Flare Observations with TRACE and Yohkoh

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XRT Performance Update
Edward DeLuca
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Science Goals
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Science Goals
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Science Goals
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Requirements Flowdown
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Mirror Properties

• Optimized Polynomial Design
• Constraints Focal Length, Pixel Size, FOV,
  Resolution
• Goal 2 resolution for the full sun FOV
• Low Scattering
• Surface roughness lt 5A RMS
• Temperature sensitivity lt 1MK (cool coronal plasma

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Mirror Status

• Mirror polishing is proceeding at Goodrich.
• We expect the mirror to meet or exceed all
  requirements.

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Entrance Filter

• Requirements
• White Light Transmission lt 10 -6
• Heat Rejection
• 5 year on orbit survival
• X-Ray transmission gt 0.7 from 1-60A
• Properties
• 1600 A Al
• 2500 A Polyimide

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Focal Plane Filters

• Requirements
• White Light Transmission lt 10 -6
• 5 year on orbit survival
• Temperature Diagnostics from 1 to gt 20 MK
• Morphology for T lt 1MK
• Properties
• Science filters are on polyimide or free standing
• Simple proven design
• Testing/Verification
• Environmental
• Transmission

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Filter Status

• Environmental tests have been performed and
  flight filters have been chosen.
• The flight focal plane filters have been received
  from LUXEL.
• Initial light leak tests have been done on all
  the flight fp filters.
• The flight fp filters are at the XACT Facility in
  Palermo Italy for calibration tests.

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Ordered Filter Set
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Optical Paths Overview
2700 mm
X-RAY
White Light
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Mirror Calibration

• SAO - Centroid Detector Assembly (CDA)
• Focus Determination
• Visible light optical axis relative to X-Ray
• XRCF
• Encircled Energy On-Axis
• Encircled Energy Off-Axis
• Effective Area
• PSF and Effective Area Off-Axis

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Mirror Calibration

• XRCF Available Lines
• C-K 0.277 keV 44.7A
• O-K 0.525 keV 23.6A
• Cu-L 0.933 keV 13.3A
• Al-K 1.49 keV 8.3A
• Ag-L 2.98 keV 4.2A
• Ti-K 4.51 keV 2.7A
• Cr-K 5.41 keV 2.3A
• Fe 6.4 keV 1.9A
• Not all lines will be used for all measurements.

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Mirror Requirements

• Focal Length 2708 /- 5mm
• Bandwidth 0.2 to 6.0 keV
• Image Performance 68 encircled energy within 27
  microns _at_ 0.523 keV at focal plane
• FOV 35 arcmin
• Effective Area gt3.0 cm2 _at_ 0.56 keV 1 keV
• Wings of On-Axis PSF - _at_6 keV signal at 1 arcmin
  lt 3x10-5 peak flux.

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Visible Light Optic Requirements

• Focal Length 2708 /- 2mm
• Central Wavelength 4305 /- 20 A
• Bandpass lt120A FWHM
• Resolution lt2 half power dia.
• FOV gt30 arcmin
• Co-Alignment lt0.5 arcmin
• Confocality w/ GI optic /- 150 microns

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Filter Calibration Plan

• Shadowgraphs
• Filters are scanned with a mosaic of exposures at
  a single energy to measure thickness and
  uniformity
• References
• Barbera, M. et al 1996 DOC OAPA-R5-1996, Sept.
  23 1996.
• Collura, A. et al. 1996 SPIE 2808, 134.

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Shadowgraphs
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Thin Be Shadowgraph
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Medium Be Shadowgraph
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Thick Be Shadowgraph
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Energy Scans

• Energy scans will measure the transmission vs.
  energy.
• These measurements are taken at one or two points
  on the filter.
• If time permits opacity at 304A will be measured
  (1e-6 lower limit).

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Energy Scans AXAF Example
Collura, A. et al 1996 SPIE 2808, 134.
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Conclusions

• XRT will provide high resolution broadband
  imaging of the corona for the Solar B mission.
• The goal of understanding the relationship
  between photospheric driving and coronal dynamics
  requires a telescope that can image the response
  at a wide range of temperatures.
• The high throughput of XRT will allow us to
  follow the coronal evolution with great accuracy.

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Filter Transmission
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XRT Exposure Times