Abstract
The production rates of nuclides made by the galactic and solar cosmic rays are important in the interpretations of measurements made with lunar samples, meteorites, and cosmic spherules. Production rates of cosmogenic nuclides have been predicted by a variety of methods that are reviewed in this paper, ranging from systematic studies of one or a group of meteorites to purely theoretical calculations. Production rates vary with the chemical composition and the preatmospheric depth of the sample and with the size and shape of the object. While the production systematics for cosmogenic nuclides are fairly well known, our ability to predict their production rates can be improved, with a corresponding increase in the scientific return. Additional detailed studies of cosmogenic nuclides in extraterrestrial objects are needed, especially for fairly small and very large objects. Nuclides made in simulation experiments and cross sections for many major nuclear reactions should be measured. Such studies are especially needed for the long-lived radionuclides that have only recently become readily measurable by accelerator mass spectrometry.
Highlights
‘ri]cinner solar system not cmly rontnin.s tile terrwtriil.i pian~ts iill(i t heir IIIW:IS, but niso a nun~twr of smaller objects an~i a variety of raciiat ions, Some of these oi)jccts rcvwh tho su rfac(? of tile varth wit II(JII I being mmpletely
The initial work on cosmogonic nuclidcs came soon after the first high-energy (above * 1 (;eV) accelerators were built, and studies of cosmogonic nuclides made by the GeV protons in the galactic cosmic rays (GCR ) with meteorites complimented work being done cm high-energy nuclear reactions at these accelerators
Alpha particles in the past using 59Ni in the top few millimeters of lunar samples, Such studies probably would be one of the first projects to do when the accelerator mass spectrometry (AMS) techniques for Ni are fairly well established because the nickel contents of lunar samples are low, so the 5uNi/stable-Ni ratios wnn’t be too low
Summary
‘ri]cinner solar system not cmly rontnin.s tile terrwtriil.i pian~ts iill(i t heir IIIW:IS, but niso a nun~twr of smaller objects an~i a variety of raciiat ions, Some of these oi)jccts rcvwh tho su rfac(? of tile varth wit II(JII I being mmpletely After the discovery ofqosmic-ray-produced (cosmogonic) nuclides about 40 years ago, a wide variety of studies soon were being done with them Very soon after the first observations of cosmogcrric nuclides, several systematic studies were done with meteoritic samples that helped to establish some initial production rates of cosmogonic nuclides in meteorites. 5]), Thick-target exp[~rimrnts at high-energy accelerators were dont~ to help in prc[!icting production rates of nuclidos mad{’ by the GCR (e.g., [6, 7]), With the return of samples from the moon, the study of solar cosmir rays (SfIR) and their effects in cxtratorrcstria. matter progr:sscd rapidly (cog,, [8, !)]). Concentrations of SCR.-produccd radionuclides should be very high in very small objects in space, such as those rccovcrwl in deep-sea sediments [17, 18]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
