NSSDCA ID: 1962-059A-05
Mission Name: Explorer 15This experiment was designed to measure the directional fluxes and spectra of low-energy trapped and auroral protons and electrons. It employed a 5-mg-thick powder phosphor scintillator covered with a 1000-A aluminum coating. Additional absorbers were inserted in the detector aperture by a 16-position stepped wheel. The aperture was pointed at 45 deg to the spin axis. Due to the thinness and type of phosphor, the detector in the pulse mode would respond only to low-energy ions, and, therefore, essentially measured the flux of protons that penetrated the absorbers and stopped in the phosphor. Both the pulse counting rate and the phototube current were telemetered once each frame period. Sixteen readings were telemetered in each wheel position, and thus one complete set of data was obtained every 256 frames (one wheel revolution = 80 s). Protons in seven energy ranges were measured. The high-energy limit was about 10 MeV for all ranges, and the low-energy cutoffs were 105, 140, 177, 254, 512, 971, and 1668 keV. The energy fluxes of electrons in three ranges were measured separately using scatter geometry, absorbers, and the phototube current. The low-energy cutoffs were 15, 21, and 27 keV, and the high-energy cutoff was about 100 keV for all three ranges. The experiment worked well throughout the life of the spacecraft. However, the directional resolution was poor because the spin rate was higher than planned.
Mass: 1.4 kg
Power (avg): 0.5 W
Bit rate (avg): 0.04 kbps
Questions and comments about this experiment can be directed to: Coordinated Request and User Support Office
Name | Role | Original Affiliation | |
---|---|---|---|
Mr. James M. Williamson | Other Investigator | NASA Goddard Space Flight Center | willijm@kscems.ksc.nasa.gov |
Mr. Leo R. Davis | Principal Investigator | NASA Goddard Space Flight Center |