XIS Calibration Report 2006 Feb 22 (revised 2006 Feb23) K. Hayashida (Osaka Univ.) and the SUZAKU XIS team

Menu Minimum Notes on XIS data processing Gain/CTI QE degradation 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 Reduction Frame Data /8sec Event data XIS cleaned event list PHAS(6) PHAS(7) XIS Response depends on the reduction procedure PHAS(0) Frame Data /8sec Dark-level Subtraction Event Pickup (PHAS(0)>Event Threshold) 5x5 mode, 3x3 mode or 2x2 mode Event data Charge Trail Correction CTI correction Grading / PHA-reproduction for PHAS(i)>Split Threshold PHA-dependent Split Threshold for BI EHK screening Bad Columns Filter xisclean XIS cleaned event list Onboard DE On the ground

Darklevel Estimation and Subtraction Dark-level of each Pixel “Dark” is determined onboard after 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 ” increases dramatically. It makes error in pixel levels, and thus in PHA and in event number. *) D 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 Grades 02346 are used as X-ray events. grade0 grade1 Pixel level is maximum among 3x3 area and larger than Event threshold Grades 02346 are used as X-ray events. 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 grade0 grade1 grade2 grade3 grade4 grade5 grade6 grade7

Charge Trailing ACTY Some charge is deposited in trailing pixels Grade0 Grade2 events ACTY ０ １０００ ５００ ２００ Vertical Some charge is deposited in trailing pixels transfer Trailing charge Grade0 Grade2 PH

Charge Trail ＰＨ（２）= preceding pixel ，ＰＨ（７）=trailing pixel BI1 5.9keV X-ray incidence PH [ADU] RAWY a b Near readout node d c b Far from readout node a c d

PHAS(2),PHAS(7) Distribution before/after Charge Trail Correction PHAS [ADU] PH [ADU]

Charge Trail Correction Grade02346 event distribution ３００　　　　　　　　　　　　０ ３００　　　　　　　　　　　　０ couns counts not uniform! After Correction Berore Correction ０ ５００ １０００ ０ ５００ １０００ ACTY ACTY Save grade7 events Correction saves 10—20% of event at high energy

Calibration Source 55Fe Doors cannot be closed again Door Close Door Open Doors cannot be closed again

Q’ = Q(1-CTI)N → CTI = (Q- Q’) / Q / N Determination CTI parameters included in rev0.6 data (H. Yamaguchi) Q’ = Q(1-CTI)N → CTI = (Q- Q’) / Q / N Q = PHA(ACTY=0) Q : Initial charge Q’ : Readout charge N : Number of P transfer PHA(Y=0) – PHA (Y=896, T) PHA(Y=0)×896 Whole Area cal src data (8/11) CTI = CTI(Seg1) = CTI(Seg 2) = [CTI(Seg0) + CTI(Seg3)] / 2 Corner cal src data (8/15～11/20) CTI = CTI_CONST + CTI_NORM×(PHAS)CTI_POW In rev0.6… CTI_POW = -0.5 CTI_CONST = 0 T Q’(T) = PHA(ACTY=896, T)

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

Results of CTI correction Mn-Kα 5.84keV (rev0.3) → 5.88keV (rev0.6) Cal src (rev0.6) by Nakajima @2006/01 OVIII line 0.654keV CTI parameters should be improved. Cygnus Loop (rev0.6) by Katsuda (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 Transfer CTI is proportional to Ex-0.5 Need to be checked its accuracy with orbital data. Mn-Ka peak ch history was made with G02346 CTI correction is for each pixel PHAS[], G0 data should be employed. We need to check the energy scale in rev0.6 data with various 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 0 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) In this case, the systematic offset of ~4ch (~15eV) in the soft X-ray region is largely reduced. Si K edge (E=1839 eV)

PKS2155 (rev0.3) residuals Structure around Si-Kedge is mainly due to broken line approximation of the Ex-PHA relation. Should update Ex-PHA relation (PHA-PI conversion) in xispi

RXJ1856.5-3754 Discovered with ROSAT Nearby (D~120pc) Isolated Neutron Star X-ray spectrum is fitted with a simple blackbody ( against NS atmosphere model). R~4-5km Quark Star ?

Suzaku Obs 2005-10-24~10-26 RMF 20051210 a-d for XIS1 Rev0.3 data -10eV offset Suzaku Obs 2005-10-24~10-26 RMF 20051210 a-d for XIS1 a: Based Cal on the Ground b: a x excess0.15mmC c: Dead Layer =Design Value d: c x excess0.15mmC

Calibration Task Share Components Location X-ray Source QE reference Chip level CSR/MIT Fluorescent X-rays (C,O,F,Al,Si,P,Ti,Mn,Cu) ACIS chips calibrated at BESSY Camera without OBF +FM AE Osaka Grating Spectrometer 0.2-2.2keV Polypro-window Gas PC & XIS-EU Kyoto Fluorescent X-rays (Al,Cl,Ti,Mn,Fe,Zn,Se) Window-less SSD OBF Synchrotron Facility Synchrotron X-rays + monochrometer (Transmission measurement with PIN diode) Camera onboard the satellite ISAS/JAXA 55Fe

QE(PC)->QE(EU)->XIS BI1 QE -1deg offset slant-PC is assumed Best Fit Estimates HfO2 0.005mm fixed Ag 0.001mm fixed SiO2 0.000±0.0005mm Si depletion 43.6±0.7mm Constant Factor 0.961±0.003 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) Wabs x BBodyrad x Varabs O/C <10%

Suzaku/XIS Contamination Measurements 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 Gaussian emission lines Galactic + SMC absorption pure C absorption from contaminant (varabs) gain shift -5 eV ~ -15 ev r2 ~ 1.6 (FIs) to 2.5 (BI) OVIII NeIX NeX OVII MgXI 2005-08-13 2005-08-31 2005-12-16 2006-01-17 2006-02-02

XIS Contamination Rate empirical correction for observers contamination rate turnover (?) SMC NH uncertainty  systematic error ±0.02 m independent of epoch change in effective C column: chip slope intercept (1016 cm-2/day) XIS0 1.6 ±0.1 4.4 ±4.0 XIS1 2.7 ±0.1 -9.6 ±15 XIS2 3.1 ±0.1 -3.2 ±14 XIS3 4.1 ±0.5 54. ±50.

Count Rate History

Count Rate History

Count Rate History

Atmospheric N-K line Map XIS1(BI) From Anabuki et al.’s poster Color code is adjusted for each map 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

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) N-K line O-K line SN1006_NE_BGD Mrk 3 N-K line O-K line A2811_offset NGC 4388 MBM12_off Cloud

Center 6mm radius / Other area N-K line O-K line Mean Free Path in C(2.2g/cc) 0.182mm for N-K line 0.375mm for O-K 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 line O-K line [Central 6mm radius count rate] / [Outer area count rate] c.r.(center) - c.r.(outer)=0.9x10-3 mm/day c.r.(center)~ 2.5x10-3 mm/day c.r.(outer)=1.6x10-3 mm/day Time(sec)

Bad (CTE) Columns Bad CTE X-ray image (number of events /pixel) Bad CTE Typically long trail in each event. Sometimes flickering pixel is observed. Rows near the readout node can be used. Identification logic without accumulating 10^7events was developed. EU= 21 bad columns/chip XIS0=14, XIS1=50, XIS2=17,XIS3=24 How should we do for adjacent columns ?

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) parameters should be checked with 2006 data. Resolution decrease (inevitable with CTI correction) should 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).