ACIS Instrumental Background Rejection Inefficiencies

09Mar99/fkb

Number of ACIS Background Events vs.
Event Grade & Amplitude Filter Measured at XRCF in Phase I

CCD
Type		 All Energies E <= 10 KeV
G02346 G0123456 B0-254 B0-255 G02346 G0123456 B0-254 B0-255
FI15015 18203 139435 781015 4629 5695 58091 628564
BI 4701 5448 25714 26636 1722 1987 5103 5320

[1] = 0.52 +/- 0.02 CR/frame at XRCF; [2] ~= 10 ct/CR (FI);

[3] ~= 1.5 ct/CR (BI); [4] 154704 frames (FI); [5] 33883 frames (BI).

Rejection Inefficiencies for Various Combinations of a
B0-254 Grade Filter and a 10 keV Amplitude Cutoff

CCD
Type		 B0-254 B0-254,<10keV <10KeV B0-254,<10keV B0-254,<10keV
B0-255 B0-254 B0-255 <10keV B0-255
FI 0.17853 0.41662 0.80480 0.09242 0.07438
BI 0.96539 0.19845 0.19973 0.95921 0.19158

Rejection Inefficiencies for Various Combinations of a
G0123456 Grade Filter and a 10 keV Amplitude Cutoff

CCD
Type		 G0123456 G0123456,<10keV <10KeV G0123456,<10keV G0123456,<10keV
B0-255 G0123456 B0-255 <10keV B0-255
FI 0.02331 0.31286 0.80480 0.00906 0.00729
BI 0.20454 0.36472 0.19973 0.37350 0.07460

Rejection Inefficiencies for Various Combinations of a
G02346 Grade Filter and a 10 keV Amplitude Cutoff

CCD
Type		 G02346 G02346,<10keV <10KeV G02346,<10keV G02346,<10keV
B0-255 G02346 B0-255 <10keV B0-255
FI 0.01922 0.30829 0.80480 0.00736 0.00593
BI 0.17649 0.36631 0.19973 0.32368 0.06465