investigation into the strong residuals seen near the oxygen edge in mos spectra of
DESCRIPTION
Investigation into the strong residuals seen near the Oxygen edge in MOS spectra of bright continuum sources. Rate Dependent CTI effect ? Steve Sembay. Event 1. Readout direction. Event 2. Trap. Emission timescales for filled traps (Holland et al. 1993, NIMS, A326, 335). - PowerPoint PPT PresentationTRANSCRIPT
XMMEPICMOS
Steve Sembay ([email protected])Mallorca 08/04/08
Investigation into the strong residuals seen
near the Oxygen edge in MOS spectra of
bright continuum sources.
Rate Dependent CTI effect ?
Steve Sembay
XMMEPICMOS
Steve Sembay ([email protected])Mallorca 08/04/08
Emission timescales for filled traps
(Holland et al. 1993, NIMS, A326, 335)
kT
E
NXt
cthnne exp
1
σn electron capture cross section
Xn entropy factor
υth electron thermal velocity
Ncdensity of states in conduction band
E energy level of trap
T temperature
XMMEPICMOS
Steve Sembay ([email protected])Mallorca 08/04/08
Emission timescales for filled traps
(Holland et al. 1993, NIMS, A326, 335)
Level (eV)
te
(-90°C)
te
(-100°C)
te
(-120°C)0.17 0.07 µs 0.19 µs 1.1 µs
0.44 3.8 s 22.9 s 1.4 x 103 s
c.f. row transfer time of MOS = 15 µs
XMMEPICMOS
Steve Sembay ([email protected])Mallorca 08/04/08
Around O edge χ2 -> 3.90 – 2.13 with gain offset = 8.7±1.0 eV
XMMEPICMOS
Steve Sembay ([email protected])Mallorca 08/04/08
Around Si and Au edge: χ2 -> 1.025 – 0.998 Offset ~ 12.5 eV
XMMEPICMOS
Steve Sembay ([email protected])Mallorca 08/04/08
MOS v RGS Line Energy: N line ~ 432 eV J. Carter (Mallorca 06)
SW Obs.
Most MOS Large Window Mode
XMMEPICMOS
Steve Sembay ([email protected])Mallorca 08/04/08
Closed Cal Al line in small window mode
XMMEPICMOS
Steve Sembay ([email protected])Mallorca 08/04/08
Closed Cal Al line in small window mode
XMMEPICMOS
Steve Sembay ([email protected])Mallorca 08/04/08
Is there a “possible” gain shift at O: CTI dependent on rate?
Method 1: Analyse spectra from different regions
XMMEPICMOS
Steve Sembay ([email protected])Mallorca 08/04/08
1) 3C 273 0094
2) MKN 421 0165
3) MKN 421 0171
4) 3C 273 0277
5) H1426+428 0278
6) PKS2155-304 0362
7) PKS2155-304 0450
8) ARK 120 0679
9) H1426+428 0852
10) PKS2155-304 1095
11) PKS2155-304 1266
12) 3C 273 1299
13) MKN 421 1357
Sample of bright AGN/BL Lacs: The “Usual Suspects”
XMMEPICMOS
Steve Sembay ([email protected])Mallorca 08/04/08
MOS1
Count Rate v Offset
In Boxes
Before/After Cooling
XMMEPICMOS
Steve Sembay ([email protected])Mallorca 08/04/08
MOS2
Count Rate v Offset
In Boxes
Before/After Cooling
XMMEPICMOS
Steve Sembay ([email protected])Mallorca 08/04/08
Is there a “possible” gain shift at O: CTI dependent on rate?
Method 2: Flag precursor events from event file
XMMEPICMOS
Steve Sembay ([email protected])Mallorca 08/04/08
0
2
4
6
8
10
12
14
16
0 5 10 15 20
Offset All Events
Offs
et N
o Pr
ecur
sor
MOS1
MOS2
XMMEPICMOS
Steve Sembay ([email protected])Mallorca 08/04/08
|Summary:
Observed offset is not affected by removal of
precursor events in CCD RAWY direction
This suggests offset is not caused by incorrect
application of CTI measurement due to trap
filling in CCD.