The HXMT inflight calibration plan Shaolin XIONG Shijie
The HXMT in-flight calibration plan Shaolin XIONG, Shijie ZHENG, Liming SONG On behalf of HXMT SGS team Institue of High Energy Physics, China 11 th IACHEC, IUCAA, PUNE (Feb 29, 2016)
In-flight operation procedures • • • Platform Functionality Test: ~ weeks – Time, pointing/scan, data, telemetry, SAA. . . Performance Verification (PV) – verify/optimize the detector performance Initial Calibration – Comprehensive tests. ~3 months Commissioning Phase Nominal Operation Phase Science Obs. : pointing, survey & deep scan Routine/Request Calibration 2
Performance Verification (PV) & In-Flight Calbiration Verification Verify the science-related performance of platform Pointing/scanning, slew rate, data transmission, etc. Verify/Optimize the payload performance Working Voltage, Thermal Control, Threshold setting, SAA Verify the Working Procedure of Ground Segment In-flight Calibration Methodology Measure the in-flight performance Adjust calibration data in CALDB derived from ground calibration Derive calibration products from CALDB Energy-Chan, Energy-FWHM; PSF, boresight; Eff. Area, RMF Time accuracy Uniformity between detectors *Background 3
In-flight calibration (1): PSF High Energy tel. Hard X-ray Modulation Telescope Na. I/Cs. I 20 -250 ke. V, ~5000 cm 2 Medium Energy tel. Si-PIN 5 -30 ke. V, ~950 cm 2 Collimators! Low Energy tel. SCD (CCD 236) 1 -15 ke. V, ~380 cm 2 ME HE LE 4
PSF & Boresight Offset • • Scan the standard 'point' source (Crab or PSR B 1509 -58) (~ 12 deg × 12 deg), 34 ks Calculate the PSF and boresight for each collimator 5
In-flight calibration (2): Energy-Channel and FWHM HE – – ME – – LE – – AGC with 241 Am (1/det. unit) Temp. range : 18 ± 2 °C 241 Am (2/det. box) Temp. range:-50 ~ 0 °C 55 Fe (1/det. box) Temp. range:-80 ~ -30 °C Calibration Source Radioactive sources on-board Fluorescent lines Lines from celestial objects Monitoring the temp. dependence Fluorescent lines (73 Ta)in HE Tycho Spectrum Fe Kα Line, 126 ks(3 σ) obs is needed 6
In-flight calibration (3): RMF, ARF, Eff. Area Pointing observing the Crab or cross-calibration the same source with other telescopes Adjust RMF and Eff. Area by fitting the observed data with the “known” source spectrum 7
In-flight calibration (4): Timing precision • Pointing observation the Crab/PSR B 1509 -58 • TOA (Time of Arrival) ~ 10 μs • Obs Time: 10 ks for Crab 1 Ms for PSR B 1509 -58 8
Background Estimation and Modeling BKG components – CXB instant – Albedo instant – Particles instant – Radioactivated delayed variable highly variable BKG Estimation Method – Multiple-FOV Method: Large FOV, small FOV, blind – Offset Pointing Method • Placing source offset from FOV center • ~ 10% of accuracy demonstrated by simulations BKG Modeling – Mass model, Monte Carlo code, orbit environment, etc. – In-flight BKG calibration observations – Establish/Adjust the BKG model 9
In-flight calibration (5): Bkg model BKG observations to the Blank sky and Night Earth routine observations Known sources and Blank sky 10
List of In-flight Calibration Sources Usage Source Name RA DEC Crab 83. 63 22. 01 PSR B 1509 -58 228. 48 -59. 14 Cas A 350. 846 58. 813 Tycho Data analysis, LE temperature drift Cyg X-1 6. 334 299. 59 64. 150 35. 20 Sco X-1 244. 98 -15. 64 Data analysis, quick-look Mrk 421 166. 11 40. 09 Blank Sky #1 145. 9975 Blank Sky #2 176. 4366 4. 3899 Background -20. 6326 Blank Sky #3 232. 5356 8. 8014 Blank Sky #4 251. 8799 55. 7135 Blank Sky #5 322. 4055 -24. 2587 Blank Sky #6 52. 6687 -59. 8347 Blank Sky #7 312. 2388 -11. 8415 Blank Sky #8 22. 5767 -76. 1370 RMF, ARF, Timing, PSF, boresight, etc. (include: Night Earth) 11
Internal/External Cross-Calibration Internal Cross-calibration Pointing observing the Crab or other sources Jointly fit HE/ME/LE data, check consistency and derive normalization factors between telescopes, etc. Cross-calibration with external telescopes Observe the same source simultaneously Adjust HXMT CALDB to match the calibrated telescopes Broad energy band for HXMT(1 -250 ke. V) Please help us! 12
Summary HXMT will launch around Nov 2016 In-Flight Calibration (initial cal. + routine cal. ) PSF & boresight Energy-channel, FWHM PSF, ARF, Eff. Area Timing precession Background (blank sky, night Earth) HXMT is open for collaborations! Cross-calibration & Guest proposals Thank you! 13
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