Rapid Acquisition Imaging Spectrograph (RAISE) Renewal Proposal Project

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	The optical design of RAISE is based on a new class of UV/EUV imaging spectrometers that use&amp;nbsp; only two reflections to provide quasi-stigmatic performance simultaneously over multiple wavelengths&amp;nbsp; and spatial fields. Figure 5 summarizes the RAISE instrument design, showing photographs of each of&amp;nbsp; the components or subsystems. The design uses an off-axis parabolic telescope mirror to form a real&amp;nbsp; image of the sun on the spectrometer entrance aperture. A slit then selects a portion of the solar image,&amp;nbsp; passing its light onto a near-normal incidence toroidal grating, which re-images the spectrally dispersed&amp;nbsp; radiation onto two array detectors. Two full spectral passbands over the same one-dimensional spatial&amp;nbsp; field are recorded simultaneously with no scanning of the detectors or grating. The two different spectral&amp;nbsp; bands (1st-order 1205-1243&amp;Aring; and 1526-1564&amp;Aring;) are imaged onto two intensified Active Pixel Sensor&amp;nbsp; (APS) detectors whose focal planes are individually adjusted for optimized performance. The telescope&amp;nbsp; and grating are coated with B4C to enhance short wavelength (2nd order) reflectance (Fig. 6), enabling the&amp;nbsp; instrument to record the brightest lines between 602-622&amp;Aring; and 761-780&amp;Aring; at the same time. Table 1&amp;nbsp; summarizes the main optical parameters for RAISE. &amp;nbsp;&amp;nbsp;&lt;/p&gt;
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	&lt;strong&gt;TVLS Grating. &lt;/strong&gt;The single toroidal variable line space (TVLS) grating has a toroidal surface&amp;nbsp; (Sagittal Radius = 640.5 mm, Tangential Radius = 635.3 mm), with varied line space (VLS) rulings of the&amp;nbsp; type developed originally for spherical substrates by Kita, Harada, and collaborators (1983, 1995). By&amp;nbsp; combining this VLS concept with toroidal surfaces, RAISE is the first to exploit this new class of&amp;nbsp; spectrometers, as described by Thomas (2003). For RAISE, the grating is placed 400 mm behind the slit,&amp;nbsp; with focus at a distance of approximately 1700 mm, for a spectrometer magnification of 4.25. By&amp;nbsp; operating at high magnification, the RAISE spectrometer most effectively utilizes the full length and&amp;nbsp; width available in the sounding rocket payload. The first RAISE grating, mechanically ruled by Bach&amp;nbsp; Research, Inc., was delivered in August 2007 and tested for figure, ruling density and total grating&amp;nbsp; efficiency.&amp;nbsp;&lt;/p&gt;
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	&lt;strong&gt;Intensified APS Cameras&lt;/strong&gt;. The RAISE Intensified APS camera systems are 1k x 1k CMOS Active&amp;nbsp; Pixel Sensors using miniature digital camera electronics and fed by an MCP intensifier. APS cameras&amp;nbsp; were chosen for RAISE (rather than CCDs) because of their extremely fast readout, direct digital output,&amp;nbsp; low mass, low power, deep full well and high radiation tolerance. The RAISE cameras were developed at&amp;nbsp; DLR (Germany) using a Cypress/Filfactory Star 1000 APS and include a 12-bit external ADC and USB&amp;nbsp; 2.0 interface. We will operate the cameras at 5-10 frames/sec readout, making dark current negligible&amp;nbsp; compared to the incoming signal. The complete camera electronics including its controller is integrated&amp;nbsp; on only one printed circuit board, and uses a rigid-flex 3D-interconnection between the boards to form a&amp;nbsp; lightweight, compact sensor head. Flight detectors were delivered by DLR in August 2008.&amp;nbsp;&lt;/p&gt;
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	&lt;strong&gt;&lt;em&gt;RAISE Chromospheric Slit Jaw Camera (SJC)&amp;nbsp; &lt;/em&gt;&lt;/strong&gt;To co-align the RAISE spectra with observations from SDO, HINODE, and IRIS, and to collect&amp;nbsp; chromospheric disk images in C IV and the continuum between 1500-1700 &amp;Aring;, the solar image at the&amp;nbsp; telescope focal plane (spectrograph entrance slit plane) is re-imaged onto a SJC mounted on the bo

Tags: active, project, wallops-flight-facility
Organization: National Aeronautics and Space Administration