1. The HXMT in-flight calibration plan Shaolin XIONG, Shijie ZHENG, Liming SONG On behalf of HXMT SGS team Institue of High Energy Physics, China 11th IACHEC, IUCAA, PUNE (Feb 29, 2016)

2. 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
Science Obs.: pointing, survey & deep scan
Routine/Request Calibration
Commissioning
Phase
Nominal Operation
Phase 2 2

3. Performance Verification (PV) & In-Flight Calbiration
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

4. In-flight calibration (1): PSF
High Energy tel.
NaI/CsI
keV, ~5000 cm2
Medium Energy tel.
Si-PIN
5-30 keV, ~950 cm2
Low Energy tel.
SCD (CCD236)
1-15 keV, ~380 cm2
Hard
X-ray
Modulation
Telescope
Collimators!
ME HE LE 4

5. PSF & Boresight Offset
Scan the standard 'point' source (Crab or PSR B ) (~ 12 deg × 12 deg), 34 ks
Calculate the PSF and boresight for each collimator 5 5

6. In-flight calibration (2): Energy-Channel and FWHMHE
AGC with 241Am (1/det. unit)
Temp. range : 18 ± 2 °C ME
241Am (2/det. box)
Temp. range：-50 ~ 0 °C LE
55Fe (1/det. box)
Temp. range：-80 ~ -30 °C
Fluorescent lines (73Ta)in HE
Calibration Source
Radioactive sources on-board
Fluorescent lines
Lines from celestial objects
Monitoring the temp. dependence
Tycho Spectrum
Fe Kα Line, 126ks(3 σ) obs is needed 6 6

7. 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

8. In-flight calibration (4): Timing precision
Pointing observation the Crab/PSR B
TOA (Time of Arrival) ~ 10 μs
Obs Time:
10ks for Crab
1Ms for PSR B 8 8

9. Background Estimation and Modeling
BKG components
CXB instant variable
Albedo instant variable
Particles instant highly variable
Radioactivated delayed 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 9

10. In-flight calibration (5): Bkg model
BKG observations to the Blank sky and Night Earth
routine observations
Known sources and Blank sky 10

11. List of In-flight Calibration Sources
Source Name RA
DEC
Usage
Crab
83.63
22.01
RMF, ARF, Timing, PSF, boresight, etc.
PSR B
228.48
-59.14
Cas A
58.813
Data analysis, LE temperature drift
Tycho
6.334
64.150
Cyg X-1
299.59
35.20
Data analysis, quick-look
Sco X-1
244.98
-15.64
Mrk421
166.11
40.09
Blank Sky #1
4.3899
Background
(include: Night Earth)
Blank Sky #2
Blank Sky #3
8.8014
Blank Sky #4
Blank Sky #5
Blank Sky #6
Blank Sky #7
Blank Sky #8 11 11

12. 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 keV)
Please help us! 12

13. Thank you! 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