Chandra High Energy Transmission Grating (HETG)

Line Response Function, E/dE, wings, scatter

• 081125 2-Gaussian Zeroth-order Streak Fit
• YYMMDD Grating Line Spread Function
  • Directory of CXC/MIT activities related to LSF products, etc.
• 021111_CXC Grating Line Spread Function
  • CXC/MIT useful info on LSF products.
• 010227 HETGS Resolution, 2/27/01
  • MARX-modelled HETGS E/dE performance for flight data use
• 000713 Wings of the HETGS LRF
• 000110 Measured and modelled zeroth-order 1D projections
• 990907 Focus analysis results from Capella observations
  • [X] Analyze Capella focus data - determine nominal HETG best focus.
• 990826 ACIS Pixel Randomization
• 990822 ACIS focus tests, 1-D FWHM expected for gratings

Focus Trends Monitoring, "HRMA" FWHM

• 131009 Zeroth-order 1D FWHM vs Time * updated *
• 130410 updated plot only * a few additional obsids added, same end date.
• 121031 Zeroth-order 1D FWHM vs Time New: files from TGCat, covers ~13 years.
• 100831 Zeroth-order 1D FWHM vs Time * updated *, covers ~11 years.
• 100105 Zeroth-order 1D FWHM vs Time * updated *, covers 10+ years.
• 090207 Zeroth-order 1D FWHM vs Time * updated *, covers 9+ years.
• 081020 Zeroth-order 1D FWHM vs Time New: No randomization, covers 8+ years.
• 080205 Zeroth-order 1D FWHM vs Time * updated *, covers 8 years.
• 071128 Zeroth-order 1D FWHM vs Time * updated * at ~ 8 years.
• 070517 Zeroth-order 1D FWHM vs Time * updated * over 7 years.
• 060728 Zeroth-order 1D FWHM vs Time * updated * ~ 7 years.
• 051024 Zeroth-order 1D FWHM vs Time * updated * 6+ years.
• 041026 Zeroth-order 1D FWHM vs Time * updated * 5+ years
• 040706 Zeroth-order 1D FWHM vs Time * updated again*
• 021113 Zeroth-order 1D FWHM vs Time * updated again*
• 020520 Zeroth-order 1D FWHM vs Time * updated again*
• 010227 Zeroth-order 1D FWHM vs Time * updated again*
• 000404 Zeroth-order 1D FWHM vs Time * updated *
• 000118 Zeroth-order 1D FWHM vs Time * first time *
  • [X] Measure and study zero-order FWHM vs time.
• 000110 Measured and modelled zeroth-order 1D projections

Wavelength Accuracy, ACIS-S Chip Gaps

• 041021 ACIS-S chip rolls, gaps and HEG-MEG relative period
  • [X] Create final adjustments of the ACIS chip gaps accurate to of order 0.1 pixel.
  • [X] Reconcile/calibrate the slight difference in HEG and MEG wavelengths.
• 021113 Chip gaps measurement with Capella obsid 2583
  • Confirm chip geom accurate to 0.5 pixel; explain gap measuring method
• 000922 ACIS Pixel-size change explains HETGS absolute wavelength error.
• 000706 HETGS Absolute Wavelengths - Preliminary
  • [x] Establish accuracy of CXCDS level 1.5 TG_LAM values compared to other calculations from the data.
  • [x] Evaluate time stability of HETG (HEG/MEG) wavelengths...
  • [x] Evaluate likely absolute accuracy of HETG (HEG/MEG) wavelengths, e.g., period x spacing values.
• 991127 HETG-ACIS-S, LETG-ACIS-S chip gap tables
  • New chip gap tables and s/w
• 991013 HETG-ACIS-S "Chip Gaps"-Update, Oct.'99
  • New gaps are looking good; HEG-MEG offset not repeatable.
• 990914 HETG-ACIS-S "Chip Gaps", Sept.'99
  • [X] Use Capella data to set ACIS-S CCD locations in dispersion direction (Chandra Y axis) so that plus and minus order wavelengths agree.

Dispersion Angles

• 990910 HETG Flight Angles, Sept.'99
  • [X] Determine updated values for the MEG and HEG grating angles.

Effective Area

• 061019 E0102 for Calibration
  • Using the HETG to model the spectrum of E0102 for calibration use.
• 040202 ACIS OBF contamination model, "fluffium"
  • One way to reconcile measurements of the ACIS contamination layer.
• 990924 HETGS BI ARFs.
  • HETGS Area if only BI CCDs are used.

ACIS PHA: Order Sorting, CTI effects

• 991202 SIM-Z Default Values to minimize CTI effect
  • Recommended SIM-Z offset values for HETG observations.
• 990923 CTI from HETG Data - Concept
  • HETG observations can measure FI CTI effects...
• 990921 CTI Criteria for HETG Use
  • Criteria for HETG-useful operation with CTI-degraded FI chips are presented... [11/27/99: CTI values less than 10x10^-4 will still allow clean order sorting.]
• 990920 ACIS-HETG Energy Comparisons
  • An initial comparison between early and later HETGS observations showing increased CTI effects (complicated by a focal-plane temperature change also.)

ACIS Pileup: Effect on Dispersed Spectra

• 070531 Pileup rate color-coded images
  • Software to make images to show level of pileup in an ACIS exposure.
• 991230 Pileup in HETGS Dispersed Spectra
  • Qualitative pileup levels seen in HETGS calibration observations.

Cross-Dispersion Profile

Background

Radiation Effects

• 010522 Proton Exposure Testing of HETG Gratings
  • No effect seen with 10 nC/cm^2 40-640 keV proton irradiation.

Other

• 000619 Effect of not-full HETG insertion on June 15, 2000
  • Effect of not-full HETG insertion on June 15, 2000
• 990923 OTG Operations as of 9/23/99
  • Details of OTG operations to date.
• 990915 HETG-HRC-I E/dE Performance, Sept.'99
  • Assess the effect of the flat HRC-I on HETG-HRC-I E/dE