Engineering topics

Smither, R. K.

Publications and source records attributed to Smither, R. K..

3 records

NASA NTRS1996

A tunable crystal diffraction telescope for the International Space Station

A focusing gamma ray telescope is proposed for use onboard the International Space Station. It consists of a tunable crystal diffraction lens which focuses gamma rays onto a small array of germanium detectors located on an extendable boom. While the weight of such an instrument is less than 500 kg, it features an angular resolution of 15 arcsec, an energy resolution of 2 keV and a 3 sigma sensitivity of the order of 10(exp -7) photons/sq cm sec for any individual narrow line at energies of between 200 and 1300 keV. The scientific potential of such a telescope is discussed. The principles of a diffraction lens and a tunable diffraction lens are described.

VonBallmoos, P.↗

NASA NTRS1981

A new method for focusing and imaging X-rays and gamma-rays with diffraction crystals

Bent diffraction crystals in which the intercrystalline-plane spacing is varied as a function of position in the crystal are used to focus monochromatic radiation from a point source or parallel beam down to a point image. Conversely, radiation from a point source can be focused into an outgoing parallel beam. The Bragg angle for diffraction of monochromatic radiation will now vary as a function of position in the crystal and this new degree of freedom is used to obtain focusing and imaging of the diffracted beam. This approach to focusing and imaging is applied to the design of a large-area, high resolution X-ray telescope that is also a high resolution monochromator with the unique feature that the width of the energy increment that is diffracted can be controlled and varied during the operation of the instrument. The field can be scanned with a wide energy increment and then switched to a narrow energy increment for the high resolution work. Both transmission and reflection type diffraction crystals can be used.

Smither, R. K.↗

NASA NTRS1969

Ge-diode detector combined with crystal-diffraction spectrometer permits high-resolution gamma ray spectroscopy

Crystal-diffraction spectrometer, combined with a lithium-drifted Ge-diode detector, performs high-resolution gamma ray spectroscopy on the complicated neutron-capture gamma ray spectra. The system is most useful in the 1-3 MeV energy range and improves the signal to background ratio.

Namenson, A. I.↗