XIS Calibration Report2006 Feb 22

(revised 2006 Feb23)

K. Hayashida (Osaka Univ.) and the SUZAKU XIS team

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• Minimum Notes on XIS data processing • Gain/CTI

– Charge Trail Correction – CTI Correction /Charge Injection– Ex-PHA Relation / Response

• QE degradation– RXJ1856,E0102,Cyg Loop, Earth Atmosphere– Modeling

• Background Study and Data Base– COR, PINUD dependence– Data Base and Subtraction method

• Data Selection Criteria• Bad Columns / Hot Pixels

XIS Data ReductionXIS Data Reduction

Frame Data /8secFrame Data /8sec Dark-level SubtractionDark-level Subtraction Event Pickup (PHAS(0)>Event Threshold)Event Pickup (PHAS(0)>Event Threshold) 5x5 mode, 3x3 mode or 2x2 mode 5x5 mode, 3x3 mode or 2x2 mode

Event dataEvent data Charge Trail CorrectionCharge Trail Correction CTI correctionCTI correction Grading / PHA-reproduction for PHAS(i)>Split ThreshGrading / PHA-reproduction for PHAS(i)>Split Thresh

oldold PHA-dependent Split Threshold for BIPHA-dependent Split Threshold for BI

EHK screeningEHK screening Bad Columns FilterBad Columns Filter xiscleanxisclean

XIS cleaned event listXIS cleaned event list

Onb

oard

DE

On

the

grou

nd

XIS Response depends on the reduction procedure PHAS(0)

PHAS(6) PHAS(7)

Darklevel Estimation and Subtraction• Dark-level of each Pixel “Dark” is determined onboard aft

er every SAA passage in DarkInit / DarkUpdate DE-mode.

• DE also calculate the Darklevel shift with time for each frame (8sec) for each (e.g. 64x64pixels) partition. We call it “LightLeak” value. – One LightLeak value for one partition

• Pixel-Level “PHAS[]” = Raw-Pixel-Level – “Dark” – “LightLeak”(of the Previous Frame)

• “LightLeak ” value shifts slowly in time. • Only when bright Earth come into the FOV, “LightLeak ” i

ncreases dramatically. It makes error in pixel levels, and thus in PHA and in event number.

• *) LLL(=increment of the LL from previous frame to the current frame) can be an indicator of such effect.

• *) “LightLeak written in the XIS data products is in 1/8 ADU unit.

Event Grades Event Grades Grades 02346 are Grades 02346 are

used as X-ray used as X-ray events.events.

grade0

grade1

grade2

grade3

grade4

grade5

grade6

grade7

Pixel level is maximum among 3x3 area and larger than Event threshold

Pixel level is larger than Split threshold and added to the PHA

Pixel level is larger than Split threshold but NOT added to the PHA

Ver

tica

l

transfer transfer transfer

Trailing chargeGrade0 Grade2

PH

Some charge is deposited in trailing pixels

Charge Trailing

Grade0 Grade2even

ts

ACTY ACTY０ １０００５００ ０ ５００ １００００

２０

０ ２０

０

０

Charge TrailCharge TrailＰＨ（２）ＰＨ（２） = preceding pixel = preceding pixel ，，ＰＨＰＨ

（７）（７） =trailing pixel=trailing pixel

PH [ADU] PH [ADU]

PH [ADU]PH [ADU]

Near readout node

Far from readout node

BI1 5.9keV X-ray incidenceR

AW

Y

d

c

b

a

a b

c d

PHAS(2),PHAS(7) Distribution before/after Charge Trail CorrectionPHAS(2),PHAS(7) Distribution before/after Charge Trail Correction 　　

PH [ADU] PH [ADU]

PH [ADU]PH [ADU]

PHAS [ADU] PHAS [ADU]

PHAS [ADU]PHAS [ADU]

not uniform!

cou

ns

Save grade7 eventsCorrection saves 10—20% of event at high energy

Charge Trail Correction

ACTY

Grade02346 event distribution

ACTYco

unt

s

Berore Correction After Correction

０ ５００ １０００ ０ ５００ １０００

３００　　　　　　　　　　　　

０ ３００　　　　　　　　　　　　

０

Calibration Source Calibration Source 5555FeFe

C C D(im ag in g re g io n )

O p tica l b lo ck in g filte r

D o o r

H in g eW in d o w

B o n n e t

C a lib ra tio n so u rce

C a lib ra tio nso u rce

Door Close

Door Open

Doors cannot be closed again

Determination CTI parameters included in rev0.6 data (H. Yamaguchi)

Whole Area cal src data (8/11)

Q = PHA(ACTY=0)

Corner cal src data (8/15 ～ 11/20)

T

Q’(T) = PHA(ACTY=896, T)

Q’ = Q(1-CTI)N

→ CTI = (Q- Q’) / Q / NQ : Initial chargeQ’ : Readout chargeN : Number of P transfer

CTI = PHA(Y=0) – PHA (Y=896, T)

PHA(Y=0)×896

CTI(Seg1) = CTI(Seg 2) = [CTI(Seg0) + CTI(Seg3)] / 2

CTI = CTI_CONST + CTI_NORM×(PHAS)CTI_POW

In rev0.6… CTI_POW = -0.5 CTI_CONST = 0

CTI correction in rev0.6

• Determine CTI_NORM for each quadrant– Column by Column difference is not taken into account.

• Fit CTI_NORM as a function of time with a straight line.• Make a CALDB table which has columns, time, CTI_NO

RM, CTI_CNST etc. One row per a week. • Fill (modeled) CTI_NORM.• Correction is done with a critical ftool “xispi” to PHAS[], a

fter Charge trail correction but in prior to event grading. – Corrected PHAS[] is not written in XIS event file.– In principle, gain shift by CTI is corrected in xispi (data reduction)

not in response. • Line broadening is inevitable even with CTI correction.

(Charge Injection data helps the broadening partially). The effect must be taken into account the response but not yet. – Response builder for that has almost prepared.

Cal src (rev0.6)by Nakajima

Cygnus Loop (rev0.6) by Katsuda

5.84keV (rev0.3) → 5.88keV (rev0.6)

@2006/01

Results of CTI correction

Mn-Kα

0.654keV

CTI parameters should be improved.

OVIII line

(CI data were obtained on 2006/01.)

Residual error in CTI Correction of rev0.6 • Simplified Assumptions:

– CTI (ACTY=0,t)=CTI(ACTY=0,t0=2005Aug) • There must be degradation in CTI Imaging to Frame Store Area Tra

nsfer– CTI is proportional to Ex-0.5

• Need to be checked its accuracy with orbital data.

• Mn-K peak ch history was made with G02346– CTI correction is for each pixel PHAS[], G0 data should be empl

oyed. • We need to check the energy scale in rev0.6 data with v

arious t, Ex, ACTY, (ACTX)– Feedback from SWG members will be acknowledged. Expected

Energy is sometimes uncertain. Need detailed knowledge for each source, too.

– (for XIS team) Ni-K line, Al-K etc in BGD might be useful, though its not certain they are imaging area event.

• NOTE: If Charge-Trail correction parameters mismatch, not only energy scale but also (effective) QE is affected.

Revision of Ex-PHA Relation: XIS2 Segment 0Revision of Ex-PHA Relation: XIS2 Segment 0

In this case, the systematic offset of ~4ch (~15eV) in the In this case, the systematic offset of ~4ch (~15eV) in the soft X-ray region is largely reduced.soft X-ray region is largely reduced.

Si K edge (E=1839 eV)

Old: Single linear function fit: 2 parameter model (caldb=ae_detgain_20050703.ext)

New: 2 linear functions for E<Esik and E>Esik: 4 parameter model (caldb=ae_xi2_makepi_2040822.fits)

PKS2155 (rev0.3) residuals PKS2155 (rev0.3) residuals

Structure around Si-Kedge is mainly due to broken line aStructure around Si-Kedge is mainly due to broken line approximation of the Ex-PHA relation. pproximation of the Ex-PHA relation.

Should update Ex-PHA relation (PHA-PI conversion) in xiShould update Ex-PHA relation (PHA-PI conversion) in xispispi

RXJ1856.5-3754RXJ1856.5-3754Discovered with ROSATDiscovered with ROSATNearby (D~120pc) Isolated Neutron StarNearby (D~120pc) Isolated Neutron StarX-ray spectrum is fitted with a simple X-ray spectrum is fitted with a simple

blackbody ( against NS atmosphere model).blackbody ( against NS atmosphere model).R~4-5km Quark Star ?R~4-5km Quark Star ?

Suzaku Obs 2005-10-24~10-26Suzaku Obs 2005-10-24~10-26RMF 20051210 a-d for XIS1RMF 20051210 a-d for XIS1

Rev0.3 data -10eV offset

a: Based Cal on the Ground

b: a x excess0.15mC

c: Dead Layer =Design Value

d: c x excess0.15mC

Calibration Task ShareCalibration Task ShareComponentsComponents LocationLocation X-ray SourceX-ray Source QE referenceQE reference

Chip levelChip level CSR/MITCSR/MIT Fluorescent X-rays (C,O,Fluorescent X-rays (C,O,F,Al,Si,P,Ti,Mn,Cu)F,Al,Si,P,Ti,Mn,Cu)

ACIS chips ACIS chips calibrated at calibrated at BESSYBESSY

Camera Camera without OBFwithout OBF

+FM AE+FM AE

OsakaOsaka Grating SpectrometerGrating Spectrometer

0.2-2.2keV0.2-2.2keV

Polypro-window Polypro-window Gas PC & XIS-Gas PC & XIS-EUEU

KyotoKyoto Fluorescent X-rays (Al,CFluorescent X-rays (Al,Cl,Ti,Mn,Fe,Zn,Se)l,Ti,Mn,Fe,Zn,Se)

Window-less Window-less SSDSSD

OBFOBF Synchrotron Synchrotron FacilityFacility

Synchrotron X-rays + moSynchrotron X-rays + monochrometernochrometer

(Transmission (Transmission measurement measurement with PIN diode)with PIN diode)

Camera Camera onboard the onboard the satellitesatellite

ISAS/JAXAISAS/JAXA 55Fe55Fe

QE(PC)->QE(EU)->QE(PC)->QE(EU)->XIS BI1 QEXIS BI1 QEBest Fit Best Fit EstimatesEstimates

HfO2HfO2 0.0050.005m fixedm fixed

AgAg 0.0010.001m fixedm fixed

SiO2SiO2 0.000±0.00050.000±0.0005mm

Si depletion

43.6±0.7±0.7mm

Constant Constant FactorFactor

0.961±0.0030.961±0.003

-1deg offset slant-PC is assumed

0.1

1

1 10

BI1_absQE

QE(Osaka)QE(Kyoto)QE(MIT)BI1 QEmodel with H2OBI1 QEmoel without H2OBI1-QE-model lowecut

Ex(keV)

Some data points exceeds 1

Difficult to reproduce 0.28keV QE with simple absorption models.

At low energy side, artificial cutoff in the form of erf(Ex) is introduced. This model QE is used as a new reference.

Rev0.6 data (with no gain shift)Rev0.6 data (with no gain shift)Wabs x BBodyrad x VarabsWabs x BBodyrad x Varabs

20 2

18 2

18 2

18 2

63.5 ( )

0.95 10 / ( )

1.49 0.04 10 /

0.00 0.09 10 /

0.00 0.14 10 /

H

C

N

O

kT eV fixed

N cm fixed

N cm

N cm

N cm

O/C <10%

Suzaku/XIS ContaminationMeasurements with E0102Suzaku/XIS ContaminationMeasurements with E0102

• E0102: SNR in SMC, bright in soft X-ray lines• excellent calibrator for low-E gain, QE changes

• contamination degrading low-E eff. area of all XIS’s

• model• thermal bremss + 24 Gau

ssian emission lines• Galactic + SMC absorption• pure C absorption from co

ntaminant (varabs)• gain shift -5 eV ~ -15 ev

• r2 ~ 1.6 (FIs) to 2.5 (BI)

2005-08-132005-08-312005-12-162006-01-17

OVIII NeIX NeX

MgXIOVII

2006-02-02

XIS Contamination RateXIS Contamination Rate

change in effective C column:

chip slope intercept(1016 cm-2/day)

XIS0 1.6 ±0.1 4.4 ±4.0XIS1 2.7 ±0.1 -9.6 ±15XIS2 3.1 ±0.1 -3.2 ±14XIS3 4.1 ±0.5 54. ±50.

• empirical correction for observers• contamination rate turnover (?)

• SMC NH uncertainty systematic error ±0.02 m independent of epoch

Count Rate HistoryCount Rate History

Count Rate HistoryCount Rate History

Count Rate HistoryCount Rate History

Atmospheric N-K line Map XIS1(BI)

N-K line

Day Earth

0 < DYE_ELV < 5

5 < DYE_ELV < 10

10 < DYE_ELV < 15

15 < DYE_ELV < 20

20 < DYE_ELV < 25

2005-8-13

2005-9-4 2005-10-22

2005-11-28

2005-12-24

2006-2-6

Color code is adjusted for each map

From Anabuki et al.’s poster

Atmospheric O-K line Map XIS1(BI)

0 < DYE_ELV < 5

Day Earth

5 < DYE_ELV < 10

10 < DYE_ELV < 15

15 < DYE_ELV < 20

20 < DYE_ELV < 25

2005-8-13

2005-9-4 2005-10-22

2005-11-28

2005-12-24

2006-2-6

Day Earth Radial Profile(vignetting corrected,normalized by center region)

E0102-72

N-K lineO-K line

N-K lineO-K line

N-K lineO-K line

SN1006_NE_BGD Mrk 3

N-K lineO-K line

N-K lineO-K line

N-K lineO-K line

A2811_offset NGC 4388 MBM12_off Cloud

N-K lineO-K line

Center 6mm radius / Other area Center 6mm radius / Other area

Mean Free Path in Mean Free Path in C(2.2g/cc)C(2.2g/cc)

0.1820.182m for N-K m for N-K lineline

0.3750.375m for O-K m for O-K line line

•Spatial Difference in Carbon contamination thickness can be modeled with Atmospheric N-K, O-K data.•Thickness at the center is evaluated by E0102 and RXJ1856 obs. •Thickness (t,detx,dety) will be modeled/introduced in arfbuilder (or rmfbuilder).

N-K lineO-K line

c.r.(center) - c.r.(outer)=0.9x10-3 m/day

[Central 6mm radius count rate] / [Outer area count rate]

c.r.(outer)=1.6x10-3 m/day

c.r.(center)~ 2.5x10-3 m/day

Time(sec)

Bad (CTE) ColumnsBad (CTE) Columns

Bad CTEBad CTE Typically long trail in each event.Typically long trail in each event. Sometimes flickering pixel is observed.Sometimes flickering pixel is observed. Rows near the readout node can be used.Rows near the readout node can be used.

Identification logic without accumulating Identification logic without accumulating 10^7events was developed. 10^7events was developed. EU= 21 bad columns/chipEU= 21 bad columns/chip XIS0=14, XIS1=50, XIS2=17,XIS3=24XIS0=14, XIS1=50, XIS2=17,XIS3=24

How should we do for adjacent columns ?How should we do for adjacent columns ?

X-ray image (number of events /pixel)

Calibration Status and Plan• QE degradation are going to be modeled as a function of

time and distance from the FOV center.E0102, RXJ1856, DarkEarth. => arf-builder or emfbuilder.– QE at C-K line on the ground is ½ of the orbital QE?

• CTI correction was introduced in rev0.6 processing. Need to be checked in various sources. (Energy, time, position dependence) Feedback from SWG is expected.

• PHA->PI conversion (xispi) should be upgraded.• Charge Trail Correction (introduced from rev0.3) parame

ters should be checked with 2006 data.• Resolution decrease (inevitable with CTI correction) sho

uld be included in the response. rmf-builder can do it. CI measurement and CTI correction by each column might be used to save the degradation

• Background data base is under construction. Bad Columns data base should be updated.

• Data-Selection Criteria will be revised from (ELV>5 && DYE_ELV>20) to (ELV>5).