1. MAXI - Monitor of All-sky X-ray Image Performance of the engineering model 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 University http://www-maxi.tksc.jaxa.jp

2. MAXI - Monitor of All-sky X-ray Image 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

3. MAXI - Monitor of All-sky X-ray Image Overview 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

4. MAXI - Monitor of All-sky X-ray Image Overview of MAXI X-ray detectors Gas Slit Camera (GSC) Solid-state Slit Camera (SSC) Attitude determination Ring Laser Gyro (RLG) Visual Star Camera (VSC) Thermal control system ATCS LHPRS

5. MAXI - Monitor of All-sky X-ray Image Scientific target for MAXI GSC (Proportional counter) Energy range : 2-30 keV E/  E=18%@6keV A eff =5340cm 2 Long-term AGN Variability X-ray Novae GRB afterglow SSC (CCD) Energy range : 0.5-10 keV E/  E=2%@6keV A eff =200cm 2 Diffuse Galactic source (line mapping at OVII, OVIII) HEAO-1 All Sky map ROSAT All Sky map

6. MAXI - Monitor of All-sky X-ray Image Overview of SSC Slit + Slat collimator + CCD Number of CCDs 16 CCDs X 2 Sensitivity 5.6mCrab/day FOV 1.5  x90  Pointing accuracy 0.1  Clocking Parallel-summing Operation Temperature < -60 o C (LHPRS+Peltier) CCDs Collimator Slit 200mm SSC-Z SSC-H

7. MAXI - Monitor of All-sky X-ray Image SSC/Collimator FOV 1.5X90 ° Slit Tungsten slit Width 2.7 mm Collimator 24 thin slats (~100  m thickness, 2.4mm intervals) FOV 1.5X90 Collimator CCD Slit Slats of collimator (phosphorus bronze) Tungsten slit

8. MAXI - Monitor of All-sky X-ray Image SSC/CCD FFTCCD-4673 (Hamamatsu) Pixel size 24 x 24  m Number of Pixels 1024 x 1024 Depletion layer ~70  m Coated with 2000Å Al SSC-EM 112mm 244mm

9. MAXI - Monitor of All-sky X-ray Image SSC Electronics SSC Electronics (SSCE) CCD driver / readout Peltier control CCD charge transfer rate = 125/62.5 kHz Readout noise < 5e - rms Energy resolution < 150 eV @ 5.9keV SSCE-EM

10. MAXI - Monitor of All-sky X-ray Image Calibration system of SSC Calibration system using fluorescent X-ray Second targets Al, Cl, Ti, V, Fe, Ni and Zn Cool down -20 o C with cryogenic cooler Kevex X-ray generator Target chamber SSC chamber

11. MAXI - Monitor of All-sky X-ray Image 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 scale Energy resolution Al Cl Ti V Fe Ni Zn Cr V spectrum

12. MAXI - Monitor of All-sky X-ray Image Low energy tail Comparison of 55 Fe spectrum of XIS and SSC Low energy tail shows similar trend but its level of SSC is about 5 times higher than that of XIS. Difference of gate structure? Energy [eV] Normalized counts MAXI/SSC ASTRO-E2/XIS

13. MAXI - Monitor of All-sky X-ray Image Energy Scale Energy scale Linear 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) Energy resolution

14. MAXI - Monitor of All-sky X-ray Image Screening results of the flight 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 resolution 66 % of flight candidate CCDs show a good energy resolution below 150 eV Kamiyama (2003)

15. MAXI - Monitor of All-sky X-ray Image Screening results of the flight CCDs (2) Quantum efficiency Quantum 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 70  m

16. MAXI - Monitor of All-sky X-ray Image Summary 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.