MAXI - Monitor of All-sky X-ray ImageMAXI - Monitor of All-sky X-ray Image

Performance of the engineering Performance of the engineering model of the MAXI/SSCmodel of the MAXI/SSC

Katayama H.a, Tomida H.a, Matsuoka M.a,

Tsunemi H.a,b, Miyata E.a,b, Kamiyama D.b, and Nemes N.b

a) Japan Aerospace Exploration Agency (JAXA)

b) Osaka Universityhttp://www-maxi.tksc.jaxa.jp

MAXI - Monitor of All-sky X-ray ImageMAXI - Monitor of All-sky X-ray Image

Outline Outline

Overview of MAXI

Overview of SSC

Calibration system of SSC

Performance of the SSC-EM

Screening results of the flight CCDs

Summary and future plan

MAXI - Monitor of All-sky X-ray ImageMAXI - Monitor of All-sky X-ray Image

Overview of MAXIOverview of MAXI

All Sky X-ray Monitor on ISS

Attached to JEM-EF

Scanning all sky every 90 min

launched by HIIA Transfer Vehicle in 2008

Mission life ~ 2years

JEM

ISS motion

MAXI

MAXI - Monitor of All-sky X-ray ImageMAXI - Monitor of All-sky X-ray Image

Overview of MAXIOverview of MAXI

X-ray detectorsGas Slit Camera (GSC) Solid-state Slit Camera (SSC)

Attitude determination

Ring Laser Gyro (RLG)Visual Star Camera (VSC)

Thermal control system

ATCSLHPRS

MAXI - Monitor of All-sky X-ray ImageMAXI - Monitor of All-sky X-ray Image

Scientific target for MAXIScientific target for MAXI

GSC (Proportional counter)Energy range : 2-30 keVE/E=18%@6keV

Aeff=5340cm2

Long-term AGN VariabilityX-ray NovaeGRB afterglow

SSC (CCD)Energy range : 0.5-10 keVE/E=2%@6keV

Aeff =200cm2

Diffuse Galactic source (line mapping at OVII, OVIII)

HEAO-1 All Sky map

ROSAT All Sky map

MAXI - Monitor of All-sky X-ray ImageMAXI - Monitor of All-sky X-ray Image

Overview of SSCOverview of SSC

Slit + Slat collimator + CCDNumber of CCDs

16 CCDs　 X 2 Sensitivity

5.6mCrab/dayFOV

1.5x90Pointing accuracy

0.1Clocking

Parallel-summingOperation Temperature

<　 -60 oC (LHPRS+Peltier)

CCDs

CollimatorSlit

200mm

SSC-Z

SSC-H

MAXI - Monitor of All-sky X-ray ImageMAXI - Monitor of All-sky X-ray Image

SSC/CollimatorSSC/Collimator

FOV1.5X90 °

SlitTungsten slit Width 2.7 mm

Collimator24 thin slats

(~100m thickness,

2.4mm intervals)FOV1.5X90

Collimator

CCD

Slit

Slats of collimator(phosphorus bronze)

Tungsten slit

MAXI - Monitor of All-sky X-ray ImageMAXI - Monitor of All-sky X-ray Image

SSC/CCDSSC/CCD

FFTCCD-4673 (Hamamatsu)

Pixel size

24x24m

Number of Pixels

1024x1024

Depletion layer~70m

Coated with 2000Å Al

SSC-EM

112mm

244mm

MAXI - Monitor of All-sky X-ray ImageMAXI - Monitor of All-sky X-ray Image

SSC ElectronicsSSC Electronics

SSC Electronics (SSCE)

CCD driver / readoutPeltier control

CCD charge transfer rate = 125/62.5 kHzReadout noise < 5e- rmsEnergy resolution < 150 eV @ 5.9keV

SSCE-EM

MAXI - Monitor of All-sky X-ray ImageMAXI - Monitor of All-sky X-ray Image

Calibration system of SSCCalibration system of SSC

Calibration system using fluorescent X-ray

Second targets Al, Cl, Ti, V, Fe , Ni and Zn

Cool down -20 oC with cryogenic coolerKevex

X-ray generator

Target chamber

SSC chamber

MAXI - Monitor of All-sky X-ray ImageMAXI - Monitor of All-sky X-ray Image

Performance of the SSC-EM(1)Performance of the SSC-EM(1)

Energy spectrum of florescent X-rays

K, K peaks are clearly resolved Readout noise ~ 5e- Main peak + low energy tail

Spectra are fitted with double gaussian + constant

Energy scaleEnergy resolution

Al Cl Ti V

Fe

Ni

Zn

Cr

V spectrum

MAXI - Monitor of All-sky X-ray ImageMAXI - Monitor of All-sky X-ray Image

Energy Scale Energy scaleLinear function

0.1% accuracy

Energy resolution

Estimated energy resolution at 0.5 keV

~ 80 eV > 60 eV (0~5e-)

Measurement of low energy response below 2 keV is needed

Performance of the SSC-EM(2)Performance of the SSC-EM(2)

Energy resolution

MAXI - Monitor of All-sky X-ray ImageMAXI - Monitor of All-sky X-ray Image

Screening results of the flight Screening results of the flight CCDs (1)CCDs (1)

Screening of the flight CCDs at Osaka University (Miyata et. al 2004)

Flight candidate CCD 64

Flight CCD 32

Spare camera CCD 16

Energy resolution66 % of flight candidate CCDs show a good energy resolution below 150 eV

Kamiyama (2003)

MAXI - Monitor of All-sky X-ray ImageMAXI - Monitor of All-sky X-ray Image

Screening results of the flight Screening results of the flight CCDs (2)CCDs (2)

Quantum efficiencyQuantum efficiency at 5.9 keV is more than 90 % for almost all CCDs

90 % efficiency corresponds to the depletion layer of 70 m

Hot pixels and dead columns

The number of hot pixels and dead columns is very small

70m

MAXI - Monitor of All-sky X-ray ImageMAXI - Monitor of All-sky X-ray Image

Summary and future planSummary and future plan

We have developed the engineering model of the MAXI/SSC.

We achieved the low readout noise (~5e- rms) and a good energy resolution (150 eV @ 5.9keV).

We selected 32 CCDs for flight camera and 16 CCDs for spare camera. These CCDs show a good performance.

Future plan…

Measurements of the soft X-ray response and quantum efficiency.

Fabrication of the flight camera is schedule to start in the end of 2004.