Accession Number : AD0848584

Title :   OV3-4 Dose Rate and Proton Spectral Measurements.

Descriptive Note : Technical rept. Oct 63-Oct 68,

Corporate Author : AIR FORCE WEAPONS LAB KIRTLAND AFB NM

Personal Author(s) : Thede, Allen L.

Report Date : JAN 1969

Pagination or Media Count : 74

Abstract : Dose rate and proton spectral measurements were made in the inner Van Allen belt aboard the OV3-4 satellite during June and July 1966. The dose rates were measured by five tissue equivalent ionization chambers shielded by 0.192 gm/sq. cm aluminum, 0.745, 2.86, and 4.74 gm/sq. cm Lucite and 4.485 gm/sq. cm brass. Analysis of data obtained from an omnidirectional proton spectrometer yielded integral proton fluxes greater than 15, 30, 55, 105, and 170 Mev. Dose rates were calculated using the OV3-4 proton environment and the shielding distributions for the ionization chambers. These calculated proton dose rates were within 50 percent of the measured values in regions where protons contribute most of the dose rate. Proton dose rate calculations made for sensors aboard the OV1-2, OV1-4, and OV1-9 satellites compare equally well with measurements made by those sensors. One very significant factor concerning the trapped proton environment presented is the validated accuracy of the high energy (>50 Mev) portion of the spectra. Before the use of the OV3-4 environment, dose rate calculations for heavily shielded dose points (>3.0 gm/sq. cm aluminum) were low by a possible factor of 6. The results presented in this report show a very significant improvement in accuracy using this environment. Since the proton dose rate in a typical manned spacecraft is the most important contribution to the total dose rate, this updated proton environment should be used whenever calculations are made for heavily shielded spacecraft. (Author)

Descriptors :   (*VAN ALLEN RADIATION BELT, DOSE RATE), (*SCIENTIFIC SATELLITES, VAN ALLEN RADIATION BELT), PROTONS, NUCLEAR RADIATION SPECTROMETERS, SHIELDING, IONIZATION CHAMBERS, CORRELATION TECHNIQUES.

Subject Categories : Atmospheric Physics
      Unmanned Spacecraft

Distribution Statement : APPROVED FOR PUBLIC RELEASE