LET spectra of trapped anomalous cosmic rays in low-Earth orbit

Tylka, A. J.; Boberg, P. R.; Adams, J. H.

doi:10.1016/0273-1177(95)00511-c

Cited by 8 publications

(6 citation statements)

References 5 publications

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“…Since the overall level of the measured fluxes is about the same where fluxes are highest, the normalizations of our model and that of Tylka et al [1996] agree there, but there is a tendency for the MAST observations to be on average higher than those of HILT toward higher L and lower toward lower L; in the lowest L bin the disagreement is about a factor of 4. If we adjust the average values of the HILT observations at each L to align better with those of MAST, this will raise the estimate of G* by the same factor, reducing but not eliminating the variation with L. This would be an arbitrary adjustment, however, as we are not certain as to the cause of our instruments' disagreement.…”

Section: Discussionsupporting

confidence: 55%

Trapped anomalous cosmic rays near the geomagnetic cutoff

Looper¹,

Blake²,

Klecker³

et al. 1996

J. Geophys. Res.

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Observations made with the mass spectrometer telescope (MAST) instrument aboard the SAMPEX spacecraft have previously been used to map the belt of geomagnetically trapped anomalous cosmic rays at L ≈ 2. Here we use the heavy ion large telescope (HILT) instrument to extend these observations to lower energies, closer to the peak of the interplanetary spectrum at 1 AU, for oxygen and neon. At lower energies than observed by MAST we see a distinct peak in the oxygen spectrum at the energy corresponding to the geomagnetic cutoff for singly charged incident ions arriving from the west, at each L where that is in the HILT energy range. This is due to the suppression of the particle source at energies below the cutoff, and the subsequent filling‐in of lower energies via slowing down of ions that had energies above the cutoff when originally trapped. In addition, our observations of oxygen confirm the MAST discovery that the pitch angle distribution at SAMPEX altitudes is nearly isotropic outside the loss cone, and we see similar variations with time, trends with L, and general level of trapped flux at the energies where the two instruments' responses overlap. The normalization of the trapped oxygen and neon fluxes as functions of L, when compared with previously published models, suggests more efficient trapping toward low L and/or additional losses at high L.

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Section: Discussionsupporting

confidence: 55%

Trapped anomalous cosmic rays near the geomagnetic cutoff

Looper¹,

Blake²,

Klecker³

et al. 1996

J. Geophys. Res.

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“…Also shown in Figure 9 is the result of a simple model for trapped ACRs which is in reasonable agreement with the experimental data. Similar models have also been described by others [Blake, 1990;Tylka, 1994;Tylka et al, 1996].…”

Section: ) Qsmentioning

confidence: 53%

Anomalous Cosmic Rays: The Principal Source of High Energy Heavy Ions in the Radiation Belts

Mewaldt

Selesnick

Cummings

2013

Radiation Belts: Models and Standards

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Recent observations from SAMPEX have shown that "anomalous cosmic rays" are the principal source of high energy(> lOMeV /nuc) heavy ions trapped in the radiation belts. This component of interplanetary particles is known to originate from interstellar atoms that has been accelerated to high energies in the outer heliosphere. The mechanism by which anomalous cosmic rays with ,...., 1 to ,...., 50 Me V / nuc are trapped in a radiation belt at L ~ 2 has now been verified. We discuss models for accelerating and trapping anomalous cosmic rays and review observations of their composition, energy spectra, pitch angle distribution, and time variations. Extrapolation of the fluxes observed at ,...., 600 km to higher altitude and other time periods is also discussed.

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“…The ACRs (mostly He, N, O, Ne ions) are believed to come from interstellar neutral particles, which have entered into the heliosphere, and are subsequently ionized by the solar wind or UV radiation and finally accelerated to energies larger than 10 MeV/nucleon, probably at the solar wind termination shock (see [54][55][56] and references therein). However, collisions in the termination shock region cause some ions to reach multiply charged states [55] and be accelerated to even larger energies.…”

Section: Solar Heliospheric and Galactic Cosmic Rays In Interplanetar...mentioning

confidence: 99%

“…These trapped particles have steep energy spectra and are unlikely to be a significant radiation hazard for (lightly-) shielded systems, i.e. with about 50 mm Al equivalent (see for instance [56]).…”

Section: Trapped Particles and Earth Magnetospherementioning

confidence: 99%

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Particle interaction and displacement damage in silicon devices operated in radiation environments

2007

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Silicon is used in radiation detectors and electronic devices. Nowadays, these devices achieving submicron technology are parts of integrated circuits of large to very large scale integration (VLSI). Silicon and silicon-based devices are commonly operated in many fields including particle physics experiments, nuclear medicine and space. Some of these fields present adverse radiation environments that may affect the operation of the devices. The particle energy deposition mechanisms by ionization and non-ionization processes are reviewed as well as the radiation-induced damage and its effect on device parameters evolution, depending on particle type, energy and fluence. The temporary or permanent damage inflicted by a single particle (single event effect) to electronic devices or integrated circuits is treated separately from the total ionizing dose (TID) effect for which the accumulated fluence causes degradation and from the displacement damage induced by the non-ionizing energy-loss (NIEL) deposition. Understanding of radiation effects on silicon devices has an impact on their design and allows the prediction of a specific device behaviour when exposed to a radiation field of interest.

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LET spectra of trapped anomalous cosmic rays in low-Earth orbit

Cited by 8 publications

References 5 publications

Trapped anomalous cosmic rays near the geomagnetic cutoff

Trapped anomalous cosmic rays near the geomagnetic cutoff

Anomalous Cosmic Rays: The Principal Source of High Energy Heavy Ions in the Radiation Belts

Particle interaction and displacement damage in silicon devices operated in radiation environments

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