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Stone, E. C.; Cohen, C. M. S.; Cook, W. R.; Cummings, A. C.; Gauld, B.; Kecman, B.; Leske, R. A.; Mewaldt, R. A.; Thayer, M. R.; Dougherty, B. L.; Grumm, R.; Milliken, B.; Radocinski, R. G.; Wiedenbeck, M. E.; Christian, E. R.; Shuman, S.; Trexel, H.; Rosenvinge, T. T. von; Binns, W. R.; Crary, David; Dowkontt, P. F.; Epstein, Jenny; Hink, P. L.; Klarmann, J.; Lijowski, M.; Olevitch, M. A.

doi:10.1023/a:1005075813033

Cited by 134 publications

(71 citation statements)

References 0 publications

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“…On the other hand, the analogous figure for O isotopes (middle panel of Figure 4) shows a clear low-energy increase in the 18 O flux. Furthermore, the observed intensity of ACR 18 O after subtracting the GCR background (filled diamonds) is in good agreement with the ACR 16 O curve scaled by the solar system 18 O/ 16 O ratio of 0.002 [23].…”

Section: Isotopic Analysismentioning

confidence: 74%

“…To better illustrate the overall shape of the spectra, higher energy data from the Cosmic Ray Isotope Spectrometer (CRIS) on ACE [18] and lower energy data from the LowEnergy Matrix Telescope (LEMT) on Wind [10] are also included in the figure. The time period of the Wind data overlaps that of the SIS measurements, but extends from November 1994 to April 1998.…”

Section: Elemental Spectramentioning

confidence: 99%

“…Above ~ 50 MeV/nucleon, where GCRs dominate, most of the observed 15 N and 18 O is produced by cosmic ray spallation during transport through the Galaxy and is not directly representative of either the GCR source or the local ISM abundances, while most of the observed 22 Ne originates in the cosmic ray source. Below ~ 30 MeV/nucleon, ACRs are the dominant contributor to the quiet time fluxes.…”

Section: Isotopic Analysismentioning

confidence: 99%

“…Because of the likelihood of background from the neighboring peaks, we report only an upper limit on the lowest energy 18 Mass Number added in quadrature to the statistical uncertainties in the 22 Ne values below 15 MeV/nucleon. Although 14 N shows the typical ACR enhancement at low energies, 15 N has no statistically significant enhancement.…”

Section: Isotopic Analysismentioning

confidence: 99%

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Anomalous cosmic ray composition from ACE

Leske¹

2000

AIP Conference Proceedings

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Abstract. During solar quiet periods, the Solar Isotope Spectrometer (SIS) on the Advanced Composition Explorer (ACE) measures the composition and energy spectra of anomalous cosmic rays (ACRs) with energies > 8 MeV/nucleon in interplanetary space at 1 AU. In particular, the spectra of individual isotopes for the ACR elements N, 0, and Ne are studied with SIS. Intensity enhancements are found in low energy 18 O and 22 Ne, with relative abundances of 18 O/ 16 O ~ 0.002 and 22 Ne/ 20 Ne ~ 0.1. The neon abundance ratio appears more similar to that found in the solar wind than in meteorites and is far below that determined for the galactic cosmic ray (GCR) source, indicating that GCRs contain material from sources other than just the local interstellar medium.

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Section: Isotopic Analysismentioning

confidence: 74%

Section: Elemental Spectramentioning

confidence: 99%

Section: Isotopic Analysismentioning

confidence: 99%

Section: Isotopic Analysismentioning

confidence: 99%

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Anomalous cosmic ray composition from ACE

Leske¹

2000

AIP Conference Proceedings

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“…In this paper we present measurements of the Ne isotopes obtained by the Cosmic Ray Isotope Spectrometer (CRIS) instrument on the ACE spacecraft (13). We have obtained the 22 Ne/ 20 Ne ratio energy dependence for the energy range 100<E/M<281 MeV/nucleon and compare these data with those from the ACE-Solar Isotope Spectrometer (SIS) instrument (14) for lower energies.…”

Section: Introductionmentioning

confidence: 99%

Galactic cosmic ray neon isotopic abundances measured on ACE

Binns¹,

Wiedenbeck²,

Christian³

et al. 2000

AIP Conference Proceedings

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Abstract. Measurements of neon isotopic abundances from the ACE-CRIS experiment are presented. Abundances have been obtained in six energy intervals over the energy range of ~100sE^280 MeV/nucleon. These measurements are compared with the ACE-SIS data for lower energies extending down to ~8 MeV/nucleon. We find that the CRIS 22 Ne/ 20 Ne abundance ratio at the source is a factor of 5.0±0.3 greater than for the solar wind. The CRIS measured abundances agree well with previous experiments. The CRIS and SIS measurements are in good agreement for the higher SIS energies. However for the lower energy SIS data, where the anomalous cosmic rays (ACR) are being sampled, the ratio decreases and agrees with solar wind abundances. The implications of these results are discussed.

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Does the worsening galactic cosmic radiation environment observed by CRaTER preclude future manned deep space exploration?

et al. 2014

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The Sun and its solar wind are currently exhibiting extremely low densities and magnetic field strengths, representing states that have never been observed during the space age. The highly abnormal solar activity between cycles 23 and 24 has caused the longest solar minimum in over 80 years and continues into the unusually small solar maximum of cycle 24. As a result of the remarkably weak solar activity, we have also observed the highest fluxes of galactic cosmic rays in the space age and relatively small solar energetic particle events. We use observations from the Cosmic Ray Telescope for the Effects of Radiation (CRaTER) on the Lunar Reconnaissance Orbiter to examine the implications of these highly unusual solar conditions for human space exploration. We show that while these conditions are not a show stopper for long‐duration missions (e.g., to the Moon, an asteroid, or Mars), galactic cosmic ray radiation remains a significant and worsening factor that limits mission durations. While solar energetic particle events in cycle 24 present some hazard, the accumulated doses for astronauts behind 10 g/cm2 shielding are well below current dose limits. Galactic cosmic radiation presents a more significant challenge: the time to 3% risk of exposure‐induced death (REID) in interplanetary space was less than 400 days for a 30 year old male and less than 300 days for a 30 year old female in the last cycle 23–24 minimum. The time to 3% REID is estimated to be ∼20% lower in the coming cycle 24–25 minimum. If the heliospheric magnetic field continues to weaken over time, as is likely, then allowable mission durations will decrease correspondingly. Thus, we estimate exposures in extreme solar minimum conditions and the corresponding effects on allowable durations.

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Cited by 134 publications

References 0 publications

Anomalous cosmic ray composition from ACE

Anomalous cosmic ray composition from ACE

Galactic cosmic ray neon isotopic abundances measured on ACE

Does the worsening galactic cosmic radiation environment observed by CRaTER preclude future manned deep space exploration?

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