Ground-based simulations of galactic cosmic ray fragmentation and transport

doi:10.1016/0273-1177(94)90548-7

Advances in Space Research

Volume 14, Issue 10, October 1994, Pages 831-840

https://doi.org/10.1016/0273-1177(94)90548-7 Get rights and content

Abstract

Since mean free paths for nuclear fragmentation are of the order of the ranges of primary Galactic Cosmic Ray (GCR) nuclei, determination of the radiation field produced by successive fragmentations of nuclei in material and tissue is essential to accurate assessment of GCR radiation risk to humans on long-duration missions outside the geomagnetosphere. We describe some recent measurements made at the Bevalac of heavy ion transport through materials, with representative results and examples of how they may be applied to aspects of the space radiation problem, including efforts to devise analytical tools for predicting biological effects and for designing spacecraft shielding.

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Cited by (2)

Twenty years of space radiation physics at the BNL AGS and NASA Space Radiation Laboratory
2016, Life Sciences in Space Research
Citation Excerpt :
The energy spectra of heavy ions in the galactic cosmic radiation (GCR) have broad peaks in the range of several hundred MeV/nucleon, fortuitously close to energies available at high energy heavy ion accelerators (Fig. 1). In the 1980s and early 1990s Walter Schimmerling and collaborators at Lawrence Berkeley National Laboratory (LBNL) carried out a number of nuclear fragmentation studies at the LBNL Bevalac (Miller 1994; Zeitlin et al., 1996ab). Following the closing of the Bevalac in the early 1990s, NASA contracted with Brookhaven National Laboratory (BNL) to make beam time available at the Alternating Gradient Synchrotron (AGS), and a rudimentary target area and data taking facility were constructed, using instrumentation salvaged from the Bevalac facility.
Highly ionizing atomic nuclei HZE in the GCR will be a significant source of radiation exposure for humans on extended missions outside low Earth orbit. Accelerators such as the LBNL Bevalac and the BNL AGS, designed decades ago for fundamental nuclear and particle physics research, subsequently found use as sources of GCR-like particles for ground-based physics and biology research relevant to space flight. The NASA Space Radiation Laboratory at BNL was constructed specifically for space radiation research. Here we review some of the space-related physics results obtained over the first 20 years of NASA-sponsored research at Brookhaven.
Water radiolysis with heavy ions of energies up to 28 GeV. 1. Measurements of primary g values as track segment yields
2008, Radiation Physics and Chemistry
Water radiolysis has been investigated with heavy ions having energies up to 28 GeV provided from the Heavy Ion Medical Accelerator in Chiba (HIMAC) at the National Institute of Radiological Sciences (NIRS). Beams of ⁴He²⁺, ¹²C⁶⁺, ²⁰Ne¹⁰⁺, ²⁸Si¹⁴⁺, ⁴⁰Ar¹⁸⁺ and ⁵⁶Fe²⁶⁺ with respective energies of 150, 400, 400, 490, 500 and 500 MeV/u corresponding LET values of 2.2, 13, 30, 54, 92 and 183 eV/nm, respectively, were taken for the irradiation. The LET changes in sample solutions can be neglected due to their high energies for the irradiation of 1-cm cells. Primary g values have been determined for three important products, hydrated electron (e⁻_aq), hydroxyl radical (·OH), and hydrogen peroxide (H₂O₂) as track segment yields (differential yields) under the conditions of neutral pH.
With increasing LET, the g values of e⁻_aq and ^·OH decrease from 2.4 and 2.6 in ⁴He²⁺ radiolysis to 0.9 and 1.1 (100 eV)⁻¹ in ⁵⁶Fe²⁶⁺ radiolysis, respectively. It was also found that the primary g value of e⁻_aq is smaller than that of ·OH for any type of ion beam. For the ¹²C⁶⁺ beam, other energies such as 290, 220, 135 MeV/u were taken for the irradiation to investigate the effects of type or atomic number of ions on the measured yields. Furthermore, effects of dissolved oxygen on enhancement of H₂O₂ production have also been investigated with aerated NaNO₃ solutions. The presence of dissolved oxygen caused 15–35% enhancement in H₂O₂ yields for all beams. In addition, the results of the present work were compared with reported track segment yields.

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Supported by the National Aeronautics and Space Administration under contract L14230C and conducted at the Lawrence Berkeley Laboratory (Department of Energy contract DE-AC03-76SF00098 to the University of California).

This work was carried out in collaboration with K. Frankel, W. Gong, L. Heilbronn, W. Schimmerling and C. Zeitlin of Lawrence Berkeley Laboratory, M. R. Shavers of Texas A&M University and L. W. Townsend and J. W. Wilson of NASA Langley Research Center

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Ground-based simulations of galactic cosmic ray fragmentation and transport☆

Abstract

Adv. Space Res.

Adv. Space Res.

Introduction to the galactic cosmic radiation

The fragmentation of 670A MeV Neon-20 as a function of depth in water. I. Experiment

Radiat. Res.