ACIS
ACIS DOSE Registered-Photon-Map
The steps we took to compute the dose map are;
- Level 1 Event files for a specified month are obtained from archive.
- Image data including I2, I3, S2, S3 CCDs are extracted from all event files.
- All the extracted image data were merged to create a month long exposure map for the month.
- The exposure map is opened with ds9, and check a distribution of count rates against energy. From this, estimate the upper threshold value. Any events beyond this upper threshold are assumed erroneous events such as bad pixels.
- Using this upper threshold, the data is filtered, and create a cleaned exposure map for the month.
- The exposure map from each month from the Sep 1999 is added up to create a cumulative exposure map for each month.
- Using fimgstatistic, we compute count rate statistics for each CCDs.
- For observations with high data drop rates (e.g., Crab nebula, Cas A), we corrected the observations by adding events.
Please check more detail plots at Telemetered Photon Dose Trend page.
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Statistics: # IMAGE NPIX MEAN RMS MIN MAX ACIS_apr26 6004901 4.666 9.221 0.0 4760 I2 node 0 262654 4.424921 2.715923 0.0 60.0 I2 node 1 262654 7.952913 7.524962 0.0 1390.0 I2 node 2 262654 6.227916 4.433847 0.0 91.0 I2 node 3 262654 4.032045 3.011655 0.0 775.0 I3 node 0 262654 4.560207 2.803518 0.0 531.0 I3 node 1 262654 4.999564 11.176822 0.0 3546.0 I3 node 2 262654 4.873408 2.921109 0.0 81.0 I3 node 3 262654 4.352831 13.203416 0.0 4760.0 S2 node 0 262654 5.086079 7.594788 0.0 3181.0 S2 node 1 262654 5.940830 5.234009 0.0 895.0 S2 node 2 262654 6.483858 12.751416 0.0 4754.0 S2 node 3 262654 6.581736 5.232080 0.0 533.0 S3 node 0 262654 11.262649 28.196090 0.0 1546.0 S3 node 1 262654 8.900412 4.451340 0.0 166.0 S3 node 2 262654 8.269263 5.058890 0.0 136.0 S3 node 3 262654 7.093585 4.870077 0.0 154.0
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Statistics: IMAGE NPIX MEAN RMS MIN MAX ACIS_total 6004901 2783.326 3500.732 0.0 169725 I2 node 0 262654 2415.534197 492.317945 514.0 16322.0 I2 node 1 262654 2556.907449 723.233453 530.0 167719.0 I2 node 2 262654 2585.996292 556.439304 551.0 18190.0 I2 node 3 262654 2597.233028 685.482595 509.0 37929.0 I3 node 0 262654 2825.761913 731.395059 508.0 18320.0 I3 node 1 262654 2881.906682 1765.261722 537.0 56128.0 I3 node 2 262654 2578.502489 487.597262 504.0 15797.0 I3 node 3 262654 2548.821551 522.246232 487.0 38734.0 S2 node 0 262654 3240.776861 525.137966 1742.0 22717.0 S2 node 1 262654 3444.722584 789.973668 1917.0 23186.0 S2 node 2 262654 3823.510960 797.005670 2332.0 34584.0 S2 node 3 262654 3779.115147 659.352806 2050.0 90518.0 S3 node 0 262654 5759.987826 3174.065861 2522.0 56888.0 S3 node 1 262654 6957.084687 2420.148884 0.0 83602.0 S3 node 2 262654 5694.143696 1401.693573 2682.0 27887.0 S3 node 3 262654 4482.663418 800.542441 2691.0 26987.0
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The Mean Detrended CTI
We report CTIs with a refined data definition. CTIs were computed for the temperature dependency corrected data. Please see CTI page for detailed explanation. CTI's are computed for Mn K alpha, and defined as slope/intercept x10^4 of row # vs ADU. Data file: here
Imaging CCDs
Spectral CCDs
Backside CCDs
Focal Plane Temperature
Apr 2026 Focal Temperature
| The Mean (max) FPT: | |
|---|---|
| -107.53 | +/- 7.69 C |
| Mean Width: | |
| 0.8 | +/- 0.58 days |
Averaged Focal Plane Temperature
We are using 10 period moving averages to show trends of peak temperatures and peak widths. Note, the gaps in the width plot are due to missing/corrupted data.
Focal Plane Temperature, Sun Angle and Altitude
Bad Pixels
The plots below were generated with a new warm pixel finding script. Please see Acis Bad Pixel Page for details.
Front Side CCDs
Back Side CCD (CCD5)
Science Instrument Background Rates
| Name | Low (keV) | High(KeV) | Description |
|---|---|---|---|
| SSoft | 0.00 | 0.50 | Super soft photons |
| Soft | 0.50 | 1.00 | Soft photons |
| Med | 1.00 | 3.00 | Moderate energy photons |
| Hard | 3.00 | 5.00 | Hard Photons |
| Harder | 5.00 | 10.00 | Very Hard photons |
| Hardest | 10.00 | Beyond 10 keV |
HRC
DOSE of Central 4K Pore-Pairs
Please refer to Maximum Dose Trends for more details.
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IMAGE NPIX MEAN STDDEV MIN MAX HRCI_04_2026.fits 16777216 0.053 0.536 0.000 51.000
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IMAGE NPIX MEAN STDDEV MIN MAX HRCI_08_1999_04_2026.fits 16777216 na na na na
No Data
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IMAGE NPIX MEAN STDDEV MIN MAX HRCS_08_1999_04_2026.fits 16777216 na na na na
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Max dose trend plots corrected for events that "pile-up"
in the center of the taps due to bad position information.
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Gratings
Grating Trends/Focus
We plot the width of the zero order streak of ACIS/HETG observations and the width of the zero order image for HRC/LETG observations of point sources. No significant defocusing trend is seen at this time. See Gratings Trends pages.
Gratings Resolving Power
We plot E/dE vs. E for fits to detected lines with fwhm_error/fwhm less than 0.15 for the plus and minus arms of HEG, MEG, and LEG. Also shown are conservative (dotted line) and optimistic (dashed line) pre-launch resolving power expectations.
We have selected only calibration observations of Capella, HR1099, and Sigma Gem. See MIT technotes for a parallel analysis.
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PCAD
ACA Trending
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Gyro Bias Drift
Radiation History
Radiation Count Rates of Apr 2026
Sun Spot History (See:NOAA Page)
SIM
SIM Shift and Twist
SIM Shift and Twist Trend The following plots show trends of SIM shifts (dy and dz) and twist (dtheta). All quantities are directly taken from pcaf*_asol1.fits files. The units are mm for dy and dz, and degree for dtheta. We fit three lines separated before and after (Days of Mission)= 1400 (May 21, 2003), 2700 (Dec 11, 2006), and 4400 (Aug 07, 2011). The unit of slopes are mm per day or degree per day.
The sudden shift around DOM = 1400, 2700 and 4400 are due to fid light drift (see a memo by Aldcroft fiducial light drift). On the dtheta plot, two tracks are clearly observed. The track around 0.01 is due to HRC-I, and all others are clustered around -0.002. For more detail, please see SIM Shift and Twist Trend page
Trending
Quarterly Trends
- EPS Batteries
| Previous Quarter | |||||||
| MSID | MEAN | RMS | DELTA/YR | DELTA/YR/YR | UNITS | DESCRIPTION | |
| eb2ci | off | -1.762e-04 | 5.337e-05 | 0.27 +/- 0.12 | 0.01 +/- 0.01 | AMP | BATT 2 CHARGE CURRENT | on | 0.001 | 0.007 | 0.26 +/- 0.01 | (0.00+/-0.00)e0 |
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| eb2di | off | -1.924e-04 | 1.073e-04 | 0.03 +/- 0.25 | 0.02 +/- 0.02 | AMP | BATT 2 DISCHARGE CURRENT | on | 1.371 | 0.771 | 0.26 +/- 1.19 | (0.00+/-0.00)e0 |
| eb2v | off | -3.396e-04 | 6.320e-05 | 32.24 +/- 0.15 | -0.01 +/- 0.02 | V | BATT 2 VOLTAGE | on | -0.486 | 0.268 | 32.11 +/- 0.41 | (0.00+/-0.00)e0 |
| ecnv1v | -1.079e-05 | 4.406e-06 | 14.89 +/- 0.01 | 0.00 +/- 0.00 | V | CONV 1 +15V OUTPUT | |
| ecnv2v | -2.270e-05 | 4.581e-06 | 14.84 +/- 0.01 | -0.01 +/- 0.00 | V | CONV 2 +15V OUTPUT | |
| ecnv3v | -4.669e-06 | 2.609e-06 | 15.26 +/- 0.01 | 0.00 +/- 0.00 | V | CONV 3 +15V OUTPUT | |
- Spacecraft Electronics
| Previous Quarter | |||||||
| MSID | MEAN | RMS | DELTA/YR | DELTA/YR/YR | UNITS | DESCRIPTION | |
| elbi | 0.004 | 5.412e-04 | 52.77 +/- 1.28 | 0.09 +/- 0.16 | AMP | LOAD BUS CURRENT | |
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| elbv | off | -0.001 | 2.096e-04 | 26.90 +/- 0.12 | -15.32 +/- 2.58 | V | LOAD BUS VOLTAGE | on | 0.007 | 0.003 | 27.71 +/- 0.36 | (0.00+/-0.00)e0 | open | 0.004 | 6.854e-05 | 26.93 +/- 0.22 | 0.01 +/- 0.02 | clos | 0.603 | 0.427 | 26.91 +/- 0.64 | (0.00+/-0.00)e0 |
- OBA Heater
| Previous Quarter | |||||||
| MSID | MEAN | RMS | DELTA/YR | DELTA/YR/YR | UNITS | DESCRIPTION | |
| oobthr04 | -0.019 | 8.217e-04 | (3.05+/-0.02)e2 | 1.08 +/- 0.57 | K | RT 27: HRMA STRUT | |
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| oobthr12 | -0.021 | 0.001 | (3.04+/-0.03)e2 | 1.07 +/- 0.87 | K | RT 35: OBA CONE | |
| oobthr26 | -0.024 | 0.002 | (3.09+/-0.04)e2 | 1.21 +/- 1.27 | K | RT 48: OBA CONE | |
| oobthr38 | 2.911e-05 | 5.927e-06 | (2.72+/-0.00)e2 | (6.51+/-23.20)e-4 | K | RT 60: TFTE CONE | |
| oobthr44 | -0.023 | 0.001 | (3.06+/-0.03)e2 | 0.88 +/- 0.95 | K | RT 66: TFTE COVER | |
| oobthr50 | -0.019 | 9.762e-04 | (3.02+/-0.02)e2 | 1.11 +/- 0.74 | K | RT 76: S/C STRUT | |
Spacecraft Motions
TSC and FA Cummulative Moter Distance
HETG and LETG Cummulative Insertion Counts
HETG/LETG Insertion/Retraction Angle
Reaction Wheel Rotations
