Precise Location of Sagittarius X-Ray Sources with a Rocket-Borne Rotating Modulation Collimator

Schnopper, H.; Bradt, H.; Rappaport, S.; Boughan, E.; Burnett, B.; Doxsey, R.; Mayer, W.; Watt, S.

doi:10.1086/180595

Cited by 45 publications

(8 citation statements)

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“…To reconstruct images the RMCs need only to provide adequate modulation, not absolute collimation of gamma rays. This collimator design has already proven functional in the far field within the NSECT energy range of interest [24]- [28].…”

Section: Introductionmentioning

confidence: 99%

Design and Development of a High-Energy Gamma Camera for Use With NSECT Imaging: Feasibility for Breast Imaging

Sharma

Tourassi

Kapadia

et al. 2007

IEEE Trans. Nucl. Sci.

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A new spectroscopic imaging technique, Neutron Stimulated Emission Computed Tomography (NSECT), is currently being developed to non-invasively and non-destructively measure and image elemental concentrations within the body. NSECT has potential for use in breast imaging as several studies have shown a link between elemental concentration and tumor status. In NSECT, a region of interest is illuminated with a high-energy (3-5 MeV) beam of neutrons that scatter inelastically with elemental nuclei within the body. The characteristic gamma rays that are emitted as the excited nuclei relax allow the identification of elements and the formation of elemental composition images. This imaging technique requires high-resolution and high-energy gamma spectroscopy; thereby eliminating current scintillation crystal based position sensitive gamma cameras. Instead, we propose to adapt high-energy gamma imaging techniques used in space-based imaging. A High Purity Germanium (HPGe) detector provides high-resolution energy spectra while a rotating modulation collimator (RMC) placed in front of the detector modulates the incoming signal to provide spatial information. Counting the number of gamma events at each collimator rotation angle allows for reconstruction of images. Herein we report on the design and testing of a prototype RMC, a Monte Carlo simulation of this camera, and the use of this simulation tool to access the feasibility of imaging a breast with such a camera. The prototype RMC was tested with a 22 Na point source and verified that the RMC modulates the gamma rays in a predictable manner. The Monte Carlo simulation accurately modeled this behavior. Other simulations were used to accurately reconstruct images of a point source located within a 10 cm cube, suggesting NSECT's potential as a breast imaging method.

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Section: Introductionmentioning

confidence: 99%

Design and Development of a High-Energy Gamma Camera for Use With NSECT Imaging: Feasibility for Breast Imaging

Sharma

Tourassi

Kapadia

et al. 2007

IEEE Trans. Nucl. Sci.

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“…The RMC was first proposed for X-ray astronomy by Schnopper et al (1968). The RMC technique was successfully used in a number of rocket flights (Schnopper et al 1970;Cruise & Willmore 1975) and balloon-borne experiments (Staubert et al 1983;Ubertini et al 1985;Sood et al 1996) for hard X-ray imaging. Nishimura et al (1978) used a balloon-borne wide-field RMC instrument to localise gamma-ray bursts.…”

Section: Introductionmentioning

confidence: 99%

Direct demodulation technique for rotating modulation collimator imaging

Chen

1998

Astron. Astrophys. Suppl. Ser.

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Abstract. Rotating modulation collimator (RMC) is an important imaging technique in hard X-ray astronomy. With traditional inversion techniques, the sensitivity, angular resolution and ability of simultaneous imaging of point sources and extended emission are not good enough in many practical cases. In this work, a new inversion technique, the direct demodulation method, is applied to analyse simulated data of an RMC telescope. The results show that the image quality from direct demodulation are improved significantly in comparison with that from traditional inversion techniques, such as the cross-correlation method and the CLEAN cross-correlation method. From an RMC telescope with a simple bi-grid collimator and the direct demodulation technique, we can do imaging for both discrete and extended sources.

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“…The technique has been used successfully in both optical and X-ray astronomy (see, for example, Schnopper et al, 1970;Rosenberg, 1972). Source positions have been mesured to a few arc minutes in a field of view of many square degrees, but only coarse energy resolution has been possible because broad-band detectors such as proportional counters were employed.…”

Section: (T) =/-T O (1)mentioning

confidence: 99%

Crystal spectrometer studies of the Sun employing a rotation modulation collimator

1975

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The use of rotating modulation collimators in high resolution solar X-ray spectroscopy is discussed with reference to the recent flight of a sounding rocket payload. This rocket carried an experiment which combined a modulation collimator and a Bragg crystal spectrometer to make moderately high resolution spectral and spatial measurements simultaneously. The response of the instrument to extended sources is described. It is shown that the technique is particularly suited to long term observations of active region emission, but that useful measurements can be made even during a short rocket flight.Our observations were made in 1972 October 26 between 0432 UT and 0436 UT. During the flight a scan of the solar X-ray spectrum was made which covered the wavelength range 1.45-1.71 nm. A small flare commenced at about 0432 UT in McMath calcium plage region 12094; the emission from this provided the major contribution to the observed spectrum. X-ray emission from a group of active regions in the SW and the small McMath region 12090 has also been detected.Spectral and spatial observations have been combined to investigate the conditions in both active region and flare plasmas.

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Precise Location of Sagittarius X-Ray Sources with a Rocket-Borne Rotating Modulation Collimator

Cited by 45 publications

References 0 publications

Design and Development of a High-Energy Gamma Camera for Use With NSECT Imaging: Feasibility for Breast Imaging

Design and Development of a High-Energy Gamma Camera for Use With NSECT Imaging: Feasibility for Breast Imaging

Direct demodulation technique for rotating modulation collimator imaging

Crystal spectrometer studies of the Sun employing a rotation modulation collimator

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