Solar Particle Tracks in Glass from the Surveyor 3 Spacecraft

A glass filter from Surveyor 3 has a surface density of ∼1 × 10$^{6}$ tracks per square centimeter from heavy solar flare particles. The variation with depth is best fitted with a solar particle spectrum dN/dE = 2.42 × 10$^{6}$ E$^{-2}$ [in particles per square centimeter per year per steradian per...

Full description

Saved in:
Bibliographic Details
Published in:Science (American Association for the Advancement of Science) 1971-03, Vol.171 (3977), p.1237-1239
Main Authors: Crozaz, G., Walker, R. M.
Format: Article
Language:English
Subjects:
Geometric planes
Lunar rocks
Nucleons
Particle density
Particle energy
Particle tracks
Protons
Solar flares
Spacecraft
Spectral index
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:A glass filter from Surveyor 3 has a surface density of ∼1 × 10$^{6}$ tracks per square centimeter from heavy solar flare particles. The variation with depth is best fitted with a solar particle spectrum dN/dE = 2.42 × 10$^{6}$ E$^{-2}$ [in particles per square centimeter per year per steradian per (million electron volts per nucleon)], where E is the energy and N is the number of particles, from 2 million electron volts per nucleon to ∼7 million electron volts per nucleon and dN/dE = 1.17 × 10$^{7}$ E$^{-3}$ at higher energies. Not much difference is observed between 0.5 and 5 micrometers, an indication that there is a lack of track-registering particles below 0.5 million electron volts per nucleon. The Surveyor data are compatible with track results in lunar rocks, provided an erosion rate of ∼10$^{-7}$ centimeter per year is assumed for the latter. The results also suggest a small-scale erosion process in lunar rocks.
ISSN:0036-8075
1095-9203
DOI:10.1126/science.171.3977.1237