The gamma ray spectrometer for the Solar Maximum Mission

Forrest, D. J.; Chupp, E. L.; Ryan, J. M.; Cherry, M. L.; Gleske, I. U.; Reppin, C.; Pinkau, K.; Rieger, E.; Kanbach, G.; Kinzer, R. L.; Share, G. H.; Johnson, W. N.; Kurfess, J. D.

doi:10.1007/bf00151381

Cited by 112 publications

(42 citation statements)

References 10 publications

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“…At 1 MeV, the energy resolution (FWHM) of COMPTEL is 9.8% and 8.8% in E tot and E 2 , respectively (Schönfelder et al 1993). At the same energy, the resolution of GRS-SMM was about 5.4% (Forrest et al 1981), and that of GRS-HEAO 3 was < ∼ 0.3% (Mahoney et al 1980). Therefore, the Ge spectrometer onboard HEAO 3 is far superior for γ-ray line studies compared to COMPTEL and GRS-SMM, which have similar resolution.…”

Section: Background Line Intensities: Comparisons and Implicationsmentioning

confidence: 95%

The COMPTEL instrumental line background

Weidenspointner

Varendorff

Oberlack

et al. 2001

A&A

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Abstract. The instrumental line background of the Compton telescope COMPTEL onboard the Compton GammaRay Observatory is due to the activation and/or decay of many isotopes. Tl. The identification of instrumental lines with specific isotopes is based on the line energies as well as on the variation of the event rate with time, cosmic-ray intensity, and deposited radiation dose during passages through the SouthAtlantic Anomaly. The characteristic variation of the event rate due to a specific isotope depends on its life-time, orbital parameters such as the altitude of the satellite above Earth, and the solar cycle. A detailed understanding of the background contributions from instrumental lines is crucial at MeV energies for measuring the cosmic diffuse gamma-ray background and for observing γ-ray line emission in the interstellar medium or from supernovae and their remnants. Procedures to determine the event rate from each background isotope are described, and their average activity in spacecraft materials over the first seven years of the mission is estimated.

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Section: Background Line Intensities: Comparisons and Implicationsmentioning

confidence: 95%

The COMPTEL instrumental line background

Weidenspointner

Varendorff

Oberlack

et al. 2001

A&A

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“…It consists of seven cylindrical 7.5 cm x 7.5 cm NaI scintillation detectors, shielded by a 2.5 cm thick CsI annulus and a 7.6 cm CsI back plate which defines a broad aperture of .1300 FWHM (Forrest et al, 1980).…”

Section: Introductionmentioning

confidence: 99%

Satellite observation of atmospheric nuclear gamma radiation

Letaw¹,

Share²,

Kinzer³

et al. 1989

J. Geophys. Res.

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We present a satellite observation of the spectrum of gamma radiation from the Earth's atmosphere in the energy interval from 300 keV to 8.5 MeV. The data were accumulated by the gamma ray spectrometer on the Solar Maximum Mission over 3½ years, from 1980 to 1983. The excellent statistical accuracy of the data allows 20 atmospheric line features to be identified. The features are superimposed on a continuum background which is modeled using a power law with index −1.16. Many of these features contain a blend of more than one nuclear line. All of these lines (with the exception of the 511‐keV annihilation line) are Doppler broadened. Line energies and intensities are consistent with production by secondary neutrons interacting with atmospheric 14N and 16O. Although we find no evidence for other production mechanisms, we cannot rule out significant contributions from direct excitation or spallation by primary cosmic ray protons. The relative intensities of the observed line features are in fair agreement with theoretical models; however, existing models are limited by the availability of neutron cross sections, especially at high energies. The intensity and spectrum of photons at energies below the 511‐keV line, in excess of a power law continuum, can be explained by Compton scattering of the annihilation line photons in traversing an average of ∼21g cm−2 of atmosphere.

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“…Before the launch of the Solar Maximum Mission (SMM) satellite with its Gamma-Ray Spectrometer (GRS) in 1980 (17), proton event intensities at 1 A.U. could only be compared with flare radio and X-ray emissions from electrons back at the Sun.…”

Section: Correlations and Associationsmentioning

confidence: 99%

Solar flare photons and energetic particles in space

Cliver¹

2000

AIP Conference Proceedings

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Abstract. I review the evolution of research on solar energetic particle events, beginning with Forbush's report of the ground level event of 1946, through the most recent observations of the Advanced Composition Explorer (ACE). The emphasis is on research that attempted to link solar flare electromagnetic emissions with the solar energetic particles (SEPs) observed in space following flares. The evolution of thought on this topic is traced from the initial paradigm in which SEPs were accelerated at the flare site (a 8-function in space and time) to the current two-class picture accommodating both impulsive acceleration at the flare site (small 3 He-rich events) and prolonged acceleration at extended shocks driven by coronal mass ejections (large proton events). I conclude with some open questions; the most prominent of these concerns the relative contributions of the flare and shock acceleration processes to "mixed" or hybrid SEP events in which the distinguishing characteristics of the impulsive and gradual classes are blended.

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The gamma ray spectrometer for the Solar Maximum Mission

Cited by 112 publications

References 10 publications

The COMPTEL instrumental line background

The COMPTEL instrumental line background

Satellite observation of atmospheric nuclear gamma radiation

Solar flare photons and energetic particles in space

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