These tests involve in-focus HSI observations of zero-order and diffracted orders of the gratings; in most of these tests the quadrant shutters are scanned. This data set can be analyzed for several purposes as given here.
- Looking for Zero-order Effects
-
The zero-order PSF when a grating is inserted is expected to be the same as the non-grating, HRMA-only PSF The tests identified in the table below allow the grating zero order image to be assembled from the four quadrant images and the relevant no-grating image to be assembled from the appropriate HRMA shell images. The plots show the projections of the images along the Y and Z axes; the HRMA projection is overlaid on the grating zero-order projection, shifted so that the peaks coincide.
There is a slight indication that the LEG zero-order is a little broader than the HRMA-only image - as would be expected from the coarse support diffraction. The fine support diffracted images are at about 290 um, outside of this field of view.
(plots above created with zero_order_effect.pro)Optic TRW_ID Date runid(s) comparison LEG D-LXH-SF-1.001 970103 107296,7,9,300 plots.ps MEG D-HXH-SF-1.002 970103 107301,2,3,4 plots.ps HEG D-HXH-SF-1.003 970103 107310,11,12,13 plots.ps Shell 1 D-IXH-PI-3.004 970104 107546 . Shell 3 D-IXH-PI-3.005 970104 107547 . Shell 4 D-IXH-PI-3.006 970104 107548 . Shell 6 D-IXH-PI-3.007 970104 107549 . Full
HRMAcombined '3.004-7 - - HRMA-HSI LRF at Al-K
( hist at 10 um bins .rdb )Full
HRMA*-IXF-P2-* Phase 1 several HRMA-FPCpinhole LRFs from Diab
- Detecting and Measuring Mis-aligned Gratings
-
Many in-focus and often shutter scanned measurements were made leading to the detection and quantization of the MEG mis-aligned gratings. Measurements also set limits on any HEG mis-aligned gratings.
*** The shell-quadrant images of Al-K +3 order were analyzed with hsi_alk_misaligned.pro to determine the angular offset of each mis-aligned grating, see the output plots (700K .ps). These plots show the 1D projection along the cross-dispersion axis (log-counts vs position) and the fits to these by up to three gaussians. The plots are for quadrants T, N, B, S from top to bottom on the page; one page for each line "***"ed above. The resulting mis-alignment angles are tabulated below; a systematic error estimated at 0.6 arc minutes applies.Grating Order Shutters TRW_ID Date runid(s) notes, etc. MEG +3 MEG,SCAN D-HXH-FC-1.010 970104 107463-6 to hlm,dsd links
***HEG +2 HEG,SCAN D-HXH-FC-1.011 970104 107467-70 . MEG +3 1,SCAN D-HXH-FC-28.001 970109 108026-29 *** MEG +3 3,SCAN D-HXH-FC-28.002 970109 108030-33 *** MEG +3 ALL,ALL, D-HXH-FC-28.003 970109 108034 . MEG -3 ALL,ALL, D-HXH-FC-28.004 970109 108035 . MEG +3 1,SCAN E-HXH-FC-28.001 970205 111316-9 *** MEG +3 3,SCAN E-HXH-FC-28.002 970208 111488-91 *** HEG +2 4,SCAN E-HXH-FC-28.005 970208 111492,4,5,6 . HEG +2 6,SCAN E-HXH-FC-28.006 970208 111497-500 . HESS Location Quadrant mis-alignment
(arc minutes)Comments 3EE2 T +7.6 . 3FF4 N -8.7 . 3FF5 N +24.8 . 3E1 B +7.0 . 1E4 B ~ +3 Not seen in SCAN data,
value inferred from ring image.1F4 S -5.8 .
- MEG mis-aligned gratings in Flight
-
Effects of the mis-aligned gratings in Flight
are demonstrated in the following
MARX simulations for different modeled roll properties of the MEGs:
- No Roll Variations
- 1 arc minute rms
- Actual roll as encoded in MARX 2.2, ~1.8 arc min rms plus mis-aligned facets
- Rowland Geometry and Virtual Detector
-
The set of Al-K FC measurements can be used to i) check the HSI focus and ii) by comparing the relative focus of various orders verify the Rowland Geometry: the translation of the HSI creating a kind of virtual detector on the Rowland circle. This is similar to the same kind of check carried out with the ACIS-S to check its Rowland conformance, see Mike Stage's SPIE paper.
For this analysis the SF and FC tests in orders 0, HEG+2, MEG+3 (above) are supplemented with the 1st order FC tests:
Grating Order Shutters TRW_ID Date runid(s) notes, etc. MEG -1 MEG,SCAN D-HXH-FC-1.006 970103 107NNN . MEG +1 MEG,SCAN D-HXH-FC-1.007 970103 107NNN . HEG -1 HEG,SCAN D-HXH-FC-1.008 970103 107NNN . HEG +1 HEG,SCAN D-HXH-FC-1.009 970103 107NNN .
HSI images of the Mg-K line in high order were taken on 970116 for each of the three Chandra gratings. The HSI was positioned at 6 defocus locations with respect to the optimal Rowland circle focus: -1000 um, -500 um, 0 um, +500 um, +1000 um, and +2000 um. A HRMA-only shutter focus set provides a reference for the Mg-K HRMA image without gratings in place.
In focus images ('i2) for LEG+5, MEG+3, and HEG+2:
(image height = 2000 um)
See all the images (i0 at top,
made with mgk_images.pro).
- Mg-K Grating Defocus Images
-
Grating Order TRW_ID runid -1000 -500 focus +500 +1000 +2000 MEG +3 D-HXH-dF-16.002 109002 i0 i1 i2 i3 i4 i5 HEG +2 D-HXH-dF-16.003 109003 i0 i1 i2 i3 i4 i5 LEG +5 D-LXH-dF-16.001 109001 i0 i1 i2 i3 i4 i5
- Mg-K HRMA-only Quadrant Images
-
TRW_ID runid Shutter D-IXH-SF-1.012 108997 T " 108998 N " 108999 B " 109000 S
These measurements should provide very useful information on the LRF in the core and near wings... Comparison of the 0, +1, and higher order (HEG 2nd or MEG 3rd) allows grating-induced effects to be untangled from HRMA PSF effects.
18 HETG measurements = 3 scans X 2 gratings X 3 orders
= [10um dispersion, 80um dispersion, 10um cross-disp] * [ HEG | MEG ] * [0, +1, +2/+3]
D-HXF-P1-19.0XX, 970116 and 970117, 109056-63, '64-70, '72-80,
see
2nd floor log and tables below.
- Dispersion direction scans: runid's and plots
-
grating aperture m=0 m=+1 m=+2,3,5 . HEG 10x200v+5 109056 109057 109058 plots: .ps " 80x500v 109064 109065 109066 plots: .ps MEG 10x200v-5 109061 109062 109063 plots: .ps " 80x500v 109068 109069 109070 plots: .ps LEG 10x200v 109082 109083 109084 plots: .ps " 80x500v 109085 109086 109087 plots: .ps
- Cross-dispersion direction scans: runid's and plots
-
(plots made with p1d_web_plots.pro using p1d_anal.pro; simulations and simulated plots created by meg_misalign_sim.pro.)grating aperture m=0 m=+1 m=+2,3,5 XRCF MARX HEG 10x200h 109078 109079 109080 plots: .ps
note double
peak structureplots: .ps
MARX hegdTheta =
1.5 arc min rmsMEG 10x200h 109072 109076 109075 plots: .ps plots: .ps
MARX megdTheta =
1.8 arc min rms,
plus mis-aligned
MEGsLEG 10x200h 109088 109089 109090 plots: .ps plots: .ps
MARX legdTheta =
1.5 arc min rms
HSI images were taken at orders +1, 0, and -1 for three different optic pitch angles in order to compare data and model. Each runid has three iterations corresponding to the 3 orders. (For LEG the orders are +5, 0, 5.) The data were taken on 970116.
- Grating Off-axis Images: runid's and TRW_ID's
-
grating Yaw = -2 Yaw = -5 Yaw = -15 HEG 109038
D-HXH-3D-21.006109040
D-HXH-3D-21.012109042
D-HXH-3D-21.016MEG 109037
D-HXH-3D-21.005109039
D-HXH-3D-21.011109041
D-HXH-3D-21.015LEG 109043
D-LXH-3D-21.021109044
D-LXH-3D-21.024109045
D-LXH-3D-21.026
- Mg with 2C1:
- MEG+3 order: G-H2C-PI-32.013(TB), '32.016(NS)
- HEG+2 order: G-H2C-PI-32.014(TB), '32.017(NS)
-
H-HAS-PI-18.001: Al-K with zero-order blanked out, alternating
frame mode. Note the piled-up cores of the Al-K lines!
in the 1st order
plots below (axes are mm w.r.t. ~zero-order.)
- MEG 1st order event plots (450k .ps)
- HEG 1st order event plots (320k .ps)
- MEG 3rd order event plots (150k .ps)
- HEG 2nd order event plots (66k .ps)
- IDL code used:h-has-pi-18.001.pro.
- H-HAS-PI-1.011: Al-K Off-axis
- H-HAS-PI-1.012: Al-K Off-axis
- H-HAS-PI-19.001: Si-K Off-axis
- H-HAS-PI-19.002: Si-K Off-axis