VETA-I x-ray detection system

Podgorski, William; Flanagan, Kathryn A.; Freeman, Mark D.; Goddard, Richard E.; Kellogg, E.; Norton, Timothy; Ouellette, Jennifer; Roy, Adrian G.; Schwartz, D. A.

doi:10.1117/12.140590

Cited by 2 publications

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“…The focused X-rays were then detected and measured with the VETA X-ray Detecting System (VXDS) built by SAO. 4 Four types of results were obtained, i.e. Full Width…”

Section: Introductionmentioning

confidence: 99%

AXAF VETA-I mirror encircled energy measurements and data reduction

et al. 1993

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The AXAF VETA-I mirror encircled energy was measured with a series of apertures and two flow gas proportional counters at five X-ray energies ranging from 0.28 to 2.3 keV. The proportional counter has a thin plastic window with an opaque wire mesh supporting grid. Depending on the counter position, this mesh can cause the X-ray transmission to vary as much as 4-9%, which directly translates into an error in the encircled energy.In order to correct this wire mesh effect, window scan measurements were made, in which the counter was scanned in both horizontal (Y) and vertical (Z) directions with the aperture fixed.Post VETA measurement of the VXDS setup were made to determine the exact geometry and position of the mesh grid. Computer models of the window mesh were developed to simulate the X-ray transmission based on this measurement.The window scan data were fitted to such mesh models and corrections were made. After this study, the mesh effect was well understood and the final results of the encircled energy were obtained with an uncertainty of less thau 0.8%.

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“…The focused X-rays were then detected and measured with the VETA X-ray Detecting System (VXDS) built by SAO. 4 Four types of results were obtained, i.e. Full Width…”

Section: Introductionmentioning

confidence: 99%

AXAF VETA-I mirror encircled energy measurements and data reduction

et al. 1993

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<title>AXAF calibration: the HXDS flow proportional counters</title>

Wargelin¹,

Kellogg²,

McDermott³

et al. 1997

Grazing Incidence and Multilayer X-Ray Optical Systems

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The design, performance, and calibration of the seven Flow Proportional Counters (FPCs) used during AXAF ground calibration are described. Five of the FPCs served as Beam Normalization Detectors (BNDs) , and two were used in the telescope focal plane in combination with a set of apertures to measure the point response functions and effective areas of the AXAF mirrors and transmission gratings. The BNDs also provide standards for determining the effective areas of the several telescope/grating/ffight-detector combinations.With useful energy resolution and quantum efficiency over the entire 100-eV to 1O-keV AXAF energy band, the FPCs provided most of the data acquired during AXAF calibration. Although the principles of proportional counter operation are relatively simple, AXAF's stringent calibration goals require detailed calibration and modeling of such effects as window-support-wire obscuration, window deformation between the support wires, electron diffusion and avalanche processes, gain nonuniformities, and gas pressure and temperature variations. Detector aperture areas and signal processing deadtime must also be precisely determined, and detector degradation during the many months of AXAF calibration must be prevented.The FPC caiibration program is based on measurement of individual components (such as window transmission and aperture size) and the relative quantum efficiencies of complete detector systems, as well as absolute QE callbration of selected detectors at the BESSY synchrotron, an X-ray source of precisely known intensity.

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VETA-I x-ray detection system

Cited by 2 publications

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AXAF VETA-I mirror encircled energy measurements and data reduction

AXAF VETA-I mirror encircled energy measurements and data reduction

<title>AXAF calibration: the HXDS flow proportional counters</title>

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