
4 FI S0 S 956 956 1 1024
4 FI S0 S 968 968 1 1024
5 BI S1 S 233 233 313 322
5 BI S1 S 233 251 313 313
5 BI S1 S 671 671 1 1024
5 BI S1 BP 161 161 206 206
5 BI S1 BP 226 226 564 564
5 BI S1 BP 341 341 427 427
5 BI S1 BP 367 367 497 497
5 BI S1 BP 607 607 281 281
5 BI S1 BP 716 716 718 718
5 BI S1 BP 1022 1023 166 167
5 BI S1 F,BP 383 383 585 586
5 BI S1 F 792 792 351 351
5 BI S1 BP 357 357 303 303
6 FI S2 BP 766 766 501 501
6 FI S2 S 58 58 1 1024
6 FI S2 S 585 585 1 1024
6 FI S2 W 683 683 1 1024
6 FI S2 W 1003 1003 1 1024
7 BI S3 F 496 498 441 1024
7 BI S3 S 497 497 1 40
7 BI S3 W 738 738 973 1024
8 FI S4 W 2 2 1 1024
8 FI S4 W 5 5 1 1024
8 FI S4 W 20 20 1 1024
8 FI S4 W 25 25 1 1024
8 FI S4 S 33 33 1 1024
8 FI S4 W 453 453 1 1024
8 FI S4 W 514 514 1 1024
8 FI S4 W 516 516 1 1024
8 FI S4 W 518 518 1 1024
8 FI S4 S 541 541 1 1024
8 FI S4 W 630 630 1 1024
8 FI S4 W 632 632 1 1024
8 FI S4 W 874 874 1 1024
8 FI S4 W 876 876 1 1024
8 FI S4 W 878 878 1 1024
8 FI S4 W 910 910 1 1024
8 FI S4 S 952 952 1 1024
8 FI S4 W 966 966 1 1024
8 FI S4 W 1005 1005 1 1024
8 FI S4 W 1007 1007 1 1024
8 FI S4 W 1009 1009 1 1024
8 FI S4 BP 603 603 23 23
9 FI S5 BP 150 150 374 374
9 FI S5 W 93 93 1 1024
9 FI S5 W 328 328 1 1024
9 FI S5 S 409 409 1 1024
9 FI S5 W 962 962 1 1024

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Last modified: 11/15/10


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